Antimicrobial activity of tulathromycin and 14 other antimicrobials against virulent Rhodococcus equi in vitro.
This study determined the antimicrobial activity of tulathromycin against Rhodococcus equi in vitro. Ninety-eight virulent isolates of R. equi from equine clinical cases were examined, of which 20 isolates were macrolide resistant. A custom 96-well antimicrobial susceptibility testing plate was used, allowing 14 additional antimicrobials to be tested against R. equi. Isolates were cultured with various concentrations of antimicrobials, and minimal inhibitory concentration (MIC) values were determined. Tulathromycin was found to have poor activity in vitro against R. equi isolates susceptible or resistant to macrolides, with MIC50 and MIC90 values >64 ug/mL for all isolates. MIC values for other macrolides tested were similar to previously published data.
Department of Large Animal Clinical Sciences, College of Veterinary and Biomedical Sciences, Texas A M University, College Station, TX 77845, USA.
Kelly L
KL
Carlson
Kyle R
KR
Kuskie
Keith M
KM
Chaffin
Melissa C
MC
Libal
Steeve
S
Giguère
Sara D
SD
Lawhon
Noah D
ND
Cohen
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004187:Disaccharides / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D006571:Heterocyclic Compounds / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D016929:Rhodococcus equi / Q000187:drug effects* / Q000472:pathogenicity; D014774:Virulence; D018942:Macrolides
D000900:Anti-Bacterial Agents; D004187:Disaccharides; D006571:Heterocyclic Compounds; C485204:tulathromycin; D018942:Macrolides