[QacEdelta1 gene frequency and biocide resistance in extended-spectrum beta-lactamase producing enterobacteriaceae...

To determine the frequency of the gene qacEdelta1 and characterize the resistance to biocides of extended-spectrum beta-lactamases producing enterobacteriaceae (ESBL-PE) obtained from clinical isolates causing nosocomial infections.

In total 59 ESBL-PE causing nosocomial infections were included: Klebsiella pneumoniae (35) and Enterobacter cloacae (24). Minimal inhibitory concentration (MIC) was tested for chlorhexidine (CHX) and benzalkonium chloride (CLBZ) by agar dilution technique. Amplification of the SHV, TLA-1 and qacEdelta1 genes were performed by PCR using specific primers and plasmid identification was done by alkaline lysis method. Matting experiments were obtained on solid agar method.

Chlorhexidine-resistance was found in 100% of the ESBL-PE and benzalkonium chloride-resistance in 80%. In 68% of the biocides-resistant strains the qacEdelta1 gene was present. The 66% of resulting transconjugants were resistant to CHX and the gene qacEdelta1 was detected in 55%.

The qacEdelta1 gene of antiseptic resistance is widespread in the EP-ESBL and can be transferred horizontally. Thus it is advisable to use combinations of antiseptics, as recommended in the literature, to avoid selection of multiresistant bacteria in hospitals, causing nosocomial infections.