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Updated: Mar 7, 2026
Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR
Published on: November 4, 2016
Prevalence and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus in Foods of Animal Origin,
Belgin Siiriken1, Tuba Yildirim2, Akif Koray Güney3
1Department of Water Products Diseases, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun 55200, Turkey.
Abstract:
In the present study, 175 coagulase-positive Staphylococcus (CPS) isolates recovered from samples of beef (n = 110), raw milk n = 56), and fish (n = 9) were analyzed for methicillin resistance using MIC and PCR assays. Methicillin-resistant (MR) Staphylococcus aureus (SA) isolates were then characterized using pulsed-field gel electrophoresis (PFGE). According to findings, 62 (35.4%) of the isolates (44 from beef, 9 from milk, and 9 from fish) were identified as S. aureus based on the presence of the nuc gene. MRCPS was detected in 18 (10.3%) of 175 CPS isolates based on the presence of the mecA gene. Among these isolates, 15 (24.2%) were MRSA: 4 (26.7%) from beef, 2 (13.3%) from milk, and 9 (60%) from fish. However, based on the MIC assay, 21 (12.0%) of the CPS isolates (1 from beef, 15 from milk, and 5 from fish) were MRCPS, indicating a discrepancy between the results of these two methods. The PFGE results indicated genetic heterogeneity of the isolates; six PFGE clusters were found. These results confirm that MRSA is present in foods of animal origin, which is a concern to human health, and indicate the importance of method selection for determination of methicillin resistance. The identity of MR isolates should be verified by PCR to obtain more reliable results.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) was found in beef, raw milk, and fish. Accurate detection of MRSA in food requires careful method selection and PCR verification for reliable results.
Area of Science:
- Food microbiology
- Antimicrobial resistance
- Molecular diagnostics
Background:
- Coagulase-positive Staphylococcus (CPS) are frequently found in food products.
- Methicillin resistance in Staphylococcus poses a significant public health concern.
- Food of animal origin can serve as a reservoir for resistant bacteria.
Purpose of the Study:
- To investigate the prevalence of methicillin resistance in CPS isolates from food.
- To compare different methods for detecting methicillin resistance.
- To characterize methicillin-resistant Staphylococcus aureus (MRSA) isolates.
Main Methods:
- Analysis of 175 CPS isolates from beef, raw milk, and fish.
- Detection of methicillin resistance using Minimum Inhibitory Concentration (MIC) and PCR assays.
- Identification of Staphylococcus aureus using the nuc gene.
- Characterization of MRSA isolates using pulsed-field gel electrophoresis (PFGE).
Main Results:
- 62 isolates (35.4%) were identified as S. aureus.
- Methicillin-resistant CPS (MRCPS) was detected in 10.3% of isolates by PCR (mecA gene).
- MRSA constituted 24.2% of the identified S. aureus isolates.
- A discrepancy was observed between MIC and PCR methods for detecting MRCPS.
- PFGE revealed genetic heterogeneity among the isolates.
Conclusions:
- MRSA is present in foods of animal origin, posing a risk to human health.
- The selection of appropriate methods is crucial for accurate methicillin resistance determination.
- PCR verification is recommended for reliable identification of methicillin-resistant isolates.
