Phenotypic and genotypic evaluation of beta-lactamases (ESBL and KPC) among enterobacteria isolated from community-acquired monomicrobial urinary tract infections.

Beta-lactamases enzymes such as extended-spectrum beta-lactamases (ESBL) and carbapenemase type beta-lactamases (KPC) confer resistance to beta-lactam drugs among Gram-negative rods, mainly Enterobacteriaceae, as those frequently related to urinary tract infections (UTI). The aim of this study was to evaluate ESBL and KPC among enterobacteria isolated from monomicrobial UTI and to establish correlations between the presence of genetic markers and the phenotypic resistance to beta-lactam antibiotics. Out of 12 304 urine samples collected during 2009, 93 enterobacteria showing an ESBL phenotype were recovered. Imipenem was used for KPC screening and modified disk approximation assay was used for detection of ESBL phenotype. Polymerase chain reaction was used for screening of bla(SHV), bla(TEM), bla(CTX-M), and bla(KPC). Considering the isolated bacteria showing ESBL phenotype 56% of the isolates were positive for two genes. The bla(TEM) was the most frequent (87·1%). Neither KPC phenotype nor bla(KPC)-harboring bacteria were observed. Monitoring the antimicrobial resistance is extremely important to sustain empirical therapy of community-acquired urinary tract infections (Co-UTI).