Printer Friendly

Diagnosis of Helicobacter pylori Using Invasive and Noninvasive Approaches.

1. Introduction

Following the groundbreaking discovery of Helicobacter pylori (H. pylori) in 1983, a challenging era in the management of gastroduodenal diseases has been initiated [1]. This usually chronic infection is thought to play an inevitable role in peptic ulcer diseases and gastric adenocarcinoma. H. pylori, as the most commonly prevalent and recognized bacterium, is carried by more than half of the world population [2-6]. Once colonized, H. pylori induces a persistent, but superficial, inflammation, resulting in duodenal ulcer, gastric ulcer, and gastric cancer [7-11]. As predicted, many recent studies have confirmed a critical role of H. pylori in the development of peptic ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer [12]. Given the causative role of H. pylori in duodenal ulcer and gastric cancer, clinicians and microbiologists are eager to find the best diagnostic approach [13-18]. Currently, there are various diagnostic methods used for H. pylori infection in different subjects (children and adults), but the only methods with both high sensitivity and high specificity remain useful and recommendable. In other words, precisive detection of this bacterium in different clinical specimens (e.g., urine, stool, saliva, biopsy, and gastric juice) attributed with successful therapeutic practice will be listed in hot topic researches interest globally [19-22]. According to a traditional classification, H. pylori infection can be diagnosed by noninvasive tests such as H. pylori antigen in stool specimen, UBT (Urea Breath Test), serology, and invasive tests such as PCR (polymerase chain reaction), culture, and histology which require endoscopic surgery and biopsy specimens [23-25]. Invasive tests (e.g., Histological examination, culture, and polymerase chain reaction) require endoscopy and noninvasive techniques (e.g., serology and urea breath) are independent of endoscopic surgery. Nonetheless, for having the best management of H. pylori-related diseases, we need to specific and accurate diagnosis, especially for treatment courses (pretreatment and posttreatment of H. pylori infection). In fact, the selection of choice method is highly dependent on the availability and feasibility of many circumstances [26]. To now, many tests had been invented for diagnosis of H. pylori; however, each one has certain advantages and disadvantages [26-29]. In current article, we will review the recent advances of invasive and noninvasive methods suggested in diagnosis of H. pylori. Moreover, application and priorities of those methods, especially in evaluating the infection following the therapeutic regimen, are secondary goals of our paper.

2. Endoscopy: A Pivotal Approach in Diagnosis of H. pylori

Although various methods had been attempted to accurately detect the H. pylori infection, noninvasive methods were preferred by gastroenterologists for many reasons [30-32]. The whole advantages and disadvantages of invasive and noninvasive methods are listed in detail (see Table 1). In a short sentence, the main rationale for choosing the noninvasive methods is to avoid endoscopy. Relatively high numbers of guidelines were recommending the noninvasive tests as first choice [33-35]. What should not be forgotten is that the endoscopy surgery is an unpleasant and uncomfortable approach for investigating the H. pylori in dyspeptic patients [36, 37]. Additionally, there are other drawbacks which limit using the invasive methods such as endoscopy; (i) patients need for 1-3 days off for this surgery, (ii) high cost for disposable forceps and other stuffs, and (iii) high risk of contamination by some viruses such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV) [38, 39]. Of course, valid evidence indicating transmission of HIV and HCV among the subjects for endoscopy is not well-documented, but many patients declined this surgery just for this unpleasant probability released in media over the last years [40, 41]. Disparate distribution (patchy) of H. pylori in stomach is causing the bias in sampling (false negative) [1]. Indeed, taking a biopsy specimen (maximally 3-4 [mm.sup.2]) cannot guarantee the existence of H. pylori-colonized in stomach environment (500-1000 [mm.sup.2] in different persons). A solution would be to increase the number of taken gastric biopsies, but for ethical limitations, gastroenterologists are highly prohibited to take 6 or more biopsies from a patient. Lastly, endoscopy is an impossible procedure for subjects such as pregnant women, children, and elderly patients [26, 42]. There are two major approaches to noninvasive tests to diagnosis the H. pylori infection: UBT and serological examinations [26,43]. The main superiority of these methods is their easy applications in epidemiological studies. Furthermore, their easy application is affecting their high popularity in studies investigating the eradication rate following the antibiotic therapy [42,44,45]. In next paragraphs, we discuss each method separately to see their priorities and limitations in clinical settings.

3. Urea Breath Test

The first report of the application of UBT was about 60 years ago by Kornberg et al. investigating the intravenous injection of [sup.14]C urea into the cat and determining the amount of decreased [sup.14]C-C[O.sub.2] in animal breath [46, 47]. Their finding was due to the colonization of Helicobacter felis in the cat. When ingesting [sup.13]C- or [sup.14C]-labeled exposed to the bacterial urease in H. pylori positive patient, hydrolyzation results in the production of C[O.sub.2] in the stomach. Thereafter, labeled C[O.sub.2] enters into the bloodstream and is exhaled in the lung. Consequently, the amount of trapped labeled C[O.sub.2] will be measurable in the exhalation [48]. As mentioned above, the principle of this test is based on the intrinsic ability of H. pylori to break down absorbed [sup.13]C or [sup.14]C-labeled urea into CO2 in acidic gastric condition. If one is colonized actively with H. pylori, the urea is metabolized to the ammonia and labeled bicarbonate [[sup.14]C-C[O.sub.2]]. Thereafter, labeled bicarbonate is transferred to the lung and produces labeled carbon dioxide. This product is detectable by the machine to confirm the existence of the infection. Because of high sensitivity and specificity, UBT is a very attractive method to measure the H. pylori active infection by microbiologists and clinicians. At least for asymptomatic subjects, the UBT is a gold standard method [49, 50]. Another preference of UBT is that the method is free of sampling errors (lack of endoscopic surgery). This superiority made it very popular for clinicians to confirm bacterial eradication, especially in asymptomatic, elderly, and pediatric subjects. Clinicians need to wait 1-2 months for performing UBT to confirm successful bacterial eradication. As noted, the false-positive result is a minor problem with UBT, and clinicians need to take care of other urease-producing organisms which may be able to change the result. Overall, the specificity and sensitivity of the UBT are mostly more than 95%. Although these high rates for both sensitivity and specificity are an advantage for this test, lack of data on antibiotic resistance and further analysis is the main limiting feature of this popular method to detect active H. pylori infection [51,52]. A major consideration for this test is about its radiation. So far, decreased dosage of radiation made it a bit convenient for children but is still prohibited for pregnant women. In recent years, stool antigen test (SAT) and UBT became more acceptable diagnostic tests to detect active H. Pylori Infection. Lacking a universal protocol to perform UBT is an unsolved problem. Till now, only the manufacturer's experiences guided current standards in order to perform this method. Given high sensitivity (>95%) in posttreatment procedures [53], one of the disadvantages with UBT is the chance of colonization by urease-forming pathogens than H. pylori [54]. This probability is existing by the relatively low rate of current reports which increased our hopes to generalize application of UBT in routine and posttherapy H. pylori detection.

4. Stool Antigen Test (SAT)

Historically, serology approach was the first suggestion in order to diagnose H. pylori infection. Although the SAT is an accurate and precise method this accuracy is influenced by several limiting factors: upper gastrointestinal bleeding, antibiotic consumption, bowel movement, and also proton pump inhibitors (PPIs) uptake [55]. This noninvasive and almost cheap test became recommended whenever UBT was not available (Table 1). The superiority of UBT versus SAT was also found by Perri et al., while they showed that the diagnosis with UBT is undertaken with higher accuracy [56]. Sequentially, SAT was introduced following the UBT into the clinic. Polyclonal antibodies-EIA gave useful reports on the diagnostic practices but occasional inconsistent findings (mostly false-positives) forced clinicians to start application of the monoclonal antibody-based approach. An actual improvement in this technique was the higher specificity which reduced the false-positive findings [57-59]. As the constructive shift in this immunologic assay, using monoclonal antibodies provided improved sensitivity and specificity rates in comparison with UBT. There are two major preferences for SAT in comparison with UBT; less expensive chemicals and materials and also not high-technology equipment are necessary. Another advantage of this method was that patients could have stored the samples at home and send it to laboratories at a suitable time. The partial insufficient condition of preservation of the stool sample inhouse (optimal temperature, shaking, and transport medium to the laboratory) beside that applied cut-off value in final measurement can determine any bias in the diagnosis of the infection. To detect H. pylori infection, there are two main types of SAT: based on enzyme immunoassay (EIA) and immunochromatography (ICA) [60]. In clinical practices, the ICA-based test is more convenient to run in the small clinics and hospitals since so complex procedures are involved. In 1997, this test was suggested for the first time and the found acceptable sensitivity and specificity (88% and 94%, respectively) initiate other groups to apply it over the clinical practices [61]. A very attractive advantage of this method is to measure successful eradication of the infection using a simple laboratory examination [62]. Of course, to target pediatrics, SAT using monoclonal antibodies can give better feasibility since it is of low cost and is easy to handle by regular laboratories personals. In recent years, a new generation of stool antigen tests was invented. The Testmate pylori antigen EIA and Testmate rapid pylori antigen are the major examples [63, 64]. Testmate rapid pylori antigen is an immunochromatography based approach which is located on the commercially patented test strip. This easy application is to drop of suspended stool sample into the test strip. In the case positive result, an immunologic complex with the red latex-labeled MAb 21 Ge will be produced and then it moves till it the red color line becomes visible in the test strip. Currently, there is a good agreement between published guidelines and consensuses that SAT using monoclonal antibodies is one of the best approaches in the measurement of successful eradication of the bacterium and also for primary detection of this microorganism in clinical settings [33, 43, 55, 65-67].

