Association of Efflux Pump and OMPs with Antibiotic Susceptibility Among ESBL-Producing Klebsiella Pneumoniae Clinical Strains in Malaysia

Abstract Multidrug-resistant (MDR) Klebsiella pneumoniae (K. pneumoniae) poses a serious public health threat. K. pneumoniae strains that produce extended-spectrum beta-lactamases (ESBL) are becoming increasingly reported in nosocomial and community-acquired infections. Besides resistance genes, integrons, and plasmids, altered membrane permeability caused by porin loss and energy-dependent efflux have also contributed to antibiotic resistance in K. pneumoniae. The objective of this study was to determine the correlation between the reduction of antibiotic susceptibility and overexpression of efflux pump as well as the lack of outer membrane proteins (OMPs) among clinical ESBLs resistant K. pneumoniae. The expression levels of ramA, acrA, ompK35 and ompK36 in 12 MDR K. pneumoniae strains with varying MICs levels were analyzed using quantitative real time-Polymerase Chain Reaction (qRT-PCR). The role of efflux pump on antibiotic resistance was also studied by using minimum inhibitory concentration (MICs) method with//without efflux pump inhibitor. The result indicated that the strains with highest resistance to cefotaxime showed the lowest level of ompK35 and ompK36 genes expression while the strains with lowest MIC level of resistance to cefotaxime showed the highest level of expression of acrA and ramA. Our finding also revealed the effect of efflux pump inhibitor phenyl-arginine-b-naphthylamide (PAβN) on the MIC levels of ceftazidime, amoxicillin-clavulanate and cefotaxime which were significantly reduced around 1–7 folds MIC levels. These results suggest that Efflux pump system and deficiently of OMPs contributing role in antibiotic susceptibility which should be taken seriously to prevent the treatment failure due to antimicrobial resistance.