We have examined 136 isolates of Yersinia species, comprising 112 strains of @entity2820 , 12 of Y. frederiksenii, 8 of Y. intermedia, and 5 of Y. kristensenii, for the presence of 40- to 50-megadalton virulence-associated plasmids and expression of the following plasmid-associated characteristics: Congo red pigmentation (CR), @entity460 @entity734 , autoagglutination, hydrophobicity, resistance to normal human serum, and pathogenicity in @entity19 . All 136 strains yielded both pigmented (CR+) and nonpigmented (CR-) variants. Only CR+ variants, however, were virulent for @entity68 -overloaded, @entity5532 -treated @entity19 (R. M. Robins-Browne and J. K. Prpic, Infect. Immun. 47:744-779, 1985). Although the in vitro virulence-associated characteristics generally occurred together, each one could be expressed independently. Strains of Y. frederiksenii, Y. intermedia, and Y. kristensenii also expressed individual virulence-associated properties. Of 53 @entity2820 strains which were virulent for @entity68 -overloaded, @entity5532 -treated @entity19 , all but one expressed every virulence-associated characteristic. Several strains which were avirulent for @entity19 , however, demonstrated these characteristics in various combinations. Because many Yersinia strains, particularly environmental isolates, carried plasmids of 40 to 50 megadaltons, detection of plasmids provided little information about bacterial pathogenicity unless virulence-associated properties were also sought. The best in vitro predictor of virulence was autoagglutination, followed by @entity460 @entity734 . Because only CR+ variants expressed virulence-associated determinants, Congo red pigmentation is useful for selecting potentially virulent strains.

In vitro assessment of virulence in XXXX and related species.

@entity5532 :: ('MESH:D003676', 'Chemical') :: ['desferrioxamine B', 'desferrioxamine'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity734 :: ('MESH:D019966', 'Disease') :: ['dependence'] @entity68 :: ('MESH:D007501', 'Chemical') :: ['iron'] @entity2820 :: ('630', 'Species') :: ['Y. enterocolitica', 'Yersinia enterocolitica']
@entity2820 :: (630,Species) :: ['Yersinia enterocolitica']
