Genomic and epidemiological comparative analysis of clinical Campylobacter isolates from public and private healthcare centers in Santiago, Chile

Campylobacteriosis remains underestimated in Latin America due to limited surveillance and diagnostic capacity. In this context, a comparison was made of clinical Campylobacter strains from two distinct healthcare settings in Santiago, Chile: a public pediatric hospital and a private tertiary clinic. Through genomic analysis, host-source attribution was observed to vary across socioeconomic profiles: poultry-associated lineages (such as ST-353 and ST-443 complexes) were, as expected, frequently identified across all analyzed populations, although comparatively more frequent in the public health settings; in contrast, cattle-associated strains (ST-22 complex) were primarily isolated from patients of higher incomes. These findings provide the first evidence of Campylobacter infection frequency in a lower-income pediatric population in Chile, highlighting this pathogen as an important cause of gastroenteritis across socioeconomic groups in this setting. Furthermore, a link was identified between the Type 6 Secretion System (T6SS) and clinical severity, corresponding to a subgroup of effectors (CJ488_00960c and CJ488_00961) significantly associated with dehydration. High percentages of resistance determinants to tetracycline (tetO) and fluoroquinolones (gyrA T86I ) are also reported. These data provide information on the main transmission path for distinct socioeconomic groups within the same city, providing valuable data that could help authorities to take informed decisions in case of potential outbreaks and highlighting the urgent need for integrated genomic surveillance in Chile.