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Updated: Dec 30, 2025
08:58
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
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Untreated HWWs Emerged as Hotpots for ARGs
Osman Kayali1, Bulent Icgen2,3
1Department of Biotechnology 06800, Middle East Technical University, Ankara, Turkey.
Bulletin of Environmental Contamination and Toxicology
|January 23, 2020
Summary
Hospital wastewaters are significant sources of antibiotic-resistance genes (ARGs). Monitoring seasonal HWWs revealed high ARG levels, emphasizing the need for treatment before discharge to prevent environmental spread.
Area of Science:
- Environmental microbiology
- Public health
- Molecular biology
Background:
- Hospital wastewaters (HWWs) are recognized reservoirs for antibiotics and antibiotic-resistant bacteria.
- There is a critical knowledge gap regarding the specific impact of HWW effluents on the dissemination of antibiotic-resistance genes (ARGs).
Purpose of the Study:
- To quantify the seasonal abundance of seven key ARGs (aadA, tetA, cmlA, sul1, qnrS, ermB, blaCTX-M) in hospital wastewaters.
- To assess the overall bacterial load in HWWs across different seasons.
- To determine the correlation between bacterial load and ARG dissemination in HWWs.
Main Methods:
- Quantitative polymerase chain reaction (qPCR) was employed to measure the copy numbers of 16S rRNA (bacterial load) and seven specific ARGs.
- Hospital wastewaters were collected seasonally.
- Seasonal variations in bacterial load and ARG profiles were analyzed.
Main Results:
- Bacterial 16S rRNA copy numbers varied seasonally, with the lowest levels (10^3 copies/mL) in winter and the highest (10^5 copies/mL) in summer and spring.
- A consistent seasonal ARG profile was observed across all hospitals: aadA > tetA > cmlA ≈ sul1 > ermB ≈ qnrS > blaCTX-M.
- Untreated HWWs were identified as significant hotspots for ARGs.
Conclusions:
- Hospital wastewaters harbor substantial levels of diverse antibiotic-resistance genes.
- Seasonal variations influence bacterial load, but ARG profiles remain relatively consistent.
- Effective treatment of HWWs is crucial to mitigate the environmental dissemination of ARGs and curb the spread of antibiotic resistance.
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