In-roads to the spread of antibiotic resistance: regional patterns of microbial transmission in northern coastal Ecuador

• Type of Material: Article
• Authors: Joseph N. S. Eisenberg, University of Michigan; Jason Goldstick, University of Michigan; William Cevallos, Universidad San Francisco de Quito; Gabriel Trueba, Universidad San Francisco de Quito; Karen Levy, Emory University; James Scott, Colby College; Bethany Percha, University of Michigan; Rosana Segovia, Universidad San Francisco de Quito; Karina Ponce, Universidad San Francisco de Quito; Alan Hubbard, University of California Berkeley; Carl Marrs, University of Michigan; Betsy Foxman, University of Michigan; David L. Smith, University of Florida; James Trostle, Trinity College
• Language: English
• Date: 2012-05-07
• Publisher: Royal Society
• Publication Version: Final Published Version
• Copyright Statement: © 2011 The Royal Society.
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1098/rsif.2011.0499
• Title of Journal or Parent Work: Interface
• ISSN: 1742-5662
• Volume: 9
• Issue: 70
• Start Page: 1029
• End Page: 1039
• Grant/Funding Information: This study was supported by grant number RO1-AI050038 from the National Institute of Allergy and Infectious Diseases (NIAID), and grant number 0811934 from the Ecology of Infectious Diseases programme, Fogarty International Centre (FIC) of the National Institutes of Health (NIH) and the National Science Foundation (NSF).
• Keywords: antibiotic resistance; COMMUNITY; COLONIZATION; PATHOGENS; Science & Technology - Other Topics; Ecuador; DAY-CARE-CENTERS; DYNAMICS; community; COMMENSAL; IMPACT; transmission models; ESCHERICHIA-COLI; TRIMETHOPRIM-RESISTANT; Escherichia coli; INFECTION; Multidisciplinary Sciences; Science & Technology
• Research Categories: Biology, Microbiology; Health Sciences, Public Health

Abstract

The evolution of antibiotic resistance (AR) increases treatment cost and probability of failure, threatening human health worldwide. The relative importance of individual antibiotic use, environmental transmission and rates of introduction of resistant bacteria in explaining community AR patterns is poorly understood. Evaluating their relative importance requires studying a region where they vary. The construction of a new road in a previously roadless area of northern coastal Ecuador provides a valuable natural experiment to study how changes in the social and natural environment affect the epidemiology of resistant Escherichia coli.We conducted seven bi-annual 15 day surveys of AR between 2003 and 2008 in 21 villages. Resistance to both ampicillin and sulphamethoxazole was the most frequently observed profile, based on antibiogram tests of seven antibiotics from 2210 samples. The prevalence of enteric bacteria with this resistance pair in the less remote communities was 80 per cent higher than in more remote communities (OR = 1.8 [1.3, 2.3]). This pattern could not be explained with data on individual antibiotic use. We used a transmission model to help explain this observed discrepancy. The model analysis suggests that both transmission and the rate of introduction of resistant bacteria into communities may contribute to the observed regional scale AR patterns, and that village-level antibiotic use rate determines which of these two factors predominate. While usually conceived as a main effect on individual risk, antibiotic use rate is revealed in this analysis as an effect modifier with regard to community-level risk of resistance.