Lucia Bonadonna

Occurrence of Cryptosporidium oocysts in sewage effluents and correlation with microbial, chemical and physical water variables.

Contaminated water are recognized as a potential source of Cryptosporidium oocysts. In Italy studies on the environmentalspread of the parasite are still scarce even if a high frequencyof serological responses could suggest high rates of endemic Cryptosporidium infections. In this investigation theoccurrence of the parasite in water samples from a municipalwastewater treatment plant was monitored with the aim to evaluatepossible correlation between oocysts and bacterial indicators,pathogens and physico-chemical parameters using a multivariateanalysis. Data collected showed high numbers of oocysts, with ahigh percentage of positive samples and a significant correlationwith pH, redox potential and total organic carbon. No correlationwas found between Cryptosporidium concentration and that of the other microrganisms. The results, through a probing statistical analysis, show that none of the selected microrganisms was a reliable predictor of the presence of theparasite.

Non-tuberculous mycobacteria and microbial populations in drinking water distribution systems

Data on the occurrence of non-tuberculous mycobacteria (NTM), in parallel with those obtained for bacterial indicators and amoebae, are presented with the aim to collect information on the spread of NTM in drinking water distribution systems in Italy. Samples were collected from taps of hospitals and households in Central and Southern Italy. The concentration values obtained for the more traditional microbial parameters complied with the mandatory requirements for drinking water. Conversely, moderate-to-high microbial loads (till 300 CFU/L) were observed for the NTM. Positive samples were obtained from 62% of the investigated water samples. Analogous results were observed for amoebae showing a higher percentage of positive samples (76%). In terms of public health, the presence of mycobacteria in water distribution systems may represent a potential risk especially for vulnerable people such as children, the elderly or immunocompromised individuals.

Fecal streptococci recoveries in different marine areas

The usual media and procedures were followed to measure the concentration of fecal streptococci (MPN on Azide Dextrose and Ethyl Violet Azide broths, membrane filtration on m-Enterococcus, KF and Pfizer Selective Enterococcus agars and according to the mE procedure) in samples collected along two different marine areas. The results were evaluated on the basis of three parameters: total concentrations, number of enterococci-like colonies (namely colonies gram positive, catalase negative, coccus shaped) and rate of strictly named fecal streptococci.From the results it appears that the various media and procedures employed gave different yields and their capacity to measure fecal streptococci varies according to the origin of samples. The accompanying bacterial flora may play an important role on the selectivity of each technique to measure the fecal streptococci.

Occurrence of Giardia and Cryptosporidium in Italian water supplies

A total of 21 samples: raw water (RW) samples; water samples after coagulation with aluminium sulfate (clarified water: CW); and water after chlorination (treated water: TW) from a water purification plant that treats river surface water from the neighbourhood of Foggia (Italy), were analysed for the presence of Giardia cysts and Cryptosporidium oocysts. Bacteriological indicator of faecal contamination (total and faecal coliforms, faecal streptococci,), total bacterial count at 22 and 36°C and physicochemical parameters (turbidity, temperature, pH) were evaluated. Cryptosporidium oocysts were not found in any samples examined, while Giardia cysts were found only in RW samples, with the maximal concentration of 8 cysts/100 l. A positive correlation was found between the Giardia densities and quality parameters such as TC, FC and TBC at 22°C. Giardia levels in raw water samples correlated (p<0.05) with TC, FC and with temperature. No other water quality parameters was consistently correlated with cysts level.

Assessment of microbiological and parasitological quality of composted wastes: health implications and hygienic measures

Feedstock and compost samples were collected from twenty composting plants and analysed from the microbiological point of view. Faecal indicator organisms were determined in order to evaluate the efficacy of processes for the removal of pathogenic micro-organisms with similar survival characteristics and to verify their suitability as appropriate markers of microbial quality of composted products. In addition to the classical bacterial indicators, selected organisms, such as Salmonella, Giardia , Cryptosporidium, Clostridium spores and helminth ova, were investigated. Statistically significant differences in the removal of the different micro-organisms were observed with regard to both the different composting plants (P < 0.05) and feedstock composition (P < 0.05). In fact, compost obtained by feedstock containing sewage sludge was shown to have a better hygienic quality in comparison with compost containing green discards and municipal solid waste as raw matter. Giardia cysts, Cryptosporidium oocysts and helminth ova were not effective indicators of hygienic quality of compost, whereas Clostridium perfringens spores, because of their high resistance to treatments, could be considered as an additional model for assessing the composting process, especially with regard to more resistant pathogen reduction.

