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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Animal Health Genomics » Research » Publications at this Location » Publication #399039

Research Project: Strategies to Control Respiratory Diseases of Cattle

Location: Animal Health Genomics

Title: Genotype classification of Moraxella bovis using MALDI-TOF MS profiles

item OLSON, HANNAH - University Of Nebraska
item LOY, JOHN - University Of Nebraska
item Clawson, Michael - Mike
item Wynn, Emily
item HILLE, MATTHEW - University Of Nebraska

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2022
Publication Date: 12/8/2022
Citation: Olson, H.G., Loy, J.D., Clawson, M.L., Wynn, E.L., Hille, M.M. 2022. Genotype classification of Moraxella bovis using MALDI-TOF MS profiles. Frontiers in Microbiology. 13. Article 1057621.

Interpretive Summary: Moraxella bovis is a bacterial cause of infectious bovine keratoconjunctivitis (IBK), a painful ocular disease of cattle. However, not all M. bovis are genetically the same. Recent research has shown that M. bovis isolated from cattle in North America place into two major genotypes at the subspecies level which differ from each other in multiple ways, including their composition of virulence determinants. It is unclear at present if the two genotypes are equally pathogenic to cattle. In this study, a test was developed that distinguishes the two genotypes on a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform. MALDI-TOF MS is commonly used as a diagnostic tool in both human and veterinary diagnostic laboratories. The test can be freely used without restriction to quickly and accurately identify the two M. bovis genotypes. This will facilitate future studies that compare the two genotypes for their associations with IBK and will likely lead to a better understanding of M. bovis pathogenesis, and potentially the development of new interventions for IBK.

Technical Abstract: Moraxella bovis (M. bovis) is regarded as a causative agent of infectious bovine keratoconjunctivitis (IBK), the most common ocular disease of cattle. Recently, whole genome sequencing identified the presence of two distinct genotypes within M. bovis that differ in chromosome content, potential virulence factors, as well as prophage and plasmid profiles. It is unclear if the genotypes equally associate with IBK or if one is more likely to be isolated from IBK lesions. We utilized 39 strains of M. bovis that had previously undergone whole genome sequencing and genotype classification to determine the utility of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) to accurately genotype M. bovis strains. We successfully developed two biomarker models that accurately classified strains according to genotype with an overall accuracy of 85.8–100% depending upon the model and sample preparation method used. These models provide a practical tool to enable studies of genotype associations with disease, allow for epidemiological studies at the sub-species level, and can be used to enhance disease prevention strategies.