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Establishing the Epidemiological Cut-Off Value (ECOFF) for Cefquinome Against Staphylococcus aureus Using
Ijaz Ahmad1, Shakoor Ahmed1, Muhammad Faizan1
1College of Veterinary Sciences, The University of Agriculture, Peshawar, Pakistan.
Abstract:
Staphylococcus aureus is a major pathogen responsible for a wide range of infections in both animals and humans, and the increasing emergence of antimicrobial resistance highlights the need for effective surveillance tools. Cefquinome, a fourth-generation cephalosporin, is widely used in veterinary medicine for the treatment of infections caused by Gram-positive and Gram-negative bacteria, including S. aureus. In this study, 110 S. aureus strains were isolated from cattle and subjected to minimum inhibitory concentration (MIC) determination using standardised agar dilution and microdilution methods. MIC values were obtained following 24 h incubation in 96-well plates. The MIC distribution was analysed using goodness-of-fit testing and non-linear least squares regression to establish the wild-type cut-off value (COWT). The MIC range for cefquinome against S. aureus was 0.03-2 µg/mL, and the epidemiological cut-off value (ECV) was determined to be 2 µg/mL, encompassing 99.1% of the wild-type population. An MIC value of 0.5 µg/mL covered 95% of the distribution, indicating its potential relevance for resistance monitoring. These findings provide a scientific basis for cefquinome susceptibility interpretation in cattle and support antimicrobial resistance surveillance. Further studies are warranted to develop population pharmacokinetic models for cefquinome in calves to optimise its therapeutic application.
Insights
This study establishes the epidemiological cut-off value for cefquinome against Staphylococcus aureus in cattle. These findings support antimicrobial resistance surveillance and guide cefquinome susceptibility testing in veterinary medicine.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Resistance
- Bacterial Pathogenesis
Background:
- Staphylococcus aureus is a significant animal and human pathogen.
- Rising antimicrobial resistance necessitates robust surveillance tools.
- Cefquinome is a vital cephalosporin antibiotic in veterinary practice.
Purpose of the Study:
- To determine the wild-type (WT) cut-off value for cefquinome against S. aureus in cattle.
- To establish epidemiological cut-off values (ECVs) for cefquinome susceptibility testing.
- To support antimicrobial resistance surveillance in food-producing animals.
Main Methods:
- Isolated 110 S. aureus strains from cattle.
- Determined minimum inhibitory concentrations (MICs) using agar dilution and microdilution.
- Analyzed MIC distribution with goodness-of-fit testing and non-linear regression.
Main Results:
- Cefquinome MIC range was 0.03–2 µg/mL.
- Epidemiological cut-off value (ECV) determined as 2 µg/mL, covering 99.1% of the wild-type population.
- MIC of 0.5 µg/mL covered 95% of the distribution, indicating potential for resistance monitoring.
Conclusions:
- Established a scientific basis for cefquinome susceptibility interpretation in cattle.
- Provided critical data for antimicrobial resistance surveillance of S. aureus.
- Highlighted the need for further research into cefquinome pharmacokinetics in calves.
