A rapid, semi‐automated SDS‐PAGE identification system for oral anaerobic bacteria

Abstract

SDS-polyacrylamide gel electrophoresis is a useful technique in bacterial differentiation and identification. A rapid, semi-automated SDS-PAGE system (Phast System) was assessed for identification of formate-fumarate-requiring, asaccharolytic, Gram-negative oral anaerobes. The system permitted loading, separation and staining of gels within 2 h. Percentage similarities between strains were determined using correlation coefficients and cluster analysis. The protein profiles were sufficiently reproducible provided that distorted profiles were disregarded. Strains were successfully separated into their species, with the exception of Bacteroides ureolyticus NCTC 10939, which appeared to be distinct from other strains of that species. Twenty-nine unidentified formate-fumarate-requiring, sub-gingival plaque strains were suitably clustered with the standard strains as verified by a series of physiological and biochemical tests.

Description of Two Morphotypes of Peptostreptococcus micros

“…Slayne et al (29) demonstrated the possibilities of the PhastSystem for this technique. We characterized the two morphotypes of P. micros and showed that with this method, it was possible to differentiate between the two morphotypes despite minor differences between strains of one group.…”

“…Before SDS-PAGE the proteins in the supernatant were alkylated as described by Heukeshoven and Dernick (10). The running conditions used for the 12.5% homogeneous acrylamide gel were the conditions described by Slayne et al (29). Low-molecularweight standard proteins were obtained from Pharmacia.…”

“…SDS-PAGE profiles were obtained by using the PhastSystem (Pharmacia LKB Biotechnology, Uppsala, Sweden). Samples of soluble proteins were prepared as described by Slayne et al (29). Cells from five blood agar plates which had been incubated for 96 h were harvested in 0.5 M Tris-HC1 (pH 6.8).…”

The family Coriobacteriaceae: reclassification of Eubacterium exiguum (Poco etal. 1996) and Peptostreptococcus heliotrinreducens (Lanigan 1976) as Slackia exigua gen. nov., comb. nov. and Slackia heliotrinireducens gen. nov., comb. nov., and Eubacterium lentum (Prevot 1938) as Eggerthella lenta gen. nov., comb. nov.

“…Eubacterium exiguum is frequently found in periodontitis and periapical infections (Wade, 1997) but is difficult to identify because it is generally unreactive in conventional biochemical tests. In this, it resembles Eubacterium lentum (Moore et al, 1971), an organism found in human faeces, with which it is often confused (Wade et al, 1990). Eubacterium lentum is only rarely reported as being isolated from the mouth when tests capable of distinguishing it from Eubacterium exiguum are performed (Wade et af., 1990).…”

“…However, some species and unnamed taxa provisionally identified as Eubacterium have DNA of high G + C content (Nakazawa & Hoshino, 1994). One such species is Eubacterium exiguum (Poco et al, 1996), formerly designated Eubacterium D6 (Moore et al, 1982(Moore et al, , 1983, Eubacterium S-group (Sato et al, 1993) or Eubacterium Cluster 2 (Wade et al, 1990(Wade et al, , 1994. Eubacterium exiguum is frequently found in periodontitis and periapical infections (Wade, 1997) but is difficult to identify because it is generally unreactive in conventional biochemical tests.…”