Hans Kollenda 1 , † , Hagen Frickmann 1 , 2 , * , † , Rania Ben Helal 4 , Dorothea Franziska Wiemer 3 , Habiba Naija 4 , Mohamed Sélim El Asli 4 , Melanie Egold 5 , Joachim Jakob Bugert 5 , Susann Handrick 5 , Roman Wölfel 5 , Farouk Barguellil 4 , Mohamed Ben Moussa 4
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.