Genetic similarity of Salmonella serovars isolated from pig farms in Sinaloa, Mexico

Salmonella is an important pathogen as a causative agent of gastroenteric diseases by consumption of contaminated food. To determine the genetic similarity of Salmonella serovars, 340 samples of feces and ileum tissue were collected from pigs of different ages and physiological stages from two farms located in the central zone of the of State of Sinaloa; ileum samples were collected from FIT slaughterhouses. Gene similarity of serovars was performed by digestion with the restriction enzyme XbaI and pulsed field gel electrophoresis (PFGE). Salmonella and serovars Anatum, Seftenberg, Untipable, Javiana, Tokoin, Newport, Typhimurium, Weltevreden, Serrakunda, Muenchen, Group C2, Group E1 (E2-E4), Group E1, Group C1 and Group F were isolated from 32 of the samples analyzed. The most frequently isolated serovar Anatum had a genetic similarity of 87.5 - 100%, Group E1 87.5 -100%, Serrekunda 88.9 -100%, Muenchen 100%, Senftenberg 96.6% and Newport 75.9%; these had a Jaccard coefficient greater than 0.75 in the PFGE analysis and were therefore considered bacterial clones. In conclusion, the percentage of genetic similarity observed was high, indicating a possible source of cross-contamination in the swine production units analyzed.