Effect of drugs on development of biofilm in M.tuberculosis H37 Rv and sensitive isolates

Abstract

A biofilm is an assemblage of microbial cells that is irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material. However, our knowledge about the diverse components of extracellular matrix is still very limited, with almost nothing being known about the EPS of mycobacteria. The current perception is that multiple mechanisms operate in a concerted strategy of the resistance to antimicrobial reagents within a single biofilm community. Although the following mechanisms are partially evidential but still speculative, one important basis is the mechanisms depend on the multicellularity and cooperation between differentiated cells within the structure. First, the biofilm structure provides the chemical barriers. This mechanism may be more relevant for antimicrobial reagent that are bound or neutralized by the EPS substances Recently, there have been found cells of another distinct phenotype called persisters. Biofilm formation in slow growers mycobacterial specie M. tuberculosis sensitive and resistant isolates and H37Rv were taken for evaluating the effect of drugs on biofilm formation. Selected mycobacterial isolates were taken to observed the effect of first line and second line drugs on planktonic cells and mycobacterial. REMA plate method was used for observed the effect of drug on planktonic cells. Crystal violet microtiter plate assay method was used for observed the effect of drug on biofilm formation. The biofilm of M.tuberculosis H37Rv are capable of growing at higher drug concentrations (i.e. have higher MICs) than suspension cultures: the MIC of selected drug concentration that inhibited exponentially growing biofilm was found to be higher than the MIC for planktonic culture. Hence, our work provides the basis for a genetic dissection of the biofilm-associated drug resistance phenomenon uncovered in this work biofilm cells.