Falco Restrepo Aura Dayana, Velásquez Nieves Mariel Alexandra, Takiff Howard
Facultad de Ciencias Básicas, Universidad Santiago de Cali, Cali 760040, Colombia; Laboratorio de Genética Molecular, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Km. 11, Carretera Panamericana, Caracas 1020A, Venezuela.
Laboratorio de Genética Molecular, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Km. 11, Carretera Panamericana, Caracas 1020A, Venezuela.
Enferm Infecc Microbiol Clin. 2017 Aug-Sep;35(7):411-416. doi: 10.1016/j.eimc.2017.01.010. Epub 2017 Mar 11.
Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria are amongst the most important causative agents of nosocomial infections worldwide. Isolates of this bacterium have been identified in Venezuela but little is known about their local spread. The aim of this study was to perform the molecular characterization of KPC-producing strains isolated from 2012 to 2013 in a public hospital in Caracas, Venezuela.
Twenty-two K. pneumoniae clinical isolates phenotypically classified as KPC producing were subjected to PCR screening for the presence of bla genes and their location within transposon Tn4401. The bla PCR product was sequenced to identify the KPC alleles. Genotypic analysis was performed by means of repetitive extragenic palindromic PCR (rep-PCR) and Multi Locus Sequence Typing (MLST). Finally, conjugation and electroporation assays were used to determine whether the bla genes were found in plasmids.
All isolates contained the bla variant, and 21 of the 22 were associated with the Tn4401b isoform. The strains were distributed in 8 sequence types (ST), three of which were new. Conjugation and electroporation assays indicated that 95.5% (n=21/22) of the isolates contained the bla gene in plasmids.
This study on circulating bacterial strains and the identification of KPC alleles may help to understand the routes of dissemination and control their spread within this hospital.
产肺炎克雷伯菌碳青霉烯酶（KPC）的细菌是全球医院感染最重要的病原体之一。委内瑞拉已鉴定出该细菌的分离株，但对其在当地的传播情况知之甚少。本研究的目的是对2012年至2013年在委内瑞拉加拉加斯一家公立医院分离出的产KPC菌株进行分子特征分析。
对22株表型分类为产KPC的肺炎克雷伯菌临床分离株进行PCR筛选，以检测bla基因的存在及其在转座子Tn4401中的位置。对bla PCR产物进行测序以鉴定KPC等位基因。通过重复外源性回文PCR（rep-PCR）和多位点序列分型（MLST）进行基因分型分析。最后，采用接合和电穿孔试验来确定bla基因是否存在于质粒中。
所有分离株均含有bla变体，22株中有21株与Tn4401b亚型相关。这些菌株分布在8种序列类型（ST）中，其中3种是新的。接合和电穿孔试验表明，95.5%（n = 21/22）的分离株在质粒中含有bla基因。
这项关于循环细菌菌株和KPC等位基因鉴定的研究可能有助于了解传播途径并控制其在该医院内的传播。
