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Zhang CZ, Ren SQ, Chang MX, Chen PX, Ding HZ, Jiang HX. Resistance mechanisms and fitness of Salmonella Typhimurium and Salmonella Enteritidis mutants evolved under selection with ciprofloxacin in vitro. Sci Rep 2017; 7:9113. [PMID: 28831084 PMCID: PMC5567280 DOI: 10.1038/s41598-017-09151-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 07/24/2017] [Indexed: 12/02/2022] Open
Abstract
The aim of this study was to investigate the difference in resistance mechanisms and fitness of Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE) mutants selected during the evolution of resistance under exposure to increasing ciprofloxacin concentrations in vitro. Mutations in quinolone target genes were screened by PCR. Phenotypic characterization included susceptibility testing by the broth dilution method, investigation of efflux activity and growth rate, and determination of the invasion of human intestinal epithelium cells in vitro. The two Salmonella serotypes exhibited differences in target gene mutations and efflux pump gene expression during the development of resistance. In the parental strains, ST had a competitive advantage over SE. During the development of resistance, initially, the SE strain was more competitive. However, once ciprofloxacin resistance was acquired, ST once again became the more competitive strain. In the absence of bile salts or at 0.1% bile, the growth rate of SE was initially greater than that of ST, but once ciprofloxacin resistance was acquired, ST had higher growth rates. ST strains showed decreased invasion of epithelial cells in 0.1% bile. These data indicate that ciprofloxacin-resistant ST strains are more competitive than ciprofloxacin-resistant SE strains.
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Affiliation(s)
- Chuan-Zhen Zhang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China.,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China
| | - Si-Qi Ren
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China.,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China
| | - Man-Xia Chang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China.,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China
| | - Pin-Xian Chen
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China.,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China
| | - Huan-Zhong Ding
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China.,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China
| | - Hong-Xia Jiang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China. .,National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, 510642, China.
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