Environmentally-related contaminants of high concern: Potential sources and analytical modalities for detection, quantification, and treatment.

The details of all steps involved in the quantification of
biofilm formation in microtiter plates are described. The
presented protocol incorporates information on assessment of
biofilm production by staphylococci, gained both by direct
experience as well as by analysis of methods for assaying
biofilm production. The obtained results should simplify
quantification of biofilm formation in microtiter plates, and
make it more reliable and comparable among different
laboratories.

Quantification of biofilm in microtiter plates: overview oftesting conditions and practical recommendations for assessmentof biofilm production by staphylococci.

Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to maintain good drinking water microbial quality up to consumer’s tap. A new definition and methodological approach for biological stability is proposed.

/pdf/biological-stability-of-drinking-water-controlling-factors-59p64dwvhr.pdf

Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

The levels of pesticides in water have increased due to their excessive use in the modern agricultural domain Choosing a suitable water treatment method for pesticide removal depends on the type of pesticide and the efficacy of the treatment process This review critically discusses and provides a detailed description of a variety of chemical, physical, and biological approaches for pesticide removal from water, such as advanced oxidation processes, adsorption, activated sludge, membrane bioreactors, and membrane technologies Both single-treatment and hybrid methods are thoroughly described and critically discussed The use of hybrid removal techniques offers potential opportunities to develop innovative pesticide removal techniques A thorough analysis of influent composition and recognition of the best removal technique is very important to design a water treatment plant that targets the maximum possible removal rate for different types of pesticides Furthermore, the decentralization of water treatment was also discussed in which it is an important approach that would lead to better effluent water quality for lower prices Many affordable techniques such as activated sludge and adsorption by agricultural adsorbents showed high efficacy in treating high levels of different pesticides

Removal of pesticides from water and wastewater: Chemical, physical and biological treatment approaches

Biofilm is the virulence factor that is responsible for chronic infection in diseases such as Cystic Fibrosis (CF) and chronic wounds. In this thesis, we examine the role of AlgX, a required protein for alginate biosynthesis in P. aeruginosa . We show that the absence of AlgX resulted in the loss of mucoidy and in silico studies demonstrated that AlgX binds alginate. Alanine mutations demonstrated that K396, T398, W400, and R406 are important for alginate binding. Alginate rescue assays confirm the importance of these amino acid residues for alginate biosynthesis and acetylation. This is the first functional demonstration of AlgX role in alginate biofilm biosynthesis and acetylation.Biofilm-producing bacteria and redox imbalance are the leading factors that turn acute wounds into chronic wounds. We demonstrated that LIGHT -/- mouse wounds contain elevated levels of reactive oxygen species (ROS). To see whether chronic wounds can be generated, we increased the redox imbalance in the LIGHT -/- wounds and infecting the wounds with biofilm-forming bacteria. We demonstrated that by using these conditions, we could induce chronic wounds in the LIGHT -/- mouse model 100% of the time. These wounds do not re-epithelialize, contain high bacterial burden, and sustained multi-species bacterial infections that are biofilm-forming and antibiotic-resistant.We also demonstrated that increasing the redox imbalance was sufficient to turn db/db wounds into chronic wounds. These wounds sustained spontaneous biofilm- producing bacterial infections. To verify that redox imbalance is critical for chronicity, we treated chronic wounds with antioxidants and found that oxidative stress was highly reduced, biofilm production was decreased, and bacteria became more sensitive to antibiotics. This is the first demonstration that chronic wounds can be generated and reversed by manipulating the wound's redox microenvironment in an animal model.Norspermidine has been shown to negatively affect the structure of extracellular polymeric substances (EPS). Using the bacteria that colonized db/db chronic wounds, we demonstrated that 2 mM norspermidine reduces the amount of adherent biofilms produced by exudate bacterial communities. Furthermore, application of norspermidine increases the bactericidal effect of gentamicin. We believe that norspermidine could be used in combination with bactericidal antibiotics to control biofilm infection in dermal chronic wounds.

/pdf/the-role-of-bacterial-biofilms-in-chronic-infections-15e6829i50.pdf

The Role of Bacterial Biofilms in Chronic Infections

Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions

https://repositorium.sdum.uminho.pt/bitstream/1822/31432/1/document_17834_1.pdf

An overview on the reactors to study drinking water biofilms.

https://repositorium.sdum.uminho.pt/bitstream/1822/41717/1/document_38962_1.pdf

The effects of sodium hypochlorite against selected drinking water-isolated bacteria in planktonic and sessile states

http://repositorium.sdum.uminho.pt/bitstream/1822/55259/1/document_47809_1.pdf

The effects of emerging environmental contaminants on Stenotrophomonas maltophilia isolated from drinking water in planktonic and sessile states.

The presence of emerging contaminants (ECs) in the environment has been consistently recognized as a worldwide concern. ECs may be defined as chemicals or materials found in the environment at trace concentrations with potential, perceived, or real risk to the “One Health” trilogy (environment, human, and animal health). The main concern regarding pharmaceuticals and in particular antibiotics is the widespread dissemination of antimicrobial resistance. Nevertheless, non-antimicrobials also interact with microorganisms in both bulk phase and in biofilms. In fact, drugs not developed for antimicrobial chemotherapy can exert an antimicrobial action and, therefore, a selective pressure on microorganisms. This review aims to provide answers to questions typically ignored in epidemiological and environmental monitoring studies with a focus on water systems, particularly drinking water (DW): Do ECs exposure changes the behavior of environmental microorganisms? May non-antibiotic ECs affect tolerance to antimicrobials? Do ECs interfere with biofilm function? Are ECs-induced changes in microbial behavior of public health concern? Nowadays, the answers to these questions are still very limited. However, this study demonstrates that some ECs have significant effects in microbial behavior. The most studied ECs are pharmaceuticals, particularly antibiotics, carbamazepine and diclofenac. The pressure caused by antibiotic and other antimicrobial agents on the acquisition and spread of antibiotic resistance seems to be unquestionable. However, regarding the effects of ECs on the development and behavior of biofilms, the conclusions of different studies are still controversial. The dissimilar findings propose that standardized tests are needed for an accurate assessment on the effects of ECs in the microbiome of water systems. The variability of experimental conditions, combined with the presence of mixtures of ECs as well as the lack of information about the effects of non-pharmaceutical ECs constitute the main challenge to be overcome in order to improve ECs prioritization.

/pdf/emerging-contaminants-affect-the-microbiome-of-water-systems-4m2fnk0lk7.pdf

Inês Gomes

Papers

Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions

An overview on the reactors to study drinking water biofilms.

The effects of sodium hypochlorite against selected drinking water-isolated bacteria in planktonic and sessile states

The effects of emerging environmental contaminants on Stenotrophomonas maltophilia isolated from drinking water in planktonic and sessile states.

Emerging contaminants affect the microbiome of water systems—strategies for their mitigation