Arcobacter species isolated from human stool samples, animal products, ready-to-eat salad mixes, and ambient water: prevalence, antimicrobial susceptibility, and virulence gene profiles.

INTRODUCTION

Arcobacter species are emerging foodborne pathogens increasingly associated with human illness worldwide. They are commonly found in the gastrointestinal tracts of animals and are frequently isolated from various food sources, including raw meat, poultry, and seafood. The aim of this study is to investigate the antimicrobial resistance patterns of Arcobacter spp. isolated from human stool samples, animal products, ready-to-eat salad mixes, and ambient water, assess the presence of resistance genes, and explore their potential implications for public health.

METHODS

In this study, a total of 683 samples were collected from the Shahrekord area over a 12-month period. Samples were obtained from human stool, chicken meat, raw cow milk, RTE salad mixes, and environmental water sources. Two different methods were used to detect Arcobacter, depending on the sample type: bacteriological isolation and identification, and molecular identification. After identification, antimicrobial susceptibility testing was conducted. Polymerase chain reaction (PCR) was used to identify ten putative Arcobacter virulence and resistance genes.

FINDINGS

The results revealed that Arcobacter spp. were present in 26.06% (178 out of 683) of the tested samples, with varying isolation rates across different sample types. A. butzleri being the most commonly isolated species across all sample types, while A. cryaerophilus was restricted to RTE salads, surface waters, and chicken meat. Notably, A. skirrowii was only isolated from chicken meat and environmental water. The differences of Arcobacter spp. in prevalence between the sample types were statistically significant (p < 0.05), and no significant seasonal variation was found across the sampling periods (p > 0.05). PCR analysis for ten putative virulence genes indicated that the cadF gene was present in all Arcobacter isolates. Similarly, 83.33% of the tested strains harbored the ciaB gene, while other genes were less frequently detected. Regarding resistance genes, tet(O) (7.69%) was the most identified gene, followed by blaOXA-61 (4.37%).

CONCLUSION

In conclusion, this study highlights the alarming prevalence of antimicrobial resistance in Arcobacter spp. Monitoring Arcobacter spp. resistance can be achieved through surveillance, risk assessments, antibiotic stewardship in agriculture, public education, research collaborations, rapid diagnostics, and harmonized policies, all aimed at reducing contamination and safeguarding public health effectively.