Prevalence, antibiotic resistance, and biofilm formation of coagulase-positive staphylococci in Izmir Tulum Cheese

Coagulase-positive staphylococci (CPS) are the main causative bacterial agents of staphylococcal food intoxication, posing a significant public health risk and causing infections in humans and animals. In this study, a hundred Izmir Tulum Cheese samples were collected from various retail outlets in the Izmir province. CPS isolates from cheese samples were identified using standard cultural methods. The phenotypic antibiotic resistance of CPS isolates was determined using the agar disk diffusion test method, while their biofilm formation capacity was assessed using the colorimetric method. In the study, CPS was isolated from 30 out of 100 analyzed Izmir Tulum Cheese samples (30%), and it was determined that 27 of these samples (27%) had CPS levels exceeding the maximum acceptable limit of 10³ CFU/g set by the Turkish Food Codex Microbiological Criteria Regulation. Antimicrobial resistance analysis revealed that among the 30 CPS isolates, 90% were resistant to penicillin, while resistance rates to other commonly used antibiotics were 83.3% for clindamycin, 56.7% for ciprofloxacin, and 53.3% for tetracycline. Additionally, 76.7% of the isolates were multidrug-resistant, meaning they were not easily killed by different antibiotics, which limits treatment options. Furthermore, 83.3% of the CPS isolates had the capacity for biofilm formation, highlighting its impact on food safety. These findings emphasize the need for stricter hygiene protocols, controlled antibiotic use, and innovative strategies to combat biofilms in dairy production.