Post-doctoral fellow, Washington State University
We investigate how sanitation and antibiotic use impact the prevalence of antimicrobial resistance
Efforts to preserve the utility of existing antibiotics have focused predominantly on improving prescription guidelines and compliance to reduce unnecessary antibiotic use. Nevertheless, the relationship between antibiotic use and antibiotic resistance remains poorly understood where socio-economic and environmental determinants impact both use and resistance. In 2013 the United Nations Human Settlements Program estimated that a quarter of the world’s urban population lives in slums; informal settlements characterized by high population densities, poor sanitation and lack of consistent access to clean water. These are characteristics that promote the spread of infectious diseases and the demand, when available, for antibiotics. Although promoting rational use of antibiotics is important for containing antimicrobial resistance, other factors such as hygiene practices, exposure to sewage, and rapid spread of pathogens due to high population density may play a more critical role. These factors present myriad challenges that may overwhelm individual decisions regarding antibiotic use, whether within or outside the healthcare system. It is likely that such conditions also promote the circulation of antibiotic-resistant bacteria within these communities. Using a five-month longitudinal study of two hundred households, we examined how sanitation and antibiotic use impact antimicrobial resistance in Kibera, a slum in Nairobi (Kenya), characterized by high population density, high burden of disease and poor sanitation. Our study found that despite the fact that 87% of respondents reported using an antibiotic in the 12 months preceding the study, antibiotic use, per se, provided little explanatory power for the prevalence of antibiotic resistance. Children eating soil and informal hand-washing stations shared by multiple households were identified as the key risk-factors for increased individual and household antimicrobial resistance levels. This suggests that this community is experiencing a “saturated” level of antimicrobial resistance where incremental changes in antibiotic use have little measurable effect on antimicrobial resistance prevalence. We surmise that poor sanitation drives disease burden, antibiotic demand, and subsequent transmission of resistant bacteria within and between households. In such communities, sanitation, hygiene and disease transmission will be the limiting factors for controlling antimicrobial resistance.