[Prevalence and characteristics of MRSA strains isolated from pigs on farms, at slaughterhouses and in pork meat at retail sale in the Czech Republic].

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[Prevalence and characteristics of MRSA strains isolated from pigs on farms, at slaughterhouses and in pork meat at retail sale in the Czech Republic].

Klin Mikrobiol Infekc Lek. 2015 Jun;21(2):41-45

Authors: Karpíšková R, Koukalová K, Koláčková I

Abstract
OBJECTIVES: To detect and characterize strains of methicillin-resistant Staphylococcus aureus (MRSA) on pig farms, at slaughterhouses and meat samples at retail sale.
MATERIAL AND METHODS: A total of 890 samples were examined in the years 2013-2015, comprising 59 samples from primary production (pig farms), 463 swabs from processing plants (slaughterhouses) and 368 samples of pork meat and liver collected at retail sale. The culture method was used for the detection of MRSA. After homogenization, the samples were enriched in buffered peptone water at 37 °C for 18-24 hours and two-stage selective enrichment was performed. Five milliliters of PPV were transferred to Mueller-Hinton medium with addition of 6.5 % NaCl and after incubation at 37 °C for 18-24 hours, 1 ml was inoculated into tryptone soy broth with cefoxitin and aztreonam. The suspension was plated onto Baird-Parker and BrillianceTM MRSA 2 agar on the next day. Suspected colonies were confirmed by PCR, the specific S. aureus fragment SA442, the mecA gene encoding resistance to methicillin and relation to the clonal complex CC398 were detected. Further, resistance test to a panel of 11 antimicrobial agents using the disk diffusion method was performed.
RESULTS: Within this study, 51 MRSA strains were obtained, of which 15 originated from live pigs, 31 isolates were from slaughterhouses and 5 were detected in retail samples. Forty-seven (92.2 %) MRSA strains belonged to the clonal complex CC398. Four non-CC398 isolates were obtained from two slaughterhouses and came from three farms. The strains often showed multiple resistance. In some MRSA isolates, resistance to erythromycin (36; 70.6 %), tetracycline (29; 56.9 %), fluoroquinolones (7; 13.7 %), co-trimoxazole (6; 11.8 %) and aminoglycosides (4; 7.8 %) was detected.
CONCLUSION: MRSA isolates of the clonal complex CC398 dominate in foods of animal origin. These strains originate from livestock and are often characterized by multiple resistance to antimicrobials. The role of the food chain in the spread of LA-MRSA is not yet clearly understood.

PMID: 26312373 [PubMed - as supplied by publisher]