Bovine Mannheimia haemolytica genotyping

M. haemolytica Genotypes

Genotype 1 – commonly present as normal commensal flora of the bovine nasopharynx, not likely a concern for herd management. Antimicrobial susceptibility testing (AST) is not routinely performed.
Genotype 2 – a pathogenic strain associated with bovine respiratory disease. AST routinely performed.

Method

M. haemolytica is genotyped by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Biomarkers distinguishing genotypes 1 or 2 are reviewed from protein spectra obtained during routine identification of M. haemolytica by MALDI-TOF MS. Presence or absence of these peaks are used to identify the isolate as either genotype 1 or genotype 2.

Peak masses published in Loy-Clawson Study:
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, 30–33.

MIC-ME-0082-A01 Revised 8-10-26. Printable version here.

Peaks representing a protein fingerprint of Mannheimia haemolytica, a bacterium isolated from cattle with and without signs of respiratory disease.

Spectral peak at 9494 m/z representing pathogenic genotype 2 of M. haemolytica.