Regina Sommer

• Medical University of Vienna

Iron and manganese (Fe/Mn) often lead to aesthetic quality issues in water supply. Strong and problematic black-brown particle formation was persistently observed in an alluvial drinking water well, even though oxygen enrichment probes, intended for in situ i.e., subsurface iron/manganese removal, were installed. To investigate the cause of the pro...

Due to public health or environmental concerns, examining the effects of preferential flow processes on the transport of pathogenic microorganisms or contaminants of emerging concern must be studied in the laboratory. However, the resulting transport parameters cannot be directly applied to field-scale groundwater models. This research explores how...

Contamination of drinking water by Cryptosporidium parvum oocysts poses a significant public health risk, as evidenced by numerous outbreaks of cryptosporidiosis worldwide. This study evaluated the effectiveness of Bacillus subtilis spores, unmodified yellow-green (YG) and yellow-orange (YO) microspheres, and glycoprotein-coated YO microspheres, in...

DNA- and RNA-based diagnostics play a pivotal role in accurately detecting and characterizing health-relevant bacteria, offering insights into bacterial presence, viability and treatment efficacy. Herein, we present the development of a novel extraction protocol for both DNA and RNA, designed to enable simple and rapid molecular diagnostics. The ex...

The contribution of ships to the microbial faecal pollution status of water bodies is largely unknown but frequently of human health concern. No methodology for a comprehensive and target-orientated system analysis was available so far. We developed a novel approach for integrated and multistage impact evaluation. The approach includes, i) theoreti...

PFAS are a class of synthetic chemicals used for many industrial and domestic purposes. However, once released in the environment, they are persistent, mobile and toxic. One of the most important transport routes to drinking water is through riverbank filtration. Although this is usually an effective strategy for removing many organic compounds, it...

The impacts on faecal pollution analysis using nucleic acid-based methods, such as PCR and sequencing, in health-related water quality research were assessed by rigorous literature analysis. A wide range of application areas and study designs has been identified since the first application more than 30 years ago (>1,100 publications). Given the con...

We developed an innovative approach to estimate the extent of fecal pollution sources for urban river catchments. The methodology consists of 1) catchment surveys complemented by literature data where needed for probabilistic estimates of daily produced fecal indicator (FIBs, E. coli, enterococci) and zoonotic reference pathogen numbers (Campylobac...

To guarantee proper protection from fecally transmitted pathogen infections, drinking water wells should have a sufficiently large setback distance from potential sources of contamination, e.g. a nearby river. The aim of this study was to provide insight in regards to microbial contamination of groundwater under different flow velocities, which can...

[This corrects the article DOI: 10.3389/fmicb.2021.668778.].

The quality of drinking water in the European Union is verified by measuring parameters established in the recast of the Drinking Water Directive (DWD) 2020/2184. Compared to the former Directive 98/93/EC, microbiological parameters have been extended to additionally cover somatic coliphages as an indicator of removal efficiency following water tre...

Groundwater and riverbank filtrate are valuable resources for drinking water production. The presence of pathogens in the environment poses a threat to drinking water quality and human health. This chapter summarizes the current approaches for evaluating pathogen fate and transport in the environment, their removal during subsurface transport in po...

Karst landscapes cover large parts of our globe. The aquifers laying below their surface are of high importance for global drinking water supply—although many of them being vulnerable to chemical and fecal pollution. This chapter intends to give an overview on the available knowledge on the microbiology of karst aquifers, typical sources of microbi...

Recent developments in water resource monitoring have increased the demand for the reliable identification of faecal pollution sources, also defined as microbial (faecal) source tracking (MST). Standardized faecal indicator bacteria (SFIB) enumeration does not directly support MST, as SFIB occur in animal and human sources. The aim of this study wa...

