Investigating the broad clonal diversity of β-lactamases producing Enterobacteriaceae strains recovered from bloodstream infection in five hospitals

Background: Detecting β-lactamases-producing Enterobacteriaceae is underestimated due to difficulties in clinical laboratory procedures. Objectives: Identify β-lactamases in Enterobacteriaceae recovered from bloodstream infection patients in five different hospitals. Methods: Phenotypic and genetic methods were used. PCR were used to detect blaTEM, blaSHV, blaCTX-M, blaGES, blaAmpC, blaCMY, blaFOX, blaDHA, blaKPC and blaNDM genes and ERIC-PCR investigated the genetic diversity. Findings: K. pneumoniae, Enterobacter cloacae complex, Enterobacter aerogenes, and Escherichia coli were recovered. ESBL production was detected in 56.8% (Double-Disk Synergy Test) and 55.6% (Etest) of all strains. Modified Hodge Test was positive for K. pneumoniae (39.2%) and Enterobacter spp. (11.1%). ESBL genes were observed in 79.5% of all strains, blaTEM in 61.3% and blaSHV in 42%. The simultaneous presences of ESBL-encoding genes were observed (37.5%). The gene blaKPC was detected in 45% of K. pneumoniae and 18.5% of Enterobacter strains. Main conclusions: Phenotypic and molecular tests detected several types of β-lactamases among the bacterial strains recovered. The obtained results also suggest that several clonal populations circulate among hospitals, and some strains were genetically identical, showing that cross infection practices must be used for all patients, in all healthcare services.