Expression analysis of efflux pump genes among drug-susceptible and multidrug-resistant Mycobacterium tuberculosis clinical isolates and reference strains.

Finding a gene or genes that are involved with multidrug resistance will be useful for finding a new target for the treatment of drug resistant tuberculosis. In this study, we aimed to compare the differences of the expression of 15 putative multidrug efflux pump genes in clinically isolated drug sensitive and multidrug resistant (MDR) Mycobacterium tuberculosis isolates, and reference strains. We found that these genes in the drug-sensitive and MDR M. tuberculosis isolates have similar rates of expressions. However, we found the expression levels of the all the genes are significantly higher in the clinical strains compared to the expression level of genes in the reference strains. In addition to this, it is found that standard strain has lower MIC value for the drugs including streptomycin and rifampin compared to the clinical isolate. We presume that the increase of the gene expression in the clinical strains is due to the exposure of antituberculosis drugs during treatment of patients, which cause constitutive expression of efflux systems, which might increase MIC levels of the major anti-tuberculosis drugs.

[Airway inflammation and lymphocyte subset analysis in patients with chronic obstructive pulmonary disease and healthy smokers]. / Stabil kronik obstrüktif akciger hastaligi olan hastalar ile sigara içenlerde hava yolu inflamasyonu ve lenfosit alt tiplerinin analizi.

Chronic airway inflammation is reported to have an important role for the development of chronic obstructive pulmonary disease (COPD), in addition to smoking, genetic and environmental factors. The present study was aimed to investigate whether the airway inflammation differed in subjects with stable COPD and healthy smokers. A total of 35 subjects (18 patients with COPD and 17 healthy smokers) were enrolled in this study. Bronchoalveolar lavage (BAL) was performed via fiberoptic bronchoscope in all subjects and cell counts and profiles and lymphocyte subset were analyzed in BAL fluids. The number of neutrophils in BAL of subjects with stable COPD was significantly higher than that of the healthy smokers (p< 0.001), and the number of macrophages was significantly lower than that of the healthy smokers (p< 0.001). Although CD4+ T:CD8+ T lymphocyte ratio was higher in healty smokers, the difference was not significant (p> 0.05). As a result, the most marked cellular change in BAL of subjects with stable COPD is the increase in neutrophils and decrease in macrophages, suggesting a very important role in the chronic airflow limitation.

Sequence analysis of rpoB mutations in rifampin-resistant clinical Mycobacterium tuberculosis isolates from Turkey.

Drug-resistant tuberculosis is a serious problem throughout the world. Resistance to Rifampicin (RIF) is mainly caused by the mutations in the rpoB gene coding the beta-subunit of RNA polymerase. In this study, we aimed to detect the distribution of rpoB gene mutations in 80 RIF-resistant clinical Mycobacterium tuberculosis (MTB) isolates from Turkey. The rpoB gene was amplified by PCR and mutations leading to RIF resistance were determined by automated sequence analysis. A total of 72 of the 80 isolates (90%) were found to carry mutations in the amplified region, whereas eight isolates (10%) carried no mutations. Overall, 24 different missense mutations affecting 14 codons, and two deletion mutants were identified. Nine new mutations, six in the hot-spot region and three outside this region, were found. The codon numbers of the most frequently encountered mutations were 531 (51.4%), 526 (18.1%), 516 (13.9%), and 513 (12.5%). As a result, 90% of the RIF-resistant MTB isolates from the Turkish patients were found to carry a mutation in the rpoB gene, Ser531Leu being the most frequent one. Although molecular methods identify mutations leading to RIF resistance very quickly, results of the antimycobacterial susceptibility tests must be taken into consideration for the patients carrying no mutations in this region.