Laboratory Medicine Center, Department of Clinical Laboratory, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, China.
Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China.
Sci Total Environ. 2024 Nov 25;953:176065. doi: 10.1016/j.scitotenv.2024.176065. Epub 2024 Sep 5.
The emergence of tmexCD-toprJ, a novel plasmid-mediated resistance-nodulation-division (RND) type efflux pump gene cluster, poses a significant threat to public health by diminishing bacterial susceptibility to the last-resort antibiotics, including tigecycline. Between 2020 and 2022, 18 Klebsiella pneumoniae strains carrying the tmexCD-toprJ gene were recovered from over 30,000 human stool samples collected from patients across five hospitals in China. Phylogenetic analysis of these 18 strains revealed clonal transmission of tmexCD-toprJ-carrying K. pneumoniae among patients and hospital settings. Comparative analysis of the 18 tmexCD-toprJ-carrying plasmids showed conservation in the genetic backgrounds of tmexCD-toprJ, despite the diverse backbone structures among the plasmids. The inactive suppressor, TNfxB1, is located in front of all tmexCD1-toprJ1, while TNfxB3 is located upstream of tmexCD3-toprJ3. Conjugation experiments demonstrated the transferability of plasmids from three strains to the recipient Escherichia coli J53. Among all 237 globally distributed tmexCD-toprJ-carrying strains, the majority (92.83 %) were from China. These strains encompassed 50 sequence types, with the most prevalent being ST11 (12.66 %), ST37 (11.81 %), and ST15 (11.39 %). Samples originated from various sources: 47.26 % from human, 38.82 % from livestock, and 13.08 % from the environment. The most common tmexCD-toprJ genotype was tmexCD1-toprJ1 (86.92 %, n = 206), followed by tmexCD2-toprJ2 (8.86 %, n = 21) and tmexCD3-toprJ3 (4.22 %, n = 10). The tmexCD1-toprJ1 gene was found in livestock (44.66 %, n = 92), humans (39.81 %, n = 82), and environmental samples (15.05 %, n = 31). In contrast, tmexCD2-toprJ2 and tmexCD3-toprJ3 were only found in human samples. Additionally, tmexCD-toprJ has been detected in 79 strains of K. pneumoniae harboring carbapenem-resistance genes. Given the presence of tmexCD-toprJ across various hosts and environments, establishing a comprehensive surveillance system from a One Health perspective is particularly vital.
新型质粒介导的耐药-结节-分裂（RND）型外排泵基因簇 tmexCD-toprJ 的出现，对公共健康构成了重大威胁，因为它降低了细菌对包括替加环素在内的最后手段抗生素的敏感性。在 2020 年至 2022 年期间，从中国五家医院的 30000 多个人类粪便样本中分离出了携带 tmexCD-toprJ 基因的 18 株肺炎克雷伯菌。对这 18 株菌的系统发育分析显示，tmexCD-toprJ 携带的肺炎克雷伯菌在患者和医院环境中存在克隆传播。对 18 株 tmexCD-toprJ 携带的质粒进行比较分析显示，尽管质粒之间的骨架结构不同，但 tmexCD-toprJ 的遗传背景具有保守性。非活性抑制剂 TNfxB1 位于所有 tmexCD1-toprJ1 的前面，而 TNfxB3 位于 tmexCD3-toprJ3 的上游。接合实验表明，来自三个菌株的质粒可转移到受体大肠杆菌 J53 中。在所有 237 株全球分布的 tmexCD-toprJ 携带菌株中，大多数（92.83%）来自中国。这些菌株包含 50 个序列类型，最常见的是 ST11（12.66%）、ST37（11.81%）和 ST15（11.39%）。样本来自不同来源：47.26%来自人类，38.82%来自家畜，13.08%来自环境。最常见的 tmexCD-toprJ 基因型是 tmexCD1-toprJ1（86.92%，n=206），其次是 tmexCD2-toprJ2（8.86%，n=21）和 tmexCD3-toprJ3（4.22%，n=10）。tmexCD1-toprJ1 基因在畜群（44.66%，n=92）、人类（39.81%，n=82）和环境样本（15.05%，n=31）中均有发现。相比之下，tmexCD2-toprJ2 和 tmexCD3-toprJ3 仅在人类样本中发现。此外，在 79 株携带碳青霉烯类耐药基因的肺炎克雷伯菌中也检测到了 tmexCD-toprJ。鉴于 tmexCD-toprJ 存在于各种宿主和环境中，从“同一健康”的角度建立一个全面的监测系统尤为重要。
