Correction: Effects of chronic exposure to arsenic on the fecal carriage of antibiotic-resistant Escherichia coli among people in rural Bangladesh.

[This corrects the article DOI: 10.1371/journal.ppat.1010952.].

Effects of chronic exposure to arsenic on the fecal carriage of antibiotic-resistant Escherichia coli among people in rural Bangladesh.

Antibiotic resistance is a leading cause of hospitalization and death worldwide. Heavy metals such as arsenic have been shown to drive co-selection of antibiotic resistance, suggesting arsenic-contaminated drinking water is a risk factor for antibiotic resistance carriage. This study aimed to determine the prevalence and abundance of antibiotic-resistant Escherichia coli (AR-Ec) among people and drinking water in high (Hajiganj, >100 µg/L) and low arsenic-contaminated (Matlab, <20 µg/L) areas in Bangladesh. Drinking water and stool from mothers and their children (<1 year) were collected from 50 households per area. AR-Ec was detected via selective culture plating and isolates were tested for antibiotic resistance, arsenic resistance, and diarrheagenic genes by PCR. Whole-genome sequencing (WGS) analysis was done for 30 E. coli isolates from 10 households. Prevalence of AR-Ec was significantly higher in water in Hajiganj (48%) compared to water in Matlab (22%, p <0.05) and among children in Hajiganj (94%) compared to children in Matlab (76%, p <0.05), but not among mothers. A significantly higher proportion of E. coli isolates from Hajiganj were multidrug-resistant (83%) compared to isolates from Matlab (71%, p <0.05). Co-resistance to arsenic and multiple antibiotics (MAR index >0.2) was observed in a higher proportion of water (78%) and child stool (100%) isolates in Hajiganj than in water (57%) and children (89%) in Matlab (p <0.05). The odds of arsenic-resistant bacteria being resistant to third-generation cephalosporin antibiotics were higher compared to arsenic-sensitive bacteria (odds ratios, OR 1.2-7.0, p <0.01). WGS-based phylogenetic analysis of E. coli isolates did not reveal any clustering based on arsenic exposure and no significant difference in resistome was found among the isolates between the two areas. The positive association detected between arsenic exposure and antibiotic resistance carriage among children in arsenic-affected areas in Bangladesh is an important public health concern that warrants redoubling efforts to reduce arsenic exposure.

Usability of Rapid Cholera Detection Device (OmniVis) for Water Quality Workers in Bangladesh: Iterative Convergent Mixed Methods Study.

BACKGROUND: Cholera poses a significant global health burden. In Bangladesh, cholera is endemic and causes more than 100,000 cases each year. Established environmental reservoirs leave millions at risk of infection through the consumption of contaminated water. The Global Task Force for Cholera Control has called for increased environmental surveillance to detect contaminated water sources prior to human infection in an effort to reduce cases and deaths. The OmniVis rapid cholera detection device uses loop-mediated isothermal amplification and particle diffusometry detection methods integrated into a handheld hardware device that attaches to an iPhone 6 to identify and map contaminated water sources. OBJECTIVE: The aim of this study was to evaluate the usability of the OmniVis device with targeted end users to advance the iterative prototyping process and ultimately design a device that easily integrates into users' workflow. METHODS: Water quality workers were trained to use the device and subsequently completed an independent device trial and usability questionnaire. Pretraining and posttraining knowledge assessments were administered to ensure training quality did not confound trial and questionnaire. RESULTS: Device trials identified common user errors and device malfunctions including incorrect test kit insertion and device powering issues. We did not observe meaningful differences in user errors or device malfunctions accumulated per participant across demographic groups. Over 25 trials, the mean time to complete a test was 47 minutes, a significant reduction compared with laboratory protocols, which take approximately 3 days. Overall, participants found the device easy to use and expressed confidence and comfort in using the device independently. CONCLUSIONS: These results are used to advance the iterative prototyping process of the OmniVis rapid cholera detection device so it can achieve user uptake, workflow integration, and scale to ultimately impact cholera control and elimination strategies. We hope this methodology will promote robust usability evaluations of rapid pathogen detection technologies in device development.

Novel Cholera Toxin Variant and ToxT Regulon in Environmental Vibrio mimicus Isolates: Potential Resources for the Evolution of Vibrio cholerae Hybrid Strains.

