The evaluation of antibiotic resistance genes of Arcobacter butzleri isolated from animal products, and chicken slaughterhouse sewage in Mazandaran province, Northern Iran.

Background: Arcobacter butzleri, the most common genus of the Campylobacter family, is considered an emerging zoonotic pathogen.

Aims: This study aimed to evaluate A. butzleri from diverse sources, in order to determine the antibiotic resistance pattern of isolates and the frequency of some genes responsible for their antibiotic resistance.

Methods: In this study, 425 samples were collected from different sources (chicken slaughterhouse sewage, poultry meat, beef, sheep meat, dairy products) during different seasons of 2020-2021. Suspicious colonies were confirmed using biochemical tests. Furthermore, the polymerase chain reaction technique was used to confirm the phenotypic results using the 16S rRNA gene. The antibiotic resistance pattern of the isolates to 16 antibiotics were determined using the disk diffusion method. Also, the minimum inhibitory concentration (MIC) of their growth was detected using the tube dilution method in the presence of tetracycline, erythromycin, and gentamicin.

Results: A total of 53 isolates of A. butzleri (12.5%) were isolated from (chicken slaughterhouse sewage=36, poultry meat=8, beef=4, sheep meat=5), which contain all three antibiotic resistance genes of abu_0814 (90.57%), OXA_464 (100%), and gyrA (83.02%). The findings of the present investigation showed the presence of A. butzleri in different sources and the high prevalence of antimicrobial resistance in the isolates. Nineteen isolates (36%) have extensive drug resistance and 34 isolates (64%) showed multi-drug resistance to the used antibiotics.

Conclusion: The elevated level of antibiotic resistance observed in A. butzleri isolates originating from various samples suggests a significant use of antibiotics and a prevalent environmental contamination.