Infection and Drug Resistance (Jul 2021)

Occurrence of mcr Positive Strains and Molecular Characteristics of Two mcr-1 Positive Salmonella typhimurium and Escherichia coli from a Chinese Women’s and Children’s Hospital

  • Zheng Z,
  • Lei Y,
  • Wang Y,
  • Lin C,
  • Lin J

Journal volume & issue
Vol. Volume 14
pp. 2925 – 2932


Read online

Zhenzhu Zheng, Ying Lei, Yinna Wang, Chunli Lin, Jiansheng Lin Department of Laboratory Medicine, Quanzhou Women’s and Children’s Hospital, Quanzhou, People’s Republic of ChinaCorrespondence: Jiansheng LinDepartment of Laboratory Medicine, Quanzhou Women’s and Children’s Hospital, 700 Fengze Street, Fengze District, Quanzhou, Fujian Province, 350122, People’s Republic of ChinaTel +86 0595 22196131Email [email protected]: The purpose of this study was to evaluate the prevalence of mobile colistin resistance genes (mcr) in Gram-negative bacteria and to analyze the molecular characteristics of mcr-1 positive Salmonella typhimurium strain 75 and Escherichia coli strain 107 from the Quanzhou Women’s and Children’s Hospital in China.Methods: The genes mcr-1 through mcr-9 were screened via multiplex PCR. Antibiotic susceptibility was detected using a GN11 card with the VITEK-2 compact automated system. Whole genomes were sequenced using PacBio’s single molecule real-time (SMRT) technology.Results: In this study, mcr-1 was detected in only four strains, with a positivity rate of 0.65% (4/616). All the four strains were resistant to more than three different kinds of antibiotics. The mcr-1 positive S. typhimurium strain 75 harbored IncHI2 plasmid, which carried mcr-1 gene, while the mcr-1 positive E. coli strain 107 contained four plasmids including one mcr-1 harboring IncHI2 plasmid, one IncFII plasmid and two IncI1-I (Alpha) plasmids. Mobile elements carrying mcr-1 in the 75_plasmid and 107_plasmid-1 were located in the IS1086(ISApl1)-IS30A(ISApl1)-mcr-1-hp and IS1086(ISApl1)-mcr-1-hp regions, respectively. Tn6010 carrying drug efflux pump genes was found in 75_plasmid, while cn_31611_IS26 carrying multi-drug resistance (MDR) genes were found in 107_plasmid-1.Conclusion: This study found that mcr-1 was prevalent at a low frequency in the Quanzhou Women’s and Children’s Hospital. A similar genetic pattern of mcr-1 transmission was found in both E. coli and S. typhimurium.Keywords: mcr-1, Salmonella typhimurium, Escherichia coli, molecular characteristics