Vwa+ phenotype of Yersinia enterocolitica

Abstract

Expression of the Vwa+ phenotype of Yersinia pestis in vitro is known to reflect maximum induction of virulence (or V and W antigens) at 37°C with concomitant restriction of cell division. Both phenomena are potentiated by 20 mM Mg2' and prevented by cultivation at 26 or 37°C with 2.5 mM Ca2+. We have now compared this classic plasmid-mediated phenotype with those of Vwa+ Yersinia pseudotuberculosis and Yersinia enterocolitica which, unlike Y. pestis, produce ancillary outer membrane peptides unrelated to the V and W antigens. All of 10 wild-type strains of Y. enterocolitica (serotypes 0:3, 0:4,32, 0:8, 0:9, 0:15, and 0:21) exhibited a nutritional requirement for Ca2' at 37°C and produced significant V antigen. Like Y. pseudotuberculosis, autoagglutination of Vwa+ Y. enterocolitica was dependent upon prior growth at 37°C but was not influenced by Ca2?. Autoagglutination of Y. pestis was never observed. Resistance of Y. enterocolitica to 10% human serum was typically dependent upon prior growth at 37°C, either with or without added Ca2', and carriage of a Vwa plasmid. In contrast, serum resistance of Y. pseudotuberculosis was temperature but not plasmid dependent and that of Y. pestis was constitutive. Many of the more severe bacterial diseases of man are caused by facultative intracellular parasites (38). Yersinia pestis, the causative agent of bubonic plague, is considered the type species of this group by virtue of its classical role in identifying virulence factors required for extracellular growth (8, 10). However, the most important determinant of this species is the ability to promote maximum expression (9) of the V and W (or virulence) antigens (Vwa+) of Burrows and Bacon (11), a property possibly required for intracellular survival. Mutation to Vwa-in Y. pestis results in a 106to 107-fold increase in the 50% lethal dose in experimental animals (10). V antigen is a 90-megadalton (mDal) protein and W antigen is a 140 mDal lipoprotein (35). Their synthesis is coordinately induced at 37 but not 26°C in synthetic medium simulating intraleukocytic fluid with respect to Ca2+ (not added) and Mg2+ (-20 mM). This environment selectively prevents in vitro division of Vwa+ cells; addition of that concentration of Ca2+ present in plasma (-2.5 mM) permits growth while coordinately repressing the V and W antigens (8). Recent work showed that restriction promoted by Ca>2 deprivation is a consequence of an ordered stepdown of macromolecular synthesis initiated by reduction of adenylate energy charge and shutoff of stable RNA synthesis (16, t Journal article no. 10633 from the Michigan Agricultural Experiment Station.

Intervening sequences (IVSs) in the 23S ribosomal RNA genes of pathogenic Yersinia enterocolitica strains. The IVSs in Y enterocolitica and Salmonella typhimurium have a common origin

“…As pathogenic Yersinia harbour a 65-70 kb virulence ptasmid (reviewed by Perry and Brubaker, 1983;Skurnik, 1985; Cornelis e/a/., 1989) it could be possible that pattern B and the cleavage activity were associated with the plasmid. This was not the case, since plasmid-cured isogenic strains also had pattern B (Fig.…”

YopH of Yersinia pseudotuberculosis interrupts early phosphotyrosine signalling associated with phagocytosis

“…The two main mechanisms for phagocytic uptake occur (i) via complement receptor type three (CR3), which recognizes the complement fragments C3b and C3bi, and (ii) via the Fc receptor, which recognizes the Fc-part of immunoglobulins . Yersinia resists phagocytosis via CR3 by avoiding deposition of the opsonizing fragments C3b and C3bi (Perry and Brubaker, 1983;China et a/., 1993;. The Fc receptor-mediated process is blocked via a Yop-mediated phagocytic inhibition that is similar to that seen during the uptake of nonopsonired bacteria (Fallman et a/., 1995).…”

Characteristics and Pathogenicity of Non‐Melibiose‐Fermenting Strains of Yersinia pseudotuberculosis O3

“…We also suggest that resistance to phagocytosis and catalase production activity are important for determining the pathogenicity of Y. pseudotuberculosis for the following reason. Resistance to phagocytosis is an important factor in the pathogenicity of Yersinia organisms; the existence of this factor stimulates infectivity and this brings about an infectious disease called yersiniosis (38)(39)(40)(41)53). It has been shown that the resistance of Yersinia organisms to phagocytosis depends on outer-membrane proteins encoded by virulence plasmids (6,7,10,36,47).…”