Interaction between bacterial enteric pathogens and aquatic macrophytes. Can Salmonella be internalized in the plants used in phytoremediation processes?

The environment is considered a reservoir of pathogens and a possible source of infection for animals and humans. The association between enteric pathogens and food plants has been demonstrated in several studies, while few studies have addressed possible interactions between human pathogens and aquatic plants. This study, performed by setting mesocosms, evaluates the interaction between an enteric pathogen (Salmonella enterica serovar Napoli, S. Napoli) and a macrophyte (Phragmites australis (Cav.) Trin. ex Steudel) and the possible ability of the bacterium to internalize into the plant. The results show that S. Napoli concentration decreased gradually in growth solution without plants (control) while it was able to persist adhering to submerged parts of plants in treated mesocosms. The adhesion of the bacterium remained stable for 20 days, then decreased gradually until the end of the experiment. In addition, S. Napoli was able to internalize and colonize stems and leaves. In conclusion, the study suggests that macrophytes can represent an alternative environmental reservoir of pathogens for humans and animals. The adhesion to roots and rhizomes and the internalization could contribute to the bacterial persistence in the aquatic ecosystems by playing an important role in ecology and transmission of pathogens.

Evaluation of two methods for the use of diatoms in drowning cases.

In this study, we compare digestive methods used in a forensic context to extract diatoms (37 % hydrochloric acid) to a method recently described in Italian protocols for analysis of benthic diatoms for ecological assessment of surface water (hydrogen peroxide digestion). The two digestive methods were performed using 5 g of brain, lung, liver, kidney, and bone marrow taken from the bodies of 10 drowning victims recovered from three different aquatic environments (ocean, lakes, and rivers). Postmortem examination was performed on all bodies, but aquatic samples were only analyzed in two cases. Tissue digestion was equal by both methods. Hydrogen peroxide (H2O2) digestion resulted in better diatom preservation, enabling identification of nine genera in all samples examined versus three obtained using hydrochloride digestion. The ideal digestive method to provide evidence for corroboration of a diagnosis of drowning still needs to be established. However, the benthic diatoms protocol can be useful because it is less chemically hazardous to the laboratory operator and supports better diatom preservation for reliable taxonomic analysis.

COVID-19 Lockdown Pandemic Period Effects in Highly Impacted Aquatic Ecosystems.

Human activities severely affect aquatic ecosystems: the lockdown restrictions due to SARS-CoV-2 (COVID-19) have proved that reducing anthropogenic activities can positively influence the environment and mitigate atmospheric pollution. In addition, studies on aquatic ecosystems have highlighted the decrease in suspended matter and pollutant concentrations associated with reduced marine transport and industrial activities. We evaluated the effects of the reduction of anthropogenic activities in highly impacted water ecosystems. Three of the sampling sites were on the Tiber River's lower stretch close to the urban area of Rome (Italy), and the other two were transitional waters located in the southern Latium region coastal area. These sampling sites have been studied by our research group for at least 20 years. The present study involved analysis of chemical and physicochemical parameters, biological communities, and land use. Microbiological fecal indicators and Salmonella spp. were also analyzed. There were two sampling campaigns, the first one in May 2020 (ID II) at the end of lockdown measures, and the second one a year later, in June 2021 (ID III). The data were compared with our old data, collected from 2002 to 2015 (ID I), to evaluate the potential effects of the restrictive measures. Biotic communities were dominated by pollution-tolerant taxa, indicating eutrophication and organic pollution. Furthermore, the high concentrations of microbiological indicators was mainly due to sewage from the urban area. The results of the research indicated no significant changes from past years (ID I) to 2020 (ID II) and 2021 (ID III). In conclusion, the restrictions adopted in Italy during the pandemic period were not sufficient to mitigate the heavy pressure of urbanization and agriculture that have long affected the studied aquatic ecosystems. Environ Toxicol Chem 2023;42:966-977. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Teratogenic effects of environmental concentration of plastic particles on freshwater organisms.