Molecular diagnostic methods are increasingly applied for food and environmental analysis. Since several steps are involved in sample processing which can affect the outcome (e.g., adhesion of DNA to the sample matrix, inefficient precipitation of DNA, pipetting errors and (partial) loss of the DNA pellet during DNA isolation), quality control is e...

The alluvial backwater areas of the Danube are valuable ecological habitats containing important drinking water resources. Due to the river regulation and the construction of power plants, the river water levels and natural dynamics of the backwater areas continuously decline, threatening their typical characteristics. The aim of this study was to...

Groundwater contamination and transport of viruses and bacteria in aquifers are a major concern worldwide. To ascertain the ability of these aquifers to remove pathogens, tracer tests with microbial surrogates are carried out. These tests are laborious and may require special permits, and therefore, column tests are often done instead. Unfortunatel...

Cryptosporidium and Giardia are waterborne protozoa that cause intestinal infections in a wide range of warm-blooded animals. Human infections vary from asymptomatic to life-threatening in immunocompromised people, and can cause growth retardation in children. The aim of our study was to assess the prevalence and diversity of Cryptosporidium and Gi...

The high level of acceptance of ultraviolet (UV) irradiation for water disinfection in the past decade is due to the development of quality standards, especially for drinking water disinfection in Europe (Austrian Standards Institute, German Standards Institute). The central parts of a UV-disinfection device are the UV lamps. Despite their importan...

Riverine wetlands are important natural habitats and contain valuable drinking water resources. The transport of human- and animal-associated fecal pathogens into the surface water bodies poses potential risks to water safety. The aim of this study was to develop a new integrative modeling approach supported by microbial source tracking (MST) marke...

DNA aptamers generated by cell-SELEX against bacterial cells have gained increased interest as novel and cost-effective affinity reagents for cell labelling, imaging and biosensing. Here we describe the selection and identification of DNA aptamers for bacterial cells using a combined approach based on cell-SELEX, state-of-the-art applications of qu...

Rivers are important for drinking water supply worldwide. However, they are often impacted by pathogen discharges via wastewater treatment plants (WWTP) and combined sewer overflows (CSO). To date, accurate predictions of the effects of future changes and pollution control measures on the microbiological water quality of rivers considering safe dri...

A novel concept for fecal pollution analysis was applied at alluvial water resources to substantially extend the information provided by fecal indicator bacteria (FIB). FIB data were linked to river connectivity and genetic microbial source tracking (MST). The concept was demonstrated at the Danube River and its associated backwater area downstream...

The last decades have seen the development of several source tracking (ST) markers to determine the source of pollution in water, but none of them show 100% specificity and sensitivity. Thus, a combination of several markers might provide a more accurate classification. In this study Ichnaea® software was improved to generate predictive models, tak...

Zusammenfassung Die vorliegende Arbeit gibt einen Überblick über die Untersuchungen zur mikrobiologisch-hygienischen Wasserqualität des Neusiedler Sees. Am Beginn steht ein historischer Abriss über die Entwicklung eines entsprechenden Monitorings. Es folgt eine statistische Analyse mikrobiologischer Langzeitdaten (1992 bis 2013) und deren Verknüpfu...

The extraction of nucleic acids from microorganisms for subsequent molecular diagnostic applications is still a tedious and time-consuming procedure. We developed a method for the rapid preparation of genomic DNA from bacteria based on hydrophilic ionic liquids (ILs). First, we tested eight ILs in different buffer systems for their inhibitory effec...

Thermal disinfection is commonly used to prevent the proliferation of culturable Legionella in engineered water systems (EWS). In response to such stress, culturable Legionella populations can switch into a viable but nonculturable (VBNC) state. The importance of such VBNC Legionella cells is currently hotly debated. Here, we investigated the stres...

The current fecal indicator concept is based on the assumption that the standard fecal indicator bacteria (SFIB) Escherichia coli , intestinal enterococci, and Clostridium perfringens multiply significantly only in the guts of humans and other homeothermic animals and can therefore indicate fecal pollution and the potential presence of pathogens fr...

