CONTAMINATION RISK ASSESSMENT OF SOURCES OF WATER INTENDED FOR HUMAN CONSUMPTION WITH AEROMONAS SPP.

mportance of Aeromonas spp as emerging pathogens in recent years has been a considerable increase, beingincluded by the World Health Organization (WHO) and Environmental Protection Agency (EPA) in the etiology ofwaterborne epidemics. We aimed to investigate the distribution of Aeromonas spp. in various aquatic ecosystems whichcan become potential sources of gastrointestinal infections. Simultaneously, the presence of this pathogen was evaluatedin relation to microbiological indicators set out in EU Directive 98/83/EC. Between March 2009 and May 2011 wereanalyzed by membrane filter technique untreated water samples, collected from surface sources (lakes, ponds) andgroundwater (wells drilled, captured springs, wells) and chlorinated water that coming from local distribution network,located in rural areas of Moldova (North-East Romania). The information was processed and interpreted statisticallyusing EpiInfo 3.5.1 software. The presence of Aeromonas spp. was detected in half of the 220 samples tested, especially,in surface waters (84%) and captured springs (80.8%) (χ 2=51.39; GL=4; p<0.001), with concentrations that ranged from1 to 3.8 x104CFU/100ml (median=4.9x103CFU/100ml), respectively, from 1 to 6.9x102CFU/100 ml (median =58CFU/100 ml) . The main species identified were A. hydrophila (22%), A. caviae (10.2%), A. veronii (6%) and A. sobria(6%) (using API 20NE galeries). Although the etiology was reported in 15.9%, chlorinated water quality was much betterthan that of untreated sources (χ 2=26.56; GL=1; p<0.001), with Odd.Ratio =0.12 (0.04 to 0.31; CI=95%). Comparativeevaluation of contamination of studied ecosystems showed a higher presence of these organisms in surface water than ingroundwater (χ 2=8.71; GL=1; p<0.003), Odd.Ratio=37 (1.4 to 8.9; CI=95%), with an increased risk of infectiontransmission through ingestion or contact. Pearson coefficient for the presence in groundwater of fecal pollutionindicators (coliform bacteria, Escherichia coli, enterococci) and Aeromonas spp. showed that there was a low significantassociation (r <0.2), while in surface water correlation was very strong (r>0.8), being influenced by exogenous humanimpact. The results of this study confirms that untreated water used in rural areas can affect public health andmicrobiological indicators have predictive value for the presence of Aeromonas spp only reporting to surface sources.