Antibiotic resistance is a global concern, although it has been studied most extensively in developed countries. We studied Escherichia coli and class 1 integrons in western Uganda by analyzing 1,685 isolates from people, domestic animals, and wild nonhuman primates near two national parks. Overall, 499 isolates (29.6%) were resistant to at least one of 11 antibiotics tested. The frequency of resistance reached 20.3% of isolates for trimethoprim-sulfamethoxazole but was nearly zero for the less commonly available antibiotics ciprofloxacin (0.4%), gentamicin (0.2%), and ceftiofur (0.1%). The frequency of resistance was 57.4% in isolates from people, 19.5% in isolates from domestic animals, and 16.3% in isolates from wild nonhuman primates. Isolates of livestock and primate origin displayed multidrug resistance patterns identical to those of human-origin isolates. The percentage of resistant isolates in people was higher near Kibale National Park (64.3%) than near Bwindi Impenetrable National Park (34.6%), perhaps reflecting local socioeconomic or ecological conditions. Across antibiotics, resistance correlated negatively with the local price of the antibiotic, with the most expensive antibiotics (nalidixic acid and ciprofloxacin) showing near-zero resistance. Among phenotypically resistant isolates, 33.2% harbored class 1 integrons containing 11 common resistance genes arranged into nine distinct gene cassettes, five of which were present in isolates from multiple host species. Overall, these results show that phenotypic resistance and class 1 integrons are distributed broadly among E. coli isolates from different host species in this region, where local socioeconomic and ecological conditions may facilitate widespread diffusion of bacteria or resistance-conferring genetic elements.
Bibliographical noteFunding Information:
We gratefully acknowledge the Uganda Wildlife Authority, the Uganda National Council for Science and Technology, and the local government councils for granting us permission to conduct this research. We also thank J. Byaruhanga, P. Katurama, A. Mbabazi, A. Nyamwija, and J. Rusoke for providing assistance in the field, and E. Estoff, M. Lee, M. Lesosky, S. Rao, T. Tranby, and K. Vashisht for providing assistance in the laboratory and with data analyses. We also thank Krista Christensen for providing assistance with data analysis, as well as Kris Bisgard, Jon Meiman, and Carrie Tomasallo for their help reviewing earlier versions of the manuscript. This material is based upon work conducted as part of the Kibale EcoHealth Project and was supported by the Morris Animal Foundation under award number D07Z0-024 and by the Earth and Society Initiative of the University of Illinois, Urbana-Champaign. The findings and conclusions in the article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
- Antibiotic resistance
- Class 1 integrons
- Escherichia coli
- Protected areas