Riverbank filtration (RBF) systems along rivers are widely used as public water supplies. In these systems, many organic micropollutants (OMPs) are attenuated, but some compounds have shown to be rather persistent. Their fate and transport has been studied in RBF sites along lakes and small rivers, but not extensively along large and dynamic rivers...

Quantitative information regarding the presence of Escherichia coli, intestinal enterococci, and Clostridium perfringens in poikilotherms is notably scarce. Therefore, this study was designed to allow a systematic comparison of the occurrence of these standard fecal indicator bacteria (SFIB) in the excreta of wild homeothermic (ruminants, boars, ca...

Background: Legionella pneumophila, the causative agent of Legionnaire's disease, may enter a viable but non-culturable (VBNC) state triggered by environmental stress conditions. Specific outer-membrane epitopes of L. pneumophila are used in many diagnostic applications and some of them are linked to important virulence-related factors or endotoxi...

Legionellae are among the most important waterborne pathogens in industrialized countries. Monitoring and surveillance of Legionella in engineered water systems is usually performed with culture-based methods. Since the advent of culture-independent techniques, it has become clear that Legionella concentrations are often several orders of magnitude...

Numerous bacterial genetic markers are available for the molecular detection of human sources of fecal pollution in environmental waters. However, widespread application is hindered by a lack of knowledge regarding geographical stability, limiting implementation to a small number of well-characterized regions. This study investigates the geographic...

Over the past 15 years, pioneering interdisciplinary research has been performed on the microbiology of hydrogeologically well‐defined alpine karst springs located in the Northern Calcareous Alps (NCA) of Austria. This article gives an overview on these activities and links them to other relevant research. Results from the NCA springs and comparabl...

Legionella infections are among the most important waterborne infections with constantly increasing numbers of cases in industrialized countries, as a result of aging populations, rising numbers of immunocompromised individuals and increased need for conditioned water due to climate change. Surveillance of water systems is based on microbiological...

Characterization of surface water - groundwater interaction in riverbank filtration (RBF) systems is of decisive importance to drinking water utilities due to the increasing microbial and chemical contamination of surface waters. These interactions are commonly assessed by monitoring changes in chemical water quality, but this might not be indicati...

Water resources from alpine and mountainous karst aquifers play an important role in the drinking water supply in many countries but require sustainable protection and management. Microbial fecal pollution is one of the most relevant contaminants in alpine karst aquifers. However, until recently, microbial fecal pollution could be detected only by...

Information on concentrations of micropollutants (such as pharmaceuticals, pesticides, and industrial chemicals) in most highly dynamic riverbank filtration (RBF) systems is lacking, in contrast to data on standard chemical parameters. Sampling protocols have thus far been based on the stabilization of standard chemical parameters in relatively pri...

Chlorination of pool water is indispensable for infection protection by inactivation waterborne pathogens and by providing the needed disinfection residuals. However, chlorine reacts with anthropogenic contaminations like urea, sweat or skin particles introduced by the bathers and forms combined chlorine, mainly chloramines. Other dissolved organic...

The microbial faecal pollution of rivers has wide-ranging impacts on a variety of human activities that rely on appropriate river water quality. Thus, detailed knowledge of the extent and origin of microbial faecal pollution is crucial for watershed management activities to maintain safe water use. In this study, the microbial faecal pollution leve...

We report a novel molecular assay, based on helicase-dependent amplification (HDA), for the detection of enterococci as markers for fecal pollution in water. This isothermal assay targets the same Enterococcus 23S rRNA gene region as the existing quantitative polymerase chain reaction (qPCR) assays of the US Environmental Protection Agency Methods...

The poster explains the requirements on UV inactivation of microorganisms in waste water when this is released to surface water (river, lake, ...). Especially considered are effluents discharged to recreational surface waters.

