Molecular prediction of serotypes of Streptococcus suis isolated from pig’s farms in Mexico

Resumen

Infections caused by Streptococcus suis (S. suis) pose a problem for the pig industry worldwide. Pigs often carry multiple serotypes of S. suis in the upper respiratory tract, where S. suis is frequently isolated from. The clinical diagnosis of the infection is presumptive and is generally based on clinical signs, the age of the animal and macroscopic lesions. In the laboratory, identification of S. suis is performed biochemically, and then, serotyping is performed with antisera to determine the serotype, but these tests can be inconclusive. To date, there are few studies that have documented the presence and diversity of S. suis serotypes in Mexico. In the present study, it was characterized S. suis strains from Mexican pig farms using molecular approaches; samples were first processed by PCR of the gdh gene to detect S. suis. Positive samples were then subjected to a two-step multiplex PCR (cps PCR) to detect and characterize each strain; the first step consisted of a grouping PCR and the second step consisted of a typing PCR. The serotypes detected in the pig farming areas of Mexico included 1/2, 2, 3, 5, 7, 8, 9, 17, and 23. These findings are important for the characterization of serotypes present in Mexico and for outbreak prevention.