Atypical El Tor strains of Vibrio cholerae O1 harboring variant ctxB genes of cholera toxin (CT) have gradually become a major cause of recent cholera epidemics. Vibrio mimicus occasionally produces CT, encoded by ctxAB on CTXФ genome; toxin-coregulated pilus (TCP), a major intestinal colonization factor; and also the CTXФ-specific receptor. This study carried out extensive molecular characterization of CTXФ and ToxT regulon in V. mimicusctx-positive (ctx+) strains (i.e., V. mimicus strains containing ctx) isolated from the Bengal coast. Southern hybridization, PCR, and DNA sequencing of virulence-related genes revealed the presence of an El Tor type CTX prophage (CTXET) carrying a novel ctxAB, tandem copies of environmental type pre-CTX prophage (pre-CTXEnv), and RS1 elements, which were organized as an RS1-CTXET-RS1-pre-CTXEnv-pre-CTXEnv array. Additionally, novel variants of tcpA and toxT, respectively, showing phylogenetic lineage to a clade of V. cholerae non-O1 and to a clade of V. cholerae non-O139, were identified. The V. mimicus strains lacked the RTX (repeat in toxin) and TLC (toxin-linked cryptic) elements and lacked Vibrio seventh-pandemic islands of the El Tor strains but contained five heptamer (TTTTGAT) repeats in ctxAB promoter region similar to those seen with some classical strains of V. cholerae O1. Pulsed-field gel electrophoresis (PFGE) analysis showed that all the ctx+V. mimicus strains were clonally related. However, their in vitro CT production and in vivo toxigenicity characteristics were variable, which could be explainable by differential transcription of virulence genes along with the ToxR regulon. Taken together, our findings strongly suggest that environmental V. mimicus strains act as a potential reservoir of atypical virulence factors, including variant CT and ToxT regulons, and may contribute to the evolution of V. cholerae hybrid strains.IMPORTANCE Natural diversification of CTXФ and ctxAB genes certainly influences disease severity and shifting patterns in major etiological agents of cholera, e.g., the overwhelming emergence of hybrid El Tor variants, replacing the prototype El Tor strains of V. cholerae This report, showing the occurrence of CTXET comprising a novel variant of ctxAB in V. mimicus, points out a previously unnoticed evolutionary event that is independent of the evolutionary event associated with the El Tor strains of V. cholerae Identification and cluster analysis of the newly discovered alleles of tcpA and toxT suggest their horizontal transfer from an uncommon clone of V. cholerae The genomic contents of ToxT regulon and of tandemly arranged multiple pre-CTXФEnv and of a CTXФET in V. mimicus probably act as salient raw materials that induce natural recombination among the hallmark virulence genes of hybrid V. cholerae strains. This report provides valuable information to enrich our knowledge on the evolution of new variant CT and ToxT regulons.

Solanum tuberosum lectin inhibits Ehrlich ascites carcinoma cells growth by inducing apoptosis and G2/M cell cycle arrest.

Recently, a lectin was purified from the potato cultivated in Bangladesh locally known as Sheel. In the present study cytotoxicity of the lectin against Ehrlich ascites carcinoma (EAC) cells was studied by MTT assay in vitro in RPMI-1640 medium and 8.0-36.0 % cell growth inhibition was observed at the range of 2.5-160 µg/ml protein concentration when incubated for 24 h. The lectin-induced apoptosis in EAC cells was confirmed by fluorescence and optical microscope. The apoptotic cell death was also confirmed by using caspase inhibitors. Cells growth inhibition caused by the lectin (36 %) was remarkably decreased to 7.6 and 22.3 % respectively in the presence of caspase-3 and -8 inhibitors. RT-PCR was used to evaluate the expression of apoptosis-related genes Bcl-X, p53, and Bax. An intensive expression of Bcl-X gene was observed in untreated control EAC cells with the disappeared of the gene in Sheel-treated EAC cells. At the same time, Bax gene expression appeared only in Sheel-treated EAC cells and the expression level of the p53 gene was increased remarkable after the treatment of EAC cells with the lectin. The lectin showed strong agglutination activity against EAC cells. Flow cytometry was used to study the cell cycle phases of EAC cells and it was observed that the lectin arrested the G2/M phase. In conclusion, Sheel lectin inhibited EAC cells growth by inducing apoptosis.

Toys and toilets: cross-sectional study using children's toys to evaluate environmental faecal contamination in rural Bangladeshi households with different sanitation facilities and practices.

