Mathlouthi Najla, Ben Lamine Yomna, Somai Rania, Bouhalila-Besbes Sophia, Bakour Sofiane, Rolain Jean-Marc, Chouchani Chedly
1 Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université , Marseille, France .
2 Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Campus Universitaire, Université Tunis El-Manar , Tunis, Tunisie.
Microb Drug Resist. 2018 Mar;24(2):136-141. doi: 10.1089/mdr.2016.0306. Epub 2017 Jul 10.
Acinetobacter baumannii is an important opportunistic and multidrug-resistant pathogen responsible for nosocomial infections in health facilities. The aim of this study was to characterize the molecular mechanisms of carbapenem resistance in A. baumannii isolates isolated from Mohamed Kassab Orthopedic Institute in Tunis, Tunisia. Twenty-five imipenem-resistant A. baumannii clinical isolates collected between 2013 and 2016 were identified using API 20NE and were confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Carbapenemase activity was detected using microbiological tests and PCR. The epidemiological relatedness of the isolates was studied using multilocus sequence typing (MLST). The isolates were resistant to all antibiotics tested with increased minimum inhibitory concentration values (>32 mg/L). The microbiological tests showed that the 25 A. baumannii were positive for modified Hodge test and for the Carba NP test; however, β-lactamase activity was not inhibited by EDTA. All the isolates harbored the naturally occurring bla-like gene and the bla-like carbapenemase gene. Among these isolates, one isolate coexpressed the bla gene. MLST revealed several sequence types (STs) with the predominance of ST2 imipenem-resistant A. baumannii (14/25; 56%). In this study we report the prevalence of ST2 imipenem resistance and for the first time the coexpression of bla and bla in clinical isolates of A. baumannii in a Tunisian hospital.
鲍曼不动杆菌是一种重要的机会致病菌，具有多重耐药性，可在医疗机构引发医院感染。本研究旨在表征从突尼斯突尼斯市穆罕默德·卡萨布骨科研究所分离出的鲍曼不动杆菌菌株对碳青霉烯类耐药的分子机制。使用API 20NE鉴定了2013年至2016年间收集的25株耐亚胺培南鲍曼不动杆菌临床分离株，并通过基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF/MS）进行了确认。使用微生物学检测和PCR检测碳青霉烯酶活性。使用多位点序列分型（MLST）研究分离株的流行病学相关性。分离株对所有测试抗生素均耐药，最低抑菌浓度值升高（>32 mg/L）。微生物学检测表明，25株鲍曼不动杆菌改良Hodge试验和Carba NP试验均为阳性；然而，β-内酰胺酶活性未被EDTA抑制。所有分离株均携带天然存在的bla样基因和bla样碳青霉烯酶基因。在这些分离株中，有一株同时表达bla基因。MLST揭示了几种序列类型（STs），其中以ST2耐亚胺培南鲍曼不动杆菌为主（14/25；56%）。在本研究中，我们报告了突尼斯一家医院中ST2耐亚胺培南鲍曼不动杆菌的流行情况，并首次报道了鲍曼不动杆菌临床分离株中bla和bla的共表达情况。
