Virulence of viable but nonculturable S. Typhimurium LT2 after peracetic acid treatment.

S. Typhimurium LT2 cells suspended in sterilized sewage effluent water (SEW) and in distilled water microcosms were exposed to 0, 7, 15 and 20 mg/l peracetic acid, and tested for viability and virulence. After treatment for one hour, colony forming units decreased by at least 5 log units at peracetic acid concentration of 7 mg/l.

Influence of peracetic acid on adhesion/invasion of Salmonella enterica serotype typhimurium LT2.

The influence of peracetic acid (PAA) disinfectant on Salmonella enterica serotype Typhimurium LT2 in sewage effluent was examined by studying its ability to adhere to and invade HeLa cells in vitro. Although the disinfectant produced a decrease of about 5 log units, the bacteria kept their adhesive and invasive abilities. Scanning microscopic observations of the PAA-treated bacteria revealed that PAA caused a loss of external microfilaments and an alteration of membrane structure.

Production of Escherichia coli group I-like heat-labile enterotoxin by Enterobacteriaceae isolated from environmental water.

Strains of Klebsiella oxytoca (2), Citrobacter freundii (2), Enterobacter cloacae (1) and Escherichia coli (1) isolated from environmental water were identified as heat-labile enterotoxin (LT) producing strains by immunological methods and polymerase chain amplification. A 322 bp amplified fragment was obtained with specific primers LTR and LTL, and hybridized to a digoxigenin-labelled LTB probe only under low stringency conditions, and not with a cholera toxin probe. These results suggest that Enterobacteriaceae may produce a LT-like toxin antigenically and genetically related to the LT enterotoxin of E.

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.

Use of peracetic acid as a disinfectant in a water-treatment plant: effect on the plasmid contents of Escherichia coli strains.

Total thermotolerant coliforms (TTC) and Escherichia coli strains were isolated from sewage from a treatment plant before and after peracetic acid (PAA) disinfection. The plasmid profiles of 120 E. coli strains were analyzed.