Population-Based Prevalence of Antibiotic Residuals in Low, Moderate and High Malaria Endemicity Areas in Tanzania

Introduction: Inappropriate antibiotic use is a big driver of bacterial antimicrobial resistance, and an increasing problem worldwide. Antibiotic use has sometimes been found to be more frequent by patients without malaria than patients with malaria. However, much uncertainty still exists, especially in places with varying malaria prevalence. In this study, the residuals of commonly used antibiotics in Tanzania were measured in samples collected from subjects living in three regions with different malaria epidemiology. Methods: A cross sectional household survey was conducted in 2015 to assess antimalarial medicine use in a population of 6000 individuals in three regions. Antibiotics residuals were measured in dried blood spots of a subset of people using broad-range tandem mass spectrometry technology. Risk factors for presence of antibiotic residuals were evaluated, including household healthcare seeking behaviors, malaria testing and other potential variables. Results: The overall prevalence of residual antibiotics in blood in the studied population was 14.4% (438/3036) with 95% CI of 11.4 – 15.8%. Stratifying by malaria transmission intensity, the antibiotic prevalence was 17.2% (95% CI: 12.9 - 17.2%) in Mwanza (low), 14.6% (95% CI: 10.6-15.0 %) in Mbeya (moderate), and 11.2% (95% CI: 7.9–11.6%) in Mtwara (high). Trimethoprim was the medication most often detected (6.1%) followed by sulfamethoxazole (4.4%), and penicillin V (0.001%).