Benefits and Challenges of Applying Bacteriophage Biocontrol in the Consumer Water Cycle.

Bacteria (including disinfection- and antibiotic-resistant bacteria) are abundant in the consumer water cycle, where they may cause disease, and lead to biofouling and infrastructure damage in distributions systems, subsequently resulting in significant economic losses. Bacteriophages and their associated enzymes may then offer a biological control solution for application within the water sector. Lytic bacteriophages are of particular interest as biocontrol agents as their narrow host range can be exploited for the targeted removal of specific bacteria in a designated environment.

Antibacterial efficacy and membrane mechanism of action of the -derived non-ionic lipopeptide, serrawettin W2-FL10.

Unlabelled: The study aimed to investigate the antibacterial activity, cytotoxicity, and mechanism of action of the non-ionic, cyclic lipopeptide, serrawettin W2-FL10 against . W2-FL10 exhibited potent activity against the Gram-positive bacteria , , , and , with minimum inhibitory concentration (MIC) values ranging from 6.3 to 31.

Comparing antibiotic resistance and virulence profiles of , , and from environmental and clinical settings.

Antibiotic resistance and virulence profiles of , , and , isolated from water sources collected in informal settlements, were compared to clinical counterparts. Cluster analysis using repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR) indicated that, for each respective species, low genetic relatedness was observed between most of the clinical and environmental isolates, with only one clinical (PAO1) and one clinical (P2) exhibiting high genetic similarity to the environmental strains. Based on the antibiograms, the clinical Ef CD1 was extensively drug resistant (XDR); all isolates ( = 12) (except ATCC 13883) were multidrug resistant (MDR), while the ( = 16) isolates exhibited higher susceptibility profiles.

Risk assessment of Enterococcus faecium, Klebsiella pneumoniae, and Pseudomonas aeruginosa in environmental water sources: Development of surrogate models for antibiotic resistance genes.

The presence of Enterococcus faecium (E. faecium), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P.

Underexplored bacteria as reservoirs of novel antimicrobial lipopeptides.

Natural products derived from microorganisms play a prominent role in drug discovery as potential anti-infective agents. Over the past few decades, lipopeptides produced by particularly , , , and cyanobacteria species, have been extensively studied for their antimicrobial potential. Subsequently, daptomycin and polymyxin B were approved by the Food and Drug Administration as lipopeptide antibiotics.

Genotypic and phenotypic comparison of clinical and environmental Acinetobacter baumannii strains.

The genotypic and phenotypic characteristics and antibiotic resistance (antibiogram) profiles of clinical (n = 13) and environmental (n = 7) Acinetobacter baumannii isolates were compared. Based on the Repetitive Extragenic Palindromic Sequence-based PCR (REP-PCR) analysis, the clinical and environmental A. baumannii isolates shared low genetic relatedness (∼60%).

Prevalence of ESKAPE pathogens in the environment: Antibiotic resistance status, community-acquired infection and risk to human health.

The ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens are characterised by increased levels of resistance towards multiple classes of first line and last-resort antibiotics. Although these pathogens are frequently isolated from clinical environments and are implicated in a variety of life-threatening, hospital-associated infections; antibiotic resistant ESKAPE strains have been isolated from environmental reservoirs such as surface water, wastewater, food, and soil.

Biological Control of : In Vitro and In Vivo Activity, Limitations, and Combination Therapies.

The survival, proliferation, and epidemic spread of () in hospital settings is associated with several characteristics, including resistance to many commercially available antibiotics as well as the expression of multiple virulence mechanisms. This severely limits therapeutic options, with increased mortality and morbidity rates recorded worldwide. The World Health Organisation, thus, recognises as one of the critical pathogens that need to be prioritised for the development of new antibiotics or treatment.

Interaction of with Gram-Negative and Gram-Positive Bacteria in Dual Species and Polymicrobial Communities.

The interaction of Bdellovibrio bacteriovorus PF13 with mixed bacterial communities, consisting of Gram-negative (Pseudomonas fluorescens and Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus and Enterococcus faecium) bacteria, was investigated to determine if this wild-type predator preferentially preys on certain bacteria and whether the presence of Gram-positive organisms influences its predation efficiency. In co-culture with P. fluorescens and K.

Metabolomics and Genomics Approach for the Discovery of Serrawettin W2 Lipopeptides from NP2.

A metabolomics/peptidomics and genomics approach, using UPLC-MS, molecular networking, and genome mining, was used to describe the serrawettin W2 lipopeptide family produced by NP2. Seven known serrawettin W2 analogues were structurally elucidated along with 17 new analogues, which varied based on the first (fatty acyl length of C, C, C, or C), fifth (Phe, Tyr, Trp, or Leu/Ile), and sixth (Leu, Ile, or Val) residues. Tandem MS results suggested that the previously classified serrawettin W3 may be an analogue of serrawettin W2, with a putative structure of cyclo(CHO-Leu-Ser-Thr-Leu/Ile-Val).

Minimizing errors in RT-PCR detection and quantification of SARS-CoV-2 RNA for wastewater surveillance.

Wastewater surveillance for pathogens using reverse transcription-polymerase chain reaction (RT-PCR) is an effective and resource-efficient tool for gathering community-level public health information, including the incidence of coronavirus disease-19 (COVID-19). Surveillance of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in wastewater can potentially provide an early warning signal of COVID-19 infections in a community. The capacity of the world's environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is increasing rapidly.

Human Pathogenic Bacteria Detected in Rainwater: Risk Assessment and Correlation to Microbial Source Tracking Markers and Traditional Indicators.

Roof-harvested rainwater (RHRW) was investigated for the presence of the human pathogenic bacteria (), spp. and (). While spp.

Insights into Bdellovibrio spp. mechanisms of action and potential applications.

