Campylobacter in meat turkeys in Italy: A survey on potential sources and vehicles of colonization

Campylobacter spp. are well recognized food-borne pathogens, causative agents of enteritis in humans, and currently representing a relevant public health problem. Poultry is the main reservoir of campylobacters and plays a relevant role in the transmission of infection to humans. Since epidemiology of Campylobacter in turkeys has been scarcely investigated, we carried out a study aimed to identify the potential sources and vehicles of Campylobacter infection in commercial meat turkey farms. A longitudinal sampling strategy was adopted over a 1-year period, including 2 meat turkey farms rearing 2 turkey flocks each. Meconium was collected from day-old chicks at the hatchery and then faecal swabs were collected three times at the farm (beginning, middle and end of the cycle). Farm sampling consisted of drinking water samples (in-house collection tank, water line and drinkers), surface swabs (anteroom door and ventilation system), air, overshoe samples in the anteroom and inside the house, mice and insects (flies, beetles and lesser mealworms). In each farm a target turkey house was selected, where the monitoring continued for the following production cycle. Water and environmental samples were also harvested during downtime. Isolation and identification of Campylobacter were performed as previously described by Giacomelli et al. (2012), slightly modified. Except for day-old chicks, C. jejuni and C. coli were isolated from birds throughout the entire cycle. C. coli was predominant over C. jejuni. Both Campylobacter species were also isolated during the production cycle from overshoe samples inside the house, water from drinkers, flies, and lesser mealworms. Downtime sampling gave always negative results. Water from collection tank was always negative, as well as air from inside the house, and surface swabs. These findings suggest that vertical transmission seems not to be an important source of flock infection, whereas horizontal transmission should be considered the major route for colonization of turkeys, as campylobacters were found in several environmental sources. Ongoing genotyping of isolates by Multilocus Sequence Typing (MLST) will strengthen the association between isolates from turkeys and from environmental sources.