Prevalence of antibiotic resistance genes in drinking and environmental water sources of the Kathmandu Valley, Nepal

Amarasiri, Mohan; Takezawa, Tsubasa; Malla, Bikash; Furukawa, Takashi; Sherchand, JB; Haramoto, Eiji; Sei, Kazunari

doi:10.3389/fmicb.2022.894014

Cited by 11 publications

(3 citation statements)

References 66 publications

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“…Similar observations were made in NW-C, where in treated water (7.97×10 −2 copies/16S rRNA), higher sul1 concentrations were recorded compared to raw water (6.03×10 −2 copies/16S rRNA). These concentrations were comparable to those reported in raw water in water in Kathmandu Valley, Nepal [ 1 ], where the researchers also studied the prevalence of ARGs in drinking and environmental water sources.…”

Section: Discussionsupporting

confidence: 80%

“…Furthermore, the intI1 concentrations in NW-E treated water were 6.12×10 −4 copies/16S rRNA. However, they were lower than those reported in the source water of Kathmandu Valley, Nepal [ 1 ]. Furthermore, the intI1 concentrations in NW-C treated water were not determined.…”

Section: Discussionmentioning

confidence: 56%

“…Antibiotics have revolutionized medicine and improved the prevention and treatment of infectious bacteria, thus reducing the mortality burden on humans and animals. Hence, antibiotic use has become common worldwide, leading to the accumulation and spread of antibiotic resistance [ 1 , 2 ]. In addition, the lack of development of new generations of antibiotics has threatened the effective treatment of infectious bacteria with common antibiotics [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

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Distribution of antibiotic resistance genes and antibiotic residues in drinking water production facilities: Links to bacterial community

Tsholo,

Molale-Tom,

Horn

et al. 2024

PLoS ONE

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There is a rapid spread of antibiotic resistance in the environment. However, the impact of antibiotic resistance in drinking water is relatively underexplored. Thus, this study aimed to quantify antibiotic resistance genes (ARGs) and antibiotic residues in two drinking water production facilities (NW-E and NW-C) in North West Province, South Africa and link these parameters to bacterial communities. Physicochemical and ARG levels were determined using standard procedures. Residues (antibiotics and fluconazole) and ARGs were quantified using ultra-high performance liquid chromatography (UHPLC) chemical analysis and real-time PCR, respectively. Bacterial community compositions were determined by high-throughput 16S rRNA sequencing. Data were analysed using redundancy analysis and pairwise correlation. Although some physicochemical levels were higher in treated than in raw water, drinking water in NW-E and NW-C was safe for human consumption using the South African Water Quality Guideline (SAWQG). ARGs were detected in raw and treated water. In NW-E, the concentrations of ARGs (sul1, intl1, EBC, FOX, ACC and DHA) were higher in treated water than in raw water. Regarding antimicrobial agents, antibiotic and fluconazole concentrations were higher in raw than in treated water. However, in NW-C, trimethoprim concentrations were higher in raw than in treated water. Redundancy analysis showed that bacterial communities were not significantly correlated (Monte Carlo simulations, p-value >0.05) with environmental factors. However, pairwise correlation showed significant differences (p-value <0.05) for Armatimonas, CL500-29 marine group, Clade III, Dickeya and Zymomonas genera with environmental factors. The presence of ARGs and antibiotic residues in the current study indicated that antibiotic resistance is not only a clinical phenomenon but also in environmental settings, particularly in drinking water niches. Consumption of NW-E and NW-C treated water may facilitate the spread of antibiotic resistance among consumers. Thus, regulating and monitoring ARGs and antibiotic residues in drinking water production facilities should be regarded as paramount.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distribution of antibiotic resistance genes and antibiotic residues in drinking water production facilities: Links to bacterial community

Tsholo,

Molale-Tom,

Horn

et al. 2024

PLoS ONE

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Occurrence of biofilm forming Escherichia coli in drinking water supply system in Kathmandu

