Unidad de Gestión Clínica de Enfermedades Infecciosas Y Microbiología Clínica, Hospital Universitario Virgen Macarena, Seville, Spain.
Spanish Network for the Research in Infectious Diseases (REIPI RD16/0016, RD16/CIII/0004/0002), Instituto de Salud Carlos III, Madrid, Spain.
Appl Microbiol Biotechnol. 2021 Dec;105(24):9231-9242. doi: 10.1007/s00253-021-11684-2. Epub 2021 Nov 30.
Carbapenemase-producing Klebsiella pneumoniae (CP-Kp) is a real global health threat. Environmental reservoirs of resistance gene determinats, such as effluents of hospital wastewaters, are acquiring increased relevance in the selection of plasmid-encoded carbapenemase genes. The presence of Hg in environmental reservoirs may exert a positive selective pressure on tolerant bacteria, favoring the co-transfer of carbapenemase genes and mer operons. In our study, 63 CP-Kp isolates were screened for mer operons by whole genome sequencing (MySeq). Conjugation assays were performed with 24 out of 63 CP-Kp isolates harboring the mer operon. Ten transconjugants (Tc-Kp) were selected with Hg. Plasmid DNA of Tc-Kp was extracted and sequenced using single-molecule real-time (SMRT) technology (PacBio, Sequel II system) with later annotation. Plasmid analysis revealed that Tc-Kp from bla (n = 3) showed a single plasmid belonging to IncC group with two complete mer operon next to bla. Tc-Kp from bla (n = 2) harbored two plasmids, one with bla in an IncL, and mer operon was in an IncFIB plasmid. Tc-Kp from bla (n = 5) showed 2 plasmids. bla was found in an IncL plasmid, whereas mer operon was (i) in an IncR plasmid associated with bla in 3 Tc-Kp-OXA-48-like, (ii) in an IncC plasmid associated with bla in 1 Tc-Kp-OXA-48-like, (iii) and in an IncFIB plasmid associated with bla in 1 Tc-Kp-OXA-48-like. This is, to our knowledge, the first study to describe in K. pneumoniae producing plasmid-encoded carbapenemase, the potential impact of Hg in the co-transfer of mer operons and carbapenemase genes located in the same or different plasmids. KEY POINTS: • Environmental reservoirs are playing an important role in the selection of carbapenemase genes. • Conjugation assays, selecting with Hg, obtained 10 transconjugants with carbapenemase genes. • mer operons were located in the same or different plasmids than carbapenemase genes.
产碳青霉烯酶肺炎克雷伯菌（CP-Kp）是真正的全球健康威胁。抗性基因决定因素的环境储库，如医院废水的流出物，在选择质粒编码的碳青霉烯酶基因方面变得越来越重要。环境储库中的汞可能对耐受细菌施加正向选择压力，有利于碳青霉烯酶基因和 mer 操纵子的共同转移。在我们的研究中，通过全基因组测序（MySeq）筛选了 63 株 CP-Kp 分离株以检测 mer 操纵子。对 63 株 CP-Kp 分离株中的 24 株携带 mer 操纵子的分离株进行了接合试验。用 Hg 选择了 10 个转导子（Tc-Kp）。用单分子实时（SMRT）技术（PacBio，Sequel II 系统）提取并测序 Tc-Kp 的质粒 DNA，并进行了后期注释。质粒分析显示，bla（n=3）的 Tc-Kp 表现为单一质粒，属于 IncC 组，紧邻 bla 的两个完整 mer 操纵子。bla（n=2）的 Tc-Kp 携带两个质粒，一个带有 bla 的 IncL 和 mer 操纵子位于 IncFIB 质粒上。bla（n=5）的 Tc-Kp 显示 2 个质粒。bla 位于 IncL 质粒上，而 mer 操纵子位于（i）与 3 株 Tc-Kp-OXA-48 样菌中的 bla 相关的 IncR 质粒上，（ii）与 1 株 Tc-Kp-OXA-48 样菌中的 bla 相关的 IncC 质粒上，（iii）与 1 株 Tc-Kp-OXA-48 样菌中的 bla 相关的 IncFIB 质粒上。这是，据我们所知，首次在产质粒编码碳青霉烯酶的肺炎克雷伯菌中描述 Hg 在 mer 操纵子和位于同一或不同质粒上的碳青霉烯酶基因的共同转移中的潜在影响。关键点：• 环境储库在选择碳青霉烯酶基因方面发挥着重要作用。• 用 Hg 进行的接合试验获得了 10 株带有碳青霉烯酶基因的转导子。• mer 操纵子位于与碳青霉烯酶基因相同或不同的质粒上。
