Occurrence and Characterization of Carbapenemase-Producing Enterobacteriaceae in a Tunisian Hospital

Abstract

Carbapenem-resistant Enterobacteriaceae have become of particular concern, since they were quickly disseminated in various areas in the world. The aim of the study was to investigate the prevalence of carbapenemase production among clinical isolates of Enterobacteriaceae recovered from the Military Hospital of Tunisia. Bacterial isolates (n = 125) were recovered from patients in diverse services from March 2014 to February 2016 and identified by Vitek II Compact^®. The multiplex PCR for bla_VIM, bla_IMP, bla_NDM, bla_KPC, and bla_OXA-48 with subsequent amplicon detection by reverse hybridization was performed with the Hyplex SuperBug ID test system (AmplexDiagnostics GmbH, Gars-Bahnhof, Germany). The 125 strains showed resistance to carbapenems of which 102 strains (81.6%) were carbapenemase-producing Enterobacteriaceae and were identified as Klebsiella pneumoniae (85.2%), Enterobacter cloacae (9.8%), Escherichia coli (2.9%), Providencia stuartii (0.9%) and Enterobacter aerogenes (0.9%). These strains were isolated mainly from blood, anal, and urine samples. Patients were mainly hospitalized in the intensive care units, surgery, and medical services. All strains were resistant to ertapenem (100%) and 55.8% showed resistance to imipenem. Carbapenemases genes detected in our study were as follows: bla_OXA-48 (84 isolates), bla_NDM-1 (8 isolates), bla_OXA-48 + bla_VIM (5 isolates), and bla_OXA-48 + bla_NDM-1 (5 isolates). Our research provides epidemiological data showing the quick spread of carbapenem-resistant bacteria in our region, which calls for new surveillance strategies and strict hygiene rules.

Keywords: CPE; Enterobacteriaceae; NDM-1; OXA-48; VIM; carbapenemase; multiplex PCR.