QAC Resistance Genes in ESBL-Producing E. coli Isolated from Patients with Lower Respiratory Tract Infections in the Central Slovenia Region—A 21-Year Survey

Abstract

Biocidal products prevent the spread of pathogenic microorganisms, including extended-spectrum β-lactamase-producing <i>Escherichia coli</i> (ESBL-EC), which is one of the most alarming health problems worldwide. Quaternary ammonium compounds (QACs) are surface-active agents that interact with the cytoplasmic membrane and are widely used in hospitals and food processing environments. A collection of 577 ESBL-EC, isolated from lower respiratory tract (LRT) samples, was screened for QAC resistance genes <i>oqxA</i>; <i>oqxB</i>; <i>qacEΔ1</i>; <i>qacE</i>; <i>qacF/H/I</i>; <i>qacG</i>; <i>sugE</i> (p); <i>emrE; mdfA; sugE</i> (c)<i>; ydgE; ydgF</i>; and for class 1, 2, and 3 integrons. The prevalence of chromosome-encoded genes ranged from 77 to 100%, while the prevalence of QAC resistance genes encoded on mobile genetic elements (MGEs) was relatively low (0-0.9%), with the exception of <i>qacEΔ1</i> (54.6%). PCR screening detected the presence of class 1 integrons in 36.3% (n = 210) of isolates, which were positively correlated with <i>qacEΔ1</i>. More correlations between QAC resistance genes, integrons, sequence type group ST131, and β-lactamase genes were presented. The results of our study confirm the presence of QAC resistance genes and also class 1 integrons commonly found in multidrug-resistant clinical isolates and highlight the potential role of QAC resistance genes in the selection of ESBL-producing <i>E. coli</i> in hospitals.