Prevalence and Resistance Patterns of Campylobacter spp. and Arcobacter spp. in Portuguese Water Bodies

Campylobacter spp. and Arcobacter spp. are recognized etiological agents of gastroenteritis worldwide. While poultry is their best-known reservoir, human exposure can also occur via environmental pathways, particularly through contaminated water sources, which play a significant role in their transmission dynamics. In addition to their pathogenicity and widespread environmental prevalence, increasing antibiotic resistance has contributed to the global emergence of multidrug-resistant strains, hindering effective treatment. Here, the distribution and antibiotic resistance potential of Campylobacter spp. and Arcobacter spp. isolates collected from water bodies in Portugal were investigated. Water samples were collected from rivers, their tributaries, and springs, at 25 sites over a six-month period. Campylobacter spp. were isolated from 13.3% of the samples, whereas Arcobacter spp. were detected in 57.6% of the samples. Of the 27 isolated Campylobacter isolates, 44.0% were resistant to at least one antibiotic, while only one strain exhibited a multidrug-resistant (MDR) phenotype. In contrast, 98.9% of the 177 Arcobacter isolates were resistant to at least one antibiotic, with 15.8% classified as MDR. These findings contribute to the surveillance of Campylobacter spp. and Arcobacter spp., highlighting the critical role of aquatic environments in their epidemiology and supporting the need to incorporate waterborne transmission pathways into integrated surveillance and control strategies within the One Health framework.