Prevalence, antibacterial susceptibility, and virulence gene profiles of Arcobacter species isolated from seafood

Abstract

Arcobacter butzleri, an emerging foodborne zoonotic pathogen, is increasingly associated with gastrointestinal and systemic infections in humans, and with diarrhea, mastitis, and abortions in animals. This study aimed to determine the prevalence, antimicrobial susceptibility, and virulence gene profiles of Arcobacter species isolated from seafood. A total of 560 samples were analyzed, including 300 fresh seafood samples (100 fresh/raw fish, 50 shrimp, 50 crabs, 50 oysters, and 50 lobsters) and 260 preserved seafood samples (70 smoked fish, 70 salted fish, 50 dried fish, and 70 frozen fish). Arcobacter spp. were isolated using an Arcobacter an enrichment and direct filtration method. Antibiotic susceptibility was assessed using the disk diffusion method following Clinical and Laboratory Standards Institute guidelines. PCR was conducted to detect ten putative virulence genes and five resistance genes. Arcobacter spp. were detected in 21.43% (120/560) of the tested seafood samples, with the highest prevalence in fresh fish (42%) and oysters (40%). Among isolates, A. butzleri was predominant (14.82%), followed by A. cryaerophilus (6.25%) and A. skirrowii (0.36%). Virulence genes were present in 84.6% of A. butzleri and 73.5% of A. cryaerophilus isolates. Resistance genes were found in 82.7% and 67.6% of these species, respectively. Antibiotic resistance was highest in A. butzleri, particularly to vancomycin, cephalosporins, ciprofloxacin, and beta-lactams, while A. skirrowii showed minimal resistance. Most isolates remained sensitive to polymyxin-B, colistin, gentamicin, and carbapenems. The study finds high rates of contamination of fresh fish, smoked fish, salted fish, dried fish, frozen fish, oysters, crabs, lobster, and shrimp, indicating the potential role of Arcobacter spp. in causing infections.