There is a geographic distribution of Mycobacterium tuberculosis strains with various rpoB gene mutations that account for rifampin resistance. We studied 17 rifampin-resistant clinical isolates from patients in Greece to identify rpoBmutations. The aim of our study was the evaluation of a commercially available line probe assay kit (INNO-LiPA Rif. TB) to detectrpoB mutations and rifampin resistance. The results obtained with the commercially available assay were compared to those obtained by automated DNA sequence analysis of amplified PCR products. Randomly amplified polymorphic DNA (RAPD) analyses of the isolates were also performed. The overall concordance of the line probe assay with phenotypic rifampin susceptibility test was 94%. Three distinctrpoB mutations in codons Ser531, His526, and Asp516 were correctly identified with the kit, but mutations in external regions and insertions were detected only by automated DNA sequence analysis. The changes in codons Ser531 and His526 accounted for the majority of rifampin resistance, as previously described for isolates from other geographic areas. The results obtained by RAPD analyses of the isolates suggested that clonally related M. tuberculosis strains can have subclones bearing distinct mutant rpoB alleles. We conclude that this line probe assay kit, which is fast and with which tests are easy to perform, can be used for the rapid detection of rifampin resistance in M. tuberculosis before the availability of results by conventional methods and for epidemiological studies but that negative results obtained by this method do not rule out rifampin resistance.

The antibiotic susceptibilities of 1,002 Streptococcus pneumoniae clinical isolates from patients with community-acquired pneumonia were determined over an 18-month period. Resistance rates were 14% for penicillin, 20%o for erythromycin, 26% for tetracycline, and 1% for chloramphenicol. Resistance to non-D.lactam antibiotics was associated with penicillin resistance at statistically significant levels.

No abstract

No abstract