Zebrafish and Mycobacterial infection / 나학회지

The zebrafish emerged as a new model of developmental research and infection. Mycobacterium marinum naturally infects the zebrafish to develop the granuloma like tuberculosis. Also production of the protein of target gene in zebrafish can be specifically and effectively inhibited by morpholino. I suppose that the zebrafish might be a model of leprosy.

Identification and Functional Characterization of Differentially Expressed Genes in Human-derived Monocytic Cell Line U937 Infected with Mycobacterium tuberculosis H37Rv and Mycobacterium marinum: Comparative Evaluation of IL-8

Although Mycobacterium marinum is closely related to M. tuberculosis H37Rv (M. tbc) genomically, clinical outcome of human infection is quite different. The role of the host macrophage in determining differential pathologic responses was analyzed using an in vitro model of macrophage infection. By using subtractive hybridization, thirty-two differentially expressed genes were identified in the monocytic cell line U937 infected with M. tbc or M. marinum. Among them, IL-8 mRNA expression was more prominent in the M. tbc-infected U937 cells by Northern hybridization than in those infected with M. marinum. The IL-8 production was significantly lower in M. marinum-infected U937 or monocytes when compared with those infected by other strains of mycobacteria, such as M. tuberculosis H37Ra, M. bovis BCG or M. smegmatis. To identify possible mechanisms underlying these differences, changes in the expression of molecules such as nuclear factor-kappaB (NF-kappaB) involved in the signaling pathway activated by mycobacteria were assessed. U937 cells infected with M. tbc showed a significant degradation of IkBa proteins compared with M. marinum-infected U937 cells. Collectively, these results implicate distinct differences in IL-8 production in human macrophages infected with M. tbc or M. marinum, and suggest important role of IL-8 in the immunopathogenesis of tuberculosis.

A Case of Sporotrichoid Fish Tank Granuloma / 대한피부과학회지

Mycobacterium marinum, group I photochromogen, is an atypical mycobacterium living in an aquatic environment including swimming pools, lagoon, lake, or fish tanks. Infections with M. marinum are not common, so only three cases have been reported in Korea. In general, skin lesions evolve as a solitary nodule or pustule but occasionally sporotrichoid spreading along the course of lymphatic vessels occurs. A 46-year-old woman visited our department with 2X1.5cm sized erythmatous ulcerated nodule on her right hand dorsum and several rice-sized subcutaneous nodules along the ascending course of lymphatic vessels on her right forearm. She had cleaned fish tank two months before the skin lesion developed. A AFB-positive microorganism was isolated by culture of the tissue specimen, which grew slowly at 30degrees C and those colonies showed yellowish color after light exposure on Ogawa medium. This microorganism was confirmed as M. marinum by polymerase chain reaction and restriction enzyme analysis. To the best of our knowledge, this is the first case of sporotrichoid granuloma due to M marinum infection occurred in association with fish tank in Korea.