OBJECTIVE: To evaluate household faecal contamination using children's toys among 100 rural Bangladeshi households categorised as 'cleaner' (toilet that reliably separates faeces from the environment and no human faeces in/around living space) or 'less clean' (no toilet or toilet that does not reliably separate faeces from the environment and human faeces in/around living space). METHODS: We distributed toy balls to each household and rinsed each study toy and a toy already owned by the household in 200 ml of Ringer's solution. We enumerated faecal coliforms and faecal streptococci from each rinse using membrane filtration methods. RESULTS: Study toys from 39 cleaner households had lower mean faecal coliform contamination than toys from 61 less clean households (2.4 log10 colony-forming units (CFU)/200 ml vs. 3.2 log10 CFU/200 ml, P = 0.03). However, wealth measures explained a portion of this relationship. Repeat measures were moderately variable [coefficient of variation (CV) = 6.5 between two toys in the household at the same time, CV = 37.6 between toys in the household at two different times 3-4 days apart]. Too few households owned a non-porous toy to compare groups without risk of bias. CONCLUSION: In rural Bangladesh, improved sanitation facilities and practices were associated with less environmental contamination. Whether this association is independent of household wealth and whether the difference in contamination improves child health merit further study. The variation found was typical for measures of environmental contamination, and requires large sample sizes to ascertain differences between groups with statistical significance.

Prevalence and antimicrobial resistance of major foodborne pathogens isolated from pangas and tilapia fish sold in retail markets of Dhaka city, Bangladesh.

Fish sold at retail markets are often contaminated with harmful bacterial pathogens, posing significant health risks. Despite the growing aquaculture industry in Bangladesh to meet high demand, little attention has been paid to ensuring the safety of fish. The objective of this study was to evaluate the microbiological quality of tilapia and pangas fish sold in retail markets across Dhaka city, Bangladesh. Specifically, the study aimed to compare the quality of fish from traditional wet markets and modern supermarkets, as well as fish samples collected during morning and evening hours. A total of 500 raw cut-fish samples (250 tilapia and 250 pangas) were collected at the point of sale from 32 wet markets and 25 supermarkets. All samples were tested for Escherichia coli, extended-spectrum ß-lactamase-producing E. coli (ESBL-Ec), along with the foodborne pathogens Salmonella, Shigella, Vibrio, and Cryptosporidium spp. Bacterial isolates were characterized using antibiotic susceptibility tests (AST) and the presence of common virulence and antibiotic-resistant genes. Fish samples from retail markets had higher prevalence of tested bacteria including E. coli (92 %), V. cholerae (62 %), ESBL-Ec (48 %), and Salmonella spp. (24 %). There was a significant difference in the prevalence of E. coli (97 % vs. 71 %), ESBL-Ec (58 % vs. 8 %) and Salmonella spp. (28 % vs. 8 %) on the wet market samples compared to supermarket samples (p < 0.005). The mean concentration of E. coli on fish from the wet market was 3.0 ± 0.9 log10 CFU/g, while that from supermarkets was 1.6 ± 0.9 log10 CFU/g. The mean concentration of ESBL-Ec in fish from wet markets and supermarkets were 2.3 ± 0.8 log10 CFU/g and 1.6 ± 0.5 log10 CFU/g, respectively. AST revealed that 46 % of E. coli isolates were multi-drug resistant (MDR), while 4 %, 2 % and 5 % of E. coli, Salmonella spp. and Vibrio spp. isolates, respectively, were resistant to carbapenems. At least 3 % of total E. coli isolates were found to be diarrheagenic, while 40 % of Salmonella isolates harbored pathogenic genes (stn, bcfC, ssaQ, avrA and sodC1), and none of the V. cholerae isolates harbored ctxA and tcpA. Our research shows that raw-cut fish samples from retail markets are contaminated with pathogenic and antibiotic-resistant bacteria, which could be a significant food safety concern. Public health interventions should be implemented to improve food safety and hygiene practices in the retail fish markets.

Hygiene intervention reduces contamination of weaning food in Bangladesh.

OBJECTIVE: This study was conducted to measure the impact of a hygiene intervention on the contamination of weaning food in Bangladesh. METHODS: Sixty households were selected: 30 study and 30 control households. Samples of weaning food were collected from all the 60 households at baseline and examined for faecal coliforms (FC), faecal streptococci (FS) and Clostridium perfringens (CP) following standard procedures. After cooking, food samples were collected on three occasions before feeding. Following Hazard Analysis Critical Control Point (HACCP) procedures, critical control points were determined. The mothers in the 30 study households were then trained for 4 weeks in how to attain the control point conditions. Then, again the food samples were collected and analysed. RESULTS: At baseline, weaning foods from study and control households were heavily contaminated with FC and FS. The FC and FS counts were 1.84 log(10) and 1.92 log(10) colony-forming unit (cfu)/g, respectively, in the study households, and 0.86 log(10) and 1.33 log(10)  cfu/g, respectively, in the control households in the first feeding. After the intervention, the FC and FS counts in study households had dropped to 0.10 log(10) and 0.09 log(10)  cfu/g, respectively, a statistically significant reduction (P < 0.001). Monitoring the sustainability of the behaviour change after 3 months showed that the mothers were maintaining food hygiene. CONCLUSIONS: A hygiene intervention following the HACCP approach reduced the weaning food contamination significantly. Awareness building among mothers about weaning food hygiene could be an important intervention for preventing weaning food-related diarrhoea in Bangladesh.

Multidrug-resistant Escherichia coli isolated from patients and surrounding hospital environments in Bangladesh: A molecular approach for the determination of pathogenicity and resistance.

Extended spectrum ß-lactamase producing Escherichia coli (ESBL E. coli) is a primary concern for hospital and community healthcare settings, often linked to an increased incidence of nosocomial infections. This study investigated the characteristics of ESBL E. coli isolated from hospital environments and clinical samples. In total, 117 ESBL E. coli isolates were obtained. The isolates were subjected to molecular analysis for the presence of resistance and virulence genes, antibiotic susceptibility testing, quantitative adherence assay, ERIC-PCR for phylogenetic analysis and whole genome sequencing of four highly drug resistant isolates. Out of the 117 isolates, 68.4% were positive for blaCTX-M, 39.3% for blaTEM, 30.8% for blaNDM-1, 13.7% for blaOXA and 1.7% for blaSHV gene. Upon screening for diarrheagenic genes, no isolates were found to harbour any of the tested genes. In the case of extraintestinal pathogenic E. coli (ExPEC) virulence factors, 7.6%, 11%, 5.9%, 4.3% and 21.2% of isolates harbored the focG, kpsMII, sfaS, afa and iutA genes, respectively. At a temperature of 25°C, 14.5% of isolates exhibited strong biofilm formation with 21.4% and 28.2% exhibiting moderate and weak biofilm formation respectively, whereas 35.9% were non-biofilm formers. On the other hand at 37°C, 2.6% of isolates showed strong biofilm formation with 3.4% and 31.6% showing moderate and weak biofilm formation respectively, whereas, 62.4% were non-biofilm formers. Regarding antibiotic susceptibility testing, all isolates were found to be multidrug-resistant (MDR), with 30 isolates being highly drug resistant. ERIC-PCR resulted in 12 clusters, with cluster E-10 containing the maximum number of isolates. Hierarchical clustering and correlation analysis revealed associations between environmental and clinical isolates, indicating likely transmission and dissemination from the hospital environment to the patients. The whole genome sequencing of four highly drug resistant ExPEC isolates showed the presence of various antimicrobial resistance genes, virulence factors and mobile genetic elements, with isolates harbouring the plasmid incompatibility group IncF (FII, FIB, FIA). The sequenced isolates were identified as human pathogens with a 93.3% average score. This study suggests that ESBL producing E. coli are prevalent in the healthcare settings of Bangladesh, acting as a potential reservoir for AMR bacteria. This information may have a profound effect on treatment, and improvements in public healthcare policies are a necessity to combat the increased incidences of hospital-acquired infections in the country.

Dependency of sanitation infrastructure on the discharge of faecal coliform and SARS-CoV-2 viral RNA in wastewater from COVID and non-COVID hospitals in Dhaka, Bangladesh.

The detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) RNA in wastewater can be used as an indicator of the presence of SARS-CoV-2 infection in specific catchment areas. We conducted a hospital-based study to explore wastewater management in healthcare facilities and analyzed SARS-CoV-2 RNA in the hospital wastewater in Dhaka city during the Coronavirus disease (COVID-19) outbreak between September 2020-January 2021. We selected three COVID-hospitals, two non-COVID-hospitals, and one non-COVID-hospital with COVID wards, conducted spot-checks of the sanitation systems (i.e., toilets, drainage, and septic-tank), and collected 90 untreated wastewater effluent samples (68 from COVID and 22 from non-COVID hospitals). E. coli was detected using a membrane filtration technique and reported as colony forming unit (CFU). SARS-CoV-2 RNA was detected using the iTaq Universal Probes One-Step kit for RT-qPCR amplification of the SARS-CoV-2 ORF1ab and N gene targets and quantified for SARS-CoV-2 genome equivalent copies (GEC) per mL of sample. None of the six hospitals had a primary wastewater treatment facility; two COVID hospitals had functional septic tanks, and the rest of the hospitals had either broken onsite systems or no containment of wastewater. Overall, 100 % of wastewater samples were positive with a high concentration of E. coli (mean = 7.0 log10 CFU/100 mL). Overall, 67 % (60/90) samples were positive for SARS-CoV-2. The highest SARS-CoV-2 concentrations (median: 141 GEC/mL; range: 13-18,214) were detected in wastewater from COVID-hospitals, and in non-COVID-hospitals, the median SARS-CoV-2 concentration was 108 GEC/mL (range: 30-1829). Our results indicate that high concentrations of E. coli and SARS-CoV-2 were discharged through the hospital wastewater (both COVID and non-COVID) without treatment into the ambient water bodies. Although there is no evidence for transmission of SARS-CoV-2 via wastewater, this study highlights the significant risk posed by wastewater from health care facilities in Dhaka for the many other diseases that are spread via faecal oral route. Hospitals in low-income settings could function as sentinel sites to monitor outbreaks through wastewater-based epidemiological surveillance systems. Hospitals should aim to adopt the appropriate wastewater treatment technologies to reduce the discharge of pathogens into the environment and mitigate environmental exposures.

