Zhai Weishuai, Tian Yingxin, Shao Dongyan, Zhang Muchen, Li Jiyun, Song Huangwei, Sun Chengtao, Wang Yang, Liu Dejun, Zhang Ying
Key Laboratory of Animal Antimicrobial Resistance Surveillance, Ministry of Agriculture and Rural Affairs, and Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Department of Laboratory Medicine, the First Medical Centre, Chinese PLA General Hospital, Beijing 100853, China.
Antibiotics (Basel). 2022 Aug 6;11(8):1068. doi: 10.3390/antibiotics11081068.
The emergence of the mobile tigecycline-resistance gene, (X4), poses a significant threat to public health. To investigate the prevalence and genetic characteristics of the (X4)-positive in humans, 1101 human stool samples were collected from a tertiary class-A hospital in Beijing, China, in 2019. Eight isolates that were positive for (X4) were identified from clinical departments of oncology ( = 3), hepatology ( = 2), nephrology ( = 1), urology ( = 1), and general surgery ( = 1). They exhibited resistance to multiple antibiotics, including tigecycline, but remained susceptible to meropenem and polymyxin B. A phylogenetic analysis revealed that the clonal spread of four (X4)-positive from different periods of time or departments existed in this hospital, and three isolates were phylogenetically close to the (X4)-positive from animals and the environment. All (X4)-positive isolates contained the IncX1-plasmid replicon. Three isolates successfully transferred their tigecycline resistance to the recipient strain, C600, demonstrating that the plasmid-mediated horizontal gene transfer constitutes another critical mechanism for transmitting (X4). Notably, all (X4)-bearing plasmids identified in this study had a high similarity to several plasmids recovered from animal-derived strains. Our findings revealed the importance of both the clonal spread and horizontal gene transfer in the spread of (X4) within human clinics and between different sources.
移动性替加环素耐药基因（X4）的出现对公众健康构成了重大威胁。为了调查人类中X4阳性的流行情况和遗传特征，2019年从中国北京一家三级甲等医院收集了1101份人类粪便样本。从肿瘤学（n = 3）、肝病学（n = 2）、肾病学（n = 1）、泌尿学（n = 1）和普通外科（n = 1）临床科室中鉴定出8株X4阳性菌株。它们对包括替加环素在内的多种抗生素耐药，但对美罗培南和多粘菌素B仍敏感。系统发育分析显示，该医院存在来自不同时间或科室的4株X4阳性菌株的克隆传播，其中3株在系统发育上与来自动物和环境的X4阳性菌株接近。所有X4阳性菌株均含有IncX1质粒复制子。3株菌株成功地将其替加环素耐药性转移至受体菌株C600，表明质粒介导的水平基因转移是传播X4的另一个关键机制。值得注意的是，本研究中鉴定出的所有携带X4的质粒与从动物源菌株中回收的几种质粒具有高度相似性。我们的研究结果揭示了克隆传播和水平基因转移在X4在人类临床环境中以及在不同来源之间传播中的重要性。
