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ARS Home » Midwest Area » Bowling Green, Kentucky » Food Animal Environmental Systems Research » Research » Publications at this Location » Publication #413486

Research Project: Developing Agronomically and Environmentally Beneficial Management Practices to Increase the Sustainability and Safety of Animal Manure Utilization

Location: Food Animal Environmental Systems Research

Title: Mycoplasma bovis 5’-nucleotidase is a virulence factor conferring mammary fitness in bovine mastitis

Author
item GELGIE, AGA - University Of Tennessee
item SCHNEIDER, PELEG - Hebrew University Of Jerusalem
item CITTI, CHRISTINE - University Of Toulouse
item DORDET-FRISONI, EMILIE - University Of Toulouse
item GILLESPIE, BARBARA - University Of Tennessee
item ALMEIDA, RAUL - University Of Tennessee
item Agga, Getahun
item AMOAH, YAA - Hebrew University Of Jerusalem
item SHPIGEL, NAHUM - Hebrew University Of Jerusalem
item KERRO DEGO, OUDESSA - University Of Tennessee
item LYSNYANSKY, INNA - Kimron Veterinary Institute

Submitted to: PLoS Pathogens
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2024
Publication Date: 11/12/2024
Citation: Gelgie, A.E., Schneider, P., Citti, C., Dordet-Frisoni, E., Gillespie, B.E., Almeida, R.A., Agga, G.E., Amoah, Y., Shpigel, N.Y., Kerro Dego, O., Lysnyansky, I. 2024. Mycoplasma bovis 5’-nucleotidase is a virulence factor conferring mammary fitness in bovine mastitis. PLoS Pathogens. https://doi.org/10.1371/journal.ppat.1012628.
DOI: https://doi.org/10.1371/journal.ppat.1012628

Interpretive Summary: Mycoplasma bovis is one of the major contagious mastitis causing bacterial species in dairy cattle. In addition to causing pain and inflammation to the udders of cows and overall wellbeing, mastitis reduces milk production. Beyond animal welfare, mastitis causes severe economic loss to dairy cattle farmers due to lost production and discarding of milk from affected cows. Mastitis has a broad societal impact by affecting the entire milk production industry, processing, distribution, and consumers. Coupled with farm hygiene practices, the use of antibiotics to prevent mastitis from occurring and treat clinically sick cows. Unfortunately, the use of antibiotics for these purposes could not be sustained to bacteria developing resistance to the commonly used antibiotics in U.S. dairy cattle production. There is also consumer pressure towards no antibiotic use in food animal production. To overcome these issues, alternative to antibiotics such as vaccines are urgently needed for food animal production. This study developed two mutant strains of a bacterial species of Mycoplasma and characterized them for infectivity and pathogenecity in causing mammary gland infections in cows. The study particularly identified a mutant strain that has the potential to be used as vaccine candidate. Further research is needed to further explore the bacterial variant. If proved to be effective, the commercialization of this product will increase the economic benefit of dairy cattle production.

Technical Abstract: Nucleases and 5’ nucleotidase (5’-NT) play essential roles in cell biology and are often associated with bacterial virulence. In Mycoplasma spp., which have limited metabolic capacities and rely on nutrient availability, these enzymes are of significant importance for nucleotide salvage. This study explores the potential role of 2 membrane-associated lipoproteins, the major nuclease MnuA and 5’-NT, in Mycoplasma bovis mastitis. Mutants deficient in MnuA (mnuA::Tn) and in 5’-NT (0690::Tn) were identified through genome-wide transposon mutagenesis of M. bovis PG45 type strain and their fitness and virulence were assessed both in vitro, in axenic medium, and in vivo, using murine and cow mastitis models. The mnuA::Tn mutant demonstrated reduced nuclease activity, while 0690::Tn exhibited slow log-phase growth and impaired hydrolase activity towards nucleotides as well as deoxynucleotides (dAMP and dGMP). In comparison to the parent strain, the 0690::Tn mutant displayed markedly reduced fitness, as evidenced by a significant decrease or even absence in post-challenge mycoplasma counts in murine and cow mammary tissues, respectively. Moreover, the 0690::Tn mutant failed to induce mastitis in both experimental models. Conversely, the mnuA::Tn mutant induced inflammation in murine mammary glands, characterized by neutrophil infiltration and increased expression of major inflammatory genes. In cows, the mnuA::Tn was able to cause an increase in somatic cell counts in a manner comparable to the wild type, recruit neutrophils, and induce mastitis. Collectively, these findings provide complementary insights, revealing that disruption of 5’-NT significantly attenuated M. bovis pathogenicity, whereas a MnuA-deficient mutant retained the ability to cause mastitis.