Acetone-treated agglutinin against Yersinia pseudotuberculosis in free-living rats.

Retrospective investigation was done on Yersinia pseudotuberculosis infection in barn rat populations living in an Yersinia endemic area and in zoo rat populations living in a nonendemic area. The OH agglutinins against Y pseudotuberculosis were normally distributed within both populations. Most of the OH agglutinin titers and many O agglutinin titers were reduced by treatment of sera with acetone. Sera with O and OH agglutinin titers were assigned to 2 groups, one with a titer less than 1:8 and the other with a titer of greater than or equal to 1:8. Rats harboring the organism did not possess O or OH agglutinin titers greater than 1:8 in acetone-treated sera. In most nontreated sera, OH agglutinin titers were higher than were the O agglutinin titers. However, in most acetone-treated sera, O agglutinin titers were equivalent to OH agglutinin titers. Differences by region and age were observed in acetone-treated O agglutinin titers of greater than or equal to 1:8 against Y pseudotuberculosis. Therefore, it is recommended that to detect antibody against Y pseudotuberculosis in rats, sera should be treated with acetone before the test and O antigen should be used.