Spatiotemporal distribution of antimicrobial resistant organisms in different water environments in urban and rural settings of Bangladesh.

The spatial distribution of clinically important antibiotic resistant bacteria (ARB) and associated genes is important to identify the environmental distribution of contamination and 'hotspots' of antimicrobial resistance (AMR). We conducted an integrated survey of AMR in drinking water, wastewater and surface water (rivers and ponds) in three settings in Bangladesh: rural households, rural poultry farms, and urban food markets. Spatial mapping was conducted via geographic information system (GIS) using ArcGIS software. Samples (n = 397) were analyzed for the presence of extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-Ec), carbapenem-resistant E. coli (CR-Ec) and resistance genes (blaCTX-M-1,blaNDM-1). In rural households, 5% of drinking water supply samples tested positive for ESBL-Ec, and a high proportion of wastewater, pond and river water samples were positive for ESBL-Ec (90%, 76%, and 85%, respectively). In poultry farms, 10% of drinking water samples tested positive for ESBL-Ec compared to a high prevalence in wastewater, pond and river water (90%, 68%, and 85%, respectively). CR-Ec prevalence in household wastewater and pond water was relatively low (8% and 5%, respectively) compared to river water (33%). In urban areas, 38% of drinking water samples and 98% of wastewater samples from food markets tested positive for ESBL-Ec while 30% of wastewater samples tested positive for CR-Ec. Wastewaters had the highest concentrations of ESBL-Ec, CR-Ec, blaCTXM-1 and blaNDM-1 and these were significantly higher in urban compared to rural samples (p < 0.05). ESBL-Ec is ubiquitous in drinking water, wastewater and surface water bodies in both rural and urban areas of Bangladesh. CR-Ec is less widespread but found at a high prevalence in wastewater discharged from urban food markets and in rural river samples. Surveillance and monitoring of antibiotic resistant organisms and genes in waterbodies is an important first step in addressing environmental dimensions of AMR.

Healthcare Facilities as Potential Reservoirs of Antimicrobial Resistant Klebsiella pneumoniae: An Emerging Concern to Public Health in Bangladesh.

The emergence of virulent extended spectrum ß-lactamase producing Klebsiella pneumoniae (ESBL-KP) including carbapenem-resistant Klebsiella pneumoniae (CRKP) in hospital-acquired infections has resulted in significant morbidity and mortality worldwide. We investigated the antibiotic resistance and virulence factors associated with ESBL-KP and CRKP in tertiary care hospitals in Bangladesh and explored their ability to form biofilm. A total of 67 ESBL-KP were isolated from 285 Klebsiella pneumoniae isolates from environmental and patient samples from January 2019 to April 2019. For ESBL-KP isolates, molecular typing was carried out using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR), antibiotic susceptibility testing, PCR for virulence and drug-resistant genes, and biofilm assays were also performed. All 67 isolates were multidrug-resistant (MDR) to different antibiotics at high levels and 42 isolates were also carbapenem-resistant. The most common ß-lactam resistance gene was blaCTX-M-1 (91%), followed by blaTEM (76.1%), blaSHV (68.7%), blaOXA-1 (29.9%), blaGES (14.9%), blaCTX-M-9 (11.9%), and blaCTX-M-2 (4.5%). The carbapenemase genes blaKPC (55.2%), blaIMP (28.4%), blaVIM (14.9%), blaNDM-1 (13.4%), and blaOXA-48 (10.4%) and virulence-associated genes such as fimH (71.6%), ugeF (58.2%), wabG (56.7%), ureA (47.8%) and kfuBC (28.4%) were also detected. About 96.2% of the environmental and 100% of the patient isolates were able to form biofilms. ERIC-PCR-based genotyping and hierarchical clustering of K. pneumoniae isolates revealed an association between environmental and patient samples, indicating clonal association with possible transmission of antimicrobial resistance genes. Our findings can help in improving patient care and infection control, and the development of public health policies related to hospital-acquired infections.