Gaihre,

Prajapati,

Dhungel

et al. 2024

Water Environment Research

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Biofilm development in gram negative bacterial contaminants in water supply systems is linked to persistence as well as antibiotic resistance, which threatens water quality and hence the public health. This study aimed to investigate phenotypic and genetic capacity of biofilm formation by Escherichia coli isolated from supply water with their antibiotic susceptibility pattern. Altogether fifty water samples collected from a city supply water distribution scheme in Kathmandu were analyzed to assess the physicochemical and microbiological quality. Comparing Nepal's national drinking water quality standards 2022, conductivity (4%), turbidity (18%), iron (28%), and residual chlorine (8%) were found exceeding the values above the standards. Among total, 40% of water samples were contaminated with total coliform bacteria. E. coli and Citrobacter species were dominant and isolated from 20 (64.52%) and 11 (35.48%) water samples, respectively. Antibiotic susceptibility testing revealed that E. coli isolates were resistant to ampicillin (20%), nitrofurantoin (10%), and cefotaxime (10%). Citrobacter spp. (54.54%) were found multidrug resistant (MDR) while none of the isolates of E. coli were MDR. Of total, 45% of the isolates developed biofilm while testing with the Microtiter plate method. Biofilm‐forming genes bcsA and csgD in E. coli isolates were detected with polymerase chain reaction (PCR) employing specific primers. bcsA and csgD genes were detected in 55% and 45% of the isolates, respectively. This study confirms the occurrences of biofilm forming and antibiotic resistant bacteria like E. coli in the drinking water supply system in Kathmandu alarming its environmental circulation and possible public health threat. Although further study is warranted, this study suggests public health and drinking water treatment interventions to mitigate the biofilm forming antibiotic resistant potential pathogens from supply water in Kathmandu, Nepal.Practitioner Points Forty percent of tested drinking water samples in Kathmandu were contaminated with total coliform bacteria. E. coli and half of Citrobacter spp. isolates were resistant to multiple antibiotics. bcsA and csgD genes were detected in biofilm producing E.coli isolates.

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Strategy to develop and validate digital droplet PCR methods for global antimicrobial resistance wastewater surveillance

Gobbo,

Fraiture,

Van Poelvoorde

et al. 2024

Water Environment Research

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According to World Health Organization (WHO), antimicrobial resistance (AMR) is currently one of the world's top 10 health threats, causing infections to become difficult or impossible to treat, increasing the risk of disease spread, severe illness, disability, and death. Accurate surveillance is a key component in the fight against AMR. Wastewater is progressively becoming a new player in AMR surveillance, with the promise of a cost‐effective real‐time tracking of global AMR profiles in specific regions. One of the most useful analytical methods for wastewater surveillance is currently based on real‐time PCR (qPCR) and digital droplet PCR (ddPCR) technologies.As stated in the EU Wastewater Treatment Directive proposal, methodological standardization, including a workflow for method development and validation, will play a crucial role in global monitoring of AMR in wastewater. However, according to our knowledge, there are currently no qPCR and ddPCR methods for AMR surveillance available that have been validated according to international standard performance criteria. Therefore, this study proposes a workflow for the development and validation of PCR‐based methods for a harmonized and global AMR surveillance, including the construction of specific sequence databases and microbial collections for an efficient method development and method specificity evaluation. Following this strategy, we have developed and validated four duplex ddPCR methods responding to international standard performance criteria, focusing on seven AMR genes (ARG's), including extended spectrum beta‐lactam (blaCTX‐M), carbapenem (blaKPC‐2/3), tetracycline (tet(M)), erythromycin (erm(B)), vancomycin (vanA), sulfonamide (sul2), and aminoglycoside (aac(3)‐IV), as well as one indicator of antibiotic (multi‐) resistance and horizontal gene transfer, named the class I integron (intl1). The performance of these ddPCR methods was successfully assessed for their specificity, as no false‐positive and false‐negative results were observed. These ddPCR methods were also considered to be highly sensitive as showing a limit of detection below 25 copies of the targets. In addition, their applicability was confirmed using 14 wastewater samples collected from two Belgian water resource recovery facilities. The proposed study represents therefore a step forward to reinforce method harmonization in the context of the global AMR surveillance in wastewater.Practitioner Points In the context of wastewater surveillance, no PCR‐based methods for global AMR monitoring are currently validated according to international standards. Consequently, we propose a workflow to develop and validate PCR‐based methods for a harmonized and global AMR surveillance. This workflow resulted here in four duplex ddPCR methods targeting seven ARGs and one general indicator for mobilizable resistance genes. The applicability of these validated ddPCR methods was confirmed on 14 wastewater samples from two Belgian water resource recovery facilities.

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Prevalence of antibiotic resistance genes in drinking and environmental water sources of the Kathmandu Valley, Nepal

Cited by 11 publications

References 66 publications

Distribution of antibiotic resistance genes and antibiotic residues in drinking water production facilities: Links to bacterial community

Distribution of antibiotic resistance genes and antibiotic residues in drinking water production facilities: Links to bacterial community

Occurrence of biofilm forming Escherichia coli in drinking water supply system in Kathmandu

Strategy to develop and validate digital droplet PCR methods for global antimicrobial resistance wastewater surveillance

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