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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #336868

Title: Rapid typing of Mannheimia haemolytica major genotypes 1 and 2 using MALDI-TOF mass spectrometry

item LOY, JOHN - University Of Nebraska
item Clawson, Michael - Mike

Submitted to: Journal of Microbiological Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2017
Publication Date: 3/4/2017
Citation: Loy, J.D., Clawson, M.L. 2017. Rapid typing of Mannheimia haemolytica major genotypes 1 and 2 using MALDI-TOF mass spectrometry. Journal of Microbiological Methods. 136:30-31.

Interpretive Summary: Multiple bacterial and viral pathogens cause bovine respiratory disease (BRD), which is a major animal health and welfare concern in the United States. Although Mannheimia haemolytica is the principal bacteria species that causes BRD, not all strains associate with it equally. M. haemolytica strains isolated from North American cattle classify into two major genotypes (1 and 2). M. haemolytica of either genotype can be found in the nasopharynx of cattle with or without signs of BRD, and the lungs of cattle with BRD. However, of the two genotypes, genotype 2 predominantly associates with the lungs of cattle with BRD, as well as integrative and conjugative elements that may contain antibiotic resistance genes. An ability to rapidly and accurately identify genotype 1 and 2 M. haemolytica in diagnostic laboratories would be a significant improvement over current techniques that identify M. haemolytica at the species level, but do not detect the major genotypes. Consequently, an assay was created to detect the two genotypes using Matrix-assisted laser desorption/ionization- time of flight mass spectrometry (MALDI-TOF MS), which is a platform increasingly being used for bacterial identification by veterinary labs in the United States.

Technical Abstract: Genotype 2 M. haemolytica predominantly associate over genotype 1 with the lungs of cattle with respiratory disease and ICEs containing antimicrobial resistance genes. Distinct protein masses were detected by MALDI-TOF MS between genotype 1 and 2 strains. MALDI-TOF MS could rapidly differentiate genotype 2 strains in veterinary diagnostic laboratories.