5. Serological Tests

In general, detection of specific-antibody following the exposure to the various H. pylori antigens can be a useful method in clinical practices. As application and logic procedure was undertaken for many other pathogenic microorganisms, H. pylori discovery was not far from serological diagnosis [68, 69]. To date, different bacterial components include whole cell lysate, specific outer membrane proteins, LPS, heat shock protein (HSP), catalase, and cagA protein and many of the adhesions were applied to induce specific antibodies in the host for facilitating the serological assay [60,70-73]. Broadly defined, human immune response to the H. pylori is very complicated since many surface antigens are contributed. Routine H. pylori serologic methods can only detect specific IgG antibodies. The clinical importance of this test emerges when antibiotics and PPIs consumption are reported. Indeed, false negative results observed for other methods can have different response using serologic analysis. In addition to those drug uptakes, gastric bleeding and gastritis atrophic condition were also caused by false negative results for other methods; again, the serologic assay can be helpful for clinicians [74, 75]. The highlighted problem with the serologic approach is the weak distinguishing power of this test to discriminate active and inactive infection. Due to the different backgrounds in host genetics, it can be expected that various H. pylori strains induce different levels of antibodies and it may be a considerable item in explaining the reported findings [76]. Because of acceptable sensitivity and specificity rates observed in many commercial IgG-bases tests exist and have been validated in recent years [77-81]. One of the interesting aspects of serology method is following the antibiotic therapy; the long-lasting antibodies are still existing and it may cause the false-positive result [82-84]. This point should be cautiously considered by epidemiologists and gastroenterologists in their examinations in populations. In total, serologic tests are inexpensive; thus the application of these antibodies-based tests in some geographical area such as developing countries is highly acknowledged. A major consideration for the regions with a low prevalence of H. pylori is that suboptimal specificity can increase the false-positive results. Moreover, IgA-based measurement was also suggested but noted that the test is less trustful and reliable than IgG-based assays [85-88]. In some interesting studies, examinations of H. pylori-specific antibodies in other sample sources than serum were investigated [89, 90]. In brief, saliva and urine were checked but because of the lower titer of antibodies in these samples in comparison with serum, clinicians are not so eager to check this sort of samples for H. pylori. Taking together, the antibody-based examination cannot guarantee the accuracy of reported H. pylori status following the antibiotic treatment; thus further analysis is needed [91].

6. Invasive Methods

No need to mention that having genomic data from the clinical samples increases our knowledge of susceptibility patterns and virulence factors. Bacterial culture, Rapid urease test, PCR assay, and histology are the invasive methods applied to diagnose the H. pylori infection in different biologic sources. The criteria for this nomination (invasive methods) are referring to undertaking the endoscopic surgery. In patients with two complaints, the gastric endoscopy will be necessary: (i) no response to antibiotic therapy, and (ii) signs indicating problematic and symptomatic gastric conditions. Usually, clinicians take biopsies from antrum, but PPI consumption will reduce diagnostic value; thereafter, stomach body would be the next place for biopsy sampling. In next paragraphs, we discuss invasive methods used to diagnose H. pylori infection in clinical samples.

7. Histology

Histology was the first method unconsciously used to detect the H. pylori in clinical samples. Our main evidence is reported by Warren in his laboratory before his collaborations with Barry Marshall ended in their great discovery. However, application of Warthin-Starry silver stain by Warren eventually caused a big triumph to visualize bacterial colonization in a biopsy sample from a patient with severe gastritis [19]. Current diagnosis of H. pylori infection is highly influenced by the histological report [92, 93]. Since typic morphology of H. pylori, histopathological confirmation of this infection can be easily achieved while further histologic changes in patterns of gastritis can be helpful to characterize the digestive diseases properly. An accurate histopathological observation can give us a detailed report of possible H. pylori colonization (and also bacterial density), and degree of inflammation and histopathology (e.g., severe atrophic gastritis, intestinal metaplasia, and malignancy [93, 94]). The identification of the bacteria in the histopathological analysis is based on different staining including hematoxylin and eosin (A&E). In order to increase specificity in detection of the H. pylori, different dyes such as Gimenez, Toluidine blue, Romanowski, Genta, Warthin-Starry silver, and Giemsa can be also used [95, 96]. The specific application of Warthin-Starry silver is in the chance of coccoid forms of the H. pylori. Histopathology examination is basically time-consuming and relatively expensive. Thus, the requirement of trained staffs besides being a consuming process resulted in a not handy method to detect H. pylori infection. Both sensitivity and specificity of the histology are nearly around the 94% [97-100]. We have searched the databases (Web of Sciences, Scopus, Medline, and Google scholar) and found not that much-published reports are investigating the specificity and sensitivity of the commercially available stains. From a scientific point of view, there is no superiority for any of those tests; however, some other aspects such as rapidity, reproducibility, cost, and being less time-consuming can be favorable for some of the tests. Rotimi et al. used modified McMullen's staining as a novel approach in comparison with other staining methods but found no significant differences (P value > 0.05) [95]. Although we have found relatively high sensitivity for this test, patchy distribution of this bacterium in the stomach can reduce the chance of histopathological changes in the taken biopsy from antrum [101-104]. Accordingly, to maintain this high rate of sensitivity and avoid sampling errors, we need to increase the number of taken biopsies [105,106]. Last but not least, being an experienced pathologist can increase the sensitivity of this approach. Regardless of our limitations in reduced sensitivity for histology, the typical shape of the H. pylori and its expectable location in the luminal surface of the cells can help pathologists for easy diagnosis of this S-shaped bacterium. There is a general agreement among the pathologists that in the case of the existence of the H. pylori, all staining methods are good, but modified Giemsa is the first choice because of less expensive materials and reproducible and sensitive results.

8. Rapid Urease Test

During the years after discovery by Marshall and Warren, it has been stated that the rapid urease test (RUT) is a one of the cheapest but rapid diagnostic tests used in detecting this infection [107]. The main biologic basis of this diagnostic test is to evaluate the presence of urease enzyme in clinical specimens shipped to the laboratories [108, 109]. Due to the historic dogma, it has hypothesized that detected gastric enzyme is a production by the human stomach to protect its epithelial cells from the acidic condition. Interestingly, following the groundbreaking introduction of H. pylori, it became widely accepted that the enzyme does not have a human origin [110]. Consequently, the detection of this bacterial product was used to identify this chronic infection. Interestingly, the specificity and sensitivity are durable for this test, but clinical experiences had shown that the optimal results are only achieved only if we take biopsies from both corpus and antrum. Some factors are influencing the final result of RUT: (i) bacterial urease concentration, (ii) temperature, (iii) waiting time for optimal reaction condition, and (iv) substrate concentrations. Staphylococci and streptococci are the other major urease-producers present in the gastric mucosa and may interfere with the detection of H. pylori based on the urease activity. There is an underestimated issue in the diagnosis of the H. pylori infection using the RUT. In some clinical settings mostly in developing countries, gastroenterologists ask the patients to keep the RUT test tube for 1-2 days and inform the hospitals' personals to add the data about likely positivity of the test [107, 111, 112]. In the case of oral colonization by H. heilmannii, the test will be positive, while it can interfere with positivity or negativity of the true H. pylori infection [113]. However, this reaction needs both higher load of H. heilmannii and longer time for positive urease reaction which mostly do not occur. Another solution to avoid this false-positive result is to check histopathological observation which is partially informative to identify H. heilmannii [114]. However, the necessary time to make RUT positive is quite different among numbered microorganisms; so far, a good specificity is promising news for gastroenterologists. Most of H. pylori contained-biopsies become red or pink within first fifty minutes after the endoscopy and placement of the biopsy in the medium [1]. The shift in the color of the medium is an indicator for the produced ammonium ion and increased pH (determined with pH indicator, e.g., phenol red). Although there are many commercial but specific mediums recommendable for detecting the urease positive organisms, some of other commonly used mediums such as Christensen medium are also useful in clinical settings [115-118]. Increasing the urea concentration (4-6 times) and reaction temperature were two potential modifications to increase the sensitivity of RUT [119]. Moreover, it has been firmly addressed that at least [10.sup.5] H. pylori isolates are required to cause a positive result in RUT (changing the color into pink). The sensitivity rates range (85-100%) made the RUT one of the highly recommendable methods in the diagnosis of the H. pylori. Similarly, relatively 100% specificity was another favorable item to make RUT popular among the gastroenterologists for rapid diagnosis of this bacterium in clinical settings [120].

