Abstract:
Water scarcity is one of the main challenges in sustainable development particularly in
developing countries. The use of wastewater effluent for irrigation of crops is common in most
water-stressed countries as this alleviates pressure on fresh water supply. Wastewater treatment
plants (WWTPs) are regarded as hotspots for antibiotic resistance determinants; antibiotic
resistant bacteria (ARB), antibiotic resistance genes (ARGs) and mobile genetic elements (e.g.
plasmids). These antibiotic resistance determinants are consequently introduced into the soil
and fresh produce through irrigation with effluent wastewater. Microcosm and field
surveillance studies in Palapye and Gaborone respectively, were carried out to evaluate the
impact of wastewater effluent irrigation in soil and vegetables in agricultural settings. Culturebased,
molecular (PCR), 16S rRNA gene metagenomics and shotgun metagenomics methods
were used to determine the occurrence, abundance, diversity and overall dynamics of ARB and
ARGs in effluent irrigated soil and vegetables. Clinically relevant bacteria (Campylobacter,
Listeria, Pseudomonas, E.coli, Enterobacter, Staphylococcus and Shigella species) were
targeted and isolated from wastewater effluent, effluent irrigated soils and selected vegetables.
The results revealed a significant reduction in total viable bacterial quantities in the storage
tank containing effluent used for microcosm irrigation. A shift in bacterial community profile
was observed as notable reduction in proteobacteria and increase in firmicutes phyla from the
microcosm soil following wastewater irrigation. Antibiotic resistance genes; beta-lactamase
resistance gene (blaTEM), tetracycline resistance gene (tetA), aminoglycoside resistance gene
(aadA), sulfonamide resistance gene (sul1), trimethoprim resistant dihydrofolate (dfrA) were
all identified by PCR in Gaborone wastewater treatment plant (GWWTP) effluent but only
blaTEM, aadA and dfrA were detected in the soil from an agricultural field irrigated using
effluent from GWWTP. Shotgun metagenomics revealed diverse ARGs belonging to different
classes of antibiotics; aminoglycoside, beta-lactam, trimethoprim, macrolide, glycopeptide,
tetracycline, sulfonamide, quinolone and oxazolidinone in Palapye wastewater treatment plant
(PWWTP) effluent used in the irrigation of the microcosm experiment. However only blaTEM
and aadA were identified in the microcosm soil, and only beta-lactamase gene blaTEM was
detected on vegetable surfaces following irrigation with PWWTP effluent wastewater. The
results from this study demonstrated the short and long-term impact of wastewater irrigation
which results in persistence and possible dissemination of wastewater-associated ARB and
ARGs into agricultural soils and vegetables. Moreover, this study enhances our understanding
of antibiotic resistance dynamics and highlights the importance of monitoring antibiotic
resistance in agro-systems, which is critical for informing policies aimed at sustainable use of
wastewater effluent in water-stressed countries.
Onthatile, O (2024). Assessing the impact of wastewater irrigation on the dynamics of antibiotic resistance in agricultural setting. Afribary. Retrieved from https://afribary.com/works/assessing-the-impact-of-wastewater-irrigation-on-the-dynamics-of-antibiotic-resistance-in-agricultural-setting
Onthatile, Onalenna "Assessing the impact of wastewater irrigation on the dynamics of antibiotic resistance in agricultural setting" Afribary. Afribary, 30 Mar. 2024, https://afribary.com/works/assessing-the-impact-of-wastewater-irrigation-on-the-dynamics-of-antibiotic-resistance-in-agricultural-setting. Accessed 04 Oct. 2024.
Onthatile, Onalenna . "Assessing the impact of wastewater irrigation on the dynamics of antibiotic resistance in agricultural setting". Afribary, Afribary, 30 Mar. 2024. Web. 04 Oct. 2024. < https://afribary.com/works/assessing-the-impact-of-wastewater-irrigation-on-the-dynamics-of-antibiotic-resistance-in-agricultural-setting >.
Onthatile, Onalenna . "Assessing the impact of wastewater irrigation on the dynamics of antibiotic resistance in agricultural setting" Afribary (2024). Accessed October 04, 2024. https://afribary.com/works/assessing-the-impact-of-wastewater-irrigation-on-the-dynamics-of-antibiotic-resistance-in-agricultural-setting