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Li SM, Zhou YF, Li L, Fang LX, Duan JH, Liu FR, Liang HQ, Wu YT, Gu WQ, Liao XP, Sun J, Xiong YQ, Liu YH. Characterization of the Multi-Drug Resistance Gene cfr in Methicillin-Resistant Staphylococcus aureus (MRSA) Strains Isolated From Animals and Humans in China. Front Microbiol 2018; 9:2925. [PMID: 30538695 PMCID: PMC6277690 DOI: 10.3389/fmicb.2018.02925] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 11/14/2018] [Indexed: 01/03/2023] Open
Abstract
We investigated cfr-positive and -negative MRSA strains isolated from animals and humans in different geographical areas of China, from 2011 to 2016. Twenty cfr-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 cfr-positive MRSA isolates were higher than that in the cfr-negative MRSA isolates. All cfr-positive MRSA isolates were co-carrying fexA and ermC, and had significantly higher optrA incidence rate vs. the cfr-negative isolates (P < 0.05). In addition, multilocus sequence typing (MLST) assays showed that ST9 and spa-type t899 were the most prevalent ST and spa types in the study strains. However, all of the 20 cfr-positive and 10 randomly selected cfr-negative MRSA isolates were clonally unrelated as determined by pulsed-field gel electrophoresis (PFGE) analyses. Importantly, the cfr gene was successfully transferred to a recipient Staphylococcus aureus strain RN4220 from 13 of the 20 cfr-positive MRSA isolates by electroporation. Among these 13 cfr-positive MRSA isolates, two different genetic contexts surrounding cfr were determined and each was associated with one type of cfr-carrying plasmids. Of note, the predominant genetic context of cfr was found to be a Tn558 variant and locate on large plasmids (∼50 kb) co-harboring fexA in 11 of the 13 MRSA isolates. Furthermore, the cfr gene was also identified on small plasmids (∼ 7.1 kb) that co-carried ermC in two of the 13 MRSA isolates. Our results demonstrated a high occurrence of multi-drug resistance in cfr-positive MRSA isolates, and the spread of cfr might be attributed to horizontal dissemination of similar cfr-carrying transposons and plasmids.
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Affiliation(s)
- Shu-Min Li
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yu-Feng Zhou
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States
| | - Liang Li
- LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States
| | - Liang-Xing Fang
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jia-Hong Duan
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Fan-Rui Liu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Hua-Qing Liang
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yu-Ting Wu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Wei-Qi Gu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xiao-Ping Liao
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jian Sun
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yan-Qiong Xiong
- LABioMed at Harbor-UCLA Medical Center, Torrance, CA, United States.,Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Ya-Hong Liu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
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