SoxR-dependent regulation of sodA1 and its impact on Stenotrophomonas maltophilia survival under external oxidative stress.

Stenotrophomonas maltophilia is an emerging global opportunistic pathogen that causes nosocomial infections. We demonstrated that the superoxide stress-sensing transcriptional regulator SoxR directly modulated the expression of an operon encompassing sodA1 (encoding manganese-containing superoxide dismutase) and fre (encoding putative flavin reductase) by directly binding to the operator site, which was located between the - 35 and -10 motifs of the sodA1 promoter. It is known that upon exposure to the superoxide generators/redox-cycling drugs, the SoxR, which is bound to the operator site, became oxidized.

16S rRNA methyltransferase KsgA contributes to oxidative stress and antibiotic resistance in Pseudomonas aeruginosa.

Ribosomal RNA (rRNA) modifications are involved in multiple biological processes. KsgA is a 16S rRNA adenine dimethyltransferase that methylates at the adenines 1518 and 1519 (A1518/1519) positions, which are located near the ribosome decoding center. These methylations are conserved and important for ribosome biogenesis and protein translation.

Acquired resistance of Stenotrophomonas maltophilia to antimicrobials induced by herbicide paraquat dichloride.

Stenotrophomonas maltophilia, a ubiquitous environmental bacterium, is an important cause of nosocomial infections. Although banned in some countries, paraquat (PQ) is commonly used to control weeds. In this study, we investigated the effects of increasing concentrations of PQ on S.

Antibiotic resistance genes and crAssphage in hospital wastewater and a canal receiving the treatment effluent.

Hospital wastewater is a major hotspot for the spread of antimicrobial resistance (AMR) in aquatic ecosystems. This study aimed to investigate the prevalence of antibiotic resistance genes (ARGs) and their correlation with crAssphage in a hospital wastewater treatment plant (HWWTP) and a receiving canal. Water samples were analyzed for 94 ARGs and crAssphage relative to the 16S rRNA using high-throughput quantitative polymerase chain reaction (HT-qPCR).

Risk-based critical concentrations of enteric pathogens for recreational water criteria and recommended minimum sample volumes for routine water monitoring.

Concerns are rising about the contamination of recreational waters from human and animal waste, along with associated risks to public health. However, existing guidelines for managing pathogens in these environments have not yet fully integrated risk-based pathogen-specific criteria, which, along with recent advancements in indicators and markers, are essential to improve the protection of public health. This study aimed to establish risk-based critical concentration benchmarks for significant enteric pathogens, i.

Regulation of curcumin reductase curA (PA2197) through sodium hypochlorite and N-ethylmaleimide sensing by TetR family repressor CurR (PA2196) in Pseudomonas aeruginosa.

Pseudomonas aeruginosa PA2196 is a TetR family transcriptional repressor. In this study, the deletion of the PA2196 gene caused increased expression of the downstream gene curA (PA2197), which encodes for a NADPH-dependent curcumin/dihydrocurcumin reductase. The PA2196 gene was then identified as curR, and a DNA footprinting assay showed that CurR directly bound to the curA promoter at an imperfect 15-bp inverted repeat, 5'-TAGTTGA-C-TGGTCTA-3'.

High throughput qPCR unveils shared antibiotic resistance genes in tropical wastewater and river water.

The global challenge posed by rising antimicrobial resistance, and the adoption of a One Health approach, has led to the prioritisation of surveillance for antibiotic resistance genes (ARGs) in various environments. Herein lies an information gap, particularly in the context of Thailand, where there is scarce data on ARG prevalence across diverse environmental matrices and throughout different seasons. This study aimed to fill this void, analysing ARG prevalence by high-throughput qPCR in influent (n = 12) and effluent wastewater (n = 12) and river water (n = 12).

The redox-sensing mechanism of Agrobacterium tumefaciens NieR as a thiol-based oxidation sensor for hypochlorite stress.

