Susceptibility testing is crucial to appropriately select treatment with antimicrobials and prevent antibiotic resistance
Clinical and Laboratory Standards Institute Veterinary Antimicrobial Susceptibility Testing Subcommittee recently approved revised interpretive criteria for susceptibility testing of Ubrolexin®
Ubrolexin® is a combination of kanamycin and cefalexin for the intramammary treatment of clinical mastitis in lactating dairy cows
Boehringer Ingelheim, a global leader in animal health, announces that Clinical and Laboratory Standards Institute (CLSI)* approved revised interpretive criteria for the susceptibility testing of Ubrolexin®.

According to the Federation of Veterinarians of Europe, wherever possible, susceptibility testing should be done to determine which antimicrobial will be most successful in treating a particular condition. Being able to test the susceptibility of an antibiotic combination that is dedicated to mastitis allows vet practitioners to appropriately select their treatment and prevent antibiotic resistance.

Ubrolexin®, a combination of kanamycin and cefalexin, has been marketed for the intramammary treatment of clinical mastitis in lactating dairy cows in 27 countries by Boehringer Ingelheim since 2008. This combination broadens the spectrum of activity attributed to either agent alone, and synergy between the two agents has been demonstrated against target mastitis pathogens1,2.

Methods for testing the susceptibility of mastitis pathogens to the kanamycin and cefalexin combination, including recommendations for interpretive criteria and quality control ranges for broth microdilution and disk diffusion susceptibility testing, were the subject of prior peer-reviewed publications3,4.

Revised interpretive criteria for the combination for broth microdilution and disk diffusion susceptibility testing were recently approved by the CLSI Veterinary Antimicrobial Susceptibility Testing (VAST) Subcommittee.

“The revised recommendations take into consideration additional susceptibility data collected on recent bovine clinical mastitis field isolates and should be used for testing kanamycin in combination with cephalexin against bovine mastitis pathogens going forward,” shared Dr Laurent Goby, Global Technical Director Ruminants, Boehringer Ingelheim.

Disk diffusion criteria were adjusted accordingly based on the approved broth criteria and resulting error-rate bounding analysis in line with CLSI M23 guidelines5 and were also approved by VAST.



*The CLSI is a not-for-profit standards development organization that brings together the global laboratory community for a common cause: fostering excellence in laboratory medicine. CLSI provides world-class guidance in antimicrobial susceptibility testing that can be used with confidence to identify and update susceptibility test interpretive criteria.



References
1 Ganiere JP, Denuault L. Synergistic interactions between cefalexin and kanamycin in Mueller-Hinton broth medium and in milk. J Appl Microbiol. 2009;107:117.
2 Maneke E, Pridmore A, Goby L, Lang I. Kill rate of mastitis pathogens by a combination of cefalexin and kanamycin. J Appl Microbiol. 2011;110:184.
3 Pillar CM, Goby L, Draghi D, Grover P, Thornsberry C. Evaluating the in vitro susceptibility of bovine mastitis pathogens to a combination of kanamycin and cefalexin: recommendations for a disk diffusion test. J Dairy Sci. 2009;92:6217.
4 Silley P, Goby L, Pillar CM. Susceptibility of coagulase-negative staphylococci to a kanamycin and cefalexin combination. J Dairy Sci. 2012;95:3448.
5 CLSI. Development of in vitro susceptibility testing criteria and quality control parameters, 5th edition. CLSI guideline M23. CLSI, 940 West Valley Road, Suite 1400, Wayne, Pennsylvania 19087-1898 USA, 2008.

Boehringer Ingelheim Animal Health
The lives of animals and humans are interconnected in deep and complex ways. We know that when animals are healthy, humans are healthier too. Across the globe, our 9,700 employees are dedicated to delivering value through innovation, thus enhancing the well-being of both.