Characterization of the Multi-Drug Resistance Gene cfr in Methicillin-Resistant Staphylococcus aureus (MRSA) Strains Isolated From Animals and Humans in China

• Published in: Frontiers in microbiology Vol. 9; p. 2925
• Main Authors: Li, Shu-Min, Zhou, Yu-Feng, Li, Liang, Fang, Liang-Xing, Duan, Jia-Hong, Liu, Fan-Rui, Liang, Hua-Qing, Wu, Yu-Ting, Gu, Wei-Qi, Liao, Xiao-Ping, Sun, Jian, Xiong, Yan-Qiong, Liu, Ya-Hong
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 27.11.2018
• Subjects: cfr; food animals; Microbiology; MRSA; multi-drug resistance; plasmid; multi-drug resistance; plasmid; food animals; cfr; MRSA
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2018.02925

We investigated -positive and -negative MRSA strains isolated from animals and humans in different geographical areas of China, from 2011 to 2016. Twenty -positive strains (15.6%) were identified from 128 MRSA strains including 17 from food animals and three from humans. The resistance rates and prevalence of the tested antibiotic resistance genes (ARGs) in the -positive MRSA isolates were higher than that in the -negative MRSA isolates. All -positive MRSA isolates were co-carrying and , and had significantly higher incidence rate vs. the -negative isolates ( < 0.05). In addition, multilocus sequence typing (MLST) assays showed that ST9 and -type t899 were the most prevalent ST and types in the study strains. However, all of the 20 -positive and 10 randomly selected -negative MRSA isolates were clonally unrelated as determined by pulsed-field gel electrophoresis (PFGE) analyses. Importantly, the gene was successfully transferred to a recipient strain RN4220 from 13 of the 20 -positive MRSA isolates by electroporation. Among these 13 -positive MRSA isolates, two different genetic contexts surrounding were determined and each was associated with one type of -carrying plasmids. Of note, the predominant genetic context of was found to be a Tn variant and locate on large plasmids (∼50 kb) co-harboring in 11 of the 13 MRSA isolates. Furthermore, the gene was also identified on small plasmids (∼ 7.1 kb) that co-carried in two of the 13 MRSA isolates. Our results demonstrated a high occurrence of multi-drug resistance in -positive MRSA isolates, and the spread of might be attributed to horizontal dissemination of similar -carrying transposons and plasmids.