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Ammonia production as a virulence expression by Mycoplasma salivarium
M Matsuura1, K Seto, T Watanabe
1Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Tsurumi University, Kanagawa.
Abstract:
Rabbits were inoculated intracutaneously with M. salivarium (ATCC 23064) cells. The size of the resulting swelling was significantly larger in 1) the sites inoculated with viable cells (7.5 x 10(9) CFU) suspended in a medium with arginine (arginine medium) than in those inoculated with killed cells, and in 2) those inoculated with cells suspended in arginine medium than with cells suspended in arginine-free medium. The swelling was enhanced when rabbits had previously been immunized with the organism. This effect was concluded to be due to ammonia which the organism produced by the hydrolysis of arginine through the arginine-dihydrolase pathway.
Insights
Viable Mycoplasma salivarium cells in arginine medium significantly increased rabbit skin swelling compared to killed cells or cells in arginine-free medium. Ammonia production via arginine hydrolysis by M. salivarium is implicated.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Mycoplasma salivarium is a bacterium known to inhabit oral cavities.
- The inflammatory response to bacterial infections can be modulated by various factors, including bacterial metabolites.
Purpose of the Study:
- To investigate the role of arginine metabolism by Mycoplasma salivarium in modulating the inflammatory response in rabbits.
- To determine if ammonia produced by M. salivarium influences swelling at inoculation sites.
Main Methods:
- Intracutaneous inoculation of rabbits with viable and killed Mycoplasma salivarium (ATCC 23064) cells.
- Suspension of bacterial cells in arginine-containing medium versus arginine-free medium.
- Measurement of skin swelling at inoculation sites.
- Prior immunization of rabbits with M. salivarium.
Main Results:
- Significantly larger swelling occurred with viable M. salivarium cells in arginine medium compared to killed cells.
- Greater swelling was observed when cells were suspended in arginine medium versus arginine-free medium.
- Pre-immunization of rabbits enhanced the swelling response.
Conclusions:
- Ammonia, produced by M. salivarium through arginine hydrolysis via the arginine-dihydrolase pathway, enhances inflammatory swelling.
- Arginine metabolism by M. salivarium plays a crucial role in modulating the host's inflammatory response.