Biomedical subjects

N Williams-Bouyer

Publications and source records attributed to N Williams-Bouyer.

6 recordsLinked to original sources

PubMed2004

Recurrent tuberculosis in Houston, Texas: a population-based study.

OBJECTIVE: To determine the predictors of recurrence of tuberculosis (TB), the drug resistance pattern of Mycobacterium tuberculosis strains recovered from recurrent TB patients, and the frequency of re-infection with a new M. tuberculosis strain among patients with recurrent disease. DESIGN: A population-based, retrospective case-control study using the Houston Tuberculosis Initiative database. RESULTS: We found that, among 100 patients with recurrent TB who completed adequate therapy for a first episode of TB, not receiving directly observed therapy, pulmonary disease, HIV/AIDS diagnosis, not having a family physician, being unemployed and using public transportation were predictors of recurrent disease. There was a significant increase in drug-resistant M. tuberculosis strains in the second episode of disease compared to the first episode (21.3% vs. 8.2%, P = 0.04). Exogenous re-infection with a new strain of M. tuberculosis was found to cause 24-31% of recurrent TB. CONCLUSION: Recurrent TB in Houston is associated with a significant increase in drug-resistant M. tuberculosis strains. Re-infection with a new M. tuberculosis strain causes a significant proportion of recurrent TB in an area of low TB incidence. Patients with HIV/AIDS constitute a population at increased risk of disease recurrence.

Adult↗

PubMed2001

Clinical Evaluation of the Gen-Probe amplified mycobacterium tuberculosis direct test for rapid detection of Mycobacterium tuberculosis in select nonrespiratory specimens.

The performance of the Amplified Mycobacterium Tuberculosis Direct Test (MTD; Gen-Probe, Inc., San Diego, Calif.) for rapid diagnosis of extrapulmonary tuberculosis was evaluated by testing 178 nonrespiratory specimens from 158 patients. Criteria for specimen inclusion were (i) a positive smear for acid-fast bacilli (n = 54) and (ii) the source if the smear was negative (tissue biopsies and aspirates and abscess material were tested; n = 124). Results were compared to those of mycobacterial culture; clinical history was reviewed when MTD and culture results disagreed. Forty-eight specimens (27.0%) were positive for mycobacteria, including 23 Mycobacterium tuberculosis complex specimens; of which 21 were smear positive. Twenty-five specimens were MTD positive; 20 of these grew M. tuberculosis complex. All of the five MTD-positive, M. tuberculosis complex culture-negative specimens were considered truly positive, based on review of the medical record. Of the three MTD-negative, M. tuberculosis complex culture-positive specimens, two contained inhibitory substances; one of the two was smear positive. Excluding the latter specimen from analysis, after chart review, the sensitivity, specificity, and positive and negative predictive values of the MTD were 92.6, 100, 100, and 98.7%, respectively, by specimen and 89.5, 100, 100, and 98.6% by patient. Given the few smear-negative samples from patients with extrapulmonary tuberculosis in our study, additional similar studies that include more smear-negative, M. tuberculosis complex culture-positive specimens to confirm our data are desirable.

Abscess↗

PubMed2000

Comparison of gen-probe AccuProbe group B streptococcus culture identification test with conventional culture for the detection of group B streptococci in broth cultures of vaginal-anorectal specimens from pregnant women.

The performance of the AccuProbe Group B Streptococcus Culture Identification Test (Gen-Probe Incorporated, San Diego, CA, USA) for the detection of group B streptococci (GBS) directly from LIM broth cultures of vaginal-anorectal swab specimens from pregnant women (two swabs per patient in most cases) was evaluated by comparing results to those of conventional GBS culture. Of 411 specimens analyzed, 82 were positive and 312 were negative for GBS by both methods. After initial testing, the percent agreement was 95.9%. The initial sensitivity, specificity, and positive and negative predictive values for the AccuProbe test were 90.1%, 97.5%, 91.1%, and 97.2%, respectively. Results were discrepant for 17 specimens: eight were GBS positive by probe and negative by culture; nine were negative by probe and positive by culture. To resolve discrepancies, culture plates were re-examined for GBS colonies, AccuProbe testing was repeated on the initial LIM broth cultures, and the second swab (if received) was inoculated to LIM broth for AccuProbe testing after overnight incubation. After discrepant resolution testing, the percent agreement between the two test methods was 97.8%. The final sensitivity, specificity, and positive and negative predictive values for the AccuProbe test were 95.6%, 98.4%, 94.6%, and 98.7%, respectively. These data suggest that the AccuProbe test is a reliable method for detecting GBS in vaginal-anorectal specimens, providing results more rapidly than conventional culture. However, strict adherence to the manufacturer's test protocol is necessary to limit technical errors.

Anal Canal↗

PubMed2000

Comparison of the BACTEC MGIT 960 and ESP culture system II for growth and detection of mycobacteria.

