Epidemiology and Infection

Application of ribotyping and IS200 fingerprinting to distinguish the five Salmonella serotype O6,7[ratio]c[ratio]1,5 groups: Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis

S. UZZAU a1c1, M. HOVI a1 and B. A. D. STOCKER a1
a1 Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA


Sixty-seven strains of the five described Salmonella serotypes having antigens 6,7[ratio]c[ratio]1,5, that is S. enterica serotype Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis, were examined for 16S rrn profile ribotype, presence of IS200 and phenotypic characters, including rate of change of flagellar-antigen phase and nutritional character. Choleraesuis sensu stricto and its Kunzendorf variant had related but distinct ribotypes. Therefore, ribotyping appears to be a suitable method for differentiating Choleraesuis non-Kunzendorf from Choleraesuis var. Kunzendorf. Some strains of Paratyphi C had 16S profiles that resembled that of Choleraesuis non-Kunzendorf, while others resembled that of Choleraesuis var. Kunzendorf. The Typhisuis profiles were like those of Choleraesuis non-Kunzendorf, while the Choleraesuis var. Decatur profiles were unlike those of any of the other four groups. Furthermore, IS200 fingerprinting discriminated between Choleraesuis var. Decatur and the other strains with antigenic formula O6,7[ratio]c[ratio]1,5, and comparison of IS200 patterns showed a high degree of genetic divergence within Choleraesuis var. Decatur. Our findings show that ribotyping and IS200 fingerprinting, combined with classical microbiological methods, distinguish the groups Choleraesuis non-Kunzendorf, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C and Typhisuis.

(Accepted March 24 1999)

c1 Author for correspondence: Dipartimento di Scienze Biomediche, Sezione di Microbiologia Sperimentale e Clinica. Università degli Studi di Sassari, Viale S. Pietro, 43B-07100-Sassari, Italy.