Sofiane Bakour1,2, Abiola Olumuyiwa Olaitan1, Houria Ammari3, Abdelaziz Touati2, Souad Saoudi2, Kenza Saoudi2, Jean-Marc Rolain1. 1. 1Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France. 2. 2Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia, 06000 Bejaia, Algérie. 3. 3Laboratoire Central de Biologie Médicale, Unité de Microbiologie, CHU Béni-Messous, Alger, Algérie.
Abstract
AIM: The aim of this study was to investigate the prevalence and the mechanisms of carbapenem and colistin resistance in Acinetobacter baumannii clinical isolates in an Algerian hospital. RESULTS: Twelve isolates were collected between October 2013 and March 2014. All isolates were resistant to almost all antibiotics tested with a high-level resistance to imipenem (minimum inhibitory concentrations [MICs] >32 mg/L) with one strain showing resistance to colistin (MIC=16 mg/L). The results of the modified Hodge test and the modified Carba NP test were positive for all isolates. Besides, the activity of β-lactamases was inhibited by EDTA in only two isolates. All the 12 isolates contained the naturally occurring blaOXA-51-like gene. Ten of them harbored the OXA β-lactamases: blaOXA-23 (six isolates) and blaOXA-24 (four isolates) genes, while two isolates were positive for blaNDM-1 gene. The colistin-resistant isolate producing OXA-24 enzyme harbored a single mutation in the pmrB gene. Multilocus sequence typing demonstrated that the 12 isolates belonged to 2 clones: 10 to ST2 and 2 to ST85. CONCLUSIONS: Here, we describe the mechanisms of carbapenem resistance and we report the first colistin and carbapenemase-producing A. baumannii clinical isolate from a patient in Algeria.
AIM: The aim of this study was to investigate the prevalence and the mechanisms of carbapenem and colistin resistance in Acinetobacter baumannii clinical isolates in an Algerian hospital. RESULTS: Twelve isolates were collected between October 2013 and March 2014. All isolates were resistant to almost all antibiotics tested with a high-level resistance to imipenem (minimum inhibitory concentrations [MICs] >32 mg/L) with one strain showing resistance to colistin (MIC=16 mg/L). The results of the modified Hodge test and the modified Carba NP test were positive for all isolates. Besides, the activity of β-lactamases was inhibited by EDTA in only two isolates. All the 12 isolates contained the naturally occurring blaOXA-51-like gene. Ten of them harbored the OXA β-lactamases: blaOXA-23 (six isolates) and blaOXA-24 (four isolates) genes, while two isolates were positive for blaNDM-1 gene. The colistin-resistant isolate producing OXA-24 enzyme harbored a single mutation in the pmrB gene. Multilocus sequence typing demonstrated that the 12 isolates belonged to 2 clones: 10 to ST2 and 2 to ST85. CONCLUSIONS: Here, we describe the mechanisms of carbapenem resistance and we report the first colistin and carbapenemase-producing A. baumannii clinical isolate from a patient in Algeria.