Wastewater surveillance of SARS-CoV-2 in Bangladesh: Opportunities and challenges.

The ongoing pandemic of the coronavirus disease 2019 (COVID-19) is a public health crisis of global concern. The progression of the COVID-19 pandemic has been monitored in the first place by testing symptomatic individuals for SARS-CoV-2 virus in the respiratory samples. Concurrently, wastewater carries feces, urine, and sputum that potentially contains SARS-CoV-2 intact virus or partially damaged viral genetic materials excreted by infected individuals. This brings significant opportunities for understanding the infection dynamics by environmental surveillance. It has advantages for the country, especially in densely populated areas where individual clinical testing is difficult. However, there are several challenges including: 1) establishing a sampling plan and schedule that is representative of the various catchment populations 2) development and validation of standardized protocols for the laboratory analysis 3) understanding hydraulic flows and virus transport in complex wastewater drainage systems and 4) collaborative efforts from government agencies, NGOs, public health units and academia.

Infrastructure alone cannot ensure resilience to weather events in drinking water supplies.

Climate resilient water supplies are those that provide access to drinking water that is sustained through seasons and through extreme events, and where good water quality is also sustained. While surface and groundwater quality are widely understood to vary with rainfall, there is a gap in the evidence on the impact of weather and extremes in rainfall and temperature on drinking water quality, and the role of changes in water system management. A three-country (Bangladesh, Nepal and Tanzania) observational field study tracked 2353 households clustered around 685 water sources across seven different geographies over 14 months. Water quality (E. coli) data was modelled using GEE to account for clustering effects and repeated measures at households. All types of infrastructure were vulnerable to changes in weather, with differences varying between geographies; protected boreholes provided the greatest protection at the point of collection (PoC). Water quality at the point of use (PoU) was vulnerable to changes in weather, through changes in PoC water quality as well as changes in management behaviours, such as safe storage, treatment and cleaning. This is the first study to demonstrate the impact of rainfall and temperature extremes on water quality at the PoC, and the role that weather has on PoU water quality via management behaviours. Climate resilience for water supplies needs to consider the infrastructure as well as the management decisions that are taking place at a community and household level.

Bacteriological assessment of drinking water supply options in coastal areas of Bangladesh.

This study was conducted to assess the bacteriological quality of alternative drinking water supply options in southwest coastal areas of Bangladesh. A total of 90 water samples were collected during both dry and wet seasons from household based rainwater harvesting systems (RWHSS), community based rain water harvesting systems (CRWHSs), pond-sand filters (PSFs) and ponds. The samples were evaluated for faecal coliform, Escherichia coli and Heterotrophic Plate Count, as well as Vibrio cholerae, Salmonella spp., Shigella spp. and Pseudomonas spp. Physico-chemical parameters (pH, electrical conductivity, and color) were also examined. In addition, sanitary inspections were conducted to identify faecal contamination sources. All options showed varying degrees of indicator bacterial contamination. The median E. coli concentrations measured for RWHSs, CRWHSS, PSFS, and ponds were 16, 7, 11, and 488 cfu/100 ml during the wet season, respectively. Vibrio cholerae 01/0139, Salmonella and Shigella spp. were not found in any samples. However, Vibrio cholerae Non-01/Non-0139 and Pseudomonas spp. were isolated from 74.4% and 91.1% of the water samples collected during the wet season. A maximum pH of 10.4 was found in CRWHSS. Estimation of the disease burden for all options in disability adjusted life years (DALYs) showed an increased disease burden during the wet season. According to sanitary inspections, poor maintenance and unprotected ponds were responsible for rainwater and PSF water contamination, respectively. The findings of the present study suggest that alternative drinking water supply options available in southwest coastal Bangladesh pose a substantial risk to public health.

Trichosanthes dioica seed lectin inhibits Ehrlich ascites carcinoma cells growth in vivo in mice by inducing G0 /G1 cell cycle arrest.

