Virulence Plasmid (pYV)-Associated Expression of Phenotypic Virulent Determinants in PathogenicYersiniaSpecies: A Convenient Method for Monitoring the Presence of pYV under Culture Conditions and Its Application for Isolation/Detection ofYersinia pestisin Food

Abstract

In Yersinia pestis, Y. pseudotuberculosis, and Y. enterocolitica, phenotypic expression of virulence plasmid (pYV: 70-kb)-associated genetic determinants may include low-calcium response (Lcr, pinpoint colony, size = 0.36 mm), colony morphology (size = 1.13 mm), crystal violet (CV) binding (dark-violet colony), Congo Red (CR) uptake (red pinpoint colony, size = 0.36 mm), autoagglutination (AA = cells agglutinate), and hydrophobicity (HP = clumping of cells). Y. pseudotuberculosis is chromosomally closely related to Y. pestis; whereas, Y. enterocolitica is chromosomally more distantly related to Y. pestis and Y. pseudotuberculosis. All three species demonstrate Lcr, CV binding, and CR uptake. The colony morphology/size, AA, and HP characteristics are expressed in both Y. pseudotuberculosis and Y. enterocolitica but not in Y. pestis. Congo red uptake in Y. pestis was demonstrated only on calcium-deficient CR magnesium oxalate tryptic soy agar (CR-MOX), whereas this phenotype was expressed on both CR-MOX and low-calcium agarose media in Y. pseudotuberculosis and Y. enterocolitica. These phenotypes were detectable at 37°C within 24 h in Y. enterocolitica and Y. pseudotuberculosis but did not appear until 48 h in Y. pestis due to its slower growth rate at 37°C. The pYV is unstable (i.e., easily lost under a variety of culture conditions) in all three species but is more unstable in Y. pestis. The specific CR uptake by Y. pestis in CR-MOX and the delayed time interval to express Lcr and CR uptake provide a means to differentiate Y. pestis from Y. enterocolitica and Y. pseudotuberculosis. These differences in pYV expression in Y. pestis can be used for its isolation and detection in food.

Yersinia pseudotuberculosis Prevalence and Diversity in Wild Boars in Northeast Germany

“…In addition, the growth of these isolates on CR-MOX at 37°C indicated that they did not contain pYV. It cannot be ruled out that the four pYV-negative isolates lost their virulence plasmid during cultivation in the laboratory, because pYV is known to be a rather unstable plasmid (41,42). Strains devoid of pYV are considered to be nonpathogenic, even though pYV-negative Y. pseudotuberculosis strains have been isolated from patients (1,43).…”

Radiation Resistance and Loss of Crystal Violet Binding Activity in Yersinia enterocolitica Suspended in Raw Ground Pork Exposed to Gamma Radiation and Modified Atmosphere

“…In contrast, other environmental stresses such as temperature, atmosphere, culture conditions, freezing, salt, and acidic pH have not been shown to induce pYV loss, and Y . enterocolitica retain the pYV and are still capable of causing food poisoning (Bhaduri , , , , ; Bhaduri and others , , ; Bhaduri and Phillips ; Bhaduri and Smith , ; Bhaduri and Sommers ). Figure shows the percentage of colonies which failed to bind CV in the presence of air, or combinations of CO 2 or N 2 .…”

“…. culture conditions, freezing, salt, acidic pH, and calcium concentration can affect virulence-plasmid associated phenotypes of Y. enterocolitica, Y. pseudotuberculosis, and Y. pestis such as Lcr, colony size, CV binding, CR-uptake, AA, and HP (Bhaduri and others 1988(Bhaduri and others , 1993(Bhaduri and others , 2011Bhaduri 1995Bhaduri , 2005Bhaduri , 2006Bhaduri , 2011Bhaduri , 2014Bhaduri and Sommers 2008;Bhaduri and Phillips 2011;Bhaduri and Smith 2012). Y. enterocolitica displays pYV-dependent formation of microcolonies in collagen gels, a system to mimic infection in living tissue when incubated at 37°C.…”

“…A number of virulent phenotypes are expressed by pYV, including colony morphology/size (size = 1.13 mm), low‐calcium response (Lcr, pin point colony, size = 0.36 mm), crystal violet (CV) binding (dark‐violet colony), Congo red (CR)‐uptake (red pin point colony, size = 0.36 mm), autoagglutination (AA = cells agglutinate), hydrophobicity (HP = forms clumps), type III secretion channels, host immune suppression, biofilm formation, and expression of a series of released proteins (Yops) (Cornelis and others ; Bhaduri ; Bhaduri and Smith ). Environmental stresses such as temperature, atmosphere, culture conditions, freezing, salt, acidic pH, and calcium concentration can affect virulence‐plasmid associated phenotypes of Y. enterocolitica , Y. pseudotuberculosis , and Y. pestis such as Lcr, colony size, CV binding, CR‐uptake, AA, and HP (Bhaduri and others , , ; Bhaduri , , , , ; Bhaduri and Sommers ; Bhaduri and Phillips ; Bhaduri and Smith ). Y. enterocolitica displays pYV‐dependent formation of microcolonies in collagen gels, a system to mimic infection in living tissue when incubated at 37 °C.…”

Isolation of <em>Yersinia pseudotuberculosis</em> in bovine mastitis: A potential milk-borne hazard

“…In this study, the isolate lacks pYV. Indeed, it should be consider that this unstable plasmid can be easily lost during cultivation in the laboratory (Bhaduri and Smith, 2011 ) and pYV-negative Y. pseudotuberculosis strains have been isolated from infected human patients (Fukushima, Sato, and Nagasako, and Takeda 1991 ). For instance, in Galindo and collaborators ( 2011 ) pYV was absent in one – fourth of the known virulent serotypes, which harbored HPI and/or YPMa.…”