title: Comprehensive antibiotic susceptibility profiling of Chilean Piscirickettsia salmonis field isolates.
abstract: Antibiotics have been extensively used against infections produced by Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis and one of the major concerns for the Chilean salmon industry. Therefore, the emergence of resistant phenotypes is to be expected. With the aim of obtaining a landscape of the antimicrobial resistance of P. salmonis in Chile, the susceptibility profiles for quinolones, florfenicol and oxytetracycline (OTC) of 292 field isolates derived from main rearing areas, different hosts and collected over 5 years were assessed. The results allowed for the determination of epidemiological cut-off values that were used to characterize the pathogen population. This work represents the first large-scale field study addressing the antimicrobial susceptibility of P. salmonis, providing evidence of the existence of resistant types with a high incidence of resistance to quinolones. Remarkably, despite the amounts and frequency of therapies, our results disclosed that the issue of resistance to florfenicol and OTC is still in the onset.
authors.affiliation: Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Henríquez
authors.affiliation: Rudolf Boehm Institute of Pharmacology and Toxicology, Medical Faculty, University of Leipzig, Leipzig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kaiser
authors.affiliation: Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile.
authors.forename: H
authors.initials: H
authors.lastname: Bohle
authors.affiliation: Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Bustos
authors.affiliation: Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile Ltda, Puerto Montt, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Mancilla
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002677:Chile; D024881:Drug Resistance, Bacterial; D005393:Fish Diseases / Q000382:microbiology*; D005399:Fishes / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D053522:Piscirickettsia / Q000187:drug effects* / Q000302:isolation & purification; D044225:Piscirickettsiaceae Infections / Q000382:microbiology* / Q000662:veterinary
chemical_list: D000900:Anti-Bacterial Agents
keywords: Piscirickettsia salmonis; antibiotic resistance; florfenicol; minimal inhibitory concentration; oxytetracycline