Trichosanthes dioica seed lectin (TDSL), having a molecular mass of 57 ± 2 kDa was purified in an alternative way. For the purification process, the galactose-sepharose-4B affinity column was used. The purified TDSL agglutinated human and mouse erythrocytes at the minimum concentration of 8  µg/ml. d-lactose and d-galactose were the most potent inhibitory sugars as observed. The purified lectin was a glycoprotein having 3.0% of a neutral sugar. The lectin exhibited maximum activity up to 60°C and pH range from 7.0 to 10.0 and stable up to 4.0 M urea as tested. The lectin demonstrated mild toxicity when administered against brine shrimp nauplii, and the LC50 value was calculated to be 84.0 µg/ml. Minimum agglutination of Ehrlich ascites carcinoma (EAC) cells caused by the lectin was found at the protein concentration of 1.56 µg/ml. TDSL inhibited 7, 50.2%, and 60.3% of the EAC cells growth in vivo in mice when administered with 0.75, 1.5, and 3.0 mg kg-1  day-1 (i.p.), respectively, for five consecutive days. After lectin treatment, red blood cell (RBC) and hemoglobin levels were increased significantly toward the normal compared with EAC cells-bearing control and normal mice. The tumor burden reduced to 29.5% and 67% after treatment with 1.5 and 3.0 mg kg-1  day-1 of the lectin. TDSL triggered the cell cycle arrest at the G0 /G1 phase, which was observed using flow cytometry. In conclusion, TDSL can be a candidate for the potent anticancer agents that exerts low toxicity toward brine shrimp nauplii. PRACTICAL APPLICATIONS: A 57 ± 2 kDa lectin (designated TDSL) was purified from Trichosanthes dioica seeds using a galactose-sepharose-4B affinity column. The lectin demonstrated mild toxicity and agglutinated Ehrlich ascites carcinoma (EAC) cells. The lectin inhibited 50.2% and 60.3% of the EAC cell growth in vivo in mice when administered with 1.5 and 3.0 mg kg-1  day-1 (i.p.), respectively, for five consecutive days. The lectin increased RBC and hemoglobin level toward the normal compared with lectin-treated EAC cells-bearing, EAC cells-bearing control and normal mice. The tumor burden reduced to 29.5% and 67% after treatment with 1.5 and 3.0 mg kg-1  day-1 lectin. TDSL triggered the cell cycle arrest at the G0 /G1 phase. The lectin can be a candidate for potent anticancer agents.

Characterization of Pathogenic Vibrio parahaemolyticus Isolated From Fish Aquaculture of the Southwest Coastal Area of Bangladesh.

Vibrio parahaemolyticus is a major foodborne pathogen responsible for significant economic losses in aquaculture and a threat to human health. Here, we explored the incidence, virulence potential, and diversity of V. parahaemolyticus isolates from aquaculture farms in Bangladesh. We examined a total of 216 water, sediment, Oreochromis niloticus (tilapia), Labeo rohita (rui), and Penaeus monodon (shrimp) samples from the aquaculture system where 60.2% (130/216) samples were positive for V. parahaemolyticus. Furthermore, we identified 323 V. parahaemolyticus strains from contaminated samples, 17 of which were found positive for trh, a virulence gene. Four isolates out of the 17 obtained were able to accumulate fluid in the rabbit ileal loop assay. The correlation between the contamination of V. parahaemolyticus and environmental factors was determined by Pearson correlation. The temperature and salinity were significantly correlated (positive) with the incidence of V. parahaemolyticus. Most of the pathogenic isolates (94.1%) were found resistant to ampicillin and amoxicillin. O8: KUT was the predominant serotype of the potentially pathogenic isolates. ERIC-PCR reveals genetic variation and relatedness among the pathogenic isolates. Therefore, this region-specific study establishes the incidence of potential infection with V. parahaemolyticus from the consumption of tilapia, rui, and shrimp raised in farms in Satkhira, Bangladesh, and the basis for developing strategies to reduce the risk for diseases and economic burden.

Human Colonization with Extended-Spectrum Beta-Lactamase-Producing E. coli in Relation to Animal and Environmental Exposures in Bangladesh: An Observational One Health Study.

BACKGROUND: Human exposure to intensively farmed livestock is a potential risk for transmission of antibiotic-resistant bacteria (ARB) but few studies have assessed the relative role of animal vs. environmental sources of ARB in low-resource community settings. OBJECTIVES: We conducted an observational study to compare ARB colonization and antibiotic-resistant gene prevalence and abundance in humans with high or low exposure to poultry in rural households, commercial poultry farms, and urban markets in Bangladesh. METHODS: Extended-spectrum ß-lactamase (ESBL)-producing and carbapenem-resistant E. coli were quantified in feces from adults with high or low poultry exposure (n=100, respectively), poultry (n=200), drinking water (n=120), and wastewater (n=120) from 40 rural households, 40 poultry farms, and 40 urban markets. RESULTS: ESBL-producing E. coli (ESBL-EC) prevalence was 67.5% (95% CI: 61.0, 74.0) in samples from adults, 68.0% (95% CI: 61.5, 74.5) in samples from poultry, and 92.5% (95% CI: 87.7, 97.3) in wastewater samples. Carbapenem-resistant E. coli prevalence was high in market wastewaters [30% (95% CI: 15.0, 45.0)] but low in humans (1%) and poultry (1%). Human, poultry, and wastewater isolates shared common resistance genes: blaCTX-M-1, qnr, and blaTEM. Human colonization was not significantly associated with exposure to poultry or setting (rural, farm, or market). Ninety-five percent of commercial poultry farms routinely administered antibiotics. Susceptibility tests were significantly different in household vs. farm and market poultry isolates for four of seven antibiotic classes. In human isolates, there were no differences except aminoglycoside resistance (16.4% high vs. 4.4% low exposure, p=0.02). Urban market wastewaters and poultry samples had significantly higher concentrations of ESBL-EC (p<0.001) and blaCTX-M-1 (p<0.001) compared with samples from farms and rural households. DISCUSSION: ESBL-EC colonization was high in humans but not significantly associated with exposure to poultry. Bidirectional transmission of antibiotic resistance is likely between humans, poultry, and the environment in these community settings, underlining the importance of One Health mitigation strategies. https://doi.org/10.1289/EHP7670.

