IS <i>26</i> Mediates the Acquisition of Tigecycline Resistance Gene Cluster <i>tmexCD1-toprJ1</i> by IncHI1B-FIB Plasmids in Klebsiella pneumoniae and Klebsiella quasipneumoniae from Food Market Sewage
Miao Wan, Xun Gao, Luchao Lv, Zhongpeng Cai, Jian–Hua Liu
Abstract
Tigecycline and colistin are considered the final options for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria, especially carbapenem-resistant Enterobacteriaceae (1). Unfortunately, the global distribution of mcr genes has challenged the clinical usage of colistin (2), leaving tigecycline as one of the limited options. Nevertheless, two novel plasmid-mediated tigecycline resistance mechanisms, i.e., tet(X) variants (3) and the resistance-nodulation-cell division family efflux pump gene cluster, tmexCD1-toprJ1 (4), have recently been detected. Unlike tet(X) variants which are rarely detected in Klebsiella pneumoniae (3, 5), tmexCD1-toprJ1 was most detected in K. pneumoniae (4, 6), one of the most serious bacterial pathogens causing a high mortality rate in patients (7). Currently, TMexCD1-TOprJ1-producing Enterobacteriaceae (TME) were mostly detected in samples from farm chickens in China (4). In addition, approximately 1.6% cecum samples of chickens at slaughter and 3.5% retail meat samples from food markets carried TME (4). Considering that TME in live poultry and retail meat sold in food markets might contaminate the market environment, we thus investigated the prevalence and characterization of TME among the environmental sewage samples from food markets in Guangzhou, China.