The main objective of this study was to determine the prevalence and antimicrobial resistance patterns of Campylobacter strains isolated from broiler chickens and Thai native chickens fed with and without probiotics or Thai medicinal plants supplemented feed. From 360 intestinal samples and 120 carcass samples collected and cultured for Campylobacter spp., we noticed that the highest prevalence of this organism was observed in Thai native chickens fed with Thai medicinal plants supplemented feed [73.33% (66/90) for intestinal samples and 96.67% (29/30) for carcass samples]. Followed by Thai native chickens fed with diet containing no Thai medicinal plants, conventional broiler chickens, and conventional broiler chickens fed with probiotics supplemented feed. When antimicrobial resistance patterns of these isolated Campylobacter strains were determined, we found that the majority of Campylobacter isolates were resistant to ciprofloxacin and nalidixic acid, while they were susceptible to gentamicin and erythromycin except some Campylobacter isolates from intestinal tracts of Thai native chickens fed with regular diet (without Thai medicinal plants) that were resistant to erythromycin. The resistance rate to tetracycline varied between production types ranging from 33.33% to 100.00%. Together, these findings reveal that Thai native chickens had higher prevalence of Campylobacter spp. Than broiler chickens. Regardless of poultry production practices, C. jejuni and C. coli in this study were generally resistant to fluoroquinolones, indicating the need for prudent measures to control and reduce the occurrence of fluoroquinolone-resistant Campylobacter in Thai poultry.
