Abstract
We characterized the prevalence, antibiotic susceptibility profiles, and genotypes of Staphylococcus aureus among US meat and poultry samples (n = 136). S. aureus contaminated 47% of samples, and multidrug resistance was common among isolates (52%). S. aureus genotypes and resistance profiles differed significantly among sample types, suggesting food animal-specific contamination.
Generated Summary
This study investigates the prevalence and antibiotic susceptibility profiles of Staphylococcus aureus in retail meat and poultry samples in the United States. The research employed a cross-sectional design, collecting samples from various retail grocery stores across five cities. The methodology involved sample collection, bacterial enrichment, and isolation, followed by antimicrobial susceptibility testing and genotyping of S. aureus isolates. The study aimed to characterize the presence of S. aureus in meat and poultry products and to identify the prevalence of multidrug resistance. The research also sought to explore the genetic diversity of S. aureus strains and determine if contamination varied by sample type, indicating potential food animal-specific contamination.
Key Findings & Statistics
- A total of 136 meat and poultry samples were collected and tested.
- S. aureus contamination was found in 47% of the samples.
- Multidrug resistance was observed in 52% of the S. aureus isolates.
- S. aureus contamination was most common in turkey samples (77%), followed by pork (42%), chicken (41%), and beef (37%).
- A subset of samples (10%; 14/136) was contaminated by multiple unique S. aureus strains.
- Ninety-six percent of the S. aureus isolates were resistant to at least one antimicrobial.
- Thirty-two unique susceptibility profiles were identified among the S. aureus isolates.
- Resistance to tetracycline, ampicillin, penicillin, and erythromycin was highly prevalent.
- Multidrug resistance was most prevalent among S. aureus isolates from turkey (79%), followed by pork (64%), beef (35%), and chicken (26%).
- Fifteen unique MLST sequence types were identified among the S. aureus isolates.
- ST5 and ST398 were the dominant sequence types.
Other Important Findings
- The study found that the distinct S. aureus populations on each product type suggest that food animals are the predominant source of contamination.
- MRSA was isolated from one sample each of beef, turkey, and pork.
- One vancomycin-intermediate-resistant isolate and one daptomycin-resistant isolate were identified.
- Fluoroquinolone-resistant S. aureus isolates were uniquely prevalent among chicken products.
Limitations Noted in the Document
- The sample size was insufficient to accurately estimate prevalence rates.
- The study acknowledges that the public health relevance of the findings is unclear.
- The study does not evaluate the risk from methicillin-susceptible multidrug-resistant S. aureus, which is more common than MRSA among food samples.
Conclusion
The study concludes that retail meat and poultry are frequently contaminated with multidrug-resistant S. aureus, highlighting the need for further investigation into the sources of contamination and the potential public health implications. The findings emphasize the role of food animals as a primary source of contamination, as evidenced by the distinct S. aureus populations found in different product types. The presence of multidrug resistance, including resistance to antibiotics commonly used to treat severe MRSA infections, raises concerns about the potential for the spread of antibiotic-resistant pathogens in the food supply. As the document states, “Our data demonstrate that retail meat and poultry are frequently contaminated with multidrug-resistant S. aureus, but the public health relevance of this finding is unclear.” The identification of unique resistance patterns and the prevalence of specific sequence types, such as ST398, underscores the importance of tracking the movement of S. aureus strains from farms to retail to understand and control the spread of these pathogens. Furthermore, the study suggests that the findings regarding multidrug-resistant S. aureus should be added to the list of antimicrobial-resistant pathogens that routinely contaminate the food supply.