Get access

Phenotypic and Genotypic Antimicrobial Resistance Traits of Foodborne Staphylococcus aureus Isolates from Shanghai

Authors

  • Jie Xu,

    1. MOST–USDA Joint Research Center for Food Safety & Dept. of Food Science and Technology, School of Agricultural and Biology, Shanghai, China
    2. State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong Univ, Shanghai, China
    Search for more papers by this author
  • Chunlei Shi,

    1. MOST–USDA Joint Research Center for Food Safety & Dept. of Food Science and Technology, School of Agricultural and Biology, Shanghai, China
    2. State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong Univ, Shanghai, China
    Search for more papers by this author
  • Minghui Song,

    1. MOST–USDA Joint Research Center for Food Safety & Dept. of Food Science and Technology, School of Agricultural and Biology, Shanghai, China
    2. State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong Univ, Shanghai, China
    Search for more papers by this author
  • Xuebin Xu,

    1. Laboratory of Microbiology, Shanghai Municipal Center for Disease Control & Prevention, Shanghai, China
    Search for more papers by this author
  • Puyu Yang,

    1. MOST–USDA Joint Research Center for Food Safety & Dept. of Food Science and Technology, School of Agricultural and Biology, Shanghai, China
    2. State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong Univ, Shanghai, China
    Search for more papers by this author
  • George Paoli,

    1. USDA–MOST Joint Research Center for Food Safety, Molecular Characterization of Foodborne Pathogens Research Unit, United States Dept. of Agriculture, Agricultural Research Service, Eastern Regional Research Center (USDA-ARS-ERRC), Wyndmoor, PA, U.S.A
    Search for more papers by this author
  • Xianming Shi

    Corresponding author
    1. MOST–USDA Joint Research Center for Food Safety & Dept. of Food Science and Technology, School of Agricultural and Biology, Shanghai, China
    2. State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong Univ, Shanghai, China
    Search for more papers by this author

  • Chunlei Shi is the co-first author.

Abstract

Staphylococcus aureus is a recognized pathogen in humans, which causes nosocomial infections and food poisoning. The transmission of antibiotic resistant S. aureus (ARSA), especially methicillin-resistant S. aureus, between food products and humans has become a serious problem. Hence, it is necessary to monitor S. aureus through the food supply chain. In this study, the disk diffusion method and epsilometer test were performed to determine the prevalence of ARSA in 78 foodborne isolates using 18 antibiotics. The highest resistance frequency was found for penicillin G (74.4%), followed by erythromycin (59.0%) and clindamycin (44.9%), whereas no vancomycin-resistant isolates were found. The 78 isolates could be subtyped into 31 resistance profiles and 11 clusters based on their antimicrobial susceptibility. Furthermore, Polymerase chain reaction (PCR) screening for the presence of 13 genes conferring antibiotic resistance was conducted. The presence of resistance genes was relatively high: blaTEM (80.8%), ermB (41.0%), grlA (38.5%), ermC (35.9%), and aac6’/aph2” (35.9%). The incidence of antibiotic resistance was significantly correlated to food types (p = 0.018), with isolates from meat and raw milk more resistant to antibiotics than those from frozen food and vegetables.

Practical Application

The antibiotic resistance of S. aureus has become a serious concern in foodstuffs and varies in different foods. Raw milk and meat have more resistant isolates than those from frozen food and vegetables. Resistance profiles and Ward's minimum variance method can be used to subtype isolates in different clusters.

Ancillary