Comparison of methods to detect fecal streptococci in marine waters

Fecal streptococci in marine water samples have been detected according to the Membrane Filtration (MF) technique on three agarized media (KF agar, M-Enterococcus agar, and Pfizer Selective Enterococcus agar), and according to the MPN methodology (Azide Dextrose broth followed by Ethyl Violet Azide Dextrose broth). Results show that these various media and techniques yield different figures. The lowest counts have been obtained with KF- agar and MPN technique. A high incubation temperature (44 °C) generally reduces the number of fecal streptococci recoveries with the only exception of KF agar. All the aforementioned systems used in this study to select fecal streptococci from sea water have shown a poor selectivity. However the highest recoveries of strictly named fecal streptococci have been found on KF agar. Two of the tested methods, MPN and MF on M-Enterococcus agar have been set by the European Economic Commission for detecting fecal streptococci in bathing waters. Results according to MPN are lower than those achieved on M-Enterococcus agar; however, they are well correlated with each other.

Occurrence of potential bacterial pathogens in coastal areas of the Adriatic Sea

A monitoring program was carried out in bathing waters along the sea-coast of the Adriatic Sea. The investigation was aimedat obtaining a quali-quantitative picture of microorganisms ofanthropic origin and of a more strictly autochthonous origin and at verifying the existence of possible reciprocal correlations and combinations of relationship between them. Results showed that the concentrations of indicators of faecal contamination, whether within or over the values established by legislation, are not always related to the presence and density of microorganisms of environmental origin but the regression modelsused can help to describe how these latter microorganisms can bein relation to levels of the other parameters. The difficultyis evident of the predictability of health effects swimming-associated; for this reason more complex models that are currently used should be taken into account for minimising the risk for bathers.

Evaluation of the wastewater treatment plant of Rome airport

The wastewater plant of Rome airport, which receives all the sewage from the airport as well as the cess from aeroplanes, was analysed for microbiological parameters. From the bacteriological point of view, in the water and sludge samples the densities of the faecal indicator of pollution and the presence of Salmonella spp and Vibrio cholerae as bacteriological pathogens were determined. At the same time, samples were analysed for the presence of enteric viruses and phages. Overall, the mean reduction of the faecal coliforms was 96%, E. coli 92% and faecal streptococci 99%. Salmonella spp was identified in all but one of the final effluents and V. cholerae in 2/10. Enteric viruses were identified in all but one of the raw waters and in three samples of final effluent. Bacteriophages (somatic coliphage, F-plus phage and B40-8), were found in all the samples but irregularly. Phages and enteric viruses were also found in the prefilter membranes used for prefiltering the raw water samples.

First detection of papillomaviruses and polyomaviruses in swimming pool waters: unrecognized recreational water-related pathogens?

Viral outbreaks associated with swimming pools have been described worldwide. The objective of this study was to examine the extent of viral contamination in indoor and outdoor swimming pools.

A case study of sanitary survey on community drinking water supplies after a severe (post-Tsunami) flooding event

This report presents a case study of a comprehensive sanitary survey on ca. 160 community drinking water supplies after a severe (post-Tsunami) flooding event in Sri Lanka. Sanitary inspection and microbiological and chemical water quality analyses were performed according to specifically-designed procedures established on the World Health Organization (WHO) guidelines. Significant hazards and critical points were identified in almost all the investigated water supplies. The overall results showed a significant level of microbiological and chemical risk associated with drinking water consumption within the investigated areas. The criteria and methods practised in this study are proposed as a model to assure an effective and reliable monitoring in post-emergencies involving possible deterioration of water quality and to identify health priorities related to water consumption.