Staphylococcus aureus is More Prevalent in Retail Beef Livers than in Pork and other Beef Cuts.

Lubna Abdalrahman,Harrington Wells,Mohamed Fakhr

doi:10.3390/pathogens4020182

Abstract

Staphylococcus aureus is one of the top five pathogens contributing to acquired foodborne illnesses causing an estimated quarter million cases every year in the US. The objectives of this study were to determine the prevalence of Methicillin Susceptible S. aureus (MSSA) and Methicillin Resistant S. aureus (MRSA) in retail beef livers, beef, and pork meats sold in Tulsa, Oklahoma and to characterize the recovered strains for their virulence and antimicrobial resistance. Ninety six chilled retail beef (50 beef livers and 46 beef other cuts), and 99 pork meat samples were collected. The prevalence in beef livers was 40/50 (80%) followed by other beef cuts 23/46 (50%) then pork 43/99 (43.3%). No isolates were positive for MRSA since none harbored the mecA or mecC gene. A total of 334 recovered S. aureus isolates (143 beef livers, 76 beef, and 115 pork isolates) were screened for their antimicrobial susceptibility against 16 different antimicrobials and their possession of 18 different toxin genes. Multidrug resistance was more prevalent in the pork isolates followed by beef then beef livers. The prevalence of enterotoxin genes such as seg, seh, and sei and the toxic shock syndrome gene tst was higher in the pork isolates than in the beef ones. The hemolysin genes, particularly hlb, were more prevalent in isolates from beef livers. Molecular typing of a subset of the recovered isolates showed that they are highly diverse where spa typing was more discriminatory than PFGE. The alarmingly high incidence of S. aureus in retail beef livers in this study should raise awareness about the food safety of such meat products.

Highlights

Foodstuff contamination with Staphylococcus aureus such as in dairy products and retail meats may occur as a result of poor hygiene during handling the food or directly from infected food-producing animals [1]
The objectives of this study were to determine the prevalence of Staphylococcus aureus and Methicillin Resistant S. aureus (MRSA) in retail beef livers, beef, and pork meats sold in the Tulsa, Oklahoma area and to characterize the recovered strains for their virulence and antimicrobial resistance
While no isolate harbored the mecA gene, a good percentage of the pork isolates were phenotypically similar to MRSA strains by being resistant to cefoxitin and oxacillin

Summary

Introduction

Foodstuff contamination with Staphylococcus aureus such as in dairy products and retail meats may occur as a result of poor hygiene during handling the food or directly from infected food-producing animals [1]. Staphylococcus aureus is listed among the top five pathogens contributing to domestically acquired foodborne illnesses causing as many as 241,148 cases annually in the United States [10]. Both Staphylococcus aureus and MRSA have been isolated from chicken, pork, beef and others. Few studies reported variable prevalence of S. aureus and/or MRSA in retail meats at different US locations including Louisiana [16], Maryland, USA [17], Detroit, Michigan [18], Iowa [19], Minnesota, and New Jersey [20], Georgia [21], and North Dakota [22,23]

Objectives

Results

Conclusion