Study and molecular charactrization of expression of whib7 among drug resistant mycobacterium tuberculosis

Fahimeh Morteza,1 Saeed zaker bostan abad,2,* Sarvenaz falsafi,3

1. Department of Biology, faculty of science , science and research branch , islamic azad university ,tehran , iran.
2. Department of biology and biotechnology,faculty of biological science , Islamic azad university Pranad branch,Tehran ,Iran
3. Department of microbiology,faculty of advanced science and technology,tehran medical science,Islamic azad university,Tehran ,Iran.



One third of the world’s population are infected by mycobacterium tuberculosis “ the main cuase of tuberculosis”.this bacteria has a family of genes which are called whibs .these genes’s function is to induce the infection,also they play a crucial role in establishment of bacteria through the this study exclusively ,the expression of whib7 has been discussed which has proved that this gene leads to antibiotic resistance and produces mdr positive species.


To do this study 25 mdr positive and 25 sensetive species of mycobacterium tuberculosis has been collected then cultured on lowenstein jensen medium(l.j) which contains rifampin , izoniaizd , ethambutol.afterwards,by the means of rotor gene real time pcr the expression of whib7 has been compared among resistant and sensitive species ,and then both resistant and sensitive species have been compared with the standard species called h37rv.


Results of antibiogram showed that all mdr positive species are resistant ,at least, to two out of three drugs that were used in l.j medium .although the results of real time pcr method indicated that whib7 expressed more in resistant species rather than sensitive ones in lower cycle of threshold ,the results of statistical analysis (based on standardization) which were done by softwares like rest and mwga6 have indicated that whib7 has shown no difference in expression among resistant and sensitive species in coparison with each others ,while both (resistant and sensitive species ) have been down regulated in comparison to h37rv.


According to genesis of new resistant species of mycobacterium tuberculosis ,we can feel the need of new identification methods to prevent the emergence of new resistant strains.the main purpose of this study was to research the effect of whib7 expression in drug resistance ,the existence of point mutations and polymorphism in sequences of this gene in mdr positive species . key words: real time pcr, mycobacterium tuberculosis ,whib7 gene.


Mycobacterium tuberculosis,real time pcr,whib7 gene,antibiotic resistance