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Disposition of oral telithromycin in foals and in vitro activity of the drug against macrolide‐susceptible and macrolide‐resistant Rhodococcus equi isolates
Author(s) -
JAVSICAS L. H.,
GIGUÈRE S.,
WOMBLE ARIEL Y.
Publication year - 2010
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.2009.01151.x
Subject(s) - telithromycin , ketolide , rhodococcus equi , erythromycin , clarithromycin , minimum inhibitory concentration , azithromycin , microbiology and biotechnology , pharmacology , medicine , streptococcus pneumoniae , antibiotics , chemistry , biology , biochemistry , virulence , gene
Javsicas, LH., Giguère, S., Womble, AY. Disposition of oral telithromycin in foals and in vitro activity of the drug against macrolide‐susceptible and macrolide‐resistant Rhodococcus equi isolates. J. vet. Pharmacol. Therap . doi: 10.1111/j.1365‐2885.2009.01151.x. The objectives of this study were to determine the serum and pulmonary disposition of telithromycin in foals and to determine the minimum inhibitory concentration ( MIC ) of telithromycin against macrolide‐susceptible and macrolide‐resistant Rhodococcus equi isolates. A single dose of telithromycin (15 mg/kg of body weight) was administered to six healthy 6–10‐week‐old foals by the intragastric route. Activity of telithromycin was measured in serum, pulmonary epithelial lining fluid (PELF), and bronchoalveolar lavage (BAL) cells using a microbiological assay. The broth macrodilution method was used to determine the MIC of telithromycin, azithromycin, clarithromycin and erythromycin against R. equi . Following intragastric administration, mean ± SD time to peak serum telithromycin activity ( T max ) was 1.75 ± 0.76 h, maximum serum activity ( C max ) was 1.43 ± 0.37 μg/mL, and terminal half‐life ( t ½ ) was 3.81 ± 0.40 h. Telithromycin activity, 4 h postadministration was significantly higher in BAL cells (50.9 ± 14.5 μg/mL) than in PELF (5.07 ± 2.64 μg/mL), and plasma (0.84 ± 0.25 μg/mL). The MIC 90 of telithromycin for macrolide‐resistant R. equi isolates (8 μg/mL) was significantly higher than that of macrolide‐susceptible isolates (0.25 μg/mL). The MIC of telithromycin for macrolide‐resistant isolates ( MIC 50 = 4.0 μg/mL) was significantly lower than that of clarithromycin ( MIC 50 = 24.0 μg/mL), azithromycin ( MIC 50 =256 μg/mL) and erythromycin ( MIC 50 = 24 μg/mL).