Distribution of antibiotic resistance genes among Staphylococcus species isolated from ready-to-eat foods
Yu-Ting Wang a,b, Yu-Tzu Lin a, Tsai-Wen Wan a, Der-Yuan Wang b, Hsu-Yang Lin c, Che-Yang Lin b, Yu-Chih Chen b, Lee-Jene Teng a,d,*
a Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of
Medicine, Taipei, Taiwan
b Division of Research and Analysis, Food and Drug Administration, Ministry of Health and Welfare, Taipei, Taiwan
c Division of Food Safety, Food and Drug Administration, Ministry of Health and Welfare, Taipei, Taiwan
d Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of
Medicine, Taipei, Taiwan
We investigated antibiotic resistance of staphylococci isolated from 1128 samples of high-circulating RTE foods in Taiwan. A total of 111 Staphylococcus aureus and 709 coagulase-negative staphylococci (CoNS) comprising 23 species were isolated. The prevalence of S. aureus differed in various category of RTE foods, highest in fresh-cut fruits/vegetables (20.5%) and lowest in low-water activity (LWA) foods (0.7%). The overall staphylococcal contamination was highest in fresh-cut fruits/vegetables (62.2%), in which multiple isolates (up to 10) or species (up to 6) in single sample were frequently found. Distinct distribution of species contributed to unique feature in each category. Prevalence of antibiotic-resistant S. aureus was higher in fresh-cut fruits/vegetables samples (14.2% in 127) compared to other food categories (0–7.1%). A total of 4 MRSA carrying SCCmec type IV or VT were identified (3.6% in 111), in which 3 belonged to sequence type ST59 and one was ST5. Among CoNS, S. epidermidis and S. warneri exhibited higher non-intrinsic antibiotic resistance than other species. Of 41 methicillin-resistant CoNS (5.8% in 709) isolates, SCCmec type IV (n = 16) and type VT (n = 6) were most frequent. Isolates of S. saprophyticus, S. xylosus and S. sciuri displayed high rates of resistance to fusidic acid. Novel fusB-family determinants were identified in S. xylosus, S. sciuri and S. kloosii, which may contribute to their intrinsic resistance to fusidic acid. Compared to other food categories, fresh-cut fruits/vegetables were more contaminated by staphylococci carrying non-intrinsic resistance determinants including methicillin resistance. This nation-wide study demonstrated that some categories may have potential risk for transmitting antibiotic resistance, in which S. epidermidis and S. warneri should be gotten more attention.
Keywords: Antibiotic resistance determinants; Methicillin-resistant staphylococci; Ready-to-eat foods; Staphylococcal community
https://doi.org/10.1016/j.jfda.2019.05.003.
(http://www.sciencedirect.com/science/article/pii/S1021949819300547)