Microbiology of the ethmoid sinus following endoscopic sinus surgery. (Original Article).Abstract
We prospectively studied the native microbiology of the ethmoid sinus ethmoid sinus,
n one of the facial cavities, located beneath the nasal bridge, through which air flows. following endoscopic en·do·scope
An instrument for examining visually the interior of a bodily canal or a hollow organ such as the colon, bladder, or stomach.
en sinus surgery in 113 patients (mean age: 41.3 yr). After each patient had regained complete mucosalization (minimum follow-up: 6 wk), we obtained a bacterial swab of the ethmoid sinus and submitted it for culture and sensitivity analysis. We then compiled data on sensitivity patterns and the number and type of bacteria isolated. Of the 113 patients, 67 (59.3%) had positive cultures, 26 (23.0%) had sterile cultures, and 20 (17.7%) had normal flora Normal flora
The mixture of bacteria normally found at specific body sites.
Mentioned in: Sputum Culture, Wound Culture . Multiple bacteria were isolated in 31 of the 113 patients (27.4%). The most common isolates were gram-positive cocci cocci /coc·ci/ (kok´si) plural of coccus.
[L.] plural of coccus. , and the most common bacteria were staphylococcal staphylococcal
pertaining to Staphylococcus spp.
staphylococcal clumping test
used as a means of measuring the quantity of fibrinogen-split products in a sample of blood. species. A significant degree (42.9%) of beta-lactamase resistance was exhibited. We conclude that the ethmoid sinus is not microbiologically sterile following endoscopic sinus surgery.
The advent of endoscopic sinus surgery has given otolaryngologists a minimally invasive, highly effective treatment modality treatment modality Medtalk The method used to treat a Pt for a particular condition for medically refractory chronic rhinosinusitis. However, not all patients respond equally well, and 6 to 8% of them will have recurrent or persistent disease that requires revision surgery. (1,2) Others will experience acute recurrences of chronic rhinosinusitis despite patent sinus ostia Ostia (ŏs`tēə), ancient city of Italy, at the mouth of the Tiber. It was founded (4th cent. B.C.) as a protection for Rome, then developed (from the 1st cent. B.C.) as a Roman port, rivaling Puteoli. . (3)
In its normal state, the maxillary sinus maxillary sinus
An air cavity in the body of the maxilla, communicating with the middle meatus of the nose. Also called antrum of Highmore, maxillary antrum. proper is considered to be sterile, as has been shown by antral puncture studies in healthy subjects. (4) However, very little is known about the bacteriology bacteriology
Study of bacteria. Modern understanding of bacterial forms dates from Ferdinand Cohn's classifications. Other researchers, such as Louis Pasteur, established the connection between bacteria and fermentation and disease. of the maxillary max·il·lar·y
Of or relating to a jaw or jawbone, especially the upper one.
A maxillar; a jawbone.
adj and ethmoid sinuses following endoscopic sinus surgery. It has been thought possible that these sinuses become sterile following wide ventilation. On the other hand, it has also been thought possible that they acquire a bacteriologic bac·te·ri·ol·o·gy
The study of bacteria, especially in relation to medicine and agriculture.
bac·te flora similar to those of the nasal cavity nasal cavity
The cavity on either side of the nasal septum, extending from the nares to the pharynx, and lying between the floor of the cranium and the roof of the mouth.
n See cavity, nasal. . If they do, knowledge of this information would be important in helping the otolaryngologist interpret culture results in patients with recurrent acute rhinosinusitis following endoscopic sinus surgery. Identification of the typical flora in the postoperative ethmoid sinus cavity, as well as a determination of the type of bacteria expected to be colonizers rather than pathogens, would also assist the physician in selecting an appropriate antibiotic. (3)
In this article, we describe our study of the microbiology of the ethmoid sinus following endoscopic sinus surgery. Our goal was to determine whether bacterial colonization of the sinuses does in fact occur.
