Dissertation: Presence and impact of antibiotics and antibiotic resistance genes in urban water systems (Kairigo)
Antimicrobial resistance is a growing global health threat. Urban wastewater from households, hospitals, and industries contains antimicrobials that persist through treatment plants and enter natural water systems. These residual antibiotics can promote the development of resistant bacteria, which can spread into broader ecosystems and reach humans if wastewater treatment is inefficient. In his thesis work, M.Sc. Pius Kairigo investigated the antimicrobials and antibiotic resistance genes in urban hydrological cycles in Kenya and Zambia.
- The findings show that antibiotic residues in water samples from Kenya and Zambia are present at levels high enough to select for antimicrobial resistance in bacteria. The failure of wastewater treatment technologies to remove antibiotics allows them to end up in natural water bodies in these locations, says project researcher Pius Kairigo from Ģֱ.
Suspended particulate matter in the wastewater effluent was considered an important route for emission of residual antimicrobials from studied wastewater treatment plants. In addition, significant levels (approx. 1 gene copy per 100 bacteria) of resistance genes targeting last-resort antibiotics were identified in environmental samples collected in Zambia, underscoring the potential risk to public health. However, risk control and reduction studies on the removal of antimicrobials from human urine using wood-based activated carbon showed that over 93% of the selected antimicrobials were removed from the urine despite the complex urine matrix.
Practical solutions to combat antimicrobial contamination at the household level
The study proposes source-based wastewater treatment systems as part of a multibarrier approach for risk control and reduction.
- Treating urine at the source offers a practical approach for the studied areas. Urine treatment using sustainable materials can be used as a tool to control the entry of antimicrobials and their metabolites into the environment. It is a relatively simple and scalable technology that can take advantage of local materials and technical solutions, explains Kairigo.
The findings call for immediate action to safeguard water systems and protect global public health. While the study focused on Kenya and Zambia, the rise in mortality related to antimicrobial-resistant bacteria is a worldwide concern.
- International collaboration and tailor-made innovative solutions are needed to prevent further contamination and deterioration of the environmental ecosystem, says Kairigo.
M.Sc. Pius Kairigo defends his doctoral dissertation "Occurrence and Fate of Antimicrobials and Antibiotic Resistance Genes in Urban Hydrological Cycles” on 11.10.2024 at 12:00 at Ylistönrinne Campus in lecture hall YAA303. Opponent is Associate Professor Jerker Fick (Umeå University, Sweden) and custos is Professor Tuula Tuhkanen (Ģֱ). The language of the dissertation is English. The dissertation can be followed in lecture hall YAA303 or online.
The dissertation "Occurrence and Fate of Antimicrobials and Antibiotic Resistance Genes in Urban Hydrological Cycles” can be read on the JYX publication archive: .