The performances of two continuously monitoring mycobacterial culture systems-ESP Culture System II (ESP II; Trek Diagnostics, Inc. , Westlake, Ohio) and BACTEC MGIT 960 (BD Biosciences, Sparks, Md. )-were compared. In addition to both liquid media, all specimens were plated onto Middlebrook 7H11/7H11 selective agar. A total of 3, 151 specimens of all types (56.3% were respiratory specimens) were cultured; 231 (7.3%) yielded mycobacteria. The most common species recovered were Mycobacterium avium complex (69 isolates) and Mycobacterium tuberculosis complex (MTBC; 65 isolates). The recovery rates for ESP II, BACTEC MGIT 960, and Middlebrook agar, respectively, were 71.2, 63.9, and 61.8% for all mycobacteria; 70.2, 72.6, and 66.3% for all mycobacteria except Mycobacterium gordonae; and 73.8, 84.6, and 87.7% for MTBC. For liquid plus solid medium combinations, recovery rates for all mycobacteria and for MTBC, respectively, were 84.1 and 92.3% for ESP II plus Middlebrook agar and 81.5 and 98.5% for BACTEC MGIT 960 plus Middlebrook agar. The differences in recovery of all mycobacteria by ESP II and by BACTEC MGIT 960 were not significant; for the individual species, the only significant difference was recovery of more isolates of M. gordonae by ESP II. For those isolates recovered in both automated systems, mean times to detection of all mycobacteria and MTBC, respectively, were 15.8 and 17.4 days for ESP II and 12.5 and 11.9 days for BACTEC MGIT 960 (P < 0.05). False-positive signals occurred with 23 (0.7%) BACTEC MGIT 960 cultures and 84 (2.7%) ESP II cultures (P < 0.01). Overall contamination rates were 17.1% for BACTEC MGIT 960, 18.9% for ESP II, and 11.0% for Middlebrook agar. In summary, the ESP II and BACTEC MGIT 960 systems performed comparably with regard to growth and detection of mycobacteria, and the contamination rates were similar. However, with ESP II, times to detection of all mycobacteria and of MTBC were significantly longer, the recovery rate of M. gordonae was significantly higher, and the number of false-positive signals was greater than with BACTEC MGIT 960.

Bacteriological Techniques↗

PubMed1999

Predicting susceptibility of Streptococcus pneumoniae to ceftriaxone and cefotaxime by cefuroxime and ceftizoxime disk diffusion testing.

In this study, disk diffusion testing with ceftizoxime and cefuroxime was evaluated for use in predicting the susceptibility of Streptococcus pneumoniae to ceftriaxone and cefotaxime. Of the 194 isolates included in this study, 138 were susceptible, 34 were intermediate, and 22 were resistant to cefotaxime by MIC testing; 138 isolates were susceptible, 35 were intermediate, and 21 were resistant to ceftriaxone by MIC testing. A zone of inhibition around the cefuroxime disk of >/=32 mm correctly categorized 101 of 138 isolates as susceptible to cefotaxime and ceftriaxone. A zone of inhibition around the ceftizoxime disk of >/=26 mm correctly categorized 111 of 138 isolates as susceptible to cefotaxime and 114 of 138 as susceptible to ceftriaxone. We conclude that disk diffusion can separate S. pneumoniae isolates susceptible to ceftriaxone and cefotaxime from those that are not susceptible. Isolates not falling into the susceptible category by disk diffusion require additional testing to determine the MIC.

Cefotaxime↗

PubMed1999

Comparison of the Vitek GPS-TB card with disk diffusion testing for predicting the susceptibility of enterococci to vancomycin.

OBJECTIVE: To compare the ability of the Vitek GPS-TB card with disk diffusion testing for determining the susceptibility of enterococci to vancomycin. DESIGN: Vitek susceptibility testing was performed using the GPS-TB card and software version R05.03. Disk diffusion susceptibility testing was performed according to National Committee for Clinical Laboratory Standards guidelines. When discrepancies occurred between the interpretation of Vitek and disk diffusion, both tests were repeated and the epsilometer test (E test) and agar screen containing 6 microgram/mL vancomycin were performed. RESULTS: Of 415 isolates tested, 313 were susceptible to vancomycin and 97 were resistant to vancomycin by both test methods. Two isolates were intermediate by Vitek and resistant by disk diffusion, 2 were intermediate by Vitek and susceptible by disk diffusion, and 1 was susceptible by Vitek and intermediate by disk diffusion. All but 1 of these latter 5 isolates (intermediate by Vitek and susceptible by disk diffusion) were available for retesting. On repeat testing, the 2 isolates that were intermediate by Vitek and resistant by disk diffusion were resistant by both methods, the 1 isolate that was intermediate by Vitek and susceptible by disk diffusion was susceptible by both methods, and the isolate that was susceptible by Vitek and intermediate by disk diffusion was also susceptible by both methods. These results were confirmed by E test and agar screen. CONCLUSION: We found the results of the GPS-TB card compared well with disk diffusion. However, isolates with intermediate results by Vitek should be retested using another method, such as the E test.

Anti-Bacterial Agents↗