[Epidemic hazard of water use in the reactivation of bacteria after disinfection].

Variability in the cultural and biochemical properties of indicator, opportunistic, and pathogenic bacteria and possibilities of their reactivation after exposure to chlorine-containing reagents and during photo-activated disinfection processes in the presence of photosensitizes were experimentally studied to enhance the epidemic reliability and adequacy of microbiological monitoring in the evaluation of the decontamination efficiency of water of its various use types. Reactivation of coliform bacteria, enterococci, salmonellas, and the total number of microbes were estimated after exposure to the bacteriostatic doses of sodium hypochlorite and chlorine dioxide when the river and waste waters were decontaminated. During photo-activated disinfection under the action of the photosensitizers methylene blue and proflavin acetate given in the bacteriostatic doses, there was transition into the uncultivated state, followed by 1-5-day reactivation of both museum strains and strains isolated from waste waters, such as Salmonella infantis spp, Salmonella enteritidis spp, Salmonella enteritidis 5765 ATCC, Pseudomonas aeruginosa 10145, Pseudomonas aeruginosa spp, Escherichia coli 1257, Staphylococcus aureus 906, and Enterococcus faecalis 29212. Moreover, Pseudomonas and Salmonellas not only regained their viability, but also multiplied up to the control level. Recommendations are given how to improve methods for monitoring the efficiency of disinfection, by taking into account a possible variability in the cultural and biochemical properties of bacteria and for reactivation by monitoring the trend in the process during 5 days.