G . B R A N D I , M . S I S T I A N D G . A M A G L I A N I . 2000. Using three sampler devices (SAS, AndersenSix-Stages and All Glass Impinger), the environmental impact of bacterial and fungal aerosols generated by municipal wastewater treatment plants operating with different methods of sludge oxygenation were evaluated. The highest microbial concentrations were recovered above the tanks (2247 cfu m À3 ) and in downwind positions (1425 cfu m À3 ), where a linear correlation (P < 0Á05) was found between the quantity of sewage treated and the entities of microbial aerosol dispersion. Moreover, an exponential increase (P < 0Á05) in the bacteria recovered from the air occurred at increasing times of treatment. However, after long-term plant operation, high bacterial and fungal concentrations were found in almost all of the sites around the plant. Coliforms, enterococci, Escherichia coli and staphylococci were almost always recovered in downwind positions. Considerable fractions (20±40%) of sampled bacteria were able to penetrate the ®nal stages of the Andersen apparatus and thus, are likely to be able to penetrate the lungs. The plant operating with a ®ne bubble diffused air system instead was found to generate rather low concentrations of bacteria and fungi; moreover, staphylococci and indicator micro-organisms were almost absent. Finally, salmonellae, Shigella, Pseudomonas aeruginosa and Aeromonas spp. were not detected in either of the plants. The results indicate a remarkable dispersion of airborne bacteria and fungi from tanks in which oxygen is supplied via a mechanical agitation of sludge, and suggest the need to convert them to diffused aeration systems which pose a lesser hazard for human health.

Many vegetables of the Cruciferae family have been found to possess antimicrobial properties against several microorganisms of clinical importance. In this study, we reported the antibacterial effect of Brassica oleracea juice on several food-borne pathogens. The juice was found to be effective in inhibiting the growth of Salmonella Enteritidis, verotoxigenic Escherichia coli O157:H7, E. coli HB producing thermolabile toxin, nontoxigenic E. coli, and Listeria monocytogenes, but not Enterococcus faecalis. All cauliflower cultivars tested suppressed bacterial growth in a dose-dependent manner after 5 h of treatments, and the reduction in the number of viable cells ranged from 1 log with a 10% juice concentration to more than 3 log with a 20% juice concentration. The foodborne bacteria tested were also markedly reduced by isothiocyanates, natural components abundant in the genus Brassica, indicating that glucosinolate-derived isothiocyanates can play a major role in the antimicrobial activity of cauliflower. The antimicrobial effect of juice was reduced in presence of cysteine, suggesting that one mechanism of action of the juice involves blocking bacterial sulfhydryl groups.

A growing number of people attend swimming facilities for recreational activities, rehabilitative treatments, or sport. Filamentous fungi and yeast can be isolated from contaminated air, water and surfaces and may represent a biological risk for employees and users. Here we investigated the occurrence of mycotic species, in a sample of Italian swimming pools (n = 10). Detection and identification of isolated species were achieved by cultural and morphological methods. Results revealed moderate mycotic titres and a high biodiversity. Penicillium spp., Aspergillus spp., Cladosporium spp. and Alternaria sp., were constantly detected in air and surfaces sampled by the swimming area, while pathogenic yeast Candida albicans was never detected. Fusarium spp. was the most common taxon isolated from surfaces. For one facility, we typed the genotypic profiles and studied, by genetic typing, the spatial and temporal distribution of isolates. Phylogenetic relationships between species were analysed by alignment of small ribosomal subunit RNA sequences.

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The ability of motile Aeromonas spp. to survive in drinking water (mineral and tap water) and in sea water was experimentally tested. Clinically isolated cytotoxic strains of A. hydrophila, A. caviae and A. sobria were selected for this study. After contamination of water samples, the survival of Aeromonas strains was studied for at least three months using viable counts. The results obtained show that the survival of the Aeromonas spp. varies considerably depending on species and water type. For all three species, the survival time was longest in mineral water, where viable bacteria of each strain were still detected after 100 d. Moreover, A. hydrophila and A. caviae also re-grew on the first day. In tap water all strains showed marked survival, although to a lesser extent than in mineral water. Aeromonas cells showed a rapid decline in sea water (90% reduction in viable cells after about two d) and thus seem to be more sensitive to saline/marine stress than chlorination.

T h e survival of mesophilic Aeronionas spp. in soil in the presence or absence of indigenous microflora was evaluated in a laboratory study. T w o cytotoxic (Aer. /zydrophila and Aer. cazirre) and one invasive (Aer. sohrzu) clinical isolate strains were selected for this study. After contamination of sterile or unsterilized soil with the three strains of Aeromonas, the number of living cells was determined over at least 5 months. F o r all strains the survival curves were characterized by an initial re-growth followed by a slow inactivation of bacteria, with significant differences due to the presence of indigenous microflora. T h e times necessary to achieve a 9So% reduction of the initial population were > 140, 113 and 62 d in sterilized soil respectively for Aer. caviae, Aer.Igdrophilu and Aer. sobrin, while the corresponding times in unsterilized soil were 42, 38 and 11 d. All strains preserved the virulence factors for the entire period of the study. These results suggest that the soil may be an important reservoir for Aeromonas spp. and, thus, may play an important role in the epidemiology of Aeromonas-associated human infections.Grrc,spponili.nre to : l h (;io,xrii Briinili. Istitirto ill Igrme. Unizwsrta Dqli Stud1 dr llrliino.

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