Faecal pollution of water and the resulting potential presence of human enteric pathogens is a predominant threat to public health. Microbiological water quality can be assessed by the detection of standard faecal indicator bacteria (SFIB) such as E. coli or certain Enterococcus species. In recent years, isothermal amplification methods have become...

In this paper we present a method to determine the power efficiency of ultraviolet (UV) disinfection plants and apply this to low pressure plants for drinking water. In UV disinfection plants the water flow is regulated to ensure that micro-organisms receive the necessary fluence for inactivation while passing through. The flow depends on the UV tr...

For the City of Vienna, the River Danube and its associated water bodies (Alte Donau, Neue Donau, Mühlwasser, Lobau backwater) play an important role for recreation and drinking water supply. Microbiological water quality is of highest relevance for all user-related aspects. Microbiological water quality monitoring for this area has been mainly bas...

Detection of enzymatic activities has been proposed as a rapid surrogate for the culture-based microbiological pollution monitoring of water resources. This paper presents the results of tests on four fully automated prototype instruments for the on-site monitoring of beta-d-glucuronidase (GLUC) activity. The tests were performed on sediment-laden...

Background Free-living amoebae (FLA) and particularly acanthamoebae serve as vehicles and hosts for Legionella pneumophila, among other pathogenic microorganisms. Within the amoebae, L. pneumophila activates a complex regulatory pathway that enables the bacteria to resist amoebal digestion and to replicate. Moreover, the amoebae provide the bacteri...

QMRAcatch, a tool to simulate microbial water quality including infection risk assessment, was previously developed and successfully tested at a Danube river site (Schijven et al. 2015). In the tool concentrations of target faecal microorganisms and viruses (TMVs) are computed at a point of interest (PI) along the main river and the floodplain rive...

Protection of drinking water resources requires addressing all relevant fecal pollution sources in the considered catchment. A freely available simulation tool, QMRAcatch, was recently developed to simulate concentrations of fecal indicators, a genetic microbial source tracking (MST) marker, and intestinal pathogens in water resources and to conduc...

This was a detailed investigation of the seasonal occurrence, dynamics, removal and resistance of human-associated genetic Bacteroidetes faecal markers (GeBaM) compared with ISO-based standard faecal indicator bacteria (SFIB), human-specific viral faecal markers and one human-associated Bacteroidetes phage in raw and treated wastewater of municipal...

The transport of human adenovirus, nanoparticles, and PRD1 and MS2 bacteriophages was tested in fine granular limestone aquifer material taken from a borehole at a managed aquifer recharge site in Adelaide, South Australia. Comparison of transport and removal of virus surrogates with the pathogenic virus is necessary to understand the differences b...

Information about the capability and performance of ultraviolet (UV) disinfection plants for drinking water is mainly available from lab-scale evaluations or prototype testing. Information about these during operation is rare. In this paper, controlled onsite measurements over a period of 10 years are presented. Measurements were taken in a UV disi...

Due to high diurnal water quality fluctuations in raw municipal wastewater, the use of proportional auto-sampling over a period of 24 h at municipal wastewater treatment plants (WWTPs) to evaluate carbon, nitrogen and phosphorus removal has become a standard in many countries. Microbial removal or load estimation at municipal WWTP however is still...

Cryptosporidium is a waterborne protozoa of great health concern. Many studies have attempted to find appropriate surrogates for assessing Cryptosporidium filtration removal in porous media. In this study, we have evaluated the filtration of Cryptosporidium parvum, biotin- and glycoprotein-coated carboxylated polystyrene microspheres (CPM) in granu...

Vibrio cholerae is a severe human pathogen and a frequent member of aquatic ecosystems. Quantification of V.cholerae in environmental water samples is therefore fundamental for ecological studies and health risk assessment. Beside time-consuming cultivation techniques, qPCR has the potential to provide reliable quantitative data and offers the oppo...