9. Culture

Since increasing body of evidence showed the long-last colonization of the H. pylori, microbiologists started to culture this bacterium in several media. The main superiority of bacterial culture for H. pylori is the possibility of antibiotic susceptibility tests to choose proper antibiotics in the treatment of subjects and avoiding a new generation of antibiotic resistance among the symptomatic patients [121-124]. Successfulness of this culture process made this approach as the gold standard in the diagnosis of this infection. Recent international guidelines still insist on performing the bacterial culture in the case of failure in antibiotic susceptibility testing as next action. Based on Sydney classification, clinicians need at least three biopsies (two biopsies from the anterior and posterior corpus and one from antrum) necessary to accurately determine positive bacterial infection in gastritis patients [87, 93, 101, 105, 121, 125]. This kind of recommendation was another factor which initiates ones to run the routine culture for H. pylori in diagnostic laboratories. H. pylori can grow slowly on many solid media under microaerophilic condition. As a general rule, H. pylori needs blood or lysed blood supplements to grow optimally on agar plates (Figure 1).

Currently, Wilkins Chalgren agar, Brain heart agar, and Columbia and Brucella agars are most used base media to propagate H. pylori culture in routine diagnosis [26, 44,126]. Because of the high risk of contaminating microorganisms including gram-positive microorganisms, fungi, and yeasts, using selective medium became a universal rule to have typical H. pylori colonies on the plates [1]. In order to increase the sensitivity and specificity of culture in the diagnosis of the H. pylori, we need multiple biopsies samples rather than a single antral biopsy [127]. As an additional suggestion to improve the sensitivity and specificity, the endoscopic surgery should not be performed in less than 3 months for patients who state the record of the consumption of PPI, antibiotics, and antisecretory drugs [26, 36]. Adil et al. used microcapillary, as a novel culture-based approach in detecting the H. pylori infection [128]. In this paper, the authors stated that microcapillary method is statistically more sensitive compared with CLO test and HE tests (P < 0.01). Although many attempts had been performed to optimize culture media for H. pylori, Adil et al. showed a novel results to standardize H. pylori culture using new ingredients and conditions. As one of the critical problems in the endoscopic surgery, contamination of the biopsy specimens was an annoying issue. The rationale for this consideration is about the risk of transmission of some agents including human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) during the endoscopy [40]. However, using the disposable forceps in last decade decreased the chance of contamination with these infectious agents very much [129, 130]. Ecologically, H. pylori can survive in all sites of them stomach, but, in some cases (e.g., consumption of antisecretory drugs), the corpus will be the likely location to give us a successful culture following the endoscopy. Many medical societies are recommending that it is better to take first biopsies for culture prior to taking samples for histopathological examination. Indeed, this superiority can decrease the chance of exposure to the fixative and infectious agents influencing the chance of H. pylori positive culture. There is a challenging discussion among the microbiologists which is do we need to grind the biopsies before transferring the specimens into the agar plates or not? Indeed, nonhomogeneous distribution of the H. pylori in biopsies caused this problem. Moreover, many studies showed that there are significant differences if we use the grinded samples. The main explanation for this phenomenon is that grinding the biopsies is increasing the exposure of more H. pylori isolates to the favorable condition of growth, so multiple colonies will appear. In other words, isolation of H. pylori single colonies is feasible only if we grind the biopsies and then streak it on the plates. The importance of current recommendation is disclosed when researchers were faced with a variable pattern of genotyping from isolated DNA from a single colony in the nongrinded biopsy sample. Therefore, using the mechanical grinder and further application of single colony bacteria can increase the accuracy of the test in the diagnosis of the H. pylori. Meanwhile, we nicely avoid DNA-contamination by other possible agents [131]. Culturing the antral biopsy specimens is a leading item to reproduce the one of the highest sensitivities and specificities in the diagnosis of the H. pylori. The problems with this test are (i) likely exposure to the oxygen and temperature, expensive materials and consumables, and (iii) it is strict transport conditions. Last but not least, in close future, improving those items can help us to have better molecular techniques needing the isolated single colonies of this rouge bacterium [128].

10. PCR

As usual for all pathogenic microorganisms, PCR-based methods were applied to detect H. pylori infections in large variety of environmental and clinical samples including water, food, vegetables, human saliva, stool, gastric juice and biopsies, and dental plaques [132]. In most of those essays, housekeeping genes were used frequently to design a sensitive and specific PCR to detect H. pylori [133-139]. Current evidences are indicating the requirement of at least one positive test (i.e., SAT, RUT, serology, and histology) in addition to the culture positive result before we can entitle a sample as H. pylori positive [26]. However, having positive result from a specific PCR approach can easily replace those time-consuming and expensive tests. The main gap to achieve this point is that optimization of DNA extraction and suitable genes pattern is not validated already. For example, there are more than twenty commercial kits for DNA extraction (i.e., Yekta Tajhiz Azma, Bioneer, Sina-clon, Qiagen, and Sigma) with large variety of the DNA yields which confuse researchers in selecting the proper product. Due to the presence of H. pylori DNA in various biologic samples, PCR-based detection was widely used to identify this problematic infection [140-143]. Biopsy samples, saliva and gastric juice, stool, and dental plaques were frequently applied to PCR detection. The main problem with stool sample is due to the existence of billions of bacteria including chemicals, gram-positive and gram-negative, which can mostly act as inhibitor for our detection. Because of variability in different DNA extraction methods, a universal approach needs to be recommended to produce reliable results, at least in clinical settings. Another important issue is the target gene to design the primer sets. As one of global housekeeping genes, 16S rRNA was used, but many mutations have been reported which disappoint clinicians to continuous application for further analysis [144,145]. Recently, 23S rRNA gene has been suggested due to the high sensitivity in detection of H. pylori in clinical samples [146,147].

11. Gold Standard Methods

Currently, urease and histological analysis are considered a gold standard approach in many clinical circumstances. In other words, there is no unique method acting as a gold standard in the diagnosis of H. pylori infection. However, we can use UBT and SAT as highly recommended tests available among the noninvasive methods. Further shreds of evidence are necessary before we can nominate any diagnostic methods as the gold standard in various clinical circumstances of patients attributed to H. pylori infections.

12. Different Diagnostic Strategies Useful in the Detection of Bacterial Eradication

Precise identification of H. pylori infections among symptomatic and asymptomatic individuals was the focus of many discussions. Following increased importance of eradication of the bacteria and its positive effects ending in gastroduodenal diseases, now another question regarding the best approach to be the gold standard for detecting the H. pylori in treated patients is disclosed [148, 149]. Using current knowledge of antimicrobial resistance and availability of various machines, equipment, and skilled staffs [150,151], we need more noninvasive methods to be sued for following the eradication of H. pylori in different targets. Thus, researches in this area will be covered by more interest.

13. Conclusive Remarks

Since the accurate diagnosis of H. pylori is idealistic view for both gastroenterologists and microbiologists, using synergistically invasive and noninvasive methods will be a future challenge in medical research topics. It is clear that recent advances in invasive and noninvasive methods for accurate diagnosis of the H. pylori can drastically change upcoming guidelines attributed with the management of this infection. No doubt that diagnosis of H. pylori infection due to its strange microniche is difficult and hard to optimize, especially for routine diagnostic. The fragility of the microorganism is another limiting factor to access necessary information on various aspects of this bacterium. Indeed, the gastroenterologists are facing a long list of various molecular and nonmolecular tests, but the problem is to optimize and designanaccuratetesttoproduce informationon(i)presence of the infection and (ii) antibiotic susceptibility profile. These are the main difficulties causing complex diagnosis of H. pylori even if for developed countries. According to the recent European guideline, the [sup.13]C-UBT is nominated as the best method in the diagnosis of H. pylori infection. This approach shows acceptable specificity and sensitivity in clinical practice [65]. Concerning the serological examinations, the results are generalizable if local antigens were applied in the tests; otherwise, many discrepancies need further analysis. Using current knowledge of antimicrobial resistance and availability of various machines, types of equipment and skilled staffs, we need more noninvasive methods to be sued for following the eradication of H. pylori in different targets. Thus, researches in this area will be covered by intense interest. To achieve this point, in-depth experiments are necessary to generalize rapid and accurate molecular tests determining both bacterial identity and antibiotic resistance profile.


The contents of current review are the sole responsibility of the author and do not necessarily represent the official views of the affiliated institutes.

Conflicts of Interest

The author declares that they have no conflicts of interest.


The author would like to thank Dr. Ronald Gorham from University of California, Riverside, USA, for critical reading of the paper and his helpful comments.


