Wang Qing, Wei Yanming, Shoaib Muhammad, Qiu Yanhua, Zhang Chao, Dai Guonian, Lin Honglin, Wang Weiwei, Zhang Jiyu
Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, Gansu, China.
Front Cell Infect Microbiol. 2025 Jul 2;15:1594982. doi: 10.3389/fcimb.2025.1594982. eCollection 2025.
The co-existence phenomenon of antibiotic resistance genes (ARGs), particularly of last-resort antibiotics in multi-drug resistant (MDR) bacteria, is of particular concern in the least studied bacterial species.
In 2023, strain M2 was isolated from the sludge sample at a commercial bovine farm in Hebei province, China, using a MacConkey plate containing meropenem. PCR amplification and Sanger sequencing verified it co-carrying and (X) genes. It was classified within the Acinetobacter genus by MALDI-TOF-MS and 16S rDNA analyses. Whole-genome sequencing (WGS) was performed on the Oxford Nanopore platform, with species-level identification via ANI and dDDH. Antimicrobial susceptibility testing was performed against 20 antibiotics. Conjugation assays employed the filter-mating method using J53 and LGJ2 as recipients.
This strain was confirmed as a novel species of genus, showing resistance to meropenem, ampicillin, ceftazidime, cefepime, gentamicin, kanamycin, fosfomycin, imipenem, ertapenem, and tetracycline. Despite carrying (X3), it remained susceptible to tigecycline, omadacycline, and doxycycline. The genome carried 11 ARG types, multiple metal resistance genes (MRGs), and virulence factor (VF) genes. The was located in a skeleton, IS - -, which was carried by an IS14-mediated rolling-circle-like structure in pM2-2-NDM-1 (rep_cluster_481). Integrative and conjugative element (ICE) and multiple pd modules (driven by the XerCD site-specific recombination (XerCD SSR) system), which were associated with the mobilization of resistance determinants, were identified in this plasmid. Chromosomal (X3) was mediated by IS, forming a skeleton, IS (X3).
The co-occurrence of and (X) in a novel species of the genus hints that substantial undiscovered bacteria co-carrying high-risk ARGs are concealing in the agroecological system, which should cause particular concern.
抗生素抗性基因（ARGs）的共存现象，尤其是多重耐药（MDR）细菌中对最后手段抗生素的抗性基因共存现象，在研究最少的细菌物种中尤为令人担忧。
2023年，从中国河北省一家商业奶牛场的污泥样本中分离出菌株M2，使用含有美罗培南的麦康凯平板。PCR扩增和桑格测序验证其共携带 和（X）基因。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）和16S rDNA分析将其归类于不动杆菌属。在牛津纳米孔平台上进行全基因组测序（WGS），通过平均核苷酸一致性（ANI）和数字化DNA-DNA杂交（dDDH）进行物种水平鉴定。对20种抗生素进行药敏试验。接合试验采用滤膜杂交法，以J53和LGJ作为受体菌。
该菌株被确认为 属的一个新物种，对美罗培南、氨苄西林、头孢他啶、头孢吡肟、庆大霉素、卡那霉素、磷霉素、亚胺培南、厄他培南和四环素耐药。尽管携带（X3），但对替加环素、奥马环素和多西环素仍敏感。该基因组携带11种ARGs类型、多个金属抗性基因（MRGs）和毒力因子（VF）基因。 位于一个骨架IS - - 中，该骨架由pM2-2-NDM-1（rep_cluster_481）中IS14介导类似滚环结构携带。在该质粒中鉴定出与抗性决定簇转移相关的整合和接合元件（ICE）和多个pd模块（由XerCD位点特异性重组（XerCD SSR）系统驱动）。染色体（X3）由IS介导，形成一个骨架IS（X3）。
和（X）在 属的一个新物种中共存，这暗示在农业生态系统中大量未被发现的共携带高风险ARGs的细菌正隐匿其中，这应引起特别关注。
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