Role of acinetobacter baumannii AdeB, AdeJ, QacE efflux genes in mediating decreased susceptibility to biocides by peyrosequencing method

Biocides and disinfectants are commonly used in hospital and laboratory settings. The frequent use of disinfectants may contribute to the emergence of disinfectant-resistant microorganisms. In the laboratorial conditions various disinfectants and biocides have been shown to result in overgrowth bacteria having increased antibiotic resistance, including Acinetobacter baumanii or that of already-resistant to antibiotics.29Recent studies have shown that active drug efflux pumps are important mechanisms of resistance in this microorganism. In this study we aimed to investigate the AdeB, AdeJ ve QacE efflux genes regions and impact of this efflux mediated resistance in the disinfectants resistance of 50 A. baumanii strains isolated in our hospital during 2009-2011.For this purpose minimum inhibitory concentrations (MICs) of 2 disinfectants (chlorhexzidin ve Benzalkonium chlorid) were investigated by broth microdilution test in the presence and absence of two efflux pump inhibitors, phenylalanyl-arginyl-ß-naphtylamide (PAßN) and 1-(1-naphythylmethyl)-piperazine (NMP) and changes in the disinfectants MICs in the presence of pump inhibitors were recorded. Additionally, adeB and adeJ genes which encode the main transporter proteins of AdeABC and AdeIJK pumps system and qacE resistance gene were investigated in the isolates by pyrosequencing method.In %40 and %78 of the isolates, MICs of Chlorhexidin decreased by in order 4-8 folds and 4-16 folds in the presence of PAßN and NMP pump inhibitors. In %43 and %68 of the isolates, MICs of Benzalkonium chloride decreased by 4-8 folds in the presence of PAßN and NMP pump inhibitors.These results showed that an RND type drug efflux pump seems very likely to contribute the disinfectants resistance in majority of the isolates.In the second part of our study, we investigated adeB, adeJ and qacE efflux genes in the isolates by Pyrosequencing method. Results obtained from studies have shown that these genes found in all isolates. There was no mutation in these genes.As a result, we conclude that there is a significant contribution of an RND type efflux pumps in our A. baumanii isolates and effluks inhibitors increase the effectiveness of the disinfectant. So additional treatment options that will make possible.