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Pharmacodynamics of florfenicol for calf pneumonia pathogens

J Illambas1, T Potter, P Sidhu

  • 1Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Campus, Hatfield, Herts., AL9 7TA, UK.

The Veterinary Record
|March 14, 2013
PubMed

Insights

Florfenicol demonstrates potent antimicrobial activity against bovine respiratory pathogens Mannheimia haemolytica and Pasteurella multocida. These in vitro findings support florfenicol

Area of Science:

  • Veterinary Pharmacology
  • Antimicrobial Efficacy
  • Bovine Respiratory Disease

Background:

  • Bovine respiratory disease (BRD) is a significant economic concern in cattle production.
  • Mannheimia haemolytica and Pasteurella multocida are primary bacterial pathogens associated with BRD.
  • Florfenicol is a broad-spectrum antibiotic used in veterinary medicine.

Purpose of the Study:

  • To evaluate the in vitro antimicrobial properties of florfenicol against key BRD pathogens.
  • To determine the efficacy and potency of florfenicol using standard microbiological assays.
  • To establish a basis for rational florfenicol dosage selection for treating calf pneumonia.

Main Methods:

  • Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).
  • In vitro time-kill curve analysis of florfenicol against six strains each of M. haemolytica and P. multocida.
  • Assessment in Mueller Hinton broth (MHB) and calf serum, with modeling of AUC24h/MIC ratios.

Main Results:

  • Low MBC:MIC ratios (≤2.4:1) indicated potent bactericidal activity.
  • Florfenicol exhibited concentration-dependent killing of M. haemolytica and time- and concentration-dependent killing of P. multocida.
  • Low interstrain variability was observed for both pathogens, with AUC24h/MIC values supporting bacteriostatic and bactericidal effects.

Conclusions:

  • Florfenicol possesses significant in vitro antimicrobial activity against M. haemolytica and P. multocida.
  • The determined efficacy indices provide a scientific rationale for florfenicol dosage optimization in treating calf pneumonia.
  • These findings contribute to effective antimicrobial stewardship in cattle health management.

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