Maurizio Semproni

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.

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.

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.

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.

Biotyping, serotyping and genotyping of aeromonads from environmental and clinical samples

Pulsed-field gel electrophoresis (PFGE) and biochemical–serological assays were used to characterize environmental and clinical aeromonads. On the basis of their biochemical characteristics, 31 strains were assigned to one of the recognized groups or species within the Aeromonas genus and 11 different serogroups were detected. Low correlation between molecular and traditional typing methods was observed. The results obtained showed that the genomic analysis performed by PFGE can be a more effective means for distinguishing between Aeromonas isolates than conventional biochemical methods.

Evaluation of an MPN test for the rapid enumeration of Pseudomonas aeruginosa in hospital waters.

In this study, the performance of a new most probable number (MPN) test (Pseudalert(®)/Quanti-Tray(®)) for the enumeration of Pseudomonas aeruginosa from hospital waters was compared with both international and national membrane filtration-based culture methods for P. aeruginosa: ISO 16266:2006 and UK The Microbiology of Drinking Water - Part 8 (MoDW Part 8), which both use Pseudomonas CN agar. The comparison based on the calculation of mean relative differences between the two methods was conducted according to ISO 17994:2014. Using both routine hospital water samples (80 from six laboratories) and artificially contaminated samples (192 from five laboratories), paired counts from each sample and the enumeration method were analysed. For routine samples, there were insufficient data for a conclusive assessment, but the data do indicate at least equivalent performance of Pseudalert(®)/Quanti-Tray(®). For the artificially contaminated samples, the data revealed higher counts of P. aeruginosa being recorded by Pseudalert(®)/Quanti-Tray(®). The Pseudalert(®)/Quanti-Tray(®) method does not require confirmation testing for atypical strains of P. aeruginosa, saving up to 6 days of additional analysis, and has the added advantage of providing confirmed counts within 24-28 hours incubation compared to 40-48 hours or longer for the ISO 16266 and MoDW Part 8 methods.