title: Time-patterns of antibiotic exposure in poultry production--a Markov chains exploratory study of nature and consequences.
abstract: This article describes the use of Markov chains to explore the time-patterns of antimicrobial exposure in broiler poultry. The transition in antimicrobial exposure status (exposed/not exposed to an antimicrobial, with a distinction between exposures to the different antimicrobial classes) in extensive data collected in broiler chicken flocks from November 2003 onwards, was investigated. All Markov chains were first-order chains. Mortality rate, geographical location and slaughter semester were sources of heterogeneity between transition matrices. Transitions towards a 'no antimicrobial' exposure state were highly predominant, whatever the initial state. From a 'no antimicrobial' exposure state, the transition to beta-lactams was predominant among transitions to an antimicrobial exposure state. Transitions between antimicrobial classes were rare and variable. Switches between antimicrobial classes and repeats of a particular class were both observed. Application of Markov chains analysis to the database of the nation-wide antimicrobial resistance monitoring programme pointed out that transition probabilities between antimicrobial exposure states increased with the number of resistances in Escherichia coli strains.
authors: AFSSA, French Food Safety Agency, Pig and Poultry Veterinary Research Laboratory, Zoopôle, BP 53, 22440 Ploufragan, France. c.chauvin@afssa.fr <c.chauvin@afssa.fr>
authors: C
authors: C
authors: Chauvin
authors: C
authors: C
authors: Clement
authors: M
authors: M
authors: Bruneau
authors: D
authors: D
authors: Pommeret
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000145:classification*; D002645:Chickens; D024881:Drug Resistance, Bacterial; D008390:Markov Chains; D011201:Poultry Diseases / Q000188:drug therapy* / Q000382:microbiology; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents