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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Prevalence, Infectious Characteristics and Genetic Diversity of Staphylococcus aureus and Methicillin-Resistant
Dimitrios Komodromos1, Charalampos Kotzamanidis2, Virginia Giantzi2
1Laboratory of Food Hygiene-Veterinary Public Health, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Abstract:
In the present study, we investigated the isolation frequency, the genetic diversity, and the infectious characteristics of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from the incoming meat and the meat products, the environment, and the workers' nasal cavities, in two meat-processing establishments in northern Greece. The isolated S. aureus strains were examined for their resistance to antimicrobials, carriage of the mecA and mecC genes, carriage of genes encoding for the production of nine staphylococcal enterotoxins, carriage of the Panton-Valentine Leukocidin and Toxic Shock Syndrome genes, and the ability to form biofilm. The genetic diversity of the isolates was evaluated using Pulsed Field Gel Electrophoresis (PFGE) and spa typing. S. aureus was isolated from 13.8% of the 160 samples examined, while only one sample (0.6%) was contaminated by MRSA carrying the mecA gene. The evaluation of the antimicrobial susceptibility of the isolates revealed low antimicrobial resistance. The higher resistance frequencies were observed for penicillin (68.2%), amoxicillin/clavulanic acid (36.4%) and tetracycline (18.2%), while 31.8% of the isolates were sensitive to all antimicrobials examined. Multidrug resistance was observed in two isolates. None of the isolates carried the mecC or lukF-PV genes, and two isolates (9.1%) harbored the tst gene. Eight isolates (36.4%) carried the seb gene, one carried the sed gene, two (9.1%) carried both the sed and sei genes, and one isolate (4.5%) carried the seb, sed and sei genes. Twenty-one (95.5%) of the isolates showed moderate biofilm production ability, while only one (4.5%) was characterized as a strong biofilm producer. Genotyping of the isolates by PFGE indicates that S. aureus from different meat-processing establishments represent separate genetic populations. Ten different spa types were identified, while no common spa type isolates were detected within the two plants. Overall, our findings emphasize the need for the strict application of good hygienic practices at the plant level to control the spread of S. aureus and MRSA to the community through the end products.
Insights
Staphylococcus aureus was found in meat products and workers, with low antimicrobial resistance. Strict hygiene is crucial to prevent the spread of S. aureus and MRSA from meat processing plants.
Area of Science:
- Food safety and microbiology
- Antimicrobial resistance
- Bacterial genomics
Background:
- Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are significant foodborne pathogens.
- Meat processing environments can harbor S. aureus, posing a risk to food safety and public health.
- Understanding the genetic diversity and infectious characteristics of S. aureus in these settings is crucial for effective control.
Purpose of the Study:
- To investigate the prevalence, genetic diversity, and infectious traits of S. aureus and MRSA in meat products, environments, and workers.
- To assess antimicrobial resistance patterns and the presence of virulence genes in isolated S. aureus strains.
- To evaluate the genetic relatedness of S. aureus isolates from different meat processing establishments.
Main Methods:
- Sampling of incoming meat, meat products, environmental surfaces, and workers' nasal cavities from two meat processing plants.
- Isolation and identification of S. aureus and MRSA.
- Antimicrobial susceptibility testing, detection of mecA, mecC, and toxin genes (sea, seb, sec, sed, see, seg, sei, sej, tst).
- Pulsed Field Gel Electrophoresis (PFGE) and spa typing for genetic diversity analysis.
- Biofilm formation assays.
Main Results:
- S. aureus was isolated from 13.8% of samples; MRSA was detected in only one sample (0.6%).
- Low overall antimicrobial resistance was observed, with higher frequencies for penicillin (68.2%), amoxicillin/clavulanic acid (36.4%), and tetracycline (18.2%).
- Specific virulence genes like seb, sed, sei, and tst were detected in some isolates, and most isolates exhibited moderate biofilm production.
- PFGE and spa typing revealed distinct genetic populations of S. aureus within each processing plant, indicating limited cross-contamination between them.
Conclusions:
- The study highlights the presence of S. aureus in meat processing facilities, although MRSA prevalence was low.
- The observed low antimicrobial resistance and limited multidrug resistance suggest that current hygiene practices may be partially effective.
- Findings underscore the critical need for stringent adherence to good hygienic practices to minimize S. aureus and MRSA contamination and dissemination into the food chain and community.
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