NieR is a TetR family transcriptional repressor previously shown to regulate the NaOCl-inducible efflux pump NieAB in Agrobacterium tumefaciens. NieR is an ortholog of Escherichia coli NemR that specifically senses hypochlorite through the redox switch of a reversible sulfenamide bond between C106 and K175. The amino acid sequence of NieR contains only one cysteine.

Quantitative microbial risk assessment of the gastrointestinal risks to swimmers at Southeast Asian urban beaches using site-specific and combined autochthonous and fecal bacteria exposure data.

Recreational exposure to microbial pollution at urban beaches poses a health risk to beachgoers. The accurate quantification of such risks is crucial in managing beaches effectively and establishing warning guidelines. In this study, we employed a quantitative microbial risk assessment (QMRA) framework to assess marine water quality and estimate the risks associated with Vibrio parahaemolyticus, an autochthonous pathogen that causes gastrointestinal illnesses, and enterococci, a traditional fecal bacteria indicator.

Microbial source tracking using molecular and cultivable methods in a tropical mixed-use drinking water source to support water safety plans.

Microbial contamination deteriorates source water quality, posing a severe problem for drinking water suppliers worldwide and addressed by the Water Safety Plan framework to ensure high-quality and reliable drinking water. Microbial source tracking (MST) is used to examine different microbial pollution sources via host-specific intestinal markers for humans and different types of animals. However, the application of MST in tropical surface water catchments that provide raw water for drinking water supplies is limited.

Induction of Antimicrobial Resistance of by Exposure to Nonlethal Levels of Antibiotics.

The effects of the sequential subculture in the presence of a driving force on antimicrobial resistance of K279a were investigated. Stationary-phase cells were inoculated into the lysogeny broth medium, with and without antibiotic supplementation, and grown until the stationary phase before being subcultured into the same antibiotic-supplemented medium for six consecutive cycles. Thirty colonies from each cycle and treatment condition were selected and their antibiotic susceptibility profiles were determined.

GidA modulates the expression of catalases at the posttranscriptional level and plays a role in virulence.

, which encodes a putative tRNA-modifying enzyme, is associated with a variety of virulence phenotypes. Here, we demonstrated that is responsible for the modifications of uridine in tRNAs . Loss of was found to have no impact on the mRNA levels of and , but it decreased KatA and KatB protein levels, resulting in decreased total catalase activity and a hydrogen peroxide-sensitive phenotype.

Monothiol Glutaredoxin Is Essential for Oxidative Stress Protection and Virulence in Pseudomonas aeruginosa.

Glutaredoxins (Grxs), ubiquitous redox enzymes belonging to the thioredoxin family, catalyze the reduction of thiol-disulfide exchange reactions in a glutathione-dependent manner. A Pseudomonas aeruginosa Δ mutant exhibited hypersensitivity to oxidative stress-generating agents, such as paraquat (PQ) and cumene hydroperoxide (CHP). studies showed that P.

Wastewater monitoring in tourist cities as potential sentinel sites for near real-time dynamics of imported SARS-CoV-2 variants.

Wastewater-based epidemiology (WBE) complements the clinical surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants' distribution in populations. Many developed nations have established national and regional WBE systems; however, governance and budget constraints could be obstacles for low- and middle-income countries. An urgent need thus exists to identify hotspots to serve as sentinel sites for WBE.

Effects of face masks and ventilation on the risk of SARS-CoV-2 respiratory transmission in public toilets: a quantitative microbial risk assessment.

Public toilets may increase the risk of COVID-19 infection via airborne transmission; however, related research is limited. We aimed to estimate SARS-CoV-2 infection risk through respiratory transmission using a quantitative microbial risk assessment framework by retrieving SARS-CoV-2 concentrations from the swab tests of 251 Thai patients. Three virus-generating scenarios were investigated: an infector breathing, breathing with a cough, and breathing with a sneeze.

Contribution of Stenotrophomonas maltophilia MfsC transporter to protection against diamide and the regulation of its expression by the diamide responsive repressor DitR.

