Clinical Microbiology Laboratory, The Second Affiliated Hospital of Zhejiang Universitygrid.412465.0 School of Medicine, Zhejiang University, Hangzhou, China.
Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Konggrid.35030.35, Hong Kong, China.
Microbiol Spectr. 2022 Dec 21;10(6):e0134622. doi: 10.1128/spectrum.01346-22. Epub 2022 Nov 14.
With the globally prevailing carbapenemase-producing (CP) spp., polymyxin antibiotics have been reconsidered as one of the last-resort treatment options. Our study was conducted to investigate the prevalence of in species. From October to November 2021, 650 fecal samples and 215 isolates were collected from healthy individuals and infected patients, respectively. Isolates were screened for the presence of the gene by the PCR method. -carrying strains were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Due to the susceptibility to colistin, spp. isolates were first induced to increase the expression of on China blue agar plates containing colistin and were then subjected to conjugation experiments. Whole-genome sequencing was performed on the Illumina NovaSeq PE150 system. The prevalence of in the genus from healthy guts and infected patients was 0.62% and 1.86%, respectively. In all -positive strains, MICs of polymyxin B were observed at ≤2 μg/mL, displaying a nonresistant phenotype. As for conjugation experiments, only one isolate successfully transferred the gene to Escherichia coli C600. Whole-genome sequencing showed that eight -positive isolates carried and genes encoding resistance to beta-lactam antibiotics, including , , , , and . We also discovered that could be located on the pKPC-CAV1321 plasmid. Our study investigated the prevalence of - in spp. in both healthy individuals and infected patients and described the carriage of on the pKPC-CAV1321 plasmid for the first time. The emergence of homologues posed a serious threat to the therapeutic efficiency of polymyxin antibiotics. Citrobacter freundii is generally regarded as an opportunistic pathogen associated with a variety of nosocomial infections. In this study, we investigated the prevalence of in spp. isolates from healthy individuals and infected patients and highlighted the importance of the rational use of antibiotics. In addition, this epidemiological investigation is the first to describe the carriage of on plasmid pKPC-CAV1321 and confirms the horizontal transfer of this plasmid. Our research may shed new light on further studies of dissemination in humans.
随着全球流行的碳青霉烯酶产生（CP） spp.，多粘菌素类抗生素已被重新考虑为最后治疗选择之一。我们的研究旨在调查 在 spp. 中的流行情况。2021 年 10 月至 11 月，分别从健康个体和感染患者中收集了 650 份粪便样本和 215 株分离株。通过 PCR 方法筛选分离株中 是否存在 基因。利用基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱法鉴定 携带菌株。由于对粘菌素的敏感性，首先在含有粘菌素的中国蓝琼脂平板上诱导 spp. 分离株增加 的表达，然后进行共轭实验。使用 Illumina NovaSeq PE150 系统对全基因组进行测序。健康肠道和感染患者中 属的 流行率分别为 0.62%和 1.86%。所有 阳性菌株的多粘菌素 B MIC 值均观察到≤2μg/ml，表现出非耐药表型。对于共轭实验，只有一个分离株成功地将 基因转移到大肠杆菌 C600 中。全基因组测序显示，八个 阳性 分离株携带 和编码对β-内酰胺类抗生素耐药的基因，包括 、 、 、 和 。我们还发现 可以位于 pKPC-CAV1321 质粒上。我们的研究调查了健康个体和感染患者中 属中 的流行情况，并首次描述了 pKPC-CAV1321 质粒上 的携带情况。同源物的出现对多粘菌素类抗生素的治疗效果构成了严重威胁。弗氏柠檬酸杆菌通常被认为是与多种医院感染相关的机会致病菌。在这项研究中，我们调查了健康个体和感染患者中 spp. 分离株中 的流行情况，并强调了合理使用抗生素的重要性。此外，这项流行病学调查首次描述了质粒 pKPC-CAV1321 上携带 ，并证实了该质粒的水平转移。我们的研究可能为进一步研究人类中 的传播提供新的思路。
