Numerical analysis of electrophoretic protein patterns of Bacteroides ureolyticus clinical isolates.

A total of 37 Bacteroides ureolyticus clinical isolates (mainly from the United Kingdom) comprising 18 nongonococcal urethritis-associated strains and 19 other strains, including the type strain (NCTC 10941T) and strains from abscesses, ulcers, and various other soft tissue lesions, and five reference strains of other Bacteroides, Fusobacterium, Megamonas, and Sebaldella species were characterized by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cellular proteins. The protein patterns, which contained 45 to 50 discrete bands, were highly reproducible and were used as the basis for a numerical analysis. Four clusters comprising 31 strains of B. ureolyticus were obtained at the 70% similarity level, and one of these was further divided to give two subclusters at the 82% similarity level. The analysis showed that the clusters obtained corresponded with three previously identified polyacrylamide gel electrophoresis types (I, II, and III) within the species, although two slightly different patterns within type I were detected. Evidence is presented for a new protein pattern (type IV) which was characteristic of NCTC 10941T and seven isolates. There was no clear-cut correlation between the pattern type and the clinical source of the isolates, except for the type Ib and type IV strains, which were nongonococcal urethritis-associated and wound isolates, respectively.