Molecular analysis of rpoB gene mutations in rifampicin resistant Mycobacterium tuberculosis isolates by multiple allele specific polymerase chain reaction in Puducherry, South India

rpoB gene mutations in Mycobacterium tuberculosis [MTB] make the bacteria resistant to rifampicin. Thus, these mutations are surrogate markers for multi-drug resistance [MDR]. The objective of this study was to evaluate an allele-specific multiplex-polymerase chain reaction [MAS-PCR] assay to detect mutations at codons 516, 526 and 531 of the rpoB gene. In total, 127 M. tuberculosis clinical isolates were subjected to standard drug susceptibility tests. A MAS-PCR assay was then performed to detect mutations in the rpoB gene. Three different allele-specific PCR assays were performed [single-step MAS-PCR] and the amplified products were sequenced. Of the 127 isolates, 69 [54.3%] were multidrug resistant M. tuberculosis [MDR-TB], 21 [16.5%] were rifampicin mono-resistant and 37 [29.1%] were drug susceptible. The frequency of mutations at codons 531, 526 and 516 was 54.4%, 18.9% and 5.6%, respectively. A triple mutation was found in 4 [4.4%] isolates. Mutations in regions other than the 81-bp region were observed at codons 413 [11.1%], 511 [12.2%] and 521 [15.6%] of the rpoB gene. The simplicity and specificity of the MAS-PCR assay allows for easy implementation in clinical laboratories to detect rifampicin drug resistance in MDR-TB strains

Effect of Oscillatoria willei – a marine cyanobacterium on hydrazine induced toxicity

Aims: To find out the effect of crude extract of Oscillatoria willei, a marine cyanobacterium on hydrazine induced toxicity. Methodology and Results: In this study, the experimental mice were injected intramuscularly with 5 mg of hydrazine/kg body weight continuously for 20 days. Crude extract of Oscillatoria willei was given to the animals induced with hydrazine toxicity. The animals were subjected to various biochemical and immunological parameters after exposing to hydrazine and followed up treatment. The results revealed that intra-peritoneal administration of O. willei reduced interleukin 2 (IL-2), reducing sugar, thiobarbituric acid reactive substances (TBARS), liver enzymes, bilirubin, creatinine and uric acid level. Conclusion, significance and impact of study: O. willei treatment was found to reduce the ill effects induced by hydrazine.