Mycobacterium mucogenicum
1. Classification
a. Higher order taxa
Bacteria: Bacteria Phylum: Actinobacteria Order: Actinomycetales Suborder: Corynebacterineae Family: Mycobacteriaceae Genus: Mycobacterium Species: Mycobacterium mucogenicum
2. Description and significance
Mycobacterium mucogenicum was first discovered in a dialysis patient who developed septicemia via a catheter line that had been washed in infected water (1). It was characterized in 1982 as Mycobacterium chelonae-like organisms and in 1995 was delineated as a unique species, M. mucogenicum. This bacterium grows rapidly (colony formation in less than 7 days), is nonpigmented, and weakly Gram-positive (2). It is nonmotile, curved, and has a smooth colony morphology. Testing also reveals it is an aerobic, acid-fast rod; it has been found in both water and soil.
M. mucogenicum are associated with a wide range of clinical diseases and has been observed in complex infections of both immunocompromised and immunocompetent individuals. M. mucogenicum is able to tolerate various disinfectants including chlorination and extreme temperature (3). The bacteria’s unique structure is relevant to correctly identifying and treating the disease outbreaks because the susceptibility pattern and epidemiological links are distinct to this species (4). Recent outbreaks continue to occur, but the time before identification, number of infections, and mortality rate are all lower than when this bacteria was first being studied. Updating procedures as well as knowledge about this species can only continue to improve outcomes in vulnerable
3. Genome structure
The genome of Mycobacterium mucogenicum has been partially sequenced. The group was originally named in 1982 as Mycobacterium chelonae-like organism because of its similarity to Mycobacterium fortuitum and Mycobacterium chelonae. This similarity in 16S rRNA sequence impedes characterization and identification of this bacterium. Because of the similarities among 16S rRNA gene sequences of similar Mycobaterium species, differences must be determined using gene analysis (5). The analysis of multiple genes including hsp65, 16S rRNA genes, rpoB, sod, and recA were the most useful in differentiating between Mycobacterium species. Finally, in 1994 the new name, Mycobacterium mucogenicum, was proposed when it became established as its own species.
Closely Related Species: The Mycobacterium mucogenicum group includes M. mucogenicum, Mycobacterium aubagnese and Mycobacterium phocaicum (5). Together they are responsible for the outbreaks in both water and hospital sources.
4. Cell structure
Mycobacterium mucogenicum is a Gram-positive, acid-fast rod. A unique characteristic of these bacteria is the absence of an outer cell membrane that occasionally yields a false Gram-negative result during staining. M. mucogenicum and mycobacterium in general have a thick, hydrophobic, waxy cell wall with a cell envelope containing lipid components made of mycolic acid (6). The presence of mycolic acid in the cellular structure is unique to this genus of bacteria and confers resistance to many alcohols and antibiotics. Additional structures of long chain, saturated fatty acids found in M. mucogenicum contribute to chlorine resistance and the bacteria’s disinfectant resistance mechanism (7).
5. Metabolic processes
Mycobacterium mucogenicum are able to grow on simple substrates by using ammonium as a nitrogen source and manitol or citrate as carbon sources. Colony growth is inhibited by 5