Characterization of plasmid-mediated β-lactamases in fecal colonizing patients in the hospital and community setting in Spain.

AIM: Active surveillance of plasmid-mediated β-lactamase-producing Enterobacteriaceae (PMBL-E) in fecal carriers in the hospital and in the community setting in a non-outbreak period of time.

METHODS: Patients were screened for carriage of Enterobacteriaceae resistant to expanded-spectrum cephalosporins and PMBL-E were characterized (extended-spectrum-β-lactamase [ESBL], plasmid-mediated AmpC β-lactamase [pAmpC], and carbapenemases) by PCR and sequencing.

RESULTS: The prevalence of ESBL and pAmpC carriers was 5.06% and 0.59%, respectively. Overall, CTX-M-like enzymes were the ESBL dominate enzymes (96.15%). The group CTX-M-9 was the most prevalent (81, 54%) [CTX-M-14 (74, 91.35%), CTX-M-9 (5, 6.17%), CTX-M-24 (1, 1.23%), and CTX-M-27 (1, 1.23%)] followed by the group CTX-M-1 (64, 42.67%) [CTX-M-15 (42, 65.63%), CTX-M-1 (13, 20.31%), CTX-M-32 (8, 12.5%), and CTX-M-3 (1, 1.56%)]. One CTX-M-10, one CTX-M-59, and three CTX-M-8 were also found. A very small representation of SHV or TEM ESBL enzymes was found (3.2% and 0.64%, respectively). pAmpC characterization revealed a predominance of CMY-2 (81.25%), followed by DHA-1 (18.75%). We did not detect the presence of carbapenemase producers.

CONCLUSIONS: The prevalence of ESBL-producers from fecal carriers is stable in our area, but colonization by pAmpC producers has emerged recently as we have confirmed. Periodic active surveillance is useful to identify these human reservoirs and control the evolution of PMBL carriage in a community over time.