Skip to main content

Research Repository

Advanced Search

Differential susceptibility to tetracycline, oxytetracycline and doxycycline of the calf pathogens Mannheimia haemolytica and Pasteurella multocida in three growth media

Mead, A; Lees, P; Mitchell, J; Rycroft, A N; Standing, J F; Toutain, P L; Pelligand, L

Authors

A Mead

P Lees

J Mitchell

A N Rycroft

J F Standing

P L Toutain

L Pelligand



Abstract

For clinical isolates of bovine Mannheimia haemolytica and Pasteurella multocida, this study reports minimum inhibitory concentration (MIC) differences for tetracycline, oxytetracycline and doxycycline between cation‐adjusted Mueller‐Hinton broth (CAMHB), foetal bovine serum (FBS) and Roswell Park Memorial Institute (RPMI) medium. MICs were determined according to CLSI standards and additionally using five overlapping sets of twofold dilutions. Matrix effect: (a) free drug MICs and minimum bactericidal concentrations (MBC) for all drugs were significantly higher in FBS than in CAMHB for both pathogens (p < 0.001); (b) MICs and MBCs were higher for CAMHB and FBS compared to RPMI for P. multocida only. Net growth rate for P. multocida in CAMHB was significantly slower than in FBS and higher than in RPMI, correlating to MIC and MBC ranking. Drug effect: doxycycline MICs and MBCs were significantly lower (p < 0.001) in both CAMHB and FBS than tetracycline and oxytetracycline for both pathogens. Only for M. haemolytica were oxytetracycline MIC and MBC significantly lower than tetracycline, precluding the use of tetracycline to predict oxytetracycline susceptibility in this species. Determining potencies of tetracyclines in a physiological medium, such as FBS, is proposed, when the objective is correlation with pharmacokinetic data for dosage determination.

Citation

Mead, A., Lees, P., Mitchell, J., Rycroft, A. N., Standing, J. F., Toutain, P. L., & Pelligand, L. (2019). Differential susceptibility to tetracycline, oxytetracycline and doxycycline of the calf pathogens Mannheimia haemolytica and Pasteurella multocida in three growth media. Journal of Veterinary Pharmacology and Therapeutics, 42(1), 52-59. https://doi.org/10.1111/jvp.12719

Journal Article Type Article
Acceptance Date Sep 1, 2018
Publication Date Jan 1, 2019
Deposit Date Oct 6, 2018
Publicly Available Date Mar 29, 2024
Journal JOURNAL OF VETERINARY PHARMACOLOGY AND THERAPEUTICS
Print ISSN 0140-7783
Publisher American Academy of Veterinary Pharmacology and Therapeutics
Peer Reviewed Peer Reviewed
Volume 42
Issue 1
Pages 52-59
DOI https://doi.org/10.1111/jvp.12719
Public URL https://rvc-repository.worktribe.com/output/1384383

Files




You might also like



Downloadable Citations