PDF(Pubmed)
Abstract：
Vancomycin variable Enterococcus (VVE) bacteria are phenotypically susceptible to vancomycin, but they harbor the vanA gene. We aimed to ascertain the prevalence of VVE among clinically isolated vancomycin-susceptible Enterococcus faecium (VSE) isolates, as well as elucidate the molecular characteristics of the vanA gene cluster within these isolates. Notably, we investigated the prevalence and structure of the vanA gene cluster of VVE. Between June 2021 and May 2022, we collected consecutive, non-duplicated vancomycin-susceptible Enterococcus faecium (VSE) samples. Real-time PCR was performed to detect the presence of vanA, vanB, and vanC. Overlapping PCR with sequencing and whole-genome sequencing were performed for structural analysis. Sequence types (STs) were determined by multilocus sequence typing. Exposure testing was performed to assess the ability of the isolates to acquire vancomycin resistance. Among 282 VSE isolates tested, 20 isolates (7.1%) were VVE. Among them, 17 isolates had partial deletions in the IS1216 or IS1542 sequences in vanS (N=10), vanR (N=5), or vanH (N=2). All VVE isolates belonged to the CC17 complex and comprised five STs, namely ST17 (40.0%), ST1421 (25.0%), ST80 (25.0%), ST787 (5.0%), and ST981 (5.0%). Most isolates were related to three hospital-associated clones (ST17, ST1421, and ST80). After vancomycin exposure, 18 of the 20 VVEs acquired vancomycin resistance. Considering the high reversion rate, detecting VVE by screening VSE for vanA is critical for appropriate treatment and infection control.
摘要：
万古霉素可变肠球菌（VVE）细菌在表型上对万古霉素敏感，但他们藏有vanA基因.我们旨在确定临床分离的对万古霉素敏感的屎肠球菌（VSE）分离株中VVE的患病率，以及阐明这些分离株中vanA基因簇的分子特征。值得注意的是,我们调查了VVE的vanA基因簇的患病率和结构。在2021年6月至2022年5月之间，我们收集了连续的，非重复万古霉素敏感屎肠球菌（VSE）样品。进行实时PCR以检测vanA的存在，vanB,还有VanC.将PCR与测序和全基因组测序重叠进行结构分析。通过多位点序列分型确定序列类型(STs)。进行暴露测试以评估分离株获得万古霉素抗性的能力。在测试的282个VSE分离株中，20株(7.1%)为VVE。其中,17个分离株在vanS中的IS1216或IS1542序列中有部分缺失（N=10），vanR(N=5),或vanH（N=2）。所有VVE分离株都属于CC17复合体，包含5个STs，即ST17（40.0%），ST1421（25.0%），ST80（25.0%），ST787（5.0%），和ST981（5.0%）。大多数分离株与三个医院相关克隆（ST17，ST1421和ST80）有关。万古霉素暴露后，20个VVE中有18个获得了万古霉素抗性。考虑到较高的回复率，通过筛查VSE中的vanA来检测VVE对于适当的治疗和感染控制至关重要。