[1] J. G. Kusters, A. H. M. van Vliet, and E. J. Kuipers, "Pathogenesis of Helicobacter pylori infection," Clinical Microbiology Reviews, vol. 19, no. 3, pp. 449-490, 2006.

[2] Y. Hu, J.-H. Wan, X.-Y. Li, Y. Zhu, D. Y. Graham, and N.-H. Lu, "Systematic review with meta-analysis: the global recurrence rate of Helicobacter pylori," Alimentary Pharmacology & Therapeutics, vol. 46, no. 9, pp. 773-779, 2017.

[3] L. B. Polish, J. M. Douglas Jr., A. J. Davidson, G. I. Perez-Perez, and M. J. Blaser, "Characterization of risk factors for Helicobacter pylori infection among men attending a sexually transmitted disease clinic: Lack of evidence for sexual transmission," Journal of Clinical Microbiology, vol. 29, no. 10, pp. 2139-2143,1991.

[4] S. Schwarz, G. Morelli, B. Kusecek et al., "Horizontal versus familial transmission of Helicobacter pylori," PLoS Pathogens, vol. 4, no. 10, Article ID e1000180, 2008.

[5] I. Mladenova-Hristova, O. Grekova, and A. Patel, "Zoonotic potential of Helicobacter spp.," Journal of Microbiology, Immunology and Infection, vol. 50, no. 3, pp. 265-269, 2017.

[6] M. Elhariri, R. Elhelw, D. Hamza, and H. S. El-Mahallawy, "Serologic evidence and risk factors for Helicobacter pylori infection in animals and humans," The Journal of Infection in Developing Countries, vol. 11, no. 5, pp. 414-419, 2017.

[7] A. T. B. Abadi, E. Ierardi, and Y. Y. Lee, "Why do we still have Helicobacter pylori in our stomachs?" Malaysian Journal of Medical Sciences, vol. 22, no. 5, pp. 70-75, 2015.

[8] P. Malfertheiner, F. K. Chan, and K. E. McColl, "Peptic ulcer disease," The Lancet, vol. 374, no. 9699, pp. 1449-1461, 2009.

[9] L. Olbe, A. Hamlet, J. Dalenback, and L. Fandriks, "A mechanism by which Helicobacter pylori infection of the antrum contributes to the development of duodenal ulcer," Gastroenterology, vol. 110, no. 5, pp. 1386-1394,1996.

[10] X. Y. Zhang, H. Y. Mo, and Y. Huang, "risk factor and mortality of peptic ulcer disease," Alimentary pharmacology & therapeutics, vol. 44, no. 4, p. 424, 2016.

[11] A. J. Smolka and M. L. Schubert, "Helicobacter pylori-induced changes in gastric acid secretion and upper gastrointestinal disease," Current Topics in Microbiology and Immunology, vol. 400, pp. 227-252, 2017.

[12] V. Camilo, T. Sugiyama, and E. Touati, "Pathogenesis of Helicobacter pylori infection," Helicobacter, vol. 22, Article ID e12405, 2017.

[13] M. J. Blaser, K. Kobayashi, T. L. Cover, P. Cao, I. D. Feurer, and G. I. Perez-perez, "Helicobacter pylori infection in japanese patients with adenocarcinoma of the stomach," International Journal of Cancer, vol. 55, no. 5, pp. 799-802,1993.

[14] A. T. B. Abadi, "Helicobacter pylori and Gastric Cancer," Frontiers in Medicine, vol. 3, no. 36, 2016.

[15] J.-M. Liou, M.-S. Wu, and J.-T. Lin, "Treatment of Helicobacter pylori infection: Where are we now?" Journal of Gastroenterology and Hepatology, vol. 31, no. 12, pp. 1918-1926, 2016.

[16] D. C. Lazar, S. Taban, M. Cornianu, A. Faur, and A. Goldis, "New advances in targeted gastric cancer treatment," World Journal of Gastroenterology, vol. 22, no. 30, pp. 6776-6799,2016.

[17] M. Kawanaka, J. Watari, N. Kamiya et al., "Effects of Helicobacter pylori eradication on the development of metachronous gastric cancer after endoscopic treatment: Analysis of molecular alterations by a randomised controlled trial," British Journal of Cancer, vol. 114, no. 1, pp. 21-29, 2016.

[18] T. L. Testerman and J. Morris, "Beyond the stomach: an updated view of Helicobacter pylori pathogenesis, diagnosis, and treatment," World Journal of Gastroenterology, vol. 20, no. 36, pp. 12781-12808, 2014.

[19] B. J. Marshall and J. R. Warren, "Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration," The Lancet, vol. 1, no. 8390, pp. 1311-1314,1984.

[20] R. M. Genta and D. Y. Graham, "Helicobacter pylori: the new bug on the (paraffin) block," Virchows Archiv, vol. 425, no. 4, pp. 339-347, 1994.

[21] A. T. B. Abadi, "Strategies used by helicobacter pylori to establish persistent infection," World Journal of Gastroenterology, vol. 23, no. 16, pp. 2870-2882, 2017.

[22] K. M. Fock, D. Y. Graham, and P. Malfertheiner, "Helicobacter pylori research: Historical insights and future directions," Nature Reviews Gastroenterology & Hepatology, vol. 10, no. 8, pp. 495-500, 2013.

[23] B. J. McMahon, M. G. Bruce, A. Koch et al., "The diagnosis and treatment of Helicobacter pylori infection in Arctic regions with a high prevalence of infection: Expert Commentary," Epidemiology and Infection, vol. 144, no. 2, pp. 225-233, 2016.

[24] Y.-K. Wang, F.-C. Kuo, C.-J. Liu et al., "Diagnosis of helicobacter pylori infection: current options and developments," World Journal of Gastroenterology, vol. 21, no. 40, pp. 11221-11235,2015.

[25] S. G. Kim, H.-K. Jung, H. L. Lee et al., "Guidelines for the diagnosis and treatment of Helicobacter pylori infection in Korea, 2013 revised edition," Journal of Gastroenterology and Hepatology, vol. 29, no. 7, pp. 1371-1386, 2014.

[26] F. Megraud and P. Lehours, "Helicobacter pylori detection and antimicrobial susceptibility testing," Clinical Microbiology Reviews, vol. 20, no. 2, pp. 280-322, 2007.

[27] J. Raymond, J. M. Thiberge, and C. Dauga, "Diagnosis of Helicobacter pylori recurrence: Relapse or reinfection? Usefulness of molecular tools," Scandinavian Journal of Gastroenterology, vol. 51, no. 6, pp. 672-678, 2016.

[28] M. Miftahussurur and Y. Yamaoka, "Diagnostic methods of Helicobacter pylori infection for epidemiological studies: critical importance of indirect test validation," BioMed Research International, vol. 2016, Article ID 4819423,14 pages, 2016.

[29] M. Granstrom, P. Lehours, C. Bengtsson, and F. Megraud, "Diagnosis of Helicobacter pylori," Helicobacter, vol. 13, no. 1, pp. 7-12, 2008.

[30] A. T. B. Abadi, R. J. L. F. Loffeld, A. C. Constancia, J. A. Wagenaar, and J. G. Kusters, "Detection of the Helicobacter pylori dupA gene is strongly affected bythe PCR design," Journal of Microbiological Methods, vol. 106, pp. 55-66, 2014.

[31] R. M. Zagari, M. Romano, V. Ojetti et al., "Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015," Digestive and Liver Disease, vol. 47, no. 11, pp. 903-912, 2015.

[32] F. Megraud, "Helicobacter pylori and antibiotic resistance," Gut, vol. 56, no. 11, p. 1502, 2007.

[33] P. Malfertheiner, F. Megraud, C. A. O'Morain et al., "Management of Helicobacter pylori infection--the Maastricht IV/ Florence consensus report," Gut, vol. 61, no. 5, pp. 646-664, 2012.

[34] P. Malfertheiner, F. Megraud, C. O'Morain et al., "Current concepts in the management of Helicobacter pylori infection: the Maastricht III Consensus Report," Gut, vol. 56, no. 6, pp. 772-781, 2007.

[35] A. T. B. Abadi and J. G. Kusters, "Management of Helicobacter pylori infections," BMC Gastroenterology, vol. 16, no. 1, article no. 94, 2016.

[36] R. Kiesslich, M. Goetz, J. Burg et al., "Diagnosing Helicobacter pylori in vivo by confocal laser endoscopy," Gastroenterology, vol. 128, no. 7, pp. 2119-2123, 2005.

[37] M. Dinis-Ribeiro, M. Areia, A. C. De Vries et al., "Management of precancerous conditions and lesions in the stomach (MAPS): guideline from the European Society of Gastrointestinal Endoscopy (ESGE), European Helicobacter Study Group (EHSG), European Society of Pathology (ESP), and the Sociedade Portuguesa de Endoscopia Digestiva (SPED)," Endoscopy, vol. 44, no. 1, pp. 74-94, 2012.

