Characterization of neurotoxigenic Clostridium butyricum strain by DNA hybridization test and by in vivo and in vitro germination tests of spores

Classification of Clostridium butyricum based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and pulsed-field gel electrophoresis

Eleven strains of Clostridium butyricum collected from different sources were analysed by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and pulsed-field gel electrophoresis (PFGE). The strains could be classified into four groups based on their banding profiles of the proteins extracted from the cells on SDS-PAGE. Group I consisted of seven strains, and these strains were further divided into five subgroups by PFGE. The strains belonging to groups II, III, and IV on SDS-PAGE were also classified into the same II to IV groups by PFGE. These data indicate that grouping of the strains of C. butyricum can be performed by employing both SDS-PAGE and PFGE.

Use of a novel method to characterize the response of spores of non-proteolytic Clostridium botulinum types B, E and F to a wide range of germinants and conditions

AIMS

Limited information is available on the germination triggers for spores of non-proteolytic Clostridium botulinum. An automated system was used to study the effect of a large number of potential germinants, of temperature and pH, and aerobic and anaerobic conditions, on germination of spores of non-proteolytic Cl. botulinum types B, E and F.

METHODS AND RESULTS

A Bioscreen analyser was used to measure germination by decrease in optical density. Results were confirmed by phase-contrast light microscopy. Spores of strains producing type B, E and F toxin gave similar results. Optimum germination occurred in L-alanine/L-lactate, L-cysteine/L-lactate and L-serine/L-lactate (50 mmol l(-1) of each). A further 12 combinations of factors induced germination. Sodium bicarbonate, sodium thioglycollate and heat shock each enhanced germination, but were not essential. Germination was similar in aerobic and anaerobic conditions. The optimum pH range was 5.5-8.0, germination occurred at 1-40 degrees C, but not at 50 degrees C, and was optimal at 20-25 degrees C.

CONCLUSIONS

The automated system enabled a systematic study of germination requirements, and provided an insight into germination in spores of non-proteolytic Cl. botulinum.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results extend understanding of germination of non-proteolytic Cl. botulinum spores, and provide a basis for improving detection of viable spores.