title: Improved Broth Microdilution Method for Antimicrobial Susceptibility Testing of Francisella Noatunensis Orientalis.
abstract: In this project we optimized a minimal inhibitory concentration testing protocol for Francisella noatunensis orientalis. Thirty-three F. noatunensis orientalis isolates recovered from different fish species and locations were tested, and Escherichia coli ATCC 25922 was used as a quality control reference strain. A modified cation-adjusted Mueller Hinton broth supplemented with 2% IsoVitalex and 0.1% glucose (MMH) was tested at a pH of 6.4 ± 0.1, 7.1 ± 0.1, and 7.3 ± 0.1. Growth curves generated for F. noatunensis orientalis indicated that MMH at a pH of 6.4 ± 0.1 provided optimal growth. There were no significant differences in the growth curves obtained from isolates recovered from different fish species or from fresh or marine water. The pH of 6.4 ± 0.1 in the MMH media interfered with the inhibitory properties of the potentiated sulfonamides (ormetoprim-sulfadimethoxine and trimethoprim-sulfamethoxazole) when using the E. coli ATCC reference strain. Minimal inhibitory concentrations of eight antimicrobials (gentamicin, enrofloxacin, ampicillin, oxytetracycline, erythromycin, florfenicol, flumequine, and oxolinic acid) were similar for all F. noatunensis orientalis isolates. The in vitro susceptibility data provided here can provide a baseline for monitoring the development of antimicrobial resistance among F. noatunensis orientalis isolates, as well as provide valuable data in the development of potential therapeutics. Received October 27, 2015; accepted April 13, 2016.
authors.affiliation: a Department of Medicine and Epidemiology, School of Veterinary Medicine , University of California , Tupper Hall 2108, 1 Shields Avenue, Davis , California 95616 , USA.|b Department of Biomedical Sciences , Ross University School of Veterinary Medicine , Post Office Box 334, Basseterre, St. Kitts, West Indies.
authors.forename: Esteban
authors.initials: E
authors.lastname: Soto
authors.affiliation: b Department of Biomedical Sciences , Ross University School of Veterinary Medicine , Post Office Box 334, Basseterre, St. Kitts, West Indies.
authors.forename: Iona
authors.initials: I
authors.lastname: Halliday-Simmonds
authors.affiliation: b Department of Biomedical Sciences , Ross University School of Veterinary Medicine , Post Office Box 334, Basseterre, St. Kitts, West Indies.
authors.forename: Stewart
authors.initials: S
authors.lastname: Francis
authors.affiliation: b Department of Biomedical Sciences , Ross University School of Veterinary Medicine , Post Office Box 334, Basseterre, St. Kitts, West Indies.
authors.forename: Trellor
authors.initials: T
authors.lastname: Fraites
authors.affiliation: c Center for Animal Disease Modeling and Surveillance, Department of Medicine and Epidemiology, School of Veterinary Medicine , University of California , Tupper Hall 2108, 1 Shields Avenue, Davis , California 95616 , USA.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Martínez-López
authors.affiliation: d Department of Pathobiological Sciences , Louisiana State University, School of Veterinary Medicine ,1909 Skip Bertman Drive, Baton Rouge , Louisiana 70803 , USA.
authors.forename: Judy
authors.initials: J
authors.lastname: Wiles
authors.affiliation: d Department of Pathobiological Sciences , Louisiana State University, School of Veterinary Medicine ,1909 Skip Bertman Drive, Baton Rouge , Louisiana 70803 , USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Hawke
authors.affiliation: e Endris Consulting , Inc., 492 Foothill Road, Bridgewater , New Jersey 08807 , USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Endris
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005603:Francisella / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents