Domingo M-C, Huletsky A, Bernal A, Giroux R, Boudreau D K, Picard F J, Bergeron M G
Centre de Recherche en Infectiologie de l'Université Laval, CHUQ, Pavillon CHUL, 2705 boul. Laurier, Sainte-Foy, Québec G1V 4G2, Canada.
J Antimicrob Chemother. 2005 Apr;55(4):466-74. doi: 10.1093/jac/dki029. Epub 2005 Feb 24.
During a hospital surveillance programme to detect VRE carriers, an anaerobic vancomycin-resistant bacterial strain CCRI-9842 containing a vanB gene was isolated from a human faecal specimen. In this study, we have characterized this strain and its vanB-containing element.
Strain CCRI-9842 was characterized by 16S rDNA sequencing and susceptibility testing. PCR mapping and sequencing of the vanB-containing element, as well as plasmid extraction and mating experiments, were carried out to investigate the genetic basis of vancomycin resistance in this strain.
Strain CCRI-9842 was identified as a Clostridium species closely related to Clostridium bolteae (96.8% 16S rDNA identity). This strain was resistant to a high level of vancomycin (MIC of 256 mg/L), but was susceptible to teicoplanin and ampicillin. The complete sequence of the CCRI-9842 vanB gene exhibited 99.1% identity with that of vanB2. PCR mapping and sequencing showed that the genetic element carrying vanB2 was similar to transposon Tn5382/Tn1549. This Tn5382-like transposon forms circular intermediates and is flanked on the left and right ends by repeat sequences of at least 700 bp in the opposite direction. No plasmid was detected in this strain, suggesting that the Tn5382-like transposon was integrated into the chromosome. The vancomycin resistance was not transferable to enterococci.
Our report shows for the first time the presence of a Tn5382-like transposon carrying vanB2 in a Clostridium species of the human intestinal flora. This suggests that the vanB2 Tn5382-like transposon is an important vector for the spread of vancomycin resistance in several bacterial species.
在一项检测耐万古霉素肠球菌（VRE）携带者的医院监测计划中，从一份人类粪便标本中分离出了一株含有vanB基因的厌氧性耐万古霉素菌株CCRI - 9842。在本研究中，我们对该菌株及其含vanB的元件进行了特性分析。
通过16S rDNA测序和药敏试验对CCRI - 9842菌株进行特性分析。对含vanB的元件进行PCR图谱分析和测序，以及质粒提取和接合试验，以研究该菌株中万古霉素耐药性的遗传基础。
CCRI - 9842菌株被鉴定为与布氏梭菌密切相关的梭菌属物种（16S rDNA同源性为96.8%）。该菌株对高水平的万古霉素耐药（MIC为256 mg/L），但对替考拉宁和氨苄西林敏感。CCRI - 9842 vanB基因的完整序列与vanB2的序列一致性为99.1%。PCR图谱分析和测序表明，携带vanB2的遗传元件与转座子Tn5382/Tn1549相似。这种类似Tn5382的转座子形成环状中间体，其左右两端由至少700 bp的反向重复序列侧翼。在该菌株中未检测到质粒，表明类似Tn5382的转座子整合到了染色体中。万古霉素耐药性不能转移到肠球菌。
我们的报告首次表明在人类肠道菌群的梭菌属物种中存在携带vanB2的类似Tn5382的转座子。这表明vanB2类似Tn5382的转座子是几种细菌物种中万古霉素耐药性传播的重要载体。
