Anna Maria D'Angelo

Detection of Emerging and Re-Emerging Pathogens in Surface Waters Close to an Urban Area

Current knowledge about the spread of pathogens in aquatic environments is scarce probably because bacteria, viruses, algae and their toxins tend to occur at low concentrations in water, making them very difficult to measure directly. The purpose of this study was the development and validation of tools to detect pathogens in freshwater systems close to an urban area. In order to evaluate anthropogenic impacts on water microbiological quality, a phylogenetic microarray was developed in the context of the EU project µAQUA to detect simultaneously numerous pathogens and applied to samples from two different locations close to an urban area located upstream and downstream of Rome in the Tiber River. Furthermore, human enteric viruses were also detected. Fifty liters of water were collected and concentrated using a hollow-fiber ultrafiltration approach. The resultant concentrate was further size-fractionated through a series of decreasing pore size filters. RNA was extracted from pooled filters and hybridized to the newly designed microarray to detect pathogenic bacteria, protozoa and toxic cyanobacteria. Diatoms as indicators of the water quality status, were also included in the microarray to evaluate water quality. The microarray results gave positive signals for bacteria, diatoms, cyanobacteria and protozoa. Cross validation of the microarray was performed using standard microbiological methods for the bacteria. The presence of oral-fecal transmitted human enteric-viruses were detected using q-PCR. Significant concentrations of Salmonella, Clostridium, Campylobacter and Staphylococcus as well as Hepatitis E Virus (HEV), noroviruses GI (NoGGI) and GII (NoGII) and human adenovirus 41 (ADV 41) were found in the Mezzocammino site, whereas lower concentrations of other bacteria and only the ADV41 virus was recovered at the Castel Giubileo site. This study revealed that the pollution level in the Tiber River was considerably higher downstream rather than upstream of Rome and the downstream location was contaminated by emerging and re-emerging pathogens.

Coliphages as indicators in a treatment plant

The potential use of coliphages as indicators of water pollution was investigated. Several strains ofE. coli hosts were used in order to detect the better marker. Analyses were carried out on a treatment plant for the convenience of phages recoveries. Results show the possibility that strains different fromE. coli 9484B can show better recoveries of PFU m1−1.

Multi-criteria approach for the environmental impact assessment of inland aquaculture

Trout farming, that represents the most important sector for aquaculture inland production in Italy, can cause negative effects on aquatic ecosystems. Recently, in the framework of Water Frame Directive 2000/60/EC and national law DL 152/2006, concerning the sustainable uses of water resources, multi-criteria approaches have been suggested to evaluate the impact of fish farming on aquatic ecosystems. In this study trout farms of central Italy were selected to investigate the effects of their effluents, on receiving water bodies using a multi-criteria approach based on physicochemical parameters, microbiological and macrobenthonic indicators, detected in sampling stations located upstream/downstream the trout farm. Moreover, antibiotic susceptibility against antibiotics allowed and/or forbidden by current law (D.lgs 193/56/06) was tested on E. coli strains. The results indicate variations of chemical parameters and biological indicators from upstream to downstream sites in some of the investigated farms. Antibiotic resistance of E. coli strains suggested a large use of tetracycline and a possible past use of chloramphenicol. This study represents a first contribute to the knowledge of fish farm impacts on aquatic systems in Central Italy.