Patients and methods
We prospectively studied a consecutive series of 113 patients--65 women and 48 men (mean age: 41.3 yr)--who underwent endoscopic sinus surgery for chronic rhinosinusitis. All patients met the American Academy of Otolaryngology--Head and Neck Surgery's criteria for a clinical diagnosis of chronic rhinosinusitis, (5) and all had failed maximal medical management. Endoscopic sinus surgery was performed in the standard fashion, and patients were placed on a 7- to 10-day course of a first-generation cephalosporin cephalosporin (sĕf'əlōspôr`ĭn), any of a group of more than 20 antibiotics derived from species of fungi of the genus Cephalosporium and closely related chemically to penicillin. Cephalosporins, e.g. (or a macrolide antibiotic macrolide antibiotic Infectious disease A broad-spectrum antibiotic–eg, erythromycin, produced by Streptomyces spp, that contains a lactone ring and inhibits protein synthesis in target bacteria. See Antibiotic resistance. in cases of penicillin allergy) for the immediate postoperative period. Patients were followed up in the usual manner.
At the 6-week postoperative follow-up visit, each patient was examined to ascertain if he or she met the criteria necessary to contribute an appropriate swab specimen from the ethmoid ethmoid /eth·moid/ (eth´moid)
1. sievelike; cribriform.
2. the ethmoid bone; see Table of Bones. .ethmoi´dal
eth·moid or eth·moi·dal
adj. labyrinth for culture. To meet the criteria, each patient had to exhibit complete mucosalization of the ethmoid cavity and each had to have refrained from taking any antibiotic for any reason during the previous 4 weeks. Patients who did not meet these criteria were re-evaluated at subsequent visits.
Culture specimens were obtained with strict adherence to proper technique to avoid contamination from the nasal vestibule vestibule /ves·ti·bule/ (ves´ti-bul) a space or cavity at the entrance to a canal.vestib´ular
vestibule of aorta a small space at root of the aorta. or the anterior nasal cavity. A nasal endoscope endoscope, any instrument used to look inside the body. Usually consisting of a fiber-optic tube attached to a viewing device, endoscopes are used to explore and biopsy such areas as the colon and the bronchi of the lungs. was placed into the nose, and the nasal ala was held laterally. Under endoscopic visualization, a standard microtip culture swab was placed through the nasal cavity and directly into the ethmoid labyrinth. No contact was allowed between the swab and the nasal vestibular skin, septum septum /sep·tum/ (sep´tum) pl. sep´ta [L.] a dividing wall or partition.
alveolar septum interalveolar s. , and lateral nasal wall. When such contact did occur, the culture swab was discarded and a new culture was drawn. Culture specimens were drawn from the side of the nose that allowed for more direct access to the ethmoid labyrinth and a lesser chance of contact between the swab and nasal structures; 69 were drawn from the left side and 44 from the right.
Each properly obtained swab was submitted for standard aerobic culture analysis; antibiotic sensitivities were also determined when appropriate. Sensitivity analysis was conducted by using published cutoff points for identifying moderate and complete resistance to antibiotics. (6) Given that the anterior ethmoid labyrinth was open to the nasal cavity following surgery, anaerobic anaerobic /an·aer·o·bic/ (an?ah-ro´bik)
1. lacking molecular oxygen.
2. growing, living, or occurring in the absence of molecular oxygen; pertaining to an anaerobe. cultures were not obtained.
Culture and sensitivity data were tabulated and analyzed by the SPSS A statistical package from SPSS, Inc., Chicago (www.spss.com) that runs on PCs, most mainframes and minis and is used extensively in marketing research. It provides over 50 statistical processes, including regression analysis, correlation and analysis of variance. statistical package system version 10.0. The prevalence of recovered bacteria was then analyzed and comparisons were made among the different bacteria, Gram's staining characteristics, and bacterial sensitivities.
All 113 patients were eventually able to submit an appropriate culture specimen (mean time from surgery to culture: 15.9 wk). Of this group, 26 patients (23.0%) had sterile cultures and 20 (17.7%) exhibited normal flora. In the remaining 67 patients (59.3%), culture identified 108 various isolates (table 1), most of them gram-positive cocci (table 2). Of these 67 patients, 36 had only one type of bacteria, 24 had two, and seven had three or more. None of the patients who exhibited potentially pathogenic bacteria Pathogenic bacteria
Bacteria that produce illness.
Mentioned in: Gastroenteritis in their postoperative culture developed a purulent pu·ru·lent
Containing, discharging, or causing the production of pus.
Consisting of or containing pus
Mentioned in: Lacrimal Duct Obstruction
containing or forming pus. sinus infection within the subsequent 2 weeks.
The sensitivity analysis of several representative anti-microbial agents revealed high degrees of resistance to penicillin, ampicillin ampicillin (ăm'pĭsĭl`ĭn), a penicillin-type antibiotic that is effective against both gram-negative microorganisms and gram-positive microorganisms such as Escherichia coli. , and erythromycin erythromycin (ĭrĭth'rōmī`sĭn), any of several related antibiotic drugs produced by bacteria of the genus Streptomyces (see antibiotic). (table 3). Of all the isolates that exhibited resistance, 40.9% demonstrated multidrug resistance ([greater than or equal to]2 antibiotic resistances per isolate).
The microbiology of chronic rhinosinusitis has been the subject of numerous studies over the past several decades. (7-11) Controversy has surrounded issues regarding the involvement of anaerobic bacteria, the causative role of organisms generally considered to be nonpathogens, and the differences between tissue cultures and mucosal surface cultures. Antral puncture studies in normal volunteers have shown that the maxillary sinus is sterile in the absence of sinonasal disease. (4)
No similar data are available on the ethmoid sinus in normal patients, but sterility has generally been inferred. Based on the presumed sterility of these sinuses, the detection of pathogenic organisms in cultures of the middle meatus or antral puncture specimens would theoretically serve to confirm a diagnosis of bacterial sinusitis in the appropriate clinical setting and help direct treatment. But in everyday practice, empiric treatment is prescribed for acute rhinosinusitis because direct culture of the maxillary and ethmoid sinuses is difficult and invasive, and access to sinonasal endoscopy endoscopy
Examination of the body's interior through an instrument inserted into a natural opening or an incision, usually as an outpatient procedure. Endoscopes include the upper gastrointestinal endoscope (for the esophagus, stomach, and duodenum), the colonoscope (for the for middle meatal culture is not always available.
One of the goals of endoscopic sinus surgery is to achieve free communication between the paranasal sinuses and the nasal cavity by creating wide and patent sinus ostia. During an acute postoperative exacerbation of chronic rhinosinusitis, such patency pa·ten·cy
The state or quality of being open, expanded, or unblocked.
the condition of being open. allows mucopurulent mucopurulent /mu·co·pu·ru·lent/ (-pur´ah-lint) containing both mucus and pus.
Containing mucus and pus. secretions to freely drain into the nose unobstructed. Under endoscopic guidance, the otolaryngologist can easily culture these secretions and plan appropriately targeted antibiotic therapy. (3) However, because postoperative sinus cavities communicate directly with the nasal cavity, it has been thought possible that they can become colonized Colonized
This occurs when a microorganism is found on or in a person without causing a disease.
Mentioned in: Isolation by normal nasal bacteria. If so, the colonization of nasal bacteria could confound the interpretation of culture results and make it more difficult for the otolaryngologist to use sinonasal swabs as a basis for assessing the patient's postoperative status. It has been shown that the nasal cavity and middle meatus contain a wide variety of natural aerobic and anaerobic flora in the asymptomatic state and that fewer than 20% of patients have a sterile middle meatus. (12) More than 75% of normal adult nasal cavities harbor potential bacterial pathogens; more than 40% of these patients have staphylococcal and streptococcal streptococcal /strep·to·coc·cal/ (-kok´al) pertaining to or caused by a streptococcus.
Pertaining to any of the Streptococcus bacteria. species. (13)
Our study was undertaken to identify the normal flora of the ethmoid sinuses following endoscopic sinus surgery to determine whether they remain sterile or become colonized with nasal flora. We found that they are not sterile in approximately 60% of such patients. The most common organism subtypes that we identified were grampositive cocci; Staphylococcus aureus and Staphylococcus epidermidis were found in approximately equal proportions. These findings suggest that the postoperative ethmoid sinus can be colonized with bacterial flora that are very similar to those that exist in the nasal cavity. (13) Interestingly, the relative distributions of the various bacteria are quite comparable to those reported in studies of culture results in acute postoperative exacerbations of rhinosinusitis. (3) This similarity suggests that the new flora in the postoperative sinonasal cavity might be responsible for postoperative infections. It is also possible that external factors, such as allergic inflammation and viral infe ction, provide a setting in which previously quiescent colonizing bacteria become pathogenic. It seems probable that most acute postoperative exacerbations of chronic rhinosinusitis are not caused by inoculation with external bacteria.
We were somewhat surprised to find that patients could remain asymptomatic even during colonization of bacteria that are considered to be truly pathogenic. None of our patients who had pathogenic culture results ultimately progressed to purulent sinusitis sinusitis
Inflammation of the sinuses. Acute sinusitis, usually due to infections such as the common cold, causes localized pain and tenderness, nasal obstruction and discharge, and malaise. within 2 weeks after culture. This finding argues that the mere presence of pathogenic bacteria is not enough to cause symptoms; instead, the presence of bacteria at a certain minimum amount or density is required to create the infection that causes symptoms. Such minimums have long been used to delineate other infections; for example, in urinary tract infection urinary tract infection (UTI),
n infection in one or more of the structures that make up the urinary system. Occurs more often in women and is most commonly caused by bacteria. , the minimum colony count cutoff point is [10.sup.5] bacteria per ml.
The prevalence of gram-negative rods in our study--11.7%--is somewhat lower than the prevalence that has been documented in infectious exacerbations of chronic rhinosinusitis, which can exceed 20%. (11) However, we suspect that these higher prevalence rates reflect either a trend toward gram-negative sinusitis as described by others or a shift in the natural sinonasal flora created by multiple courses of antibiotics prior to endoscopic sinus surgery.
The results of our sensitivity analysis illustrate that the bacterial flora that colonize col·o·nize
v. col·o·nized, col·o·niz·ing, col·o·niz·es
1. To form or establish a colony or colonies in.
2. To migrate to and settle in; occupy as a colony.
3. the ethmoid cavity postoperatively are often resistant to the standard first-line antibiotics that are usually considered for acute rhinosinusitis. The high rates of complete resistance to penicillin (81.5%), ampicillin (42.9%), and erythromycin (25.9%) suggest that patients who experience acute exacerbations of chronic rhinosinusitis following endoscopic sinus surgery will likely require second-line therapy on an empiric basis. Fortunately, most of these bacteria do not exhibit multidrug resistance and most are sensitive to the second-generation cephalosporins Cephalosporins Definition
Cephalosporins are medicines that kill bacteria or prevent their growth.
Cephalosporins are used to treat infections in different parts of the body—the ears, nose, throat, lungs, sinuses, and and quinolone antibiotics. We encountered only one case of methicillin-resistant Saureus in the postoperative cavity; other authors have reported that this potentially distressing situation has occurred with greater frequency. (14)
Our data provide information on the expected flora of the ethmoid sinus following endoscopic sinus surgery, and they should be considered when interpreting the results of cultures in patients with acute exacerbations of chronic rhinosinusitis. Given that colonization with gramnegative bacteria is relatively uncommon, detecting such on endoscopic culture in acute exacerbations of chronic rhinosinusitis likely means that the patient has a true pathogenic infection, and antibiotic treatment can be considered. In contrast, it is likely that many of the grampositive cocci--especially S aureus The aureus (pl. aurei) was a gold coin of ancient Rome valued at 25 silver denarii. The aureus was regularly issued from the 1st century BC to the beginning of the 4th century AD, when it was replaced by the solidus. and S epidermidis--are colonizers of the nasal cavity. When gram-positive cocci are recovered on culture during acute exacerbations of chronic rhinosinusitis, treatment decisions can be more difficult. Further study might help us determine whether bacterial colony counts are more appropriate for assessing the pathogenic impact of gram-positive cocci. Because a significant percentage of even the colonizing bacteria in the post operative sinonasal cavity are beta-lactamase producers, the initial antibiotic chosen for acute exacerbations should confer beta-lactamase stability. Given the potential for bacterial resistance and the wide variety of colonizing bacteria that we found, we believe that purulent infections that fail to respond promptly to empiric therapy should be cultured and that further treatment should be based on culture and sensitivity results.
Table 1 Distribution of bacterial species Bacteria No. isolates Staphylococci 64 Coagulase-negative staphylococci 36 Staphylococcus aureus 27 Methicillin-resistant S aureus 1 Diphtheroids 11 Alpha-hemolytic streptococci 8 Group G streptococci 4 Serratia marcescens 3 Acinetobacter spp. 2 Hemophilus influenzae 2 Pseudomonas spp. 2 Corynebacterium spp. 1 Enterobacter spp. 1 Enterobacter aerogenes 1 Enterobacter cloacae 1 Enterococci 1 Escherichia coli 1 Hemophilus parainfluenzae 1 Neisseria spp. 1 Propionibacterium acnes 1 Pseudomonas aeruginosa 1 Salmonella enteritidis 1 Xanthomonas spp. 1 No growth/oral flora 46 Total 154 Table 2 Distribution of isolates according to staining characteristics Type n (%) Gram-positive cocci 77 (50.0) Gram-negative rods 18 (11.7) Gram-positive rods 11 (7.1) Gram-negative cocci 1 (0.7) No growth/oral flora 46 (29.9) Unknown 1 (0.6) Total 154 (100.0) Table 3 Patterns of sensitivity to representative antibiotics Moderately Completely Sensitive resistant resistant Drug n(%) n(%) n(%) Clindamycin (n = 22) 21 (95.5) 1 (4.5) Ciprofloxacin (n = 21) 20 (95.2) 1 (4.8) Cephalexin or cefazolin (n = 28) 23 (82.1) 5 (17.9) Erythromycin (n = 27) 19 (70.4) 1 (3.7) 7 (25.9) Ampicillin (n = 21) 11 (52.4) 1 (4.8) 9 (42.9) Penicillin (n = 27) 5 (18.5) 22 (81.5) Totals (n = 146) 99 (67.8) 2 (1.4) 45 (30.8)
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From the Division of Otolaryngology, Brigham and Women's Hospital Brigham and Women's Hospital (BWH) is a hospital in the Longwood Area of the Boston, Massachusetts neighborhood of Mission Hill. With Massachusetts General Hospital, it is one of the two founding members of Partners HealthCare. , Boston (Dr. Bhattacharyya), the Division of Otolaryngology, Beth Israel-Deaconess Medical Center, Boston (Dr. Gopal), and the Department of Otology otology /otol·o·gy/ (o-tol´ah-je) the branch of medicine dealing with the ear, its anatomy, physiology, and pathology.otolog´ic
The branch of medicine that deals with the ear. and Laryngology laryngology /lar·yn·gol·o·gy/ (-gol´ah-je) the branch of medicine dealing with the throat, pharynx, larynx, nasopharynx, and tracheobronchial tree.
n. , Harvard Medical School Harvard Medical School (HMS) is one of the graduate schools of Harvard University. It is a prestigious American medical school located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts. , Boston (Dr. Bhattacharyya and Dr. Gopal).
Reprint requests: Neil Bhattacharyya, MD, Division of Otolaryngology, 333 Longwood Ave., Boston, MA 02115. Phone: (617) 713-2092; fax: (617) 713-2078; e-mail: email@example.com