Stenotrophomonas maltophilia contains an operon comprising mfsB and mfsC, which encode membrane transporters in the major facilitator superfamily (MFS). The results of the topological analysis predicted that both MfsB and MfsC possess 12 transmembrane helices with the N- and C-termini located inside the cells. The deletion of mfsC increased the susceptibility to diamide, a chemical oxidizing agent, but not to antibiotics and oxidative stress-generating substances relative to wild-type K279a.

Comparative genomic analyses of pathogenic bacteria and viruses and antimicrobial resistance genes in an urban transportation canal.

Water commuting is a major urban transportation method in Thailand. However, urban boat commuters risk exposure to microbially contaminated bioaerosols or splash. We aimed to investigate the microbial community structures, identify bacterial and viral pathogens, and assess the abundance of antimicrobial resistance genes (ARGs) using next-generation sequencing (NGS) at 10 sampling sites along an 18 km transportation boat route in the Saen Saep Canal, which traverses cultural, commercial, and suburban land-based zones.

Characterisation of the triclosan efflux pump TriABC and its regulator TriR in Agrobacterium tumefaciens C58.

TriR serves as a repressor for a resistance-nodulation-cell division (RND) efflux pump TriABC involved in triclosan (TCS) resistance in Agrobacterium tumefaciens. The triR gene is transcribed divergently from the triABC operon. TriR specifically bound to the triR-triA intergenic region, at an imperfect 10 bp inverted repeat, 5'-TTGACTAttC-GgtTAGTCAA-3' (TriR box), that was revealed by DNase I footprinting and electrophoretic mobility shift assay.

Persistence of Tilapia tilapinevirus in fish rearing and environmental water and its ability to infect cell line.

Tilapia tilapinevirus, or Tilapia Lake Virus (TiLV), is a RNA virus associated with mass morbidity and mortality in tilapia, leading to severe economic losses for global tilapia aquaculture. In this study, we investigated the persistence of TiLV in water by spiking sterile distilled water (SDW), freshwater collected from rearing fish tanks (FW) and natural pond water (PW) at 27°C as a representative of environmental water conditions with 0.6 ml of stock virus (3.

SARS-CoV-2 RNA surveillance in large to small centralized wastewater treatment plants preceding the third COVID-19 resurgence in Bangkok, Thailand.

Wastewater surveillance for SARS-CoV-2 RNA has been a successful indicator of COVID-19 outbreaks in populations prior to clinical testing. However, this has been mostly conducted in high-income countries, which means there is a dearth of performance investigations in low- and middle-income countries with different socio-economic settings. This study evaluated the applicability of SARS-CoV-2 RNA monitoring in wastewater (n = 132) to inform COVID-19 infection in the city of Bangkok, Thailand using CDC N1 and N2 RT-qPCR assays.

Persisting antibiotic resistance gene pollution and its association with human sewage sources in tropical marine beach waters.

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are pollutants of worldwide concern that threaten human health and ecosystems. Anthropogenic activities and wastewater could be ARB and ARG pollution sources; however, research on ARG abundance and microbial source tracking (MST) of contamination in tropical marine waters is limited. This study examined spatiotemporal variations of six ARGs (bla, bla, bla, mcr-1, sul1, and tetQ) against the widely used antibiotic groups and a class 1 integron-integrase gene (intI1) at two Thai tropical recreational beaches (n = 41).

Integrated analyses of fecal indicator bacteria, microbial source tracking markers, and pathogens for Southeast Asian beach water quality assessment.

The degradation of coastal water quality from fecal pollution poses a health risk to visitors at recreational beaches. Fecal indicator bacteria (FIB) are a proxy for fecal pollution; however the accuracy of their representation of fecal pollution health risks at recreational beaches impacted by non-point sources is disputed due to non-human derivation. This study aimed to investigate the relationship between FIB and a range of culturable and molecular-based microbial source tracking (MST) markers and pathogenic bacteria, and physicochemical parameters and rainfall.