In order to elucidate the main predictors of Vibrio cholerae dynamics and to estimate the risk of V.cholerae related diseases, a recently developed direct detection approach based on FISH and solid phase cytometry (CARD-FISH/SPC) was applied in comparison to cultivation for water samples from the lake Neusiedler See, Austria and three shallow alkal...

Fecal microbial pollution is a major problem throughout the Danube River Basin, posing a threat to various types of water use, including drinking water production from river bank filtrates, water supply for agricultural and industrial use, and the role of the river as a recreational space. Fecal microbial pollution is introduced into the river by p...

Groundwater locations at alluvial backwaters and its riverbank filtration (RBF) systems are widely used as a means of obtaining public water supplies. Riverbank filtration is an effective way to remove pathogens and micropollutants from the receiving surface water. Due to the low abundance of pathogenic and indicator microorganisms in groundwater,...

Water systems are the primary reservoir for Legionella spp., where the bacteria live in association with other microorganisms, such as free-living amoebae. A wide range of disinfection treatments have been studied to control and prevent Legionella colonization but few of them were performed considering its relation with protozoa. In this study, the...

Legionella pneumophila is known as the causative agent of Legionnaireś disease and free-living amoebae (FLA) can serve as vehicles for legionellae. The aim of this study was to screen industrial waters for the occurrence of FLA and their co-occurrence with legionellae. A total of 201 water samples, including 129 cooling waters and 72 process waters...

Disinfection by low-pressure monochromatic ultraviolet (UVC) radiation (253.7 nm) became an important technique to sanitize drinking water and also wastewater in tertiary treatments. In order to prevent the transmission of waterborne viral diseases, the analysis of the disinfection kinetics and the quantification of infectious viral pathogens and i...

The main goal of our investigations is the quantitative measurement of the microbicidal effi cacy of UV disinfection systems. Despite progresses in calculation methodology, e.g. by computational fl uid dynamics (CFD), the delivered UV fl uence cannot be determined with suffi cient reliability. This is because a UV system represents a three-dimensio...

Investigations on the pollution of groundwater with pathogenic microorganisms, e.g. tracer studies for groundwater transport, are constrained by their potential health risk. Thus, microspheres are often used in groundwater transport studies as non-hazardous surrogates for pathogenic microorganisms. Even though pathogenic microorganisms occur at low...

Recirculation Mode Causes Unreliable Results in Biodosimetry

UV-Inactivation and Photoreactivation of Vibrio cholerae and Vibriophages

Environmental factors are highly relevant to the global dissemination of viral pathogens. However, the specific contribution of major effectors such as temperature and sunlight on the inactivation of waterborne viruses is not well characterized. In this study, the effect of temperature (7, 20, and 37 °C), UVB and UVA radiation on viral inactivation...

Biofilms forming inside dialysis water treatment systems are one of the main sources of microbiological contamination. Among the bacteria found in biofilms, Ralstonia pickettii is frequently encountered in dialysis water treatment systems and has been shown to develop extreme oligotrophic talents. In Austria, R. pickettii was exclusively detected i...

Numerous quantitative PCR assays for microbial fecal source tracking (MST) have been developed and evaluated in recent years. Widespread application has been hindered by a lack of knowledge regarding the geographical stability and hence applicability of such methods beyond the regional level. This study assessed the performance of five previously r...

This paper demonstrates the additional benefit of the microbicidal efficacy of an ozonation plant implemented for micropollutant removal from tertiary effluent. Due to the low amount of viruses and protozoa in the tertiary effluent, bacteriophage MS2 and spores of Bacillus subtilis were dosed as surrogates. At specific ozone consumptions of 0.6 and...

During a 3-year study, Clostridium perfringens was investigated in defined fecal sources from a temperate alluvial backwater area of a large river system. The results reveal that using C. perfringens as a conservative water quality indicator for total fecal pollution monitoring is no longer justified but suggest that it can be used as a tracer for...