[38] J. Kovaleva, "Infectious complications in gastrointestinal endoscopy and their prevention," Best Practice & Research Clinical Gastroenterology, vol. 30, no. 5, pp. 689-704, 2016.

[39] E. Sakai, T. Higurashi, H. Ohkubo et al., "Investigation of Small Bowel Abnormalities in HIV-Infected Patients Using Capsule Endoscopy," Gastroenterology Research and Practice, vol. 2017, Article ID 1932647, 2017.

[40] J. Kovaleva, F. T. M. Peters, H. C. van der Mei, and J. E. Degener, "Transmission of infection by flexible gastrointestinal endoscopy and bronchoscopy.," Clinical Microbiology Reviews, vol. 26, no. 2, pp. 231-254, 2013.

[41] G. E. Fischer, M. K. Schaefer, B. J. Labus et al., "Hepatitis C virus infections from unsafe injection practices at an endoscopy clinic in Las Vegas, Nevada, 2007-2008," Clinical Infectious Diseases, vol. 51, no. 3, pp. 267-273, 2010.

[42] C. Ricci, J. Holton, and D. Vaira, "Diagnosis of Helicobacter pylori: invasive and non-invasive tests," Best Practice & Research Clinical Gastroenterology, vol. 21, no. 2, pp. 299-313, 2007.

[43] E. Bessede, V. Arantes, F. Megraud, and L. G. Coelho, "Diagnosis of Helicobacter pylori infection," Helicobacter, vol. 22, Article ID e12404, 2017.

[44] A. F. Cutler, S. Havstad, C. K. Ma, M. J. Blaser, G. I. Perez-Perez, and T. T. Schubert, "Accuracy of invasive and noninvasive tests to diagnose Helicobacter pylori infection," Gastroenterology, vol. 109, no. 1, pp. 136-141, 1995.

[45] L. Monteiro, A. De Mascarel, A. M. Sarrasqueta et al., "Diagnosis of Helicobacter pylori infection: Noninvasive methods compared to invasive methods and evaluation of two new tests," American Journal of Gastroenterology, vol. 96, no. 2, pp. 353-358, 2001.

[46] H. L. Kornberg, R. E. Davies, and D. R. Wood, "The activity and function of gastric urease in the cat," Biochemical Journal, vol. 56, no. 3, pp. 363-372, 1954.

[47] H. L. Kornberg, R. E. Davies, and D. R. Wood, "The breakdown of urea in cats not secreting gastric juice," Biochemical Journal, vol. 56, no. 3, pp. 355-363, 1954.

[48] J. C. Atherton and R. C. Spiller, "The urea breath test for Helicobacter pylori," Gut, vol. 35, no. 6, pp. 723-725,1994.

[49] H. Sardarian, H. Fakheri, V. Hosseini, T. Taghvaei, I. Maleki, and M. Mokhtare, "Comparison of hybrid and sequential therapies for helicobacter pylori eradication in iran: a prospective randomized trial," Helicobacter, vol. 18, no. 2, pp. 129-134, 2013.

[50] H. A. Metanat, S. M. Valizadeh, H. Fakheri et al., "Comparison Between 10- and 14-Day Hybrid Regimens for Helicobacter pylori Eradication: A Randomized Clinical Trial," Helicobacter, vol. 20, no. 4, pp. 299-304, 2015.

[51] D. Pantoflickova, D. R. Scott, G. Sachs, G. Dorta, and A. L. Blum, "13C urea breath test (UBT) in the diagnosis of Helicobacter pylori: Why does it work better with acid test meals?" Gut, vol. 52, no. 7, pp. 933-937, 2003.

[52] V. De Francesco, A. Zullo, F. Perna et al., "Helicobacter pylori antibiotic resistance and [13C] urea breath test values," Journal of Medical Microbiology, vol. 59, no. 5, pp. 588-591, 2010.

[53] M. Moshkowitz, F. M. Konikoff, Y. Peled et al., "High Helicobacter pylori numbers are associated with low eradication rate after triple therapy," Gut, vol. 36, no. 6, pp. 845-847,1995.

[54] T. Osaki, K. Mabe, T. Hanawa, and S. Kamiya, "Urease-positive bacteria in the stomach induce a false-positive reaction in a urea breath test for diagnosis of Helicobacter pylori infection," Journal of Medical Microbiology, vol. 57, no. 7, pp. 814-819, 2008.

[55] T. Shimoyama, "Stool antigen tests for the management of Helicobacter pylori infection," World Journal of Gastroenterology, vol. 19, no. 45, pp. 8188-8191, 2013.

[56] F. Perri, G. Manes, M. Neri, D. Vaira, and G. Nardone, "Helicobacter pylori antigen stool test and 13C-urea breath test in patients after eradication treatments," American Journal of Gastroenterology, vol. 97, no. 11, pp. 2756-2762, 2002.

[57] J. P. Gisbert, F. De La Morena, and V. Abraira, "Accuracy of monoclonal stool antigen test for the diagnosis of H. pylori infection: a systematic review and meta-analysis," American Journal of Gastroenterology, vol. 101, no. 8, pp. 1921-1930, 2006.

[58] I. M. Simoons-Smit, B. J. Appelmelk, T. Verboom et al., "Typing of Helicobacter pylori with monoclonal antibodies against Lewis antigens in lipopolysaccharide," Journal of Clinical Microbiology, vol. 34, no. 9, pp. 2196-2200,1996.

[59] S. Koletzko, N. Konstantopoulos, D. Bosman et al., "Evaluation of a novel monoclonal enzyme immunoassay for detection of Helicobacter pylori antigen in stool from children," Gut, vol. 52, no. 6, pp. 804-806, 2003.

[60] N. Konstantopoulos, H. Russmann, C. Tasch et al., "Evaluation of the Helicobacter pylori stool antigen test (HpSA) for detection of Helicobacter pylori infection in children," American Journal of Gastroenterology, vol. 96, no. 3, pp. 677-683, 2001.

[61] A. Makristathis, E. Pasching, K. Schutze, M. Wimmer, M. L. Rotter, and A. M. Hirschl, "Detection of Helicobacter pylori in stool specimens by PCR and antigen enzyme immunoassay," Journal of Clinical Microbiology, vol. 36, no. 9, pp. 2772-2774, 1998.

[62] D. Vaira, P. Malfertheiner, F. Megraud et al., "Diagnosis of Helicobacter pylori infection with a new non-invasive antigen-based assay," The Lancet, vol. 354, no. 9172, pp. 30-33,1999.

[63] T. Shimoyama, M. Sawaya, A. Ishiguro, N. Hanabata, T. Yoshimura, and S. Fukuda, "Applicability of a rapid stool antigen test, using monoclonal antibody to catalase, for the management of Helicobacter pylori infection," Journal of Gastroenterology, vol. 46, no. 4, pp. 487-491, 2011.

[64] X. Calvet, M.-J. R. Lazaro, P. Lehours, and F. Magraud, "Diagnosis and epidemiology of Helicobacter pylori infection," Helicobacter, vol. 18, no. 1, pp. 5-11, 2013.

[65] P. Malfertheiner, F. Megraud, C. A. O'Morain, J. P. Gisbert, E. J. Kuipers, A. T. Axon et al., "Management of Helicobacter pylori infection--the Maastricht V/Florence Consensus Report," Gut, vol. 66, 2017.

[66] M. Asaka, M. Kato, S.-I. Takahashi et al., "Guidelines for the management of Helicobacter pylori infection in Japan: 2009 revised edition," Helicobacter, vol. 15, no. 1, pp. 1-20, 2010.

[67] W. D. Chey and B. C. Y. Wong, "Practice Parameters Committee of the American College of G. American College of Gastroenterology guideline on the management of Helicobacter pylori infection," The American Journal of Gastroenterology, vol. 102, no. 8, pp. 1808-1825, 2007.

[68] D. M. Jones, A. M. Lessells, and J. Eldridge, "Campylobacter like organisms on the gastric mucosa: Culture, histological, and serological studies," Journal of Clinical Pathology, vol. 37, no. 9, pp. 1002-1006,1984.

[69] B. J. Rathbone, J. I. Wyatt, B. W. Worsley et al., "Systemic and local antibody responses to gastric Campylobacter pyloridis in non-ulcer dyspepsia," Gut, vol. 27, no. 6, pp. 642-647,1986.

[70] H. M. Mitchell, S. L. Hazell, Y. Li, and P. Hu, "Serological response to specific Helicobacter pylori antigens: Antibody against CagA antigen is not predictive of gastric cancer in a developing country," American Journal of Gastroenterology, vol. 91, no. 9, pp. 1785-1788,1996.

[71] M. Camorlinga-Ponce, J. Torres, G. Perez-Perez et al., "Validation of a serologic test for the diagnosis of Helicobacter pylori infection and the immune response to urease and CagA in children," American Journal of Gastroenterology, vol. 93, no. 8, pp. 1264-1270, 1998.

