Intrastrain variation of lipopolysaccharide of Pasteurella multocida in turkeys.

OBJECTIVE

To document intrastrain variation of lipopolysaccharide (LPS) in Pasteurella multocida and correlate these changes with changes in determinants associated with virulence.

ANIMALS

25 broad-breasted white turkeys.

PROCEDURE

Phenotypic bacterial variants were identified by lectin affinity and were assayed for adherence to epithelial cells and complement resistance in vitro. The LPS purified from these variants was subjected to polyacrylamide gel electrophoresis and lectin affinity analysis. Turkeys were challenge exposed, then observed for 1 week. At first sign of disease, or at the end of the study, turkeys were euthanatized, necropsied, and inspected for gross lesions.

RESULTS

The LPS variant designated as Ricinus communis agglutinin-positive had greater adherence to epithelial cells, complement resistance, and virulence in turkeys than did the variant designated as R communis agglutinin-negative.

CONCLUSIONS

Intrastrain variation of LPS exists in P multocida, and changes in LPS are correlated with changes in virulence.