WHOLE-CELL AND PERIPLASMIC PROTEIN BANDING-PATTERNS OF ENVIRONMENTAL AND HUMAN BACTEROIDES-FRAGILIS STRAINS

In order to investigate the relationship among virulent and avirulent Bacteroides fragilis strains, SDS-PAGE of whole-cell proteins (WP) and periplasmic proteins (PP) were used to establish a protein profile of strains isolated from human infections, fecal flora and environmental water. Despite different sources of the strains, no significant diffe rences were observed as determined by the WP SDS-PAGE analysis. In con trast, the proteins obtained from the bacterial periplasm showed diffe rences in the electrophoretic protein profile. Two distinct PP profile patterns were obtained. Pattern A included 6 out of the 8 virulent st rains and pattern B, 6 out of 8 avirulent strains. Interestingly, an e nvironmental strain that was capable of inducing abscesses in mice, ha d a PP profile highly similar to that of the virulent strains from hum an infections. These data indicate that PP from B. fragilis may be use ful to characterize differences among virulent and avirulent strains. Moreover, strains isolated from environmental water may also be a sour ce of exogenous infections by B. fragilis.