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

Table 1

Comparison of selected phenotypic expression of pYV-bearing Y. enterocolitica, Y. pseudotuberculosis, and Y. pestis (adapted from [7]).

Organism^a	Strain	CM^b	CV binding^c	Lcr^d	CR-uptake^e	AA^f	HP^g	Plasmid^h
Y. enterocolitica	GER	+	+	+	+	+	+	+
Y. enterocolitica-RE	GER	+	+	+	+	+	+	+
Y. enterocolitica-C	GER	−	−	−	−	−	−	−
Y. pseudotuberculosis	PB1/+	+	+	+	+	+	+	+
Y. pseudotuberculosis-RE	PB1/+	+	+	+	+	+	+	+
Y. pseudotuberculosis-C	PB1/+	−	−	−	−	−	−	−
Y. pestis	KIM5	−	+	+	+	−	−	+
Y. pestis-RE	KIM5	−	−	−	−	−	−	−
Y. pestis-C	KIM5	−	−	−	−	−	−	−
pYV-less Y. pestis	Kuma	−	−	−	−	−	−	−

^aCells recovered from red pinpoint colonies and subcultured in BHI broth at 28°C are designated as RE. The pYV-negative strains of Y. enterocolitica, Y. pseudotuberculosis, and Y. pestis are designated as C (cured).
^bCM: colony morphology. On calcium-adequate BHA (1500 μM Ca²⁺), and TSA (1400 μM Ca²⁺) the P⁺ cells appeared as small colonies (1.13 mm in diameter) as compared to larger P⁻ colonies (2.4 mm in diameter).
^cCV binding: crystal violet binding. The P⁺ cells appeared as small dark-violet colonies, and the P⁻ cells showed large white colonies on calcium-adequate BHA (1500 μM Ca²⁺) and TSA (1400 μM Ca²⁺), low-calcium CR-BHO (238 μM Ca²⁺), CR-TSO (311 μM Ca²⁺), and calcium-deficient CR-MOX.
^dLcr: low calcium response/calcium-dependent growth. P⁺ cells appeared as pinpoint colonies (0.36 in diameter), and P⁻ cells appeared large colonies (1.37 in diameter) on low-calcium CR-BHO (238 μM Ca²⁺), CR-TSO (311 μM Ca²⁺), and calcium-deficient CR-MOX.
^eCR-Uptake: Congo red-uptake. The P⁺ cells appeared as red pinpoint colonies (0.36 in diameter), and the P⁻ cells appeared large white or light orange colonies (1.13 mm in diameter) on calcium-deficient CR-MOX.
^fAA: autoagglutination. The P⁺ cells agglutinated. The P⁻ cells remained dispersed.
^gHP: hydrophobicity by latex particles. The P⁺ cells formed clumps showing hydrophobicity. The P⁻ cells remained dispersed.
^hPlasmid: presence of 70-kb pYV by PCR assay.