Influence of peracetic acid on Escherichia coli H10407 strain in laboratory microcosms

The bactericidal properties of peracetic acid (PAA) were tested using Escherichia coli H10407, in sterilized artificial seawater, sewage effluent water, and distilled water microcosms. No LT enterotoxin synthesis was detected by GM1 enzyme-linked immunosorbent assay of the water supernatants, but a specific fragment of the eltB gene was always amplified by polymerase chain reaction for 21 days after PAA treatment. The resuscitation capacity of starved cells was assayed in rich medium and their inability to overcome the effects of PAA stress was observed, despite the emergence of viable but nonculturable cells in microcosms 24 or 48 h after treatment. Moreover, no obvious differences in response were obtained, concerning enterotoxigenesis, between bacteria subjected to osmotic and (or) nutrient starvation-induced stress with or without PAA treatment.Key words: peracetic acid, disinfection, enterotoxigenic Escherichia coli.