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New approaches to the diagnosis of vaginitis.

Overview

Genital tract infections (GTIs) are highly prevalent and most women will have a vaginal infection during their lifetime. (1) Specifically, approximately 75% of women will have at least 1 episode of vulvovaginal candidiasis (VVC) and more than 2.3 million women in the United States will contract a trichomoniasis infection. It is estimated that 29% of women in the United States have bacterial vaginosis (BV). (2) Given the scope of vaginitis prevalence, it is vital that clinicians have access to the most sensitive and specific diagnostic tools.

Effective treatment of vaginitis is highly dependent on the clinician's ability to make an accurate diagnosis. Signs and symptoms alone do not provide a precise diagnosis; therefore, clinicians will typically utilize laboratory tests to determine the exact nature of the vaginal infection.

Vaginal infections have traditionally been diagnosed using a combination of gynecologic examination, vaginal pH, microscopic evaluation of Gram stain and/or wet mount, and an amine odor test. However, most clinicians do not have access to microscopy and as a result empiric diagnoses are common and lead to incorrect treatment and management. (3)

Nucleic acid amplification testing (NAAT) has been the mainstay of diagnosis for gonorrhea and chlamydia for several years. This testing platform results in high sensitivity and specificity and has rendered culture-based testing for these infections all but obsolete. (4) TABLE 1 illustrates the sensitivity and specificity of a nucleic acid probe assay relative to 2 reference methods (microscopy and culture).

Nucleic acid amplification tests are designed to target the microorganisms that are most likely causing vaginal symptoms. Targeted testing is the most clinically appropriate testing choice for women with high-risk histories or symptoms as shown in TABLE 2.

This supplement will address some of the more prevalent GTIs that may develop in women. While many of the following infections are associated with signs and symptoms, affected patients are just as often asymptomatic. Moreover, many signs and symptoms of some GTIs can overlap those of other GTIs, confounding diagnosis based simply on signs and symptoms.

Bacterial vaginosis

Bacterial vaginosis is a condition characterized by the imbalance of flora in the vagina. In women of childbearing age, BV is the most common vaginal infection. (6) In BV, normal hydrogen peroxide-producing Lactobacillus species are replaced with higher than normal concentrations of anaerobic bacteria, Gardnerella vaginalis, ureaplasma, mycoplasma, and many fastidious or uncultivated anaerobes. (1)

The cause behind this change in microbial balance is not well understood. The most significant risk factor for a new case of BV is sex with a new partner while the most significant risk for recurrent BV is sex with the same partner. (7-9) Women cannot get BV from everyday activities, such as using a toilet seat or swimming in a pool. (6) Bacterial vaginosis likely does not occur in women with no history of any type of sexual activity. (10)

Most women with BV will be asymptomatic, however, there are some signs and symptoms associated with this condition, including a white or gray, thin vaginal discharge that may be accompanied by an unpleasant, "fishy" odor. (1,6) The vaginal discharge will typically have a pH of 5.0 to 5.5. (11) Women may also report a burning sensation during urination or itching around the exterior of the vagina. (6)

In the majority of cases, women with BV will experience no complications. However, some serious risks with BV exist, such as an increased susceptibility to HIV, if exposed to an infected sexual partner. (6) Bacterial vaginosis can increase the risk of acquiring other sexually transmitted infections (STIs), such as herpes simplex virus, chlamydia, or gonorrhea. An association between BV and postsurgical infections, such as hysterectomy or abortion, has been demonstrated.

Bacterial vaginosis is a common condition in pregnant women. (6) Pregnant women with BV may be at an increased risk for adverse pregnancy complications, including premature rupture of membranes, preterm labor, preterm delivery, intra-amniotic infection, and postpartum endometritis. (1) Pregnant women with BV are also more likely to have a newborn with low birth weight (<5.5 lb). (6)

Diagnosis of BV has traditionally relied on the Amsel criteria, where the clinician confirms the presence of 3 out of 4 criteria: vaginal discharge, vaginal-fluid pH >4.5, a positive "whiff" test, and microscopic examination of clue cells. (12) However, some of these conditions can be seen with other vaginal infections, such as Trichomonas vaginalis, and inexperience with microscopy or failure to utilize all of the criteria could lead to error in diagnosis. Furthermore, many clinicians do not have access to microscopy; thus, diagnosis is often empiric based on a patient's symptoms.

Recently, NAAT has become available for diagnosing BY. Various formats are available, ranging from "pick your bacteria of interest" to well-designed panels that have been clinically validated. The identification of a single bacteria in the vagina is of no value in diagnosing BV and results in significant expense and unnecessary concern for the patient. For example, a qualitative result of G vaginalis vaginosis has very little value as this bacteria is present in 50% to 60% of women who do not meet the established diagnostic criteria for BV. The qualitative presence of G vaginosis has poor specificity as an indicator of BV. (12) Another study showed that the molecular quantification of Atopobium vaginae (DNA level, [10.sup.8] copies/mL) and G vaginalis (DNA level, [10.sup.9] copies/mL) had the highest predictive value for BV, with excellent sensitivity (95%), specificity (99%), and positive (95%) and negative (99%) predictive values, whereas G vaginalis concentration alone of <105 org/mL had less than 35% positive predictive value. (13)

Panels on the other hand, which have been carefully validated for the diagnosis of BV based on Amsel and Nugent criteria, may have value. (14,15)

Trichomoniasis

Trichomoniasis is caused by infection with the protozoan parasite Trichomonas vaginalis. (1) Trichomoniasis is one of the most prevalent curable STIs, with the prevalence of T vaginalis infection among women aged 14 to 49 years estimated to be 2.3 million (3.1%) in the United States. (16,17) Trichomoniasis is an STI and sexual partners should also be treated.

The majority of people (about 70%) infected with T vaginalis are asymptomatic. (16) Some women may exhibit symptoms that include a persistent, malodorous, yellow-green vaginal discharge and/or vulvar irritation that can include swelling and tenderness

of the labia minora. (1,11) Symptoms may manifest 5 to 28 days after infection; however, some people may not experience symptoms until much later. (16)

Trichomoniasis may contribute to the development or spread of other STIs (eg, trichomoniasis-related genital inflammation may increase the passing of HIV during sexual intercourse). (16) Patients diagnosed with trichomoniasis have a high rate of reinfection. (1) Based on this, the CDC discusses rescreening for T vaginalis in sexually active women at 3 months following the initial infection.

Women with trichomoniasis who are pregnant may be at risk for preterm delivery. (16) Moreover, for pregnant women who have trichomoniasis, there is an increased chance of having a newborn with a low birth weight.

Microscopic examination of vaginal secretion is one method of diagnosis for trichomoniasis. This technique requires immediate assessment of a wet preparation slide by an experienced microscopist; however, it only has a sensitivity of approximately 60% to 70%.1 Papinacolaou smears offer a similar sensitivity (about 60%). (11) Culture is a method of diagnosis that has a better sensitivity and specificity. (1) Cultures, however, are often time-consuming and results are not readily available in the clinical setting. (18)

Another option for the diagnosis of T vaginalis is molecular detection using nucleic acid-based technology. A recent study compared the Affirm VPIII (BD) assay, a DNA-probe-based diagnostic test, with the Aptima T vaginalis assay (Hologic Gen-Probe), which uses transcription-mediated amplification (TMA), for the detection of T vaginalis. (19) The study found that screening with TMA was more sensitive in the detection of T vaginalis compared with the Affirm DNA-probe diagnostic test.

Candidiasis

Vulvovaginal candidiasis is a condition usually caused by Candida albicans; however in some cases it can be caused by other Canclida species. (1) Vulvovaginal candidiasis is ordinarily referred to as a "yeast infection," and is a common infection in women. (20) In fact, approximately 75% of women will have at least 1 occurrence of VVC within their lifetime. (1) Moreover, 40% to 45% of women will have at least 2 episodes of VVC during their lifetime. The infection will often occur during pregnancy.

Vulvovaginal candidiasis is rarely acquired through sexual intercourse, although it can occur concomitantly with other STIs. (1) In fact, Candida is always present in the body in small amounts. A yeast infection will occur if there is an imbalance within the vagina (occuring from a change in hormonal balance or normal acidity) and Candida multiply. (20)

Vulvovaginal candidiasis can be classified as either uncomplicated or complicated, based upon clinical presentation. (1) The following examples are classified as "uncomplicated WC": sporadic or infrequent VVC, mild-to-moderate VVC, VVC likely caused by C albicans, or WC in nonimmunocompromised women. Conversely, these examples are classified as "complicated VVC": recurrent WC, severe WC, WC not caused by Calbicans, or VVC in women with uncontrolled diabetes or immunosuppression.

A small percentage of women (<5%) will experience recurrent VVC (RVVC), which is defined as having 4 or more episodes of symptomatic VVC within 1 year. (1) The pathogenesis of RVVC is not well understood and no predisposing or underlying conditions are apparent in women with RVVC.

Signs and symptoms of VVC can include itching, vaginal soreness, dyspareunia, external dysuria, fissures, and/or an abnormal "cheese-like" vaginal discharge. (1,21) Patients may also experience a burning sensation during urination, especially if there is a chafing of the skin due to scratching." It is important to note that these symptoms are not exclusive to VVC, and, in fact, are similar to other types of genital infections. (1,21)

Diagnosis for VVC cannot be made solely by a physical examination, although it can be suggested based upon symptoms. (1,22) Testing for VVC includes a wet preparation (saline, 10% potassium hydroxide) or Gram stain of vaginal secretions to determine if there are an abnormal number of Candida organisms present. Vulvovaginal candidiasis is associated with normal vaginal pH (<4.5); therefore, pH testing is not a useful diagnostic tool for this condition. A vaginal culture to test for Candida may also be considered and should be obtained from patients with RVVC to confirm the clinical diagnosis and to identify unusual species (including non-Calbicans species), particularly Candida glabrata. Conventional antimycotic therapies are not as effective against these species as they are against Calbicans. (1) Non-C albicans species account for 10% to 20% of VVC.)

Nucleic acid amplification tests, some of which provide bacterial species, have become commercially available for the diagnosis of Candida and are another option for diagnosis. However, as with culture, NAAT has the propensity to detect small numbers of organisms, which may represent colonization as opposed to infection, so it is important to rule out other causes of vaginitis.

Chlamydia

Chlamydia trachomatis infection is the most frequently reported notifiable infectious disease in the United States. (1) In 2011, more than 1.4 million cases of chlamydial infection were reported to the CDC. (23) The highest prevalence of chlamydia infection was found in individuals aged 25 years or younger. (1) In the United States, chlamydial infections were reported 2.5 times more in women than in men. (23) Of note, in sexually active women, those younger than age 20 years are 2 to 3 times more likely to acquire C trachomatis than older women. (24) Higher chlamydial infection rates are associated with an increased number of sexual partners.

Chlamydiae are microorganisms that attach to columnar epithelial cells without invading the deep tissue. (24) This characteristic leads to the often asymptomatic nature of C trachomatis infections. Symptoms indicative of C trachomatis infection that patients can present with include mucopurulent cervicitis, dysuria, and/or postcoital bleeding. (11)

C trachomatis infections can lead to serious complications, particularly in women. Chronic conditions that can result from C trachomatis infections include pelvic inflammatory disease (PID), ectopic pregnancy, and infertility. (1) In pregnancy, chlamydial infections can be associated with premature delivery and postpartum infections. (24) Moreover, newborn babies have a near 50% chance of developing neonatal conjunctivitis when the mother has cervical chlamydial infection during her pregnancy.

The CDC recommends annual screening for chlamydial infection in all sexually active women 25 years of age and younger. (1) Indeed, results of a randomized controlled trial suggested that a screening program may lead to a nearly 60% reduction in PID as a result of chlamydial infection. (25)

Chlamydial infections can only be diagnosed through laboratory testing. (24) Cell culture (50%-90% sensitivity) may offer the greatest specificity; however, high cost and an up to 7-day delay in diagnosis can make this method prohibitive. Direct fluorescent antibody testing (90% sensitivity) can be nearly as accurate as cell culture testing but does require an experienced microscopist, a satisfactory specimen, and a fluorescence microscope. Another option is enzyme immunoassay testing, which offers 40% to 60% sensitivity. (11)

Nucleic acid amplification tests, including polymerase chain reaction, can offer a more rapid and less expensive option, with sensitivity ranging up to 100%. (11,24) These tests offer a diagnosis of C trachomatis in a matter of hours. (24)

Gonorrhea

Gonorrhea is the second most frequently reported notifiable infectious disease in the United States. (26) More than 321000 cases of gonorrhea were reported in the United States in 2011. According to 2011 data, gonorrhea rates in the United States have been declining from 1975 to 2010; however, a slight increase in the gonorrhea rate was seen in 2010 and 2011. The prevalence of gonorrhea is varied among populations and communities. (1) The CDC recommends that health care practitioners consider local gonorrhea epidemiology when making screening decisions.

Since 2002, rates of gonococcal infection have been higher among women than among men. (26) After exposure to an infected partner, estimates reveal that nearly 60% to 90% of women will become infected. (11)

Neisseria gonorrhoeae is a Gram-negative diplococcus that may be found in the urethra, cervix, and anal canal. (11) The incubation period is approximately 3 to 5 days. Most women with gonococcal infections are asymptomatic. In those cases, infection may not recognizable until symptoms from complications (eg, pelvic inflammatory disease) are present. (1) When symptomatic, women may present with vaginal discharge, urinary frequency or dysuria, and rectal discomfort. (11) Inflammation, along with itching and burning sensations, can be found in the vulva, vagina, cervix, and urethra.

A major complication from gonococcal infection is salpingitis. (11) In fact, approximately 50% of women with salpingitis have N gonorrhoeae found in their cervix. Some of the sequelae that develop in asymptomatic women with gonorrhea include tubal scarring, infertility, and an increased risk for ectopic gestations.

Testing for gonococcal infection is recommended in sexually active women who are considered at increased risk for infection. (1) This includes women who are pregnant. Any individual who tests positive for gonorrhea should also be tested for other STIs, including chlamydia, syphilis, and HIV. In fact, when gonococcal infection is diagnosed, patients are frequently coninfected with C trachomatis.

Specific diagnosis of gonococcal infection in women can be executed by testing endocervical, vaginal, or urine specimens. (1) For the detection of genitourinary infection with N gonorrhoeae, suggested tests are culture and NAAT. The CDC reports that the sensitivity of NAAT for detecting N gonorrhoeae infection is superior to culture in genital and nongenital anatomic sites. (1) Detection rates will vary by NAAT type.

Summary

Genital tract infections are a serious issue for women in the United States. Because GTIs have such high prevalence and many symptoms overlap, it is clear that clinicians should have access to the most accurate diagnostic tools available. As with testing for gonorrhea and chlamydia, molecular testing has become available for vaginal infections. Clinicians should be aware of the advantages and limitations of these new testing modalities and determine if a particular test has been clinically validated before instituting its use.

KEY POINTS

* Most women will have a vaginal infection during their lifetime.

* Many signs and symptoms of genital tract infections (GTIs) can overlap those of other GTIs. Signs and symptoms alone will not provide a precise diagnosis.

* Patients with vaginal infections may be asymptomatic at a clinical encounter.

* The following are some of the more prevalent GTIs that may develop in women:

* Bacterial vaginosis

* Trichomoniasis

* Candidiasis

* Chlamydia

* Gonorrhea

* Clinicians will typically utilize laboratory tests to determine the exact nature of the vaginal infection.

* Nucleic acid amplification testing (NAAT) offers high sensitivity and specificity when testing for GTIs and has become the mainstay of diagnosis for gonorrhea and chlamydia.

* NAAT is now available to clinicians for the diagnosis of bacterial vaginosis.

* The case studies highlight clinical encounters where the physician opted to use the NAAT SureSwab[R] (Quest Diagnostics, Madison, New Jersey) to make an accurate diagnosis.

Universal Opt-Out Testing for Chlamydia

An abstract by Owusu-Edusei et al exploring universal opt-out chlamydia testing for young women in the United States was recently published in Sexually Transmitted Infections. The authors, all researchers at the Centers for Disease Control and Prevention, noted that the current testing rates for chlamydia are low in the United States; approximately two-thirds of sexually active young women are not tested at clinical encounters.

Dr Owusu-Edusei and colleagues evaluated a patient-directed, universal, opt-out testing program model for women aged 15 to 24 years with a minimum 1 clinical encounter per year. The authors assessed the potential health and economic outcomes of this model, including health insurance coverage and utilization rates. The authors assumed a participation rate of 75% of sexually active women and 5% of sexually inactive women. Over a 3-year period, the annual testing rate would increase to about 52% and the prevalence of chlamydial infections would decrease by 60% to approximately 1%. Of note, when the authors increased participation rates to 85% or greater, the overall chlamydia prevalence decreased to zero.

The authors note that this type of opt-out testing program would be cost-effective as there are no additional costs beyond testing and treatment. Testing coverage of sexually active young women may increase with the implementation of a universal opt-out testing program for chlamydia.

Source: Owusu-Edusei K, Hoover KW, Hart-Cooper GD, Gift TL. An exploratory evaluation of universal opt-out chlamydia testing during clinical encounters for young women in the United States. Sex Transm Infect. 2013;89(suppl 1):A37-A38. Abstract 006.5.

REFERENCES

(1.) Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2010. MMWR. 2010;59(No. RR-12):1-110.

(2.) Centers for Disease Control and Prevention. National Center for Health Statistics. NHANES 1999-2002. http://www.cdc.gov/ nchs/nhanes.htm. Accessed August 21, 2013.

(3.) Wiesenfeld H, Macio I. The infrequent use of office-based diagnostic tests for vaginitis. Am J Obstet Gynecol. 1999;181(1): 39-41.

(4.) Brown HL, Fuller DD, Jasper LT, Davis TE, Wright JD. Clinical evaluation of affirm VPIII in the detection and identification of Trichomonas vaginalis, Gardnerella vaginalis, and Candida species in vaginitis/vaginosis. Infect Dis Obstet Gynecol. 2004;12(1):17-21.

(5.) BD Affirm[TM] VPIII Microbial Identification Test. http://www. bd.com/ds/technicalCenter/inserts/pkglnserts.asp#PF8. Accessed August 21, 2013.

(6.) Centers for Disease Control and Prevention. Bacterial vaginosis--CDC fact sheet, http://www.cdc.gov/std/bv/STDFactBacteriaI-Vaginosis.htm. Accessed May 23, 2013.

(7.) Hawes SE, Hillier SL, Benedetti J, et al. Hydrogen peroxide-producing lactobacilli and acquisition of vaginal infections. J Infect Dis. 1996;174(5):1058-1063.

(8.) Schwebke JR, Desmond R. Risk factors for bacterial vaginosis in women at high risk for sexually transmitted diseases. Sex Transm Dis. 2005;32(11):654-658.

(9.) Bradshaw CS, Morton, AN, Hocking J, et al. High recurrence rates of bacterial vaginosis over the course of 12 months following oral metronidazole and factors associated with recurrence. J Infect Dis. 2006;193(11):1478-1486.

(10.) Fethers KA, Fairley CK, Morton A, et al. Early sexual experiences and risk factors for bacterial vaginosis. J Infect Dis. 2009;200(11):1662-1670.

(11.) Mazdisnian F. Benign disorders of the vulva & vagina. In: DeCherney AH, Nathan L, Goodwin TM, Laufer N, eds. Current Diagnosis & Treatment Obstetrics & Gynecology. 10th ed. New York, NY: McGraw-Hill Companies; 2007:5 98-622.

(12.) Fredricks DN, Fiedler TL, Thomas KK, Oakley BB, Marrazzo JM. Targeted PCR for detection of vaginal bacteria associated with bacterial vaginosis. J Clin Microbiol. 2007;45(10): 3270-3276.

(13.) Menard JP, Fenollar F, Henry M, Bretellef, Raoult D. Molecular quantification of Gardnerella vaginalis and Atopobium vaginae loads to predict bacterial vaginosis. Clin Infect Dis. 2008;47(1):33-43.

(14.) SureSwab unpublished data.

(15.) Cartwright CP, Lembke BE, Ramachandran K, et al. Development and validation of a semiquantitative, multitarget PCR assay for diagnosis of bacterial vaginosis. J Clin Microbiol. 2012;50(7):2321-2329.

(16.) Centers for Disease Control and Prevention. Trichomoniasis-CDC fact sheet, http://www.cdc.gov/std/trichomonas/stdfacttrichomoniasis.htm. Accessed August 21, 2013.

(17.) Centers for Disease Control and Prevention. Trichomoniasis-CDC statistics, http://www.cdc.gov/std/trichomonas/stats. htm. Accessed August 21, 2013.

(18.) Lowe NK, Neal JL, Ryan-Wenger NA. Accuracy of the clinical diagnosis of vaginitis compared with a DNA probe laboratory standard. Obstet Gynecol. 2009;113(1):89-95.

(19.) Andrea SB, Chapin KC. Comparison of Aptima Trichomonas vaginalis transcription-mediated amplification assay and BD affirm VPIII for detection of T. vaginalis in symptomatic women: performance parameters and epidemiological implications. J Clin Microbiol. 2011;49(3):866-869.

(20.) Centers for Disease Control and Prevention. Candidiasis: definition of genital/vulvovaginal candidiasis, http://www.cdc. gov/fungal/Candidiasis/genital/definition.html. Accessed May 21, 2013.

(21.) Centers for Disease Control and Prevention. Candidiasis: symptoms of genital/vulvovaginal candidiasis, http:// www.cdc.gov/fungal/Candidiasis/genital/symptoms.html. Accessed May 21, 2013.

(22.) Centers for Disease Control and Prevention. Candidiasis: diagnosis & testing of genital/vulvovaginal candidiasis, http:// www.cdc.gov/fungal/Candidiasis/genital/diagnosis.html. Accessed May 21, 2013.

(23.) Centers for Disease Control and Prevention. 2011 sexually transmitted disease surveillance: chlamydia, http://www.cdc. gov/std/stats11/chlamydia.htm. Accessed May 17, 2013.

(24.) Ainbinder SW, Ramin SM, DeCherney AH. Sexually transmitted diseases & pelvic infections. In: DeCherney AH, Nathan L, Goodwin TM, Laufer N, eds. Current Diagnosis & Treatment Obstetrics & Gynecology. 10th ed. New York, NY: McGraw-Hill Companies; 2007:662-695.

(25.) Scholes D, Stergachis A, Heidrich FE, Andrilla H, Holmes KK, Stamm WE. Prevention of pelvic inflammatory disease by screening for cervical chlamydial infection. N Engl J Med. 1996;334(21):1362-1366.

(26.) Centers for Disease Control and Prevention. 2011 sexually transmitted disease surveillance: gonorrhea, http://www.cdc. gov/std/stats11/gonorrhea.htm. Accessed May 20, 2013.

Jane Schwebke, MD

Professor of Medicine/Infectious Diseases

University of Alabama at Birmingham

Birmingham, Alabama

Author Disclosures

Dr Schwebke reports that she is a consultant to Combe Incorporated. Additionally, she has received grant and research support from LabCorp, BD Diagnostics, Hologic Inc., and Embil. Dr Schwebke received compensation from Quest Diagnostics for her participation in preparing this supplement.

Dr Randell reports that he is a consultant to LabCorp and a member of the speakers' bureau for Quest Diagnostics. Dr Randell received compensation for his participation in preparing this supplement.

TABLE 1 Clinical sensitivity and specificity of a nucleic
acid probe assay relative to 2 reference methods (5)

                                    Nucleic acid probe assay

                                     Relative to microscopy

Organism      Sample size, N   Sensitivity (%)   Specificity (%)

Candida            740              --                --
species

Gardnerella        299             84 (b)            100 (b)
vaginalis

Trichomonas        852             93 (c)            100 (c)
vaginalis

                   Nucleic acid probe assay

                     Relative to culture

Organism      Sensitivity (%)   Specificity (%)

Candida           81 (a)            98 (a)
species

Gardnerella         96                99
vaginalis

Trichomonas       100 (a)           99 (a)
vaginalis

(a) Culture is the accepted reference method.

(b) Based on Gram stain, the accepted reference method.

(c) Based on wet mount.

TABLE 2 Women who are appropriate
for targeted genital tract infection
testing (1)

Targeted testing is the most clinically appropriate
choice for women with:

* Symptoms of vaginosis/vaginitis

* History of high-risk sexual behavior or a previous
sexually transmitted infection

* History of pregnancy complications (eg, ectopic
pregnancy, premature rupture of the membranes,
preterm labor and delivery)

* Cervicitis, pelvic inflammatory disease, urethritis

* Chronic pelvic pain, difficult urination, painful
intercourse

* Risk of postoperative gynecologic infection
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