An investigation into fecal shedding of Streptococcus suis serotypes in nursery pigs.

OBJECTIVE

The objective of this study was to monitor Streptococcus suis fecal shedding in nursery pigs on a farm with a history of S. suis disease involving serotypes 2 and 9.

ANIMAL AND PROCEDURE: Four cohorts of pigs (n = 480) were monitored from weaning to end of nursery. Rectal swabs from 297 pigs were tested and S. suis serotypes 15 (n = 7), 31 (n = 3), or untypeable (n = 6) isolates were recovered from 16 (5.4%) pigs.

RESULTS

There was no significant association between S. suis fecal shedding and diarrhea. Streptococcus suis isolates recovered from pigs euthanized due to neurological signs or severe lameness were serotypes 9 (meninges) and 31 (tonsil) or untypeable (meninges, tonsil). Serotypes 9 (meninges, tonsil), 15 (spleen, tonsil), 16 (tonsil), 29 and 33 (nasal swabs), and untypeable (meninges, tonsil, and lung) isolates were identified in lame pigs.

CONCLUSION AND CLINICAL RELEVANCE: These results suggest that feces may not be a source of infection for the S. suis serotypes producing disease in pigs; however, the association between S. suis fecal shedding and diarrhea needs further investigation. The coincidence of untypeable isolates in feces from healthy pigs and their isolation from meninges of pigs with neurological signs warrants further investigation to determine the molecular characteristics of those isolates.