Clinical Evaluation of a Line-Probe Assay for Tuberculosis Detection and Drug-Resistance Prediction in Namibia.

Treatment of tuberculosis requires rapid information about Mycobacterium tuberculosis (Mtb) drug susceptibility to ensure effective therapy and optimal outcomes. At the tuberculosis referral hospital in Windhoek, Namibia, a country of high tuberculosis incidence, we evaluated the diagnostic accuracy of a line-probe-assay (LPA), GenID, for the molecular diagnosis of Mtb infection and drug resistance in patients with suspected tuberculosis (cohort 1) and confirmed rifampin (RIF)-resistant tuberculosis (cohort 2). GenID test results were compared to Xpert MTB/RIF and/or Mtb culture and antimicrobial suceptibilty testing. GenID LPA was applied to 79 and 55 samples from patients in cohort 1 and cohort 2, respectively. The overall sensitivity of GenID LPA for the detection of Mtb DNA in sputum from patients with detectable and undetectable acid-fast bacilli by sputum smear microscopy was 93.3% (56/60; 95% confidence interval = 83.8-98.2) and 22.7% (5/22; 7.8-45.4). The sensitivity/specificity for the detection of drug resistance was 84.2% (32/38; 68.7-94.0)/100% (19/19; 82.4-100.0) for RIF, 89.7% (26/29; 72.6-97.8)/91.7% (22/24; 73.0-99.0) for isoniazid, and 85.7% (6/7; 42.1-99.6)/94.7% (18/19; 74.0-99.9) for fluoroquinolones; 23.6% of tests for second-line injectable resistance were invalid despite repeat testing. The diagnosis of tuberculosis by detection of Mtb DNA in sputum by GenID LPA depends strongly on the detection of acid-fast bacilli in sputum specimen. Prediction of drug resistance by GenID did not reach the World Health Organization (WHO) target product profile. IMPORTANCE Mycobacterium tuberculosis (Mtb) drug-resistance detection is crucial for successful control of tuberculosis. Line-probe assays (LPA) are frequently used to detect resistance to rifampin, isoniazid, fluoroquinolones (FQs), and second-line injectables (SLIs). GenID RIF/isoniazid (INH), FQ, and SLI LPA have not been widely tested and used so far. This study tested the diagnostic performance of the GenID LPA in a high-incidence TB/HIV, real-world setting in Namibia. The LPA demonstrates only an acceptable diagnostic performance for Mtb and drug-resistance detection. The diagnostic sensitivity and specificity fall short of the WHO suggested target product profiles for LPA.

The prevalence, risks, and management of Chlamydia trachomatis infections in fertile and infertile patients from the high socioeconomic bracket of the South African population.

OBJECTIVE: The main objective of the study was to evaluate the prevalence of Chlamydia trachomatis endocervicitis in an infertile population. DESIGN: Forty consecutive patients were enrolled in the study group and 41 in the control group. SETTING: The study was undertaken in the Department of Obstetrics and Gynaecology of the University of the Orange Free State, Bloemfontein, Republic of South Africa. PATIENTS: Infertile white females, visiting an infertility clinic in an academic hospital and fertile white female patients visiting an antenatal clinic. INTERVENTIONS: Endocervical swabs were taken, and monoclonal direct immunofluorescence for C. Trachomatis were done on each. MAIN OUTCOME MEASURES: A difference was expected between the prevalence of C. trachomatis infection in the fertile and infertile population. RESULTS: In the study group, 14(35.9%) positive, 25(64.1%) negative, and 1 fallout were obtained. In the control group, 3 patients (7.32%) tested positive. CONCLUSION: Although no correlation was found between C. trachomatis infection of the female genital tract and the clinical history, it showed a significant correlation with infertility. This justifies routine screening tests and antibiotic treatment of positive infertile couples. Analysis of cost-effectiveness showed that empirical treatment of new infertile couples is justified in some populations.

PIP: Health workers at the Department of Obstetrics and Gynecology of the University of the Orange Free State in Bloemfontein, South Africa enrolled 40 consecutive infertile white couples 41 consecutive pregnant white females into a case control study to determine the prevalence of Chlamydia trachomatis infections in an infertile population. Both groups were from the middle to upper socioeconomic class. Laboratory personnel used the monoclonal direct immunofluorescence test to each cervical cytology smear. They had to repeat the test on 5% of the smears. Prevalence of C. trachomatis in the study group stood much higher than it did in the control group (35.9% vs. 7.3%; p.002). No association existed between clinical history and presence of C. trachomatis in the fertile group. 19.5% of the fertile patients had taken antibiotics during the 3 months prior to the study. None reported earlier episodes of salpingitis and/or pelvic inflammatory disease. The researchers proposed a possible reason for the very high rate of C. trachomatis in infertile patients. Perhaps the infertile clinic only examined unresolved infertile cases who may have had an exceptionally high rate of C. trachomatis. The infertility clinic chose to treat all new couples with lymecycline because studies showed that it is always effective against C. trachomatis. Indeed this treatment proved to be the most beneficial at the lowest cost.

[The prevalence of Chlamydia trachomatis infections in new patients at the Infertility Clinic, UOFS, Bloemfontein]. / Die prevalensie van Chlamydia trachomatis-infeksie in nuwe pasiënte aan die Infertiliteitskliniek, UOVS, Bloemfontein.

Chlamydia trachomatis is a common sexually transmitted agent causing infertility. Routine screening tests or empirical antibiotic treatment of infertile couples may be justified by the prevalence of this organism. In this study the female partner of 40 consecutive infertile couples was investigated. As a screening test direct immunofluorescence (DIF) was performed on fixed smears from endocervical swabs. Of a total of 40 specimens, 11 (27.5%) were positive, 25 (62.5%) were negative and 4 (10.0%) were equivocal. DIF was repeated on smears from 3 of the last 4 patients and all 3 specimens were positive for C. trachomatis. One patient was lost to follow-up and excluded from the study. Of a total of 39 specimens the final results yielded 14 (35.9%) positive and 25 (64.1%) negative. Statistical analysis showed no correlation between the clinical history and the presence of C. trachomatis infection.