Ben Tanfous Farah, Alonso Carla Andrea, Achour Wafa, Ruiz-Ripa Laura, Torres Carmen, Ben Hassen Assia
1 Université de Carthage , Faculté des Sciences de Bizerte, 7021, Tunis, Tunisie.
2 Service des Laboratoires, Centre National de Greffe de Moelle Osseuse , Tunis, Tunisie.
Microb Drug Resist. 2017 Apr;23(3):365-375. doi: 10.1089/mdr.2016.0090. Epub 2016 Oct 18.
The aim of this study was to investigate the molecular features among Klebsiella pneumoniae and Escherichia coli strains showing a resistant/intermediate-resistant phenotype to ertapenem (R/IR-ERT), implicated in colonization/infection in patients of the Hematology and Graft Units of the National Bone Marrow Transplant Center of Tunisia (3-year period, 2011-2014). The major carbapenemase, extended-spectrum beta-lactamase, and plasmidic AmpC beta-lactamase genes were analyzed and characterized by PCR and sequencing. Genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE) using XbaI and multilocus sequencing typing. The bla and bla carbapenemase genes were detected among R/IR-ERT isolates. All R/IR-ERT K. pneumoniae strains (n = 19) had bla gene, and 14/19 strains also harbored the bla gene. Eight different PFGE patterns were detected among these K. pneumoniae isolates, and they showed eight different sequences types, ST11 and ST15 being the most prevalent ones. Two out of three R/IR-ERT E. coli isolates carried bla and one coproduced the bla gene. One E. coli strain, ascribed to the new sequence type ST5700, harbored the bla gene. E. coli isolates were not clonally related and belonged to different sequence types (ST5700, ST227, and ST58). To our knowledge, this is the first report in Tunisia of either KPC-2 carbapenemase in E. coli or OXA-48 carbapenemase in K. pneumoniae of lineage ST15.
本研究旨在调查在突尼斯国家骨髓移植中心血液科和移植科患者中引起定植/感染的、对厄他培南表现出耐药/中介耐药表型（R/IR-ERT）的肺炎克雷伯菌和大肠埃希菌菌株的分子特征（2011年至2014年，为期3年）。通过聚合酶链反应（PCR）和测序对主要碳青霉烯酶、超广谱β-内酰胺酶和质粒型AmpCβ-内酰胺酶基因进行分析和鉴定。使用XbaI通过脉冲场凝胶电泳（PFGE）和多位点测序分型确定遗传相关性。在R/IR-ERT分离株中检测到bla和bla碳青霉烯酶基因。所有R/IR-ERT肺炎克雷伯菌菌株（n = 19）都有bla基因，14/19株还携带bla基因。在这些肺炎克雷伯菌分离株中检测到8种不同的PFGE模式，它们显示出8种不同的序列类型，其中ST11和ST15最为常见。三株R/IR-ERT大肠埃希菌分离株中有两株携带bla，一株同时产生bla基因。一株属于新序列类型ST5700的大肠埃希菌菌株携带bla基因。大肠埃希菌分离株无克隆相关性，属于不同的序列类型（ST5700、ST227和ST58）。据我们所知，这是突尼斯关于大肠埃希菌中KPC-2碳青霉烯酶或ST15谱系肺炎克雷伯菌中OXA-48碳青霉烯酶的首次报告。