Given the widespread presence of plastics, especially in micro- and nanoscale sizes, in freshwater systems, it is crucial to identify a suitable model organism for assessing the potential toxic and teratogenic effects of exposure to plastic particles. Until now, the early life stage of freshwater organisms and the regeneration capacity in relation to plastic particles exposure is a still poorly investigated topic. In this study, we examine the teratogenic effect on diatom Cocconeis placentula and cnidarian Hydra vulgaris under controlled exposure conditions of poly(styrene-co-methyl methacrylate) (P(S-co-MMA)) particles. Significant effects were observed at the lowest concentrations (0.1 µg/L). A significant increase in the teratological frequency in C. placentula and a significant decrease in the regeneration rate in H. vulgaris were found at the lowest concentration. The delay in hydra regeneration impaired the feeding capacity and tentacles reactivity at 96 h of exposure. No effects on diatom growth were observed upon exposure to P(S-co-MMA) particles (0.1, 1, 100, 10,000 µg/L) for 28 days and these findings agree with other studies investigating algal growth. The application of the Teratogenic Risk Index, modified for diatoms, highlighted a moderate risk for the lowest concentration evaluating C. placentula and low risk at the lowest and the highest concentrations considering H. vulgaris. This study suggests the importance of testing organisms belonging to different trophic levels as diverse teratogenic effects can be found and the need to evaluate environmentally relevant concentrations of plastic particles.

Mercury (Hg) and methylmercury (MeHg) in sediment and biota: A case study in a lagoon in Central Italy.

A quantification of total mercury (Hgtot) and methylmercury (MeHg) concentrations in sediment and mussels was carried out in the east basin of the Orbetello lagoon in order to assess their bioaccumulation potential. The sediment was sampled in four macroareas, mussels were transplanted in the same sites and collected after seven weeks. The results show that Hgtot concentrations in sediments exceeded (0.21-16.9 mg/kg dry weight (dw)) the environmental quality standard of the Italian legislation (0.3 mg/kg dw). The Hgtot concentration in mussels (0.050-0.324 mg/kg wet weight (ww)) does not exceed the limit values (0.5 mg/kg ww) of the European food legislation. The biota-sediment accumulation factors (BSAFs) derived for MeHg (80-306.7) and a biomagnification factor (BMF) greater than 1 for Hgtot demonstrate that in the lagoon, these compounds can be transferred in the upper levels of the trophic chain and pose a risk to human health.

A Patented Rapid Method for Identification of Italian Diatom Species.

The study of diatoms-unicellular algae of the class Bacillariophyceae-has several applications, first and foremost the evaluation of freshwater ecosystem quality according to the Water Frame Directive 2000/60/EC (WFD). Identification at the species level is a crucial step in diatom studies, considering that species belonging to the same genus have different geographical distributions and different ecological requirements. The Rapid Method for Identification of Italian Diatom Species is aimed at guiding users in the classification of freshwater diatom species. It consists of a digitized flow chart that leads, step by step, to the identification, starting with an image capture by light or electron microscopy. This rapid and easy tool could be useful to workers of an environmental agency when performing the operational monitoring required by the WFD to classify surface waters. It will also expand the application of diatoms in numerous fields. This method has been patented in Italy.

Health and Climate Change: science calls for global action.

Climate changes affect social and environmental health determinants such as clean air, ecosystems health, safe drinking water and safe sufficient food. Globally, people at greatest risk of adverse health effects associated with climate change include children, the elderly and other vulnerable groups. Temperature-related death and illness, extreme events, polluted or stressed ecosystems represent relevant issues raising concern for both health and economic consequences. The aim of the Symposium "Health and Climate Change" (Istituto Superiore di Sanità, Rome 3-5 December 2018) was to promote an inter-sectoral and multidisciplinary approach to estimate and prevent climate change-related events as well as to call the authorities to put in place measures to reduce adverse health effects. At the end of the Symposium the Rome International Charter on Health and Climate Change was presented. It includes a series of actions and recommendations, discussed and shared by all the participants, intended to inform policy makers and all the stakeholders involved in the management of climate changes.

Molecular detection of a potentially toxic diatom species.

A few diatom species produce toxins that affect human and animal health. Among these, members of the Pseudo-nitzschia genus were the first diatoms unambiguously identified as producer of domoic acid, a neurotoxin affecting molluscan shell-fish, birds, marine mammals, and humans. Evidence exists indicating the involvement of another diatom genus, Amphora, as a potential producer of domoic acid. We present a strategy for the detection of the diatom species Amphora coffeaeformis based on the development of species-specific oligonucleotide probes and their application in microarray hybridization experiments. This approach is based on the use of two marker genes highly conserved in all diatoms, but endowed with sufficient genetic divergence to discriminate diatoms at the species level. A region of approximately 450 bp of these previously unexplored marker genes, coding for elongation factor 1-a (eEF1-a) and silicic acid transporter (SIT), was used to design oligonucleotide probes that were tested for specificity in combination with the corresponding fluorescently labeled DNA targets. The results presented in this work suggest a possible use of this DNA chip technology for the selective detection of A. coffeaeformis in environmental settings where the presence of this potential toxin producer may represent a threat to human and animal health. In addition, the same basic approach can be adapted to a wider range of diatoms for the simultaneous detection of microorganisms used as biomarkers of different water quality levels.

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.

First isolation of Salmonella enterica serovar Napoli from wild birds in Italy.

Salmonella enterica serovar Napoli (S. Napoli) is an emerging serovar in Italy. It accounts for 2-4% of all serovars isolated from human infections. The zoonotic origin of this serovar is still unknown and this makes difficult to apply any control intervention. We report here the isolation of S. Napoli from a river nightingale (Cettia cetti, Temminck 1820) which represents the first description of this serovar from wild birds. This finding adds knowledge to the ecology of S. Napoli and addresses further studies aimed to assess the epidemiologic link between S. Napoli isolated from wild birds, food, environmental sources and human infections.

Water quality assessment of rivers using diatom metrics across Mediterranean Europe: a methods intercalibration exercise.

The European Water Framework Directive establishes a framework for the protection of water resources. However, common water management tools demand common understanding of assessment methods, so quality goals are equally met. Intercalibration of methods ensures the comparability of biological elements across similar geographical areas. Many aspects can influence the outcome of intercalibration: data sampling, treatment methods, taxonomic reliability of databases, choice of metrics for ecological quality status classification, and criteria for selecting reference sites. This study describes the potentials and constraints of the intercalibration of indices using diatoms for assessment of Mediterranean rivers. Harmonisation of diatom taxonomy and nomenclature was based on a previous ring test which took place at the European level. Four diatom indices (Indice de Polluosensibilité Spécifique-IPS, Indice Biologique Diatomées-IBD 2007, Intercalibration Common Metric Italy-ICMi and Slovenian Ecological Status assessment system) were intercalibrated using data from six European Mediterranean countries (Cyprus, France, Italy, Portugal, Slovenia and Spain). Boundaries between High/Good and Good/Moderate quality classes were harmonised by means of the Intercalibration Common Metric (ICM). Comparability between countries was assured through boundary bias and class agreement. The national boundaries were adjusted when they deviated more than a quarter of a class equivalent (0.25) from the global mean. All national methods correlated well with the ICM, which was sensitive to water quality (negatively correlated to nutrients). Achnanthidium minutissimum sensu lato was the most discriminative species of Good ecological status class. Planothidium frequentissimum, Gomphonema parvulum and Nitzschia palea were the most contributive to Moderate ecological status class. Some taxa were discriminative for both Good and Moderate ecological status classes due to low indication and ecological discriminative power but also due to differences in taxonomy between countries. This intercalibration exercise allowed establishment of common water quality goals across Mediterranean Europe, which is substantiated with the ICM.

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 physico-chemical 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.

Microbiological indicators and sediment management.

The Water Frame Directive 2000/60/CE underlines the importance of sediments and requests the creation of a European net (SedNet) for their management. Sediments play an important role for the river basin and offer a variety of habitats to many aquatic organisms. Microorganisms, such as Clostridia, are indispensable for a lot of symbiotic and pathogenic relationships with higher organisms and the disappearance of these communities could cause extinction of many species. Thus, Clostridia communities represent the most suitable microbiological indicators to characterize the ecological quality of sediments. The creation of SedNet may make it possible to develop a series of best recommendation in sediment management.