Background. Emergence of multidrug-resistant tuberculosis (MDR-TB) poses a major challenge to prevailing disease management. MDR-TB arises from mutations in several genes comprising the resistance determining regions, including rpoB, katG and gyrA. Objective. To detect and characterize mutations in rpoB, katG and gyrA. Methods. Thirty selected Mycobacterium tuberculosis isolates from the IDS-PGH were subjected to PCR amplification and sequencing. Sequences were compared to the wild type strain H37Rv. Results. Mutations were detected in codons 512, 513, 516, 522, 526, 531 and 533 of rpoB, codons 280, 281, 315 and 333 of katG, and codons 90 and 94 of gyrA sequences. The most frequently mutating codons for rpoB, katG and gyrA were 531, 315 and 94, respectively. A clustering analysis of the sequences showed occurrence of seven, four and three clusters for the genes rpoB, katG and gyrA, respectively. The eight clusters obtained from the concatenated sequences of the three genes represent the eight potential genotypes of local strains. One cluster represents the wild type strain genotype, another cluster represents the XDR strain genotype, and six clusters represent the MDR strain genotypes. Conclusion. These findings indicate the utility of multiple RDR sequence analysis in both identifying specific drug resistance mutation and genotyping of various M. tuberculosis isolates.
TUBERCULOSIS ; THERAPEUTICS ; THERAPY

BACKGROUND AND AIM: Current standard diagnostic tests for leptospirosis are time-consuming and laborious. The urine DOT-ELISA for leptospirosis is a non-invasive, rapid test utilizing monoclonal antibody to detect leptospiral antigens in the urine. We aimed to determine the clinical utility of urine monoclonal antibody-based DOT-ELISA in the rapid diagnosis of leptospirosis compared with the standard microscopic agglutination test (MAT) and urine and blood cultures.

METHODS: This cross-sectional study was done in a university tertiary hospital in Manila, Philippines. We obtained specimens from patients for blood and urine cultures for leptospirosis, MAT and urine ELISA upon admission and 7 days later.

RESULTS: We included 117 patients over a 15-month period. The median duration of illness before inclusion was 9 days (IQR 7-14) and 64 percent received antibiotics before testing. During the acute phase of illness, the sensitivity, specificity, negative and positive predictive values of the urine ELISA compared to culture and MAT were 27.3 percent (95 percent CI 13.2-48.2 percent), 97.7 percent (95 percent CI 80.0-98.3 percent), 66 percent (95 percent CI 51.7-77.8 percent) and 75 percent (95 percent CI 40.9-92.5 percent), respectively. For patients with symptoms more than 7 days of illness, the sensitivity increased to 40.9 percent (95 percent CI 23.3, 61.3 percent) and the specificity increased to 97.5 percent (95 percent CI 87.1, 99.9 percent), with negative and positive predictive values of 75 percent (95 percent CI 61.8, 84.8 percent) and 90 percent (95 percent CI 59.6, 99.5 percent), respectively. On sub-analysis of the effect of antibiotic use, the sensitivity rates differed significantly among patients with antibiotic use versus for those without antibiotic use, 48.4 percent vs. 15.4 percent, respectively (p = 0.001). The specificity rates did not vary with antibiotic use, 98 percent vs. 97 percent.

CONCLUSION: The DOT-ELISA urine antigen test is highly specific with fair accuracy of 73 percent. Its low sensitivity makes it a poor screening test but its high specificity makes it a useful confirmatory test in the diagnosis of leptospirosis. (Author)