Identification and Characterization of Conjugative Plasmids That Encode Ciprofloxacin Resistance in Salmonella

Kaichao Chen; Ning Dong; Shaohua Zhao; Lizhang Liu; Ruichao Li; Miaomiao Xie; Dachuan Lin; Edward Wai-Chi Chan; Jianghong Meng; Patrick F McDermott; Sheng Chen

doi:10.1128/AAC.00575-18

Identification and Characterization of Conjugative Plasmids That Encode Ciprofloxacin Resistance in Salmonella

Antimicrob Agents Chemother. 2018 Jul 27;62(8):e00575-18. doi: 10.1128/AAC.00575-18. Print 2018 Aug.

Authors

Kaichao Chen^{1

2}, Ning Dong^{1

2}, Shaohua Zhao³, Lizhang Liu^{1

2}, Ruichao Li^{1

2}, Miaomiao Xie^{1

2}, Dachuan Lin^{1

2}, Edward Wai-Chi Chan^{1

2}, Jianghong Meng⁴, Patrick F McDermott³, Sheng Chen^{5

2}

Affiliations

¹ Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, People's Republic of China.
² State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
³ National Antimicrobial Resistance Monitoring System, Office of Research, Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland, USA.
⁴ Joint Institute for Food Safety and Applied Nutrition, Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA.
⁵ Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, People's Republic of China sheng.chen@polyu.edu.hk.

Abstract

This study aimed to characterize novel conjugative plasmids that encode transferable ciprofloxacin resistance in Salmonella In this study, 157 nonduplicated Salmonella isolates were recovered from food products, of which 55 were found to be resistant to ciprofloxacin. Interestingly, 37 of the 55 Cip^rSalmonella isolates (67%) did not harbor any mutations in the quinolone resistance-determining regions (QRDR). Six Salmonella isolates were shown to carry two novel types of conjugative plasmids that could transfer the ciprofloxacin resistance phenotype to Escherichia coli J53 (azithromycin resistant [Azi^r]). The first type of conjugative plasmid belonged to the ∼110-kb IncFIB-type conjugative plasmids carrying qnrB-bearing and aac(6')-Ib-cr-bearing mobile elements. Transfer of the plasmid between E. coli and Salmonella could confer a ciprofloxacin MIC of 1 to 2 μg/ml. The second type of conjugative plasmid belonged to ∼240-kb IncH1/IncF plasmids carrying a single PMQR gene, qnrS Importantly, this type of conjugative ciprofloxacin resistance plasmid could be detected in clinical Salmonella isolates. The dissemination of these conjugative plasmids that confer ciprofloxacin resistance poses serious challenges to public health and Salmonella infection control.

Keywords: PMQR genes; Salmonella; ciprofloxacin resistance; conjugative plasmid.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents / pharmacology*
Bacterial Proteins / genetics
Ciprofloxacin / pharmacology*
Drug Resistance, Bacterial / genetics
Escherichia coli / drug effects
Escherichia coli / genetics
Microbial Sensitivity Tests
Plasmids / genetics
Salmonella / drug effects*
Salmonella / genetics*

Substances

Anti-Bacterial Agents
Bacterial Proteins
Ciprofloxacin

Grants and funding

U01 FD001418/FD/FDA HHS/United States