Incidence of salmonellosis and identification of serogroups and serotypes in a pig commercial farm in Yucatan.

A study was conducted in order to detect the presence of Salmonella spp in fattening pigs, to identify the serogroups present and to determine the sensibility to the antibiotics more used in the region. The farm was a breeding farm of a multiple-site system. Of the total farrowings of a week, 55 sows and one piglet from each sow were selected. All pigs were negative to Salmonella spp. at the star of the study. Piglets were monitored from day two of age (six times; every 23 days approximately) up to finishing (23 weeks of age). Samples of feces (1 g/animal) were collected directly from the pig's rectum. The first positive pig was found at the second sampling (25 days) and the highest number of positive cases in the fifth sampling (117 days). The cumulative incidence was 52.7%. Thirty-four out of the 40 Salmonellas isolated corresponded to the B serogroup and 6 to the C2 serogroup. The serotypes found in the B serogroup were: S. typhimurium (28/34) and S. agona (6/34). Regarding serogroup C2 these were: S. romanby and S ajiobo. Salmonella spp B serogroup included three of the serotypes more commonly isolated in humans: S. typhimurium, S. agona and S. heidelberg.