[72] J. Torres, Y. Leal-Herrera, G. Perez-Perez et al., "A community-based seroepidemiologic study of Helicobacter pylori infection in Mexico," The Journal of Infectious Diseases, vol. 178, no. 4, pp. 1089-1094, 1998.

[73] B. Khanna, A. Cutler, N. R. Israel et al., "Use caution with serologic testing for Helicobacter pylori infection in children," The Journal of Infectious Diseases, vol. 178, no. 2, pp. 460-465, 1998.

[74] C. M. Shin, N. Kim, H. S. Lee et al., "Validation of diagnostic tests for Helicobacter pylori with regard to grade of atrophic gastritis and/or intestinal metaplasia," Helicobacter, vol. 14, no. 6, pp. 512-519, 2009.

[75] A. Oksanen, L. Veijola, P. Sipponen, K.-O. Schauman, and H. Rautelin, "Evaluation of Pyloriset Screen, a rapid whole-blood diagnostic test for Helicobacter pylori infection," Journal of Clinical Microbiology, vol. 36, no. 4, pp. 955-957,1998.

[76] D. Vaira and N. Vakil, "Blood, urine, stool, breath, money, and Helicobacter pylori," Gut, vol. 48, no. 3, pp. 287-289, 2001.

[77] S.-Y. Lee, H.-W. Moon, M. Hur, and Y.-M. Yun, "Validation of western Helicobacter pylori IgG antibody assays in Korean adults," Journal of Medical Microbiology, vol. 64, pp. 513-518, 2015.

[78] Y. K. Yee, K. T. Yip, T. L. Que et al., "Efficacy of enzyme immunoassay for the detection of Helicobacter pylori antigens in frozen stool specimens: local validation," Alimentary Pharmacology & Therapeutics, vol. 16, no. 10, pp. 1739-1742, 2002.

[79] N. P. Breslin, J. M. Lee, M. J. Buckley, E. Balbirnie, D. Rice, and C. A. O'Morain, "Validation of serological tests for Helicobacter pylori infection in an irish population," Irish Journal of Medical Science, vol. 169, no. 3, pp. 190-194, 2000.

[80] P. Moayyedi, A. M. Carter, A. Catto, R. M. Heppell, P. J. Grant, and A. T. R. Axon, "Validation of a rapid whole blood test for diagnosing Helicobacter pylori infection," British Medical Journal, vol. 314, article 119,1997.

[81] U. Blecker, S. Lanciers, and B. Hauser, "Validation of a new serologic test for the detection of Helicobacter pylori," Acta Gastro-Enterologica Belgica, vol. 56, no. 5-6, pp. 309-314, 1993.

[82] E. Lahner, C. Bordi, E. Di Giulio et al., "Role of Helicobacter pylori serology in atrophic body gastritis after eradication treatment," Alimentary Pharmacology & Therapeutics, vol. 16, no. 3, pp. 507-514, 2002.

[83] G. I. Perez-Perez, A. F. Cutler, and M. J. Blaser, "Value of serology as a noninvasive method for evaluating the efficacy of treatment of Helicobacter pylori infection," Clinical Infectious Diseases, vol. 25, no. 5, pp. 1038-1043,1997.

[84] A. Cutler, A. Schubert, and T. Schubert, "Role of Helicobacter pylori serology in evaluating treatment success," Digestive Diseases and Sciences, vol. 38, no. 12, pp. 2262-2266, 1993.

[85] H. B. Pandya, J. S. Patel, H. H. Agravat, and N. K. R. Singh, "Non-invasive diagnosis of helicobacter pylori: Evaluation of two enzyme immunoassays, testing serum IgG and IgA response in the Anand district of central Gujarat, India," Journal of Clinical and Diagnostic Research, vol. 8, no. 6, 2014.

[86] S. Li, A.-P. Lu, L. Zhang, and Y.-D. Li, "Anti-Helicobacter pylori immunoglobulin G (IgG) and IgA antibody responses and the value of clinical presentations in diagnosis of H. pylori infection in patients with precancerous lesions," World Journal of Gastroenterology, vol. 9, no. 4, pp. 755-758, 2003.

[87] R. A. Veenendaal, J. M. Gotz, V. Schroijen et al., "Diagnosis of Helicobacter pylori infection by specific gastric mucosal IgA and IgG pylori antibodies," Journal of Clinical Pathology, vol. 48, no. 11, pp. 990-993, 1995.

[88] C. Granberg, A. Mansikka, O.-P. Lehtonen et al., "Diagnosis of Helicobacter pylori infection by using Pyloriset EIA-G and EIA-A for detection of serum immunoglobulin G (IgG) and IgA antibodies," Journal of Clinical Microbiology, vol. 31, no. 6, pp. 1450-1453, 1993.

[89] P. Berloco, A. Cavallini, A. Di Leo, and F. Russo, "Saliva samples not a reliable tool for diagnosis of Helicobacter pylori infection," European Journal of Clinical Microbiology & Infectious Diseases, vol. 20, no. 1, pp. 68-70, 2001.

[90] J. M. L. Christie, C. A. M. McNulty, N. A. Shepherd, and R. M. Valori, "Is saliva serology useful for the diagnosis of Helicobacter pylori?" Gut, vol. 39, no. 1, pp. 27-30,1996.

[91] H. Korean, "Diagnosis and treatment of Helicobacter pylori infection in Korea," The Korean Journal of Gastroenterology, vol. 32, no. 3, pp. 275-289,1998.

[92] C. P. Dooley, H. Cohen, P. L. Fitzgibbons et al., "Prevalence of helicobacter pylori infection and histologic gastritis in asymptomatic persons," The New England Journal of Medicine, vol. 321, no. 23, pp. 1562-1566, 1989.

[93] A. B. Price, "The Sydney System: histological division," Journal of Gastroenterology and Hepatology, vol. 6, no. 3, pp. 209-222, 1991.

[94] V. J. Desmet, M. Gerber, J. H. Hoofnagle, M. Manns, and P. J. Scheuer, "Classification of chronic hepatitis: diagnosis, grading and staging," Hepatology, vol. 19, no. 6, pp. 1513-1520,1994.

[95] O. Rotimi, A. Cairns, S. Gray, P. Moayyedi, and M. F. Dixon, "Histological identification of Helicobacter pylori: Comparison of staining methods," Journal of Clinical Pathology, vol. 53, no. 10, pp. 756-759, 2000.

[96] L. Laine, D. N. Lewin, W. Naritoku, and H. Cohen, "Prospective comparison of H&E, Giemsa, and Genta stains for the diagnosis of Helicobacter pylori" Gastrointestinal Endoscopy, vol. 45, no. 6, pp. 463-467,1997.

[97] R. Shrestha, K. Bataaoo, K. Koirala, and K. Shiv Raa, "Helicobacter pylori infection among patients with upper gastrointestinal symptoms: prevalence and relation to endoscopy diagnosis and histopathology," Journal of Family Medicine and Primary Care, vol. 3, no. 2, p. 154, 2014.

[98] H. Khedmat, A. Karami, Z. Safiri et al., "Helicobacter pylori genotypes can predict gastric tissue histopathology: A longitudinal study of Iranian patients," Journal of Infection and Public Health, vol. 5, no. 2, pp. 153-158, 2012.

[99] K. T. Tham, R. M. Peek Jr., J. C. Atherton et al., "Helicobacter pylori genotypes, host factors, and gastric mucosal histopathology in peptic ulcer disease," Human Pathology, vol. 32, no. 3, pp. 264-273, 2001.

[100] C. Nogueira, C. Figueiredo, F. Carneiro et al., "Helicobacter pylori genotypes may determine gastric histopathology," The American Journal of Pathology, vol. 158, no. 2, Article ID 64006, pp. 647-654, 2001.

[101] F. Gottrand, F. Cullu, D. Turck et al., "Normal gastric histology in Helicobacter pylori-infected children," Journal of Pediatric Gastroenterology and Nutrition, vol. 25, no. 1, pp. 74-78,1997.

[102] D. I. Grove, G. Koutsouridis, and A. G. Cummins, "Comparison of culture, histopathology and urease testing for the diagnosis of Helicobacter pylori gastritis and susceptibility to amoxycillin, clarithromycin, metronidazole and tetracycline," Pathology, vol. 30, no. 2, pp. 183-187, 1998.

[103] L. M. Resende, D. M. Queiroz, A. J. Barbosa, E. N. Mendes, G. A. Rocha, L. G. Coelho et al., "Histology of the mucosa of gastric antrum and body before and after eradication of Helicobacter pylori," Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas, vol. 26, no. 12, pp. 1279-1289, 1993.

[104] S. Ito, Y. Kohli, and T. Kato, "Histology of Helicobacter pylori (Hp) infection: gastric local immunity to Hp," Nippon rinsho. Japanese journal of clinical medicine, vol. 51, no. 12, pp. 3072-3075, 1993.

[105] J. A. Nowak, "Limitation of histology for detecting Helicobacter pylori," Gastrointestinal Endoscopy, vol. 41, no. 2, pp. 175-176, 1995.

[106] F. Megraud, "Advantages and Disadvantages of Current Diagnostic Tests for the Detection of," Scandinavian Journal of Gastroenterology, vol. 31, no. sup215, pp. 57-62, 2009.

[107] B. J. Marshall, J. R. Warren, G. J. Francis, S. R. Lang ton, C. S. Goodwin, and E. D. Blincow, "Rapid Urease Test in the Management of Campylobacter pyloridis-Associated Gastritis," American Journal of Gastroenterology, vol. 82, no. 3, pp. 200-210, 1987.

[108] P. Raj, J. F. Thompson, and D. H. Pan, "Helicobacter pylori serology testing is a useful diagnostic screening tool for symptomatic inner city children," Acta Paediatrica, vol. 106, no. 3, pp. 470-477, 2017.

[109] N. Kashani and A. Talebi Bezmin Abadi, "Reliability of rapid urease test for screening gastric cancer in high-risk populations," Scandinavian Journal of Gastroenterology, p. 1, 2017.

[110] H. L. T. Mobley, M. J. Cortesia, L. E. Rosenthal, and B. D. Jones, "Characterization of urease from Campylobacter pylori," Journal of Clinical Microbiology, vol. 26, no. 5, pp. 831-836, 1988.

[111] S. K. Lam and N. J. Talley, "Report of the 1997 Asia Pacific Consensus Conference on the management of Helicobacter pylori infection," Journal of Gastroenterology and Hepatology, vol. 13, no. 1, pp. 1-12, 1998.

[112] C. W. Howden and R. H. Hunt, "Guidelines for the management of Helicobacter pylori infection," American Journal of Gastroenterology, vol. 93, no. 12, pp. 2330-2338,1998.

[113] Y. Okiyama, K. Matsuzawa, E. Hidaka, K. Sano, T. Akamatsu, and H. Ota, "Helicobacter heilmannii infection: Clinical, endoscopic and histopathological features in Japanese patients," Pathology International, vol. 55, no. 7, pp. 398-404, 2005.

[114] C. Dieterich, H. Bouzourene, A. L. Blum, and I. E. Corthasy-Theulaz, "Urease-based mucosal immunization against Helicobacter heilmannii infection induces corpus atrophy in mice," Infection and Immunity, vol. 67, no. 11, pp. 6206-6209, 1999.

[115] M. C. Shepard and C. D. Lunceford, "Differential agar medium (A7) for identification of Ureaplasma urealyticum (human T mycoplasmas) in primary cultures of clinical material," Journal of Clinical Microbiology, vol. 3, no. 6, pp. 613-625,1976.

[116] T. L. Testerman, D. J. McGee, and H. L. T. Mobley, "Helicobacter pylori growth and urease detection in the chemically defined medium Ham's F-12 nutrient mixture," Journal of Clinical Microbiology, vol. 39, no. 11, pp. 3842-3850, 2001.

[117] H. L. T. Mobley, L.-T. Hu, and P. A. Foxall, "Helicobacter pylori urease: Properties and role in pathogenesis," Scandinavian Journal of Gastroenterology, vol. 26, no. 187, pp. 39-46,1991.

[118] P. Midolo and B. J. Marshall, "Accurate diagnosis of Helicobacter pylori. Urease tests," Gastroenterology Clinics of North America, vol. 29, no. 4, pp. 871-878, 2000.

[119] L. Boyanova, I. Stancheva, D. Todorov et al., "Comparison of three urease tests for detection of Helicobacter pylori in gastric biopsy specimens," European Journal of Gastroenterology & Hepatology, vol. 8, no. 9, pp. 911-914,1996.

[120] A. T. B. Abadi, T. Taghvaei, and L. Wolfram, "Inefficiency of rapid urease test for confirmation of Helicobacter pylori," Saudi Journal of Gastroenterology, vol. 17, no. 1, pp. 84-85, 2011.

[121] E. Perez-Trallero, M. Montes, M. Alcorta, P. Zubillaga, and E. Telleria, "Non-endoscopic method to obtain Helicobacter pylori for culture," The Lancet, vol. 345, no. 8950, pp. 622-623, 1995.

[122] H. X. Xia, C. T. Keane, and C. A. O'Morain, "Culture of Helicobacter pylori under aerobic conditions on solid media," European Journal of Clinical Microbiology & Infectious Diseases, vol. 13, no. 5, pp. 406-409, 1994.

[123] B. Ho and S. Vijayakumari, "A simple and efficient continuous culture system for Helicobacter pylori.," Microbios, vol. 76, no. 306, pp. 59-66, 1993.

[124] M. Assous, A. Zone, J. Watine, G. Paul, and J. Guerre, "Frozen biopsy specimens and culture rates of Helicobacter pylori," The Lancet, vol. 337, no. 8754, pp. 1412-1413, 1991.

[125] L. M. Best, D. J. M. Haldane, G. S. Bezanson, and S. J. O. Veldhuyzen van Zanten, "Helicobacterpylori: primary susceptibility to clarithromycin in vitro in Nova Scotia," Canadian Journal of Gastroenterology & Hepatology, vol. 11, no. 4, pp. 298-300,1997.

[126] S. Ohara, "Diagnostic methods for H. pylori infection," Nippon rinsho. Japanese journal of clinical medicine, vol. 67, no. 12, pp. 2279-2283, 2009.

[127] R. M. Genta and D. Y. Graham, "Comparison of biopsy sites for the histopathologic diagnosis of Helicobacter pylori: a topographic study of H. pylori density and distribution," Gastrointestinal Endoscopy, vol. 40, no. 3, pp. 342-345,1994.

[128] A. M. Allahverdiyev, M. Bagirova, R. Caliskan et al., "Isolation and diagnosis of Helicobacter pylori by a new method: Microcapillary culture," World Journal of Gastroenterology, vol. 21, no. 9, pp. 2622-2628, 2015.

[129] W. A. Rutala and D. J. Weber, "Reprocessingendoscopes: United States perspective," Journal of Hospital Infection, vol. 56, no. 2, pp. S27-S39, 2004.

[130] Y. Sakurai, M. Nakatsu, Y. Sato, and K. Sato, "Endoscope contamination from HBV- and HCV-positive patients and evaluation of a cleaning/disinfecting method using strongly acidic electrolyzed water," Digestive Endoscopy, vol. 15, no. 1, pp. 19-24, 2003.

[131] D. A. Israel, N. Salama, U. Krishna et al., "Helicobacter pylori genetic diversity within the gastric niche of a single human host," Proceedings of the National Acadamy of Sciences of the United States of America, vol. 98, no. 25, pp. 14625-14630, 2001.

[132] W.-H. Zhang, Y. Wang, H.-F. Guo, Y.-J. Bai, and X.-J. Yan, "Detection of antibody against Helicobacter pylori UreB by fluorescence polarized immunoassay using single epitope synthetic peptide as antigen," Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology, vol. 21, no. 3, pp. 371-374, 2005.

[133] T. Taghvaei, A. Talebi Bezmin Abadi, A. Ghasemzadeh, B. K. Naderi, and A. Mohabbati Mobarez, "Prevalence of horB gene among the Helicobacter pylori strains isolated from dyspeptic patients: First report from Iran," Internal and Emergency Medicine, vol. 7, no. 6, pp. 505-508, 2012.

[134] T. S. Bharath, M. S. Reddy, R. Dhanapal, N. G. R. Kumar, P. V. N. Raju, and T. R. Saraswathi, "Molecular detection and corelation of Helicobacter pylori in dental plaque and gastric biopsies of dyspeptic patients," Journal of Oral and Maxillofacial Pathology, vol. 18, no. 1, pp. 19-24, 2014.

[135] K. Dadashzadeh, M. Milani, M. Rahmati, and A. Akbarzadeh, "Real-time PCR detection of 16S rRNA novel mutations associated with Helicobacter pylori Tetracycline resistance in Iran," Asian Pacific Journal of Cancer Prevention, vol. 15, no. 20, pp. 8883-8886, 2014.

[136] B. D. Gold, M. A. Gilger, and S. J. Czinn, "New Diagnostic Strategies for Detection of Helicobacter pylori Infection in Pediatric Patients," Gastroenterology & hepatology, vol. 10, supplement 7, no. 12, pp. 1-19, 2014.

[137] C. B. Holman, D. S. Bachoon, E. Otero, and A. Ramsubhag, "Detection of Helicobacter pylori in the coastal waters of Georgia, Puerto Rico and Trinidad," Marine Pollution Bulletin, vol. 79, no. 1-2, pp. 354-358, 2014.

[138] M. Kaymakci, M. Aydin, S. Yazici, O. Sagir, O. E. R. Gur, and M. Sayan, "Detection of Helicobacter pylori in adenoid tissue by real-time polymerase chain reaction," Kulak burun bogaz ihtisas dergisi : KBB = Journal of ear, nose, and throat, vol. 24, no. 2, pp. 78-82, 2014.

[139] A. A. Trespalacios, E. Rimbara, W. Otero, R. Reddy, and D. Y. Graham, "Improved allele-specific PCR assays for detection of clarithromycin and fluoroquinolone resistant of Helicobacter pylori in gastric biopsies: Identification of N87I mutation in GyrA," Diagnostic microbiology and infectious disease, vol. 81, no. 4, pp. 251-255, 2015.

[140] J. J. Redondo, P. M. Keller, R. Zbinden, and K. Wagner, "A novel RT-PCR for the detection of Helicobacter pylori and identification of clarithromycin resistance mediated by mutations in the 23S rRNA gene," DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE, vol. 90, no. 1, pp. 1-6, 2018.

[141] F. Khadangi, M. Yassi, and M. A. Kerachian, "Review: Diagnostic accuracy of PCR-based detection tests for Helicobacter Pylori in stool samples," Helicobacter, vol. 22, no. 6, Article ID e12444, 2017.

[142] S. Talarico, M. Safaeian, P. Gonzalez et al., "Quantitative Detection and Genotyping of Helicobacter pylori from Stool using Droplet Digital PCR Reveals Variation in Bacterial Loads that Correlates with cagA Virulence Gene Carriage," Helicobacter, vol. 21, no. 4, pp. 325-333, 2016.

[143] S. Ahmad, F. Ahmad, F. U. Rahman et al., "PCR based detection of phase variable genes in Pakistani based clinical Helicobacter pylori strains," Jundishapur Journal of Microbiology, vol. 9, no. 7, Article ID e31824, 2016.

[144] J.-J. Lu, C.-L. Perng, R.-Y. Shyu, C.-H. Chen, Q. Lou, S. K. Chong et al., "Comparison of Five PCR Methods for Detection Of Helicobacter pylori DNA in Gastric Tissues," Journal of clinical microbiology, vol. 37, no. 3, pp. 772-774,1999.

[145] S. Hoshina, S. M. Kahn, W. Jian et al., "Direct detection and amplification of Helicobacter pylori ribosomal 16S gene segments from gastric endoscopic biopsies," Diagnostic microbiology and infectious disease, vol. 13, no. 6, pp. 473-479,1990.

[146] L.-J. Van Doorn, Y. Glupczynski, J. G. Kusters et al., "Accurate prediction of macrolide resistance in Helicobacter pylori by a PCR line probe assay for detection of mutations in the 23S rRNA gene: Multicenter validation study," Antimicrobial Agents and Chemotherapy, vol. 45, no. 5, pp. 1500-1504, 2001.

[147] S.-A. Ho, J. A. Hoyle, F. A. Lewis et al., "Direct polymerase chain reaction test for detection of Helicobacter pylori in humans and animals," Journal of Clinical Microbiology, vol. 29, no. 11, pp. 2543-2549, 1991.

[148] N. S. S. Atkinson and B. Braden, "Helicobacter Pylori Infection: Diagnostic Strategies in Primary Diagnosis and After Therapy," Digestive Diseases and Sciences, vol. 61, no. 1, pp. 19-24, 2016.

[149] S. Lario, M. J. Ramlrez-Lazaro, A. Montserrat et al., "Diagnostic accuracy of three monoclonal stool tests in a large series of untreated Helicobacter pylori infected patients," Clinical Biochemistry, vol. 49, no. 9, pp. 682-687, 2016.

[150] A. M. Hirschl and A. Makristathis, "Methods to detect Helicobacter pylori: From culture to molecular biology," Helicobacter, vol. 12, no. 2, pp. 6-11, 2007.

[151] A. P. Lage, E. Godfroid, A. Fauconnier et al., "Diagnosis of Helicobacter pylori infection by PCR: Comparison with other invasive techniques and detection of cagA gene in gastric biopsy specimens," Journal of Clinical Microbiology, vol. 33, no. 10, pp. 2752-2756, 1995.

Amin Talebi Bezmin Abadi

Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran

Correspondence should be addressed to Amin Talebi Bezmin Abadi;

Received 24 January 2018; Accepted 12 April 2018; Published 22 May 2018

Academic Editor: Jose Yuste

Caption: Figure 1: Successful isolation of Helicobacter pylori on Brucella agar supplemented with 5% horse blood.
Table 1: Overview of H. pylori diagnosis with invasive and
noninvasive methods.

Name             Type        Reference method     Characteristics

UBT *        Noninvasive            No          Sensitivity: >95%
                                                 Specificity: >95%

Serology     Noninvasive            No           Sensitivity: >96%

SAT ***      Noninvasive            No           Sensitivity: >95%
                                                 Specificity: >95%

Culture        Invasive            Yes          Sensitivity: 50-95%
                                                 Specificity: >95%

Histology      Invasive            Yes             Sensitivity:
                                                 Specificity: >95%

RUT ****       Invasive             No           Sensitivity: 95%

PCR            Invasive             No           Sensitivity: 80%
                                                 Specificity: 100%

Name        Advantages

UBT *       (i) High specificity and sensitivity
            (ii) Useful to confirm H. P eradication
            (iii) Useful to detect gastroduodenal
            (iv) Relatively cheap, simple and safe
            (v) A gold standard only for
            asymptomatic patients
            (vi) No sampling errors, good for
            epidemiological studies
            (vii) practically useful for children -100%

Serology    (i) Has no false negative result
            (ii) Cheap, simple and safe
            (iii) Highly recommended for initial H.
            pylori screening
            (iv) Not affected by gastric bleeding
            (v) No false negative result in the case of
            PPI** consumption (a unique character)

SAT ***     (i) High specificity and sensitivity
            (ii) Good popularity among patients
            (iii) Relatively fast and simple
            (iv) Easy modification to produce better
            (v) No need to skilled staffs

Culture     (i) Existing the data about antibiotic resistance
            (ii) High specificity but low sensitivity
            (lhe most specific method existing)
            (iii) The possibility of having the pure
            bacterium and chance of preservation for a long time

Histology   (i) The gold standard for direct H. pylori
            (ii) Almost cheap method for using in the
            universal scale
            (iii) Simple method

RUT ****    (i) Rapid, simple and cheap method
            (ii) High specificity (-99%), but low
            sensitivity (-80%)
            (iii) The most handful test in a
            clinical setting

PCR         (i) Existing data about antibiotic
            (ii) High specificity and sensitivity
            (iii) Tracking the mutations involved in
            antibiotic resistance
            (iv) The possibility of virulence typing
            (v) Useful to detect the bacterium in
            environmental samples
            (vi) Rapid and accurate results

Name        Disadvantages

UBT *       (i) Rarely false positive results refer to
            urease positive organisms
            (ii) Radiation in the case of application of
            14 C-UBT
            (iii) No data about antibiotic resistance

Serology    (i) No data about antibiotic resistance
            (ii) Failure in distinguish between active
            and past infection
            (iii) No application in clinical practice
            and hospitals

SAT ***     (i) No data about antibiotic resistance
            (ii) The false positive result in the
            case of PPI and antibiotics
            (iii) Variation in specificity and
            sensitivity over the different clinical

Culture     (i) Need optimal incubation conditions
            and highly skilled operators
            (ii) Fast processes after endoscopy in
            necessary to avoid bacterial death
            (iii) Risk of the false negative result in the
            case of PPI and antibiotic consumption
            (iv) Need strict condition in transport
            before culturing (cool temperature)
            (v) Time-consuming and also the most
            expensive method

Histology   (i) Contradictory results following the
            PPI consumption
            (ii) Need extra biopsy sample and facing
            with ethical limitations
            (iii) Fluorescent microscope required
            method (limiting wide-spread usage)
            (iv) The relatively high rate of false
            negative reports

RUT ****    (i) No data about antibiotic resistance
            (ii) Decreased sensitivity in patients with
            gastric bleeding
            (iii) Increased false negative results in the
            case of antibiotics & PPI consumption
            and achlorhydria
            (iv) Not useful for screening the
            eradication in epidemiologic studies

PCR         (i) High cost
            (ii) Risk of contamination
            (iii) Time consuming and requirement to
            skilled staff (low feasibility in all
            (iv) Lack of data about phenotypic
            antibiotic susceptibility profile

* Ureabreath test; ** proton pump inhibitor; *** stool antigen test;
**** rapid urease test.
COPYRIGHT 2018 COPYRIGHT 2010 SAGE-Hindawi Access to Research
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2018 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Abadi, Amin Talebi Bezmin
Publication:Journal of Pathogens
Date:Jan 1, 2018
Previous Article:Risk of Shiga Toxigenic Escherichia coli O157:H7 Infection from Raw and Fermented Milk in Sokoto Metropolis, Nigeria.
Next Article:Prevalence of Asymptomatic Mycobacterium tuberculosis Infection in Charcoal Producers: A Cross-Sectional Study in Kaase, Ghana.

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters