A Spatial Analysis of Aerosolized Antibiotic Resistance Genes and Waste Flows in La Paz, Bolivia: Environmental and Built Environment Characteristics Open Access

Nichols, Dennis (Spring 2020)

Permanent URL: https://etd.library.emory.edu/concern/etds/x920fz07q?locale=en


Antimicrobial resistance (AMR) is a growing threat to Global Health. The transfer of antibiotic genes (ARGs) between bacterial populations through conjugation or direct uptake from the environment are among the major modes of AMR transmission. Surface water bodies may mediate this environmental transmission of AMR organisms or ARGs much as they do for diarrheal pathogens. The aerosolization of AMR organisms and ARGs from fluids or surfaces has been considered as another pathway of environmental AMR transmission. While some studies of aerosolized ARGs have been conducted in high-income countries, few have occurred in low-income settings with environmental risk factors such as poor water and sanitation infrastructure. Nor have these studies employed GIS technologies to spatially analyze the associations between aerosolized ARGs and environmental characteristics. In order to address these knowledge gaps, we conducted environmental surveillance for aerosolized ARGs near open waste flows in La Paz, Bolivia. A spatial analysis was then performed to assess associations between aerosolized concentrations of the ARG blaTEM and various environmental and built environment parameters, specifically focusing on the proximity of sampling sites to waste flows and hospitals. We found significant (p<0.05) associations between log-transformed aerosolized blaTEM concentrations and the distance of sample sites from the nearest river (waste flow) and the number of hospitals upstream of a given sample site. The strongest effect size we observed was a ~0.3 log unit increase in sampled blaTEM concentrations associated with each additional hospital upstream. We also observed a diurnal pattern in the importance of model variables suggesting that complex meteorological factors may be influencing aerosolized ARG transport in La Paz. Our findings are consistent with previous studies which have demonstrated the ubiquity of beta-lactam resistance genes both in hospitals and the environment, and furthermore have demonstrated their presence in hospital effluent. This analysis demonstrates the need for further study of the aeromicrobiological pathway of AMR transmission in relation to hospitals and waste flows along with accurate meteorological measurements of sample site microclimates. Our results also show that proper disposal of hospital effluents could be an important mitigation measure in the struggle to contain AMR transmission.

Table of Contents

Chapter 1: Introduction. 1

Chapter 2: Review of Literature. 3

Burden of Disease from AMR.. 3

The development of AMR.. 5

Factors in Environmental Transmission. 6

The Bioaerosol Route. 12

Bolivia AMR Burden and La Paz environmental AMR evidence. 15

Chapter 3: Methodology. 17

Chapter 4: Results. 31

Chapter 5: Discussion. 37

Chapter 6: Implications and Recommendations 41

References. 45

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