Effect of transportation and acid neutralization on recovery of mycobacteria from processed specimens.

Because of the increasing incidence of tuberculosis, more rapid detection of mycobacteria has become an important issue. Realizing that not every clinical laboratory has a rapid detection system for growing mycobacteria, this study was conducted to examine the feasibility of submitting sediments of processed specimens to a reference laboratory for further testing in a radiometric system. Using N-acetyl-L-cysteine-NaOH solution, 247 respiratory specimens were processed at a diagnostic laboratory. Half of each sediment was cultured on conventional media. The remainder was kept at 4 degrees C for a period of up to 1 week before transportation to a reference laboratory for culture by BACTEC system. Both laboratories recovered 25 organisms: 15 as Mycobacterium tuberculosis (MT) and 10 as M avium complex (MAC). Additionally, mycobacteria (MT[3], MAC[6], M gordonae [4], and M fortuitum [1]) were recovered from 14 specimens by the diagnostic laboratory that were not grown by the reference laboratory. These results indicate a significant decrease in viability of mycobacteria after processing of the specimens. Acid neutralization of the digested respiratory sediments significantly improved the recovery rate of mycobacteria even after 2 days of delay in culture. This preliminary work suggests that more extensive studies will provide useful information to delineate approaches to submitting neutralized sediments for mycobacterial cultures.

Superiority of conventional culture technique over rapid detection of group A Streptococcus by optical immunoassay.

An optical immunoassay (OIA) has been reported to be more sensitive than conventional culture for the detection of Group A Streptococcus, eliminating the need for culture. We attempted to confirm the sensitivity and specificity through a laboratory quantitation study and a clinical trial. OIA did not detect Group A Streptococcus below 10(5) colony forming units (CFU). Culture detected Streptococcus to 10(2) CFU from the inoculated swab. In the clinical study, throat swabs were obtained from 77 patients in an outpatient clinic. Compared with culture, the sensitivity of OIA was 78% and the specificity was 90%. These results demonstrate that OIA was less sensitive than culture in seeded experiments and missed 22% of positives in clinical practice. Our study, contrary to previous reports, suggests that OIA is not sensitive enough to be used as the sole assay for Group A Streptococcus pharyngitis.

Observations concerning the microbial etiology of acute salpingitis.

OBJECTIVES: The specific aims of this study were (1) to describe the microbiologic characteristics of patients with acute salpingitis and (2) to determine the incidence of bacterial vaginosis in patients with acute salpingitis and whether bacterial vaginosis microorganisms were common upper-genital-tract isolates in these patients. STUDY DESIGN: Women with pelvic inflammatory disease underwent laparoscopy to confirm the diagnosis of acute salpingitis and for culture of the fallopian tubes and cul-de-sac. Endometrial and minute fimbrial biopsies were performed, and specimens were evaluated for evidence of inflammation. Bacterial vaginosis was diagnosed by vaginal Gram stain. RESULTS: Eighty-four patients had visually confirmed acute salpingitis. Neisseria gonorrhoeae or Chlamydia trachomatis was isolated from 65 (77.4%) patients. Vaginal microorganisms were isolated from the endometrium in 16 (31.4%) of 51 cases and from the cul-de-sac in 12 (14.3%) of 84 cases. Bacterial vaginosis was present in 61.8% of patients with acute salpingitis, and 100% of anaerobes isolated from the upper genital tract of patients with acute salpingitis were bacterial vaginosis microorganisms. These anaerobes were isolated from the upper genital tract in the absence of a concurrent gonococcal, chlamydial, or Haemophilus influenzae infection in only two cases. CONCLUSIONS: The initiation of acute salpingitis is predominantly due to the ascending spread of sexually transmitted microorganisms. Bacterial vaginosis is a common concurrent disorder of women with acute salpingitis, and bacterial vaginosis microorganisms are commonly isolated from the upper genital tracts of patients with pelvic inflammatory disease.

Comparison of culture and rapid enzyme immunoassay for the detection of group B streptococcus in high-risk pregnancies.

OBJECTIVE: The purpose of this study was to evaluate the Equate Strep B(R) test for clinical use in patients at high risk for complications from group B streptococcus (GBS) disease. METHODS: Vaginoperineal swabs were obtained from patients with preterm premature rupture of the membranes and/or preterm labor and semiquantitative GBS cultures and Equate(R) assay were performed. RESULTS: From May 14, 1990, to April 30, 1992, 650 patients were enrolled; 626 had both culture and Equate(R) results available, of whom 24% were colonized with GBS. The sensitivity, specificity, positive predictive value, and negative predictive value of the rapid assay were 28%, 84%, 35%, and 79%, respectively. Although the prevalence of GBS was higher in patients with ruptured membranes compared with those with intact membranes, rupture of membranes did not affect test sensitivity or specificity. CONCLUSIONS: We conclude that the Equate(R) rapid assay is not a sensitive method of GBS detection in high-risk patients.

Production of urinary ethanol after sample collection.

As the interest in urine drug testing grows, ethanol is frequently included in drug-abuse screening. Collection of urine for drug testing is less invasive than blood collection and is used to screen employees in a large cross-section of occupations. Because alcohol can be produced from carbohydrates via fermentation, our interest was to determine: (1) if ethanol could be produced in glucose-positive urine (2) under what microbiological conditions would this process occur, and (3) would the urine ethanol concentration be significant. Fourteen urine specimens were selected from the Urinalysis Laboratory of a large medical center. All specimens were tested for ethanol concentration on the day of voiding and were found to be negative (< 0.01 mg/100 mL). Urine glucose concentrations ranged from 0 to > or = 2000 mg/dL. Microbiological examinations were performed on all specimens. Storing the samples at room temperature, five of the specimens produced ethanol over the time course of the study (1 to 21 days) in concentrations ranging from 0.036 to 2.327 g/100 mL. Yeast was identified in the five glucose positive urine samples producing ethanol. Six glucose positive urine samples that did not produce ethanol were found to be yeast negative. Findings indicate that significant ethanol concentrations can develop from glucose and yeast positive urine, after the day of voiding.

Biology of fetal repair: the presence of bacteria in fetal wounds induces an adult-like healing response.

The minimal acute inflammatory response to tissue injury is one of the most dramatic differences between fetal and adult wound healing. Considering the prominent role of inflammation in adult tissue repair, this study tested the hypothesis that the minimal fetal inflammatory response to tissue injury plays a central role in the "scarless" fetal repair process. Sponge implants were treated with lethally irradiated or live bacteria and placed subcutaneously in fetal rabbits to test the ability of the fetus to mount an acute inflammatory response to bacterial antigens present at the wound site and to analyze the effects of this inflammatory response on fetal fibroplasia and neovascularization. After harvest, these implants were examined histologically for inflammation, fibroblast infiltration, collagen deposition, and neovascularization, and collagen deposition was measured using hydroxyproline quantitation by high-performance liquid chromatography. Bacteria-treated implants showed dose-dependent acute inflammatory responses and significant increases in collagen deposition compared with control sponges. Implants containing live bacteria demonstrated maximal fibroplasia and neovascularization. These findings suggest that, despite neutropenia and immaturity of the fetal immune system, the fetus is capable of mounting an acute inflammatory response to avirulent bacteria present at the wound site. Fetal inflammatory cells which respond to this bacterial stimulus appear capable of initiating an adult-like healing response. Thus, by failing to provide a bacterial stimulus for leukocyte recruitment at the site of tissue injury, the sterile fetal environment appears to play a role in effecting "scarless" fetal wound healing.

Vaginal flora in postmenopausal women: the effect of estrogen replacement.

OBJECTIVE: To determine the effect of estrogen replacement therapy (ERT) on the vaginal flora of postmenopausal women. METHODS: Vaginal cultures were obtained from 15 postmenopausal women whose hormonal statuses were documented by serum follicle-stimulating hormone (FSH) and serum estrogen levels. After 8 weeks of ERT, consisting of 0.1 mg of estradiol delivered daily by dermal patch, the vaginal cultures were repeated, as were measurements of the vaginal pH, serum FSH, and serum estrogen levels. RESULTS: Vaginal cultures revealed no significant change in the incidence of lactobacilli or of all aerobes. However, the incidence of anaerobic species fell after treatment from 47% to 13% (P = 0.05), and the incidence of anaerobic gram-negative rods declined after treatment from 40% prior to ERT to 7% (P = 0.035). Prior to ERT, the difference in mean vaginal pH between lactobacilli-positive and lactobacilli-negative subjects was not significant, but, following the administration of exogenous estrogen, the lactobacilli-positive subjects exhibited a significantly lower mean vaginal pH (4.4 +/- 0.4) relative to the lactobacilli-negative population (5.2 +/- 0.3) (P = 0.02). CONCLUSIONS: We conclude that women on ERT are less likely to have vaginal colonization with anaerobic bacteria when compared with women not using replacement therapy. Estrogen replacement may potentiate the effect of lactobacilli on vaginal pH.

Identification of species-specific, non-cross-reactive proteins of Borrelia burgdorferi.

The low specificity of diagnostic tests for Lyme disease is due to the fact that Borrelia burgdorferi possesses many antigenic proteins that are cross-reactive with other spirochetes and bacteria. The low sensitivity is a result of high (> or = 1:100) dilutions used for patient sera during testing to eliminate non-specific cross-reactivity. The present study was conducted to identify species-specific non-cross-reactive protein(s) of B. burgdorferi that might be used as antigen(s) in serologic tests. Whole-cell sonicates of B. burgdorferi were tested against pooled sera from patients with symptoms, signs, and serologic features diagnostic of Lyme disease (LD), rheumatoid arthritis, infectious mononucleosis, systemic lupus erythematosus, Rocky Mountain spotted fever, secondary syphilis, and from healthy individuals. Different LD pools were also tested against whole-cell sonicates of Treponema pallidum, Treponema phagedenis, Leptospira interrogans, and Escherichia coli. Comparison among patterns obtained by each serum pool revealed that IgM antibodies to species-specific 39-, 23-, and 22-kD proteins and IgG antibodies to 34- and 31-kD proteins were present only in the patients with LD and absent from patients with rheumatoid arthritis, infectious mononucleosis, systemic lupus erythematosus, Rocky Mountain spotted fever, secondary syphilis, and healthy individuals pools. These results suggest that 39-, 23-, and 22-kD proteins may be used in an IgM immunoassay for diagnosis of LD.

Microbial etiology of urban emergency department acute salpingitis: treatment with ofloxacin.

OBJECTIVES: We attempted to define the microbiologic characteristics of acute salpingitis in women presenting to an urban emergency department with pelvic inflammatory disease and to determine the effectiveness of ofloxacin in treating this disease. STUDY DESIGN: Women with pelvic inflammatory disease underwent laparoscopy to confirm the diagnosis and to culture the fallopian tubes and cul-de-sac. All patients (n = 36) were treated with parenteral ofloxacin and discharged on a regimen of oral ofloxacin to complete a 10- to 14-day course. RESULTS: Neisseria gonorrhoeae was isolated from at least one site in 25 patients (69.4%) including the fallopian tube or cul-de-sac in 12 of them. Chlamydia trachomatis was isolated from the endocervix and/or endometrium in 6 patients (16.7%); concomitant Neisseria gonorrhoeae was present in 4 patients (66.6%). A polymicrobial infection was identified in only one patient. All patients responded to antibiotic therapy with ofloxacin. CONCLUSIONS: Acute salpingitis in our urban emergency department population is related primarily to upper genital tract infection with Neisseria gonorrhoeae. Ofloxacin is effective therapy for this disease.

Evaluation of two ELISA's for detecting Chlamydia trachomatis from endocervical swabs.

Two enzyme immunoassays (EIAs) detecting Chlamydia trachomatis from endocervical swabs, Syva MicroTrak (MT) and Abbott Chlamydiazyme (CZ), were compared with a tissue culture (TC) standard. Initially, 8% (100 of 1250) of specimens were TC positive, yielding sensitivities of 94% (94 of 100) for MT and 79% (79 of 100) for CZ with identical 98% specificities (1129 of 1150 for MT and 1130 of 1150 for CZ). Discrepant specimens were retested by both EIAs and assayed for elementary bodies (EBs) by a fluorescent antibody test. After discrepancy analysis, 9.5% (118) of 1240 patients were either TC or EB positive, yielding sensitivities of 94.1% for MT (111 of 118) and 79.7% for CZ (94 of 118) with identical specificities of 100% (1122 of 1122). These results indicate that the MT is significantly more sensitive (p less than 0.05, McNemar test) than CZ in detecting C. trachomatis from endocervical swabs.

Rapid identification of motile Aeromonas.

The clinical relevance and taxonomy of motile Aeromonas species are areas of current controversy. Strains of motile Aeromonas isolates (n = 60) from various sources were identified to species level using the following tests (all incubated at 30 degrees and 37 degrees C): esculin hydrolysis; formation of gas from glucose; production of acetoin; production of acid from mannitol and arabinose; decarboxylation of lysine and ornithine, dihydrolation of arginine; and pyrazinamide hydrolysis in a semisolid medium. The tests' results were similar at incubation temperatures of 30 degrees and 37 degrees C. Of the strains, 59 (98%) of 60 were identified to species level by the full battery of tests: 25 as A. hydrophila, 18 as A. caviae, 14 as A. sobria, one as A. veronii, and one as A. schubertii. (The only A. veronii and A. schubertii isolates identified were ATCC strains). All (25 of 25) strains of A. hydrophila and 17 (94%) of 18 of A. caviae hydrolyzed pyrazinamide in less than 24 hr, whereas all strains of A. sobria showed no pyrazinamidase activity. Absence of pyrazinamidase was, thus, a convenient phenotypic marker for A. sobria. Four additional tests (esculin hydrolysis, acetoin production, lysine decarboxylation, and gas production from glucose) identified within 24 hr all examples of the three common species of Aeromonas. Recently proposed species did not contribute to our ability to discriminate among stool, other clinical, and environmental isolates of Aeromonas spp.

Suture removal-induced bacteremia: a possible endocarditis risk.

Multiple intraoral suture removal isn't always a benign procedure for cardiac patients at high risk from bacteremia. Under certain conditions, antibiotic prophylaxis is recommended.

The importance of wound infection in antibiotic failures in the therapy of postpartum endometritis.

A prospective, randomized, double-blind trial was done to compare the efficacy of cefoxitin (2 grams given intravenously every six hours) with ceftizoxime (2 grams given intravenously every 12 hours) in the treatment of postpartum endometritis. Thirty-eight patients received cefoxitin and 43 received ceftizoxime. Demographic variables (age, gravidity, parity and estimated gestational age) and risk factors (cesarean section, operating time, duration of ruptured membranes and labor, number of vaginal examinations and internal monitoring) were not statistically different in the two antibiotic groups. In the cefoxitin group, eight of 38 patients failed initial antibiotic therapy and six of 43 patients in the ceftizoxime group failed (p = 0.399). In the univariate analysis, abdominal wound infection (p = 0.003) and higher gestational age (p = 0.008) were associated with failure of the antibiotic. With multiple logistic regression, only abdominal wound infection was associated with failure of the antibiotic (p = 0.0002). We conclude that cefoxitin and ceftizoxime are equally effective in the therapy of postpartum endometritis and that abdominal wound infection is primarily responsible for persistent fever and, therefore, failure of the antibiotic in patients with postpartum endometritis.

Multicentre study on antibiotic susceptibilities of anaerobic bacteria to cefoperazone-sulbactam and other antimicrobial agents.

The antibiotic susceptibilities of 241 anaerobic bacteria recovered from six geographic sites in North America were tested by agar dilution to cefoperazone-sulbactam and other drugs. Of the 189 Bacteroides fragilis group isolates, only one was resistant to cefoperazone-sulbactam (0.5%) or ampicillin-sulbactam (0.5%), and none was resistant to ticarcillin-clavulanate or chloramphenicol. No resistance to cefoperazone-sulbactam was observed among the other Bacteroides spp., Clostridium spp., or Peptostreptococcus spp. Resistance to cefoperazone-sulbactam is not commonly observed against anaerobic bacteria recovered from different geographical sites across North America.

Evaluation of the effects of a female condom on the female lower genital tract.

The purposes of this study were to determine if use of the female condom (Reality) was traumatic to the vaginal mucosa and/or vulvar skin and to determine its effect on resident vaginal bacterial flora. Thirty subjects were randomly assigned to utilize the female condom or diaphragm during the study period. Initially and during 3 follow-up visits, each subject underwent colposcopic examination of the vagina, cervix, and vulva with photographic record, and qualitative fungal, aerobic and anaerobic cultures of the vagina. The two groups were compared with respect to the frequency of abnormal physical findings determined by both macroscopic and colposcopic examination. Visits were compared within each contraceptive group with respect to changes in resident vaginal flora. There was no evidence of significant trauma associated with the use of either contraceptive device during the study period. The resident vaginal flora did not significantly change during the three follow-up visits in patients using the female condom. In diaphragm users, lactobacilli were less frequently isolated at the third (14/15 vs 6/15, P = 0.008) and fourth (14/15 vs 7/15, P = 0.039) follow-up visits when compared to the initial visit. In addition, aerobic gram-negative rods were more frequently isolated during the fourth visit (1/15 vs 9/15, P = 0.021) when compared to the first visit. We conclude that neither the female condom (Reality) nor the diaphragm is associated with trauma to the lower genital tract. Subjects using the diaphragm undergo a significant change in vaginal bacterial flora, becoming more likely to be colonized with coliform microorganisms and less likely to maintain lactobacilli colonization.

PIP: The purposes of this study were to determine if use of the female condom (Reality) was traumatic to the vaginal mucosa and/or vulvar skin and to determine its effect on resident vaginal bacterial flora. 30 subjects were randomly assigned to utilize either the female condom or diaphragm during the study period. Initially and during 3 follow-up visits, each subject underwent colposcopic examination of the vagina, cervix, and vulva with photographic record, and qualitative fungal, aerobic, and anerobic cultures of the vagina. The 2 groups were compared with respect to the frequency of abnormal physical findings determined by both macroscopic and colposcopic examination. Visits were compared within each contraceptive group for changes in resident vaginal flora. There was no evidence of significant trauma associated with the use of either contraceptive device during the study period. Resident vaginal flora did not significantly change during the 3 follow-up visits in those patients using the female condom. In diaphragm users, lactobacilli were less frequently isolated at the 3rd (14/15 vs. 6/15, p=.008) and 4th (14/15 vs. 7/15, p=.039) follow-up visits when compared to the initial visit. In addition, aerobic gram-negative rods were more frequently isolated during the 4th visit (1/15 vs. 9/15, p=.021) when compared to the 1st visit. The authors conclude that neither the Reality condom nor the diaphragm is associated with trauma to the lower genital tract. Subjects using the diaphragm undergo a significant change in vaginal bacterial flora with greater likelihood of colonization with coliform microorganisms and less likelihood of maintenance of lactobacilli colonization.

False-positive cultures of the cul-de-sac associated with culdocentesis in patients undergoing elective laparoscopy.

We studied 21 women undergoing elective laparoscopy to determine whether positive bacterial cultures obtained by culdocentesis were contaminants from the vaginal mucosa. Cultures for aerobic and anaerobic microorganisms were prepared from swabs of the posterior vaginal fornix, laparoscopic cul-de-sac aspirates, culdocentesis aspirates, and repeat laparoscopic aspirates of the cul-de-sac. Cultures were positive from the vaginal fornix in all cases. All cultures from the cul-de-sac before culdocentesis were negative. Five of seven cultures (71.4%) from culdocentesis specimens and seven of nine cultures (77.8%) from repeat laparoscopic cul-de-sac aspirates were positive in women without povidone-iodine vaginal preparation. Five of 12 cultures (41.7%) from culdocentesis specimens and three of 12 cultures (25%) from repeat laparoscopic cul-de-sac aspirates were positive in the women with vaginal preparation. Both aerobic and anaerobic bacteria were recovered. We conclude that false-positive culdocentesis cultures occur and that bacterial contamination of the cul-de-sac following culdocentesis may lead to false-positive cultures of specimens obtained during subsequent laparoscopy.

Derivation and validation of a clinical diagnostic model for chlamydial cervical infection in university women.

We developed and prospectively tested a logistic regression model for chlamydial cervical infection. Study subjects included 2271 women receiving gynecologic care in our student health clinic. Clinical data were collected in a standardized fashion. We identified cell culture--isolated Chlamydia trachomatis from 133 (9%) of 1458 subjects in the derivation set and 73 (10%) of 729 subjects in the validation set. Model variables included a new sexual partner within 2 months or more than one sexual partner within 6 months; cervical ectopy; cervical friability; at least 20 polymorphonuclear leukocytes per high-power field in cervical secretions; white blood cells in vaginal secretions; and use of an antibiotic active against C trachomatis within a month. This model can distinguish women with low, medium, and high risks of chlamydial infection (on derivation set: receiver operating characteristic curve area, 0.710; SE, 0.026; on validation set: area, 0.698; SE, 0.035) using simple clinical information obtained in the office.

Clinical and microbiological evidence for endemic pharyngitis among adults due to group C streptococci.

Group C beta-hemolytic streptococci cause rare epidemic outbreaks of pharyngitis, but their role in sporadic endemic pharyngitis has been uncertain. We addressed the question of whether non-group A beta-hemolytic streptococci are associated with endemic pharyngitis in two ways. First, we compared rates of isolation from throat swabs of group A, B, C, and G and ungrouped beta-hemolytic streptococci ("culture negative") in adult patients vs those rates in controls. Second, we collected in standardized form clinical indexes of patients with pharyngitis: signs and symptoms graded for severity, the examining physician's subjective estimate of the probability of streptococcal pharyngitis, a logistic regression score predicting streptococcal pharyngitis, and whether antibiotic therapy was prescribed. After collecting data and cultures on 1425 patients with sore throats and cultures on 284 controls, we found the following: group C streptococci were isolated significantly more frequently in patients with sore throats than in controls (6% vs 1.4%); four clinical signs and two symptoms distinguished group C-associated pharyngitis as more severe than culture-negative pharyngitis; and six clinical signs and one symptom distinguished group C-associated pharyngitis as less severe than group A pharyngitis. Physicians' subjective estimates, logistic regression scores, and antibiotic treatment all characterized group C-associated pharyngitis as more severe than culture-negative sore throats but less severe than group A pharyngitis. From these data we present the first definitive evidence that group C streptococci are associated with endemic pharyngitis, show that clinical presentation distinguishes a group of patients with group C-associated pharyngitis from populations with culture-negative sore throats and from those with group A pharyngitis. Physicians' response to that presentation merits consideration in the context of rapid group-specific diagnosis of streptococcal pharyngitis by group A antigen tests.

Two confirmatory tests for identification of Neisseria gonorrhoeae from primary culture.

We compared a fluorescent monoclonal antibody and a DNA probe for identification of Neisseria gonorrhoeae (GC) from primary genital cultures of presumptive GC and selected bacterial isolates other than GC. The monoclonal antibody was sensitive (94%) and specific (100%) enough to identify GC in selective primary genital culture. The DNA probe was sensitive (95%) but not adequately specific (65%) to function as a confirmatory test.

Clinical predictors of infection of central venous catheters used for total parenteral nutrition.

To identify predictors of infection in catheters used for total parenteral nutrition (TPN), clinical and microbiological data were prospectively collected on 169 catheter systems (88 patients). Based on semiquantitative catheter cultures, infection was associated with a positive insertion site skin culture taken close to the time of catheter removal (relative risk [RR] = 4.50), especially one yielding greater than or equal to 50 colonies of an organism other than coagulase-negative staphylococci. Infection was also associated with erythema at the insertion site greater than 4 mm in diameter (RR = 2.93). In a subset of 67 catheters for which blood cultures were obtained, infection was also associated with a positive peripheral venous blood culture (RR = 5.90) and a positive central venous blood culture obtained through the catheter (RR = 5.44). Based on a logistic regression model, periodic cultures of the insertion site should be useful in evaluating subsequent fever in stable patients with indwelling central venous catheters. Another source of fever is likely if inflammation is absent and there is either no colonization or there is colonization by less than 50 colonies of coagulase-negative staphylococci at the insertion site. Conversely, the catheter should be removed and cultured semiquantitatively if the site is colonized by an organism other than coagulase-negative staphylococci. We suggest that blood culture results add little to the risk estimate in these situations.