The prevalence, enterotoxigenic properties and antimicrobial susceptibility of Staphylococcus aureus isolated from various foods of animal origin

This study aimed to determine the prevalence, enterotoxigenic properties and antimicrobial resistance profile of Staphylococcus aureus isolated from 850 food samples, including bulk tank milk, Tulum cheese, chicken meat and beef carcasses, in Türkiye. S. aureus contamination rates and the mean contamination levels of 86 positive samples from bulk tank milk, Tulum cheese, chicken meat and beef carcasses were 10.8% (n:49) and 3.01±0.48 log cfu/ml, 17% (n:17) and 3.08±0.42 log cfu/g, 12% (n:12) and 2.89±0.27 log cfu/g, and 4% (n:8) and 1.28±0.54 log cfu/cm2 , respectively. 39 out of 86 isolates (45.3%) had one or more enterotoxin genes (sea-see, seg-selj, sep). sed was the most common classical enterotoxin gene, whereas sei was the most common new enterotoxin gene. Antimicrobial susceptibility testing against 16 antibiotics performed by VITEK 2 showed that 61 isolates (70.9%) were resistant to various antibiotics. 32.8% of the resistant isolates were multidrug resistant (MDR) and the mean multiple antimicrobial resistance (MAR) index was 0.301. The isolates were mostly resistant to penicillin (63.9%), followed by oxacillin (24.4%), clindamycin (19.7%) and erythromycin (12.7%). mecA was detected in 13 isolates (15.1%), but no mecC was found. It was concluded that most of the S. aureus isolates had enterotoxin genes which might cause foodborne intoxications. The high antibiotic resistance rates observed in these strains, including MRSA, may also result in some public health hazards.