Corynebacterium mastitidis

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1. Classification

a. Higher order taxa

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2. Description and significance

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3. Genome structure

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4. Cell structure

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5. Metabolic processes

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C. mastitidis, like all other species of Corynebacteria, is aerobic, catalase positive, and oxidase negative [4]. Species of Corynebacteria do not reduce nitrate or hydrolyze esculin or gelatin. Some strains of Corynebacteria are able to hydrolyze urea, but this is a highly variable quality [4]. Several characteristics are present that distinguish C. mastitidis from other species in the genus Corynebacterium. C. mastitidis cells do not ferment glucose, maltose, sucrose, or ribose. C. mastitidis does not produce tuberculosteric acid, pyrrolidonylarylamidase, -Galactosidase, or -Glucoronidase. Its production of urea is variable and it is able to produce alkaline phosphatase and pyrazinamidase [4]. C. mastitidis is able to hyrdolyze 2-Naphthylmyristate, L-Leucyl-2-naphthylamide, L-Valyl-2-naphthylamide, L-Cystyl-2-naphthylamide, and 2-Naphthylphosphate (phosphatase acid). However, its hydrolysis of Naphthol-AS-BI- phosphate is variable [4]. In the lab, C. mastitidis formed small, rough, whitish colonies after three days of incubation at 37°C degrees on blood agar. The colonies formed were nonhemolytic [4]. C. mastitidis is susceptible to antibiotics including penicillin G and ampicillin [4].

6. Ecology

Habitat; symbiosis; contributions to the environment.

C. mastitidis is a member of the genus Corynebacterium. Members of the Corynebacterium obtain a commensal relationship with their host, meaning they derive food and resources from the host without hurting or benefitting the host [2]. They commonly colonize the skin and mucous membranes of different mammals [2]. Corynebacteria are a part of the normal flora on human skin [9].

7. Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

C. mastitidis are known to cause opportunistic infections in immunocompromised mammals [2]. C. mastitidis has been found in several mammals including sheep, humans and mice. C. mastitidis has been isolated from the milk of sheep with subclinical mastitis [4]. Corynebacteria have also been identified as the most common bacterial group associated with historical diagnosis of granulomatous lobular mastitis (GLM) in humans [6]. GLM is an inflammatory disease that affects the breast tissues of mature human females within a few years of their last childbirth [6]. Symptoms of GLM include breast mass, inflammation, abscess, and mammary duct fistula [9]. GLM can become chronic. It is of unknown etiology and there is no standard treatment [9]. Possible pathologies for GLM include microbial, autoimmune, and hormonal, however, none of these pathologies has been confirmed or denied [9]. C. mastitidis has also been identified as a part of the normal microbiota of the human ocular surface and also identified on the ocular surface of mice [2]. In mice, C. mastitidis initiates the release of antimicrobials into the tears of the mice to protect the eyes from different pathogens. C. mastitidis has also been discovered to play a role in the suppurative inflammation and preputial gland abscesses associated with fight wounds [2]. C. mastitidis has been identified in lesions formed on mice preputial glands, which suggests that C. mastitidis plays a role in the formation of the lesions [8]. The origin of C. mastitidis on the mice is unknown, but a theory is that C. mastitidis is also a natural commensal flora of the murine oral cavity and is transmitted to the preputial glands through biting where C. mastitidis causes the development of lesions [8]. This theory is supported through the presence of bacteria similar to C. mastitidis, like C. kutscheri, that have isolated from the oral cavity of healthy rodents and have been found to cause infections in bite wounds [8].

8. Current Research

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C. mastitidis was recently discovered as an important immunoresponse factor in ocular health of mice [3]. Using a mouse model of an ocular surface, C mastitidis was isolated and proved to play a role in the immunological response to several eye infections [2]. C. mastitidis was found to have a commensal relationship with the ocular microbiome by initiating the production of interleukin-17 by γδ T cells in the ocular mucosa [3]. The interleukin-17 response induces the recruitment of neutrophil into the conjunctiva, which then releases antimicrobial molecules into the tears. The antimicrobial molecules protect against invasive infections like Candida albicans and Pseudomonas aeruginosa [3]. This immune response initiated by C. mastitidis was found to be essential to the local ocular immunity in the mice that had been exposed to the bacterium. While a consistent ocular microbiome signature is lacking and controversial due to the constant tear washing and antimicrobial environment of the eye, C. mastitidis was found to have the ability to colonize the ocular surface of both humans and mice [3]. The role of C. mastitidis in the conjunctiva immune response sets a platform for future research in the ocular microbiome and the diseases that originate there [3].

9. References

It is required that you add at least five primary research articles (in same format as the sample reference below) that corresponds to the info that you added to this page. [Sample reference] Faller, A., and Schleifer, K. "Modified Oxidase and Benzidine Tests for Separation of Staphylococci from Micrococci". Journal of Clinical Microbiology. 1981. Volume 13. p. 1031-1035.