PRODUCTION AND PROPERTIES OF CRUDE ENTEROTOXIN OF PSEUDOMONAS-AERUGINOSA

Pseudomonas aeruginosa CTM-3 was found to be the most potentially enteroxigenic strain out of the 12 isolates recovered from milk, as a high fluid length ratio, i.e. F/L (1.1) in rabbit gut and a strong permeability response in rabbit skin (38.5 mm2 necrotic zone) was obtained with this culture. No clear-cut relationship between the two tests was observed. Six of the ethidium bromide (300 μg/ml) cured variants of this culture completely lost their ability to produce enterotoxin indicating the possible involvement of a plasmid in enterotoxin synthesis. The crude enterotoxin from P. aeruginosa CTM-3 was completely inactivated in 15 s at 72°C. However, it was fairly stable at pH values in the range 4.5-7.5. Both pepsin and trypsin inactivated the enterotoxin activity at a concentration of 40 μg/ml. Organic acids, formalin and hydrogen peroxide had no significant effect on the enterotoxin activity. The need for further investigations with purified preparations is emphasized. © 1990.