ESBL Producing Escherichia coli in Faecal Sludge Treatment Plants: An Invisible Threat to Public Health in Rohingya Camps, Cox's Bazar, Bangladesh.

Introduction: Human faecal sludge contains diverse harmful microorganisms, making it hazardous to the environment and public health if it is discharged untreated. Faecal sludge is one of the major sources of E. coli that can produce extended-spectrum ß-lactamases (ESBLs). Objective: This study aimed to investigate the prevalence and molecular characterization of ESBL-producing E. coli in faecal sludge samples collected from faecal sludge treatment plants (FSTPs) in Rohingya camps, Bangladesh. Methods: ESBL producing E. coli were screened by cultural as well as molecular methods and further characterized for their major ESBL genes, plasmid profiles, pathotypes, antibiotic resistance patterns, conjugation ability, and genetic similarity. Results: Of 296 isolates, 180 were phenotypically positive for ESBL. All the isolates, except one, contained at least one ESBL gene that was tested (blaCTX-M-1, blaCTX-M-2, blaCTX-M-8, blaCTX-M-9, blaCTX-M-15, blaCTX-M-25, blaTEM , and blaSHV ). From plasmid profiling, it was observed that plasmids of 1-211 MDa were found in 84% (151/180) of the isolates. Besides, 13% (24/180) of the isolates possessed diarrhoeagenic virulence genes. From the remaining isolates, around 51% (79/156) harbored at least one virulence gene that is associated with the extraintestinal pathogenicity of E. coli. Moreover, 4% (3/156) of the isolates were detected to be potential extraintestinal pathogenic E. coli (ExPEC) strains. Additionally, all the diarrhoeagenic and ExPEC strains showed resistance to three or more antibiotic groups which indicate their multidrug-resistant potential. ERIC-PCR differentiated these pathogenic isolates into seven clusters. In addition to this, 16 out of 35 tested isolates transferred plasmids of 32-112 MDa to E. coli J53 recipient strain. Conclusion: The present study implies that the faecal sludge samples examined here could be a potential origin for spreading MDR pathogenic ESBL-producing E. coli. The exposure of Rohingya individuals, living in overcrowded camps, to these organisms poses a severe threat to their health.

Bioremediation of Hexavalent Chromium by Chromium Resistant Bacteria Reduces Phytotoxicity.

Chromium (Cr) (VI) has long been known as an environmental hazard that can be reduced from aqueous solutions through bioremediation by living cells. In this study, we investigated the efficiency of reduction and biosorption of Cr(VI) by chromate resistant bacteria isolated from tannery effluent. From 28 screened Cr(VI) resistant isolates, selected bacterial strain SH-1 was identified as Klebsiella sp. via 16S rRNA sequencing. In Luria-Bertani broth, the relative reduction level of Cr(VI) was 95%, but in tannery effluent, it was 63.08% after 72 h of incubation. The cell-free extract of SH-1 showed a 72.2% reduction of Cr(VI), which indicated a higher activity of Cr(VI) reducing enzyme than the control. Live and dead biomass of SH-1 adsorbed 51.25 mg and 29.03 mg Cr(VI) per gram of dry weight, respectively. Two adsorption isotherm models-Langmuir and Freundlich-were used for the illustration of Cr(VI) biosorption using SH-1 live biomass. Scanning electron microscopy (SEM) analysis showed an increased cell size of the treated biomass when compared to the controlled biomass, which supports the adsorption of reduced Cr on the biomass cell surface. Fourier-transform infrared analysis indicated that Cr(VI) had an effect on bacterial biomass, including quantitative and structural modifications. Moreover, the chickpea seed germination study showed beneficial environmental effects that suggest possible application of the isolate for the bioremediation of toxic Cr(VI).