Recent studies investigating Bdellovibrio spp. have found that although this predator predominantly preys on Gram-negative organisms, under certain conditions (nutrient/prey limitation), it will adapt to survive and grow axenically (without prey) or in the presence of Gram-positive bacterial prey. These advances in the understanding of predatory bacteria have stimulated a renewed interest in these organisms and the potential applications of Bdellovibrio spp.

A Metabolomics and Molecular Networking Approach to Elucidate the Structures of Secondary Metabolites Produced by Strains.

An integrated approach that combines reverse-phase high-performance liquid chromatography (RP-HPLC), electrospray ionization mass spectrometry, untargeted ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS) and molecular networking (using the Global Natural Products Social molecular network platform) was used to elucidate the metabolic profiles and chemical structures of the secondary metabolites produced by pigmented (P1) and non-pigmented (NP1) () strains. Tandem mass spectrometry-based molecular networking guided the structural elucidation of 18 compounds for the P1 strain (including 6 serratamolides, 10 glucosamine derivatives, prodigiosin and serratiochelin A) and 15 compounds for the NP1 strain (including 8 serratamolides, 6 glucosamine derivatives and serratiochelin A) using the MS fragmentation profiles. The serratamolide homologues were comprised of a peptide moiety of two L-serine residues (cyclic or open-ring) linked to two fatty acid chains (lengths of C, C, or C).

Expression of attack and growth phase genes of Bdellovibrio bacteriovorus in the presence of Gram-negative and Gram-positive prey.

The expression of attack phase (AP) and growth phase (GP) genes of Bdellovibrio bacteriovorus (B. bacteriovorus) was compared in the presence of Gram-negative [Escherichia coli (E. coli) and Klebsiella pneumoniae (K.

Exploring the antimicrobial resistance profiles of WHO critical priority list bacterial strains.

Background: The antimicrobial resistance of clinical, environmental and control strains of the WHO "Priority 1: Critical group" organisms, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa to various classes of antibiotics, colistin and surfactin (biosurfactant) was determined.

Methods: Acinetobacter baumannii was isolated from environmental samples and antibiotic resistance profiling was performed to classify the test organisms [A. baumannii (n = 6), P.

Broad-spectrum antimicrobial activity of secondary metabolites produced by Serratia marcescens strains.

The genus Serratia is a predominantly unexplored source of antimicrobial secondary metabolites. The aim of the current study was thus to isolate and evaluate the antimicrobial properties of biosurfactants produced by Serratia species. Forty-nine (n = 34 pigmented; n = 15 non-pigmented) biosurfactant producing Serratia strains were isolated from environmental sources and selected isolates (n = 11 pigmented; n = 11 non-pigmented) were identified as Serratia marcescens using molecular typing.

Binary interactions between the yeast Candida albicans and two gut-associated Bacteroides species.

The yeast Candida albicans forms part of the natural gut microbiota of healthy human individuals and its interactions with other microbial symbionts can impact host well-being. We therefore studied binary interactions between potentially pathogenic representatives of the gut-associated bacterial genus Bacteroides and C. albicans using anaerobic bacteria/yeast co-cultures prepared with a quarter-strength brain heart infusion (¼ BHI; 9.

and in Wastewater and Surface Water Environments.

and spp. are significant contributors to the global waterborne disease burden. Waterways used as sources of drinking water and for recreational activity can become contaminated through the introduction of fecal materials derived from humans and animals.

Abundance of Naegleria fowleri in roof-harvested rainwater tank samples from two continents.

Roof-harvested rainwater (RHRW) has been used as an alternative source of water in water scarce regions of many countries. The microbiological and chemical quality of RHRW has been questioned due to the presence of bacterial and protozoan pathogens. However, information on the occurrence of pathogenic amoeba in RHRW tank samples is needed due to their health risk potential and known associations with opportunistic pathogens.

Resistance of Legionella and Acanthamoeba mauritaniensis to heat treatment as determined by relative and quantitative polymerase chain reactions.

Legionella and Acanthamoeba spp. persist in harvested rainwater pasteurized at high temperatures (> 72°C) and the interaction mechanisms exhibited between these organisms need to be elucidated. The resistance of two Legionella reference strains (Legionella pneumophila ATCC 33152 and Legionella longbeachae ATCC 33462), three environmental strains [Legionella longbeachae (env.

Variants of lipopeptides and glycolipids produced by Bacillus amyloliquefaciens and Pseudomonas aeruginosa cultured in different carbon substrates.

The quantitative and qualitative effect of water immiscible and miscible carbon-rich substrates on the production of biosurfactants, surfactin and rhamnolipids, by Bacillus amyloliquefaciens ST34 and Pseudomonas aeruginosa ST5, respectively, was analysed. A small-scale high throughput 96 deep-well micro-culture method was utilised to cultivate the two strains in mineral salt medium (MSM) supplemented with the water miscible (glucose, glycerol, fructose and sucrose) and water immiscible carbon sources (diesel, kerosene and sunflower oil) under the same growth conditions. The biosurfactants produced by the two strains were isolated by acid precipitation followed by an organic solvent extraction.

Characterisation and antimicrobial activity of biosurfactant extracts produced by Bacillus amyloliquefaciens and Pseudomonas aeruginosa isolated from a wastewater treatment plant.

Biosurfactants are unique secondary metabolites, synthesised non-ribosomally by certain bacteria, fungi and yeast, with their most promising applications as antimicrobial agents and surfactants in the medical and food industries. Naturally produced glycolipids and lipopeptides are found as a mixture of congeners, which increases their antimicrobial potency. Sensitive analysis techniques, such as liquid chromatography coupled to mass spectrometry, enable the fingerprinting of different biosurfactant congeners within a naturally produced crude extract.