|THAKALI, OCEAN - Tulane University|
|TANDUKAR, SARMILA - Tulane University|
|SHERCHAN, SAMENDRA - Tulane University|
|SHERCHAND, JEEVAN - Tribhuvan University|
|HARAMOTO, EIJI - Tulane University|
Submitted to: Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2020
Publication Date: 2/7/2020
Citation: Thakali, O., Tandukar, S., Brooks, J.P., Sherchan, S.P., Sherchand, J.B., Haramoto, E. 2020. The occurrence of antibiotic resistance genes in an urban river in nepal. Water. 12:450. https://doi.org/10.3390/w12020450.
Interpretive Summary: Humans contaminate and affect urban water systems, such as rivers, which can then act as storage for DNA such as antibiotic resistance genes. The purpose of this study was to determine the amount of contamination in selected water systems in Nepal. We targeted selected DNA genes as markers for contamination in the surface water. Water samples were collected periodically throughout a year. Overall, we found that all genes were detected throughout the water samples with the exception of two resistance genes or similar genes. Levels were relatively high and indicated that human contamination was the source as upstream levels were lower than downstream levels. This indicates that Nepalese water can act as environmental storage for these types of genes and further facilitate the spread of these genes further downstream of their origin source.
Technical Abstract: Urban rivers affected by anthropogenic activities can act as reservoirs of antibiotic resistance genes (ARGs). This study aimed to describe the occurrence of selected ARGs (blaTEM, ermF, mecA, and tetA) and a class 1 integron (intI1) in an urban river in Nepal. A total of 18 water samples were collected periodically from upstream, midstream, and downstream sites along the Bagmati River over a 1-year period. All ARGs except mecA and intI1 were consistently detected by quantitative polymerase chain reaction in the midstream and downstream sites, with concentrations ranging from 3.1 to 7.8 log copies/mL. ARG abundance was significantly lower at the upstream site (p < 0.05), reflecting the impact of anthropogenic activities on increasing concentrations of ARGs at midstream and downstream sites. Our findings demonstrate that clinically relevant ARGs are persistent in an urban river water of Nepal, suggesting a need for mitigating strategies to prevent the spread of antibiotic resistance in the environment.