Yinxia Li1, Yaowen Zhang1, Maoyi Chen2, Jie Hu2, Haoran Zhang3, Ying Xiang3, Haiyan Yang4, Shaofu Qiu5, Hongbin Song6. 1. Department of Epidemiology, College of Public Health of Zhengzhou University, Zhengzhou, China; Chinese PLA Center for Disease Control and Prevention, Beijing, China. 2. Jingzhou City Center for Disease Control and Prevention, Hubei, China. 3. Chinese PLA Center for Disease Control and Prevention, Beijing, China. 4. Department of Epidemiology, College of Public Health of Zhengzhou University, Zhengzhou, China. Electronic address: yhy@zzu.edu.cn. 5. Chinese PLA Center for Disease Control and Prevention, Beijing, China. Electronic address: qiushf0613@hotmail.com. 6. Chinese PLA Center for Disease Control and Prevention, Beijing, China. Electronic address: hongbinsong@263.net.
Abstract
BACKGROUND: Antimicrobial resistance of Salmonella enterica is a major global concern. Recent findings suggest that colistin as a last resort treatment for multidrug-resistant gram-negative bacteria is seriously threatened by the report of plasmid-mediated colistin resistance gene mcr-1 in China. METHODS: A total of 827 S. Typhimurium isolates were recovered from 4 cities of China, including Henan, Shanghai, Zhejiang, and Hubei provinces. Subsequently, mcr-1 presence was identified by PCR screening. Antimicrobial susceptibility testing was performed by broth microdilution using a 96-well microtiter plate. Plasmid conjugation transfer experiments were conducted using Escherichia coli J53 as the recipient. RESULTS: Only one mcr-1 positive strain from the stool sample of an infant with acute diarrhea was isolated. Apart from colistin, the mcr-1-positive isolate showed co-resistance to the third-generation cephalosporins, ampicillin, nalidixic acid, tetracycline, chloramphenicol, sulfisoxazole, gentamicin, and cefotaxime revealing a multidrug-resistant phenotype. This strain harbored mcr-1 on a 227 kb IncHI2 plasmid, termed pJZ26, which could be transferred to E. coli J53. In addition to mcr-1, pJZ26 coharbored other resistance genes, including aph(4)-Ia, aac(3)-IVa, fosA, floR, sul2, and blaCTX-M-14. Compared with p2474-MCR1 and pHYEC7-IncHI2, pJZ26 contains an additional 4.6 kb fragment harboring the resistance gene tet(A) and its regulator tetR located on TnAs1 transposable element, which could mediate resistance to tetracycline. CONCLUSIONS: These findings highlight that the fact the mcr-1-harboring plasmid pJZ26 has a high potential to disseminate the mcr-1 gene and further challenge the clinical treatment.
BACKGROUND: Antimicrobial resistance of Salmonella enterica is a major global concern. Recent findings suggest that colistin as a last resort treatment for multidrug-resistant gram-negative bacteria is seriously threatened by the report of plasmid-mediated colistin resistance gene mcr-1 in China. METHODS: A total of 827 S. Typhimurium isolates were recovered from 4 cities of China, including Henan, Shanghai, Zhejiang, and Hubei provinces. Subsequently, mcr-1 presence was identified by PCR screening. Antimicrobial susceptibility testing was performed by broth microdilution using a 96-well microtiter plate. Plasmid conjugation transfer experiments were conducted using Escherichia coli J53 as the recipient. RESULTS: Only one mcr-1 positive strain from the stool sample of an infant with acute diarrhea was isolated. Apart from colistin, the mcr-1-positive isolate showed co-resistance to the third-generation cephalosporins, ampicillin, nalidixic acid, tetracycline, chloramphenicol, sulfisoxazole, gentamicin, and cefotaxime revealing a multidrug-resistant phenotype. This strain harbored mcr-1 on a 227 kb IncHI2 plasmid, termed pJZ26, which could be transferred to E. coli J53. In addition to mcr-1, pJZ26 coharbored other resistance genes, including aph(4)-Ia, aac(3)-IVa, fosA, floR, sul2, and blaCTX-M-14. Compared with p2474-MCR1 and pHYEC7-IncHI2, pJZ26 contains an additional 4.6 kb fragment harboring the resistance gene tet(A) and its regulator tetR located on TnAs1 transposable element, which could mediate resistance to tetracycline. CONCLUSIONS: These findings highlight that the fact the mcr-1-harboring plasmid pJZ26 has a high potential to disseminate the mcr-1 gene and further challenge the clinical treatment.
Authors: Guerino Recinella; Giovanni Marasco; Giovanni Serafini; Lorenzo Maestri; Giampaolo Bianchi; Paola Forti; Marco Zoli Journal: Aging Clin Exp Res Date: 2020-10-08 Impact factor: 3.636