Veterinary Research Forum

Abstract Biofilm formation is a key virulence factor in Staphylococcus aureus, contributing to bacterial persistence, antimicrobial resistance, and chronic infections. This study aimed to investigate the presence of biofilm-associated genes (fib, fnbA, fnbB, clfA, and clfB) in S. aureus isolates from dogs in Ilam, Iran. From December 2022 to September 2023, 250 swab samples were collected from nasal, oral, and rectal sites of dogs, yielding 81 S. aureus isolates confirmed by PCR amplification of the nuc gene. The prevalence of biofilm-associated genes varied, with clfA, clfB, and fnbA detected in 98.80% of isolates, fib in 63.00%, and fnbB in 16.00%. Notably, fnbA, clfA, and clfB were present in all rectal isolates, while fnbB was absent in this group. The findings highlighted the widespread presence of biofilm-related genes in S. aureus from dogs, suggesting their potential role in colonization and zoonotic transmission. The high prevalence of adhesion-associated genes underscored the need for monitoring biofilm-forming S. aureus in companion animals to mitigate antimicrobial resistance and public health risks.

Abstract Staphylococcus aureus is one of food poisoning bacteria. This study assessed the prevalence, virulence factors, and antimicrobial susceptibility profiles of S. aureus isolated from frozen fish and shrimp in Egypt. Ninety samples from frozen fish fillets and shrimps (45 for each) were examined for S. aureus prevalence using VITEK 2 compact system, followed by molecular confirmation by nuc gene, virulence characterization, and its resistance genes. The overall prevalence rate of S. aureus was 14.44% (13/90). Fish fillet had the highest mean total S. aureus count (9.50 ± 3.50 × 10⁵ colony forming unit g^-1), followed by shrimp (7.50 ± 3.30 × 10⁵ colony-forming unit g^-1), with a non-significant difference among fish fillet and shrimp. All confirmed S. aureus isolates were lecithinase producers and showed β-hemolysis, and coagulase positive, and confirmed molecularly coa gene positive. All isolates were resistant to ampicillin (100%), both erythromycin and clindamycin (69.23%), and tetracycline (61.53%), followed by vancomycin (46.15%). However, all isolates were sensitive to linezolid, tigecycline (84.70%), and trimethoprim/sulfamethoxazole (61.53%). Twelve (92.30%) phenotypically cefoxitin and oxacillin-resistant and molecularly mecA recovered S. aureus isolates were confirmed as methicillin-resistant S. aureus, while based on vancomycin-resistant pheno-typically, and molecularly vanA recovered S. aureus isolates were confirmed as vancomycin-resistant S. aureus. The emergence of multidrug-resistant methicillin-resistant S. aureus and vancomycin-resistant S. aureus in frozen fish fillets and shrimp indicates public health hazards, so there is a need for food safety measures alongside reliable detection methods of resistant bacteria along the food chain.