Carbapenem resistance in non-fermentative bacterial species and in Enterobacteriaceae isolates from hospitalized patients in different health-care settings

Abstract

Aim. Carbapenem-resistant strains have been increasingly reported over the last few years. In this study  we used laboratory records to determine the occurrence of carbapenem-resistant strains from hospitalized patients with emphasis on the comparative analysis of the incidence in various health-care settings. 

Materials and methods. From January 2012 to November 2012 and from May 2013 to November 2013, we evaluated 566 strains (Acinetobacter spp., Pseudomonas aeruginosa, Escherichia coli, and Klebsiella spp.). All isolates were tested and analyzed according to their antibiotic resistance phenotypic pattern. Laboratory results were correlated with data regarding admission in different clinical wards.

Results. Among 566 isolates, 191 carbapenem-resistant or carbapenem-intermediate strains (33.74%) were detected. Non-fermentative species were the most prevalent carbapenem-resistant organisms, 80.62% of 191 carbapenem-resistant or carbapenem-intermediate strains isolated were Acinetobacter spp., and 17.27% of 191 were Pseudomonas aeruginosa. Apart from that, only 4 (2.09%) carbapenem-resistant Enterobacteriaceae (CRE) strains were identified. We identified 59.30% of 172 strains isolated from patients hospitalized in anesthesia and intensive care units non-susceptible to carbapenems. The main mechanism associated with carbapenem resistance could be the production of carbapenemase in combination with impermeability.

Conclusions. Our study demonstrates that infections with carbapenem-resistant strains are correlated with hospitalization in intensive care units. Our data showed a predominant carbapenem-resistant Acinetobacter spp. strain in intensive care units.