INSERTION-SEQUENCE IS200 FINGERPRINTING OF SALMONELLA-TYPHI - AN ASSESSMENT OF EPIDEMIOLOGIC APPLICABILITY

When Pst I-generated digests of genomic DNA from each of the type stra ins of 49 of the Vi phage types of Salmonella typhi were probed with a PCR-amplified IS200 gene probe, all strains were found to possess at least 11 IS200 elements carried on fragments in the range 24.2-1.2 kb. Fourteen fingerprints were identified but two patterns designated IS2 00Sty1. and IS200Sty2 predominated. In one strain, a. plasmid-mediated IS200 element was identified. When IS200 fingerprinting was applied t o epidemiologically-unrelated strains of S. typhi isolated in Ecuador, 3 patterns were identified in 10 strains belonging to 9 different pha ge types. It is concluded that Vi phage typing remains the method of c hoice for the primary differentiation of X. typhi but that IS200 finge rprinting way be of limited use in laboratories which do not have acce ss to phage typing.