Background Carbapenem-resistance is frequently detected in Enterobacteriaceae isolated from patients in Tunisia. The study was performed to identify frequent carbapenemases in Tunisian isolates. Methods Between May 2014 and January 2018, 197 ertapenem-resistant Enterobacteriaceae were isolated at the microbiological department of the Military Hospital of Tunis. The strains were phenotypically characterized and then subjected to in-house polymerase chain reaction (PCR) targeting the carbapenemase genes bla IMP , bla VIM , bla NDM , bla SPM , bla AIM , bla DIM ,bla GIM , bla SIM , bla KPC , bla BIC , and bla OXA-48 . Results The assessed 197 ertapenem-resistant Enterobacteriaceae from Tunis comprised 170 Klebsiella pneumoniae , 19 Enterobacter cloacae , 6 Escherichia coli , 1 Citrobacter sedlakii , and 1 Enterobacter asburiae. Thereby, 55 out of 197 isolates (27.9%) were from blood cultures, suggesting a systemic disease. The carbapenemase gene bla OXA-48 quantitatively dominated by far with 153 detections, followed by bla NDM with 14 detections, which were distributed about the whole study interval. In contrast, bla BIC and bla VIM were only infrequently identified in 5 and 3 cases, respectively, while the other carbapenamases were not observed. Conclusions The carbapenemase gene bla OXA-48 was identified in the vast majority of ertapenem-resistant Tunisian Enterobacteriaceae while all other assessed carbapenemases were much less abundant. In a quantitatively relevant minority of isolates, the applied PCR-based screening approach did not identify any carbapenemases.

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, bla, bla, bla, and bla 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 (84 isolates), bla (8 isolates), bla + bla (5 isolates), and bla + bla (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.