Evaluation the Expression of Efflux Pump Genes “Tap & P55 in Mycobacterium Tuberculosis Clinical Isolates in Fars, Iran

Background: The increasing drug resistance in Mycobacterium tuberculosis isolates has become a global problem for tuberculosis therapy programs. Genetic mutations in rifampin (RIF), one of the key drugs in the treatment of tuberculosis are main mechanism of resistant to this drug in M. tuberculosis . Absence of mutation in target genes, other mechanisms such as efflux pump suggests possible role of drug resistant.The objective of this study was to find out mutations in rpoB genes in rifampin resistant isolates and to compare the expression level of tap and p55 efflux pump genes in non mutated isolates, mutated isolates in rpoB genes and susceptible isolates.MethodsIn this study, antimicrobial sensitivity test on first line drugs was performed on 200 M. tuberculosis isolates, obtained from TB center in Shiraz (IRAN) and genetic mutations were evaluated in rpoB gene in RIF resistant isolates by multiplex PCR, followed expression level evaluated by Real-time PCR.Resultsout of the 200 isolates tested, 23 (34.33%) showed resistant to RIF. 12 of 23 RIF resistant isolates have mutation in rpoB gene, and frequency of mutations in codons 516, 526 and 531 were 3 (25%), 4 (33.33%) and 5 (41.67%) respectively. The expression level of tap and p55 genes was considerably higher in resistant isolates which had no mutation compared to the expression level of genes in the isolates which had mutation in target genes.ConclusionThe accumulating data suggest the probable role of efflux pump in M. tuberculosis drug resistance, the validation of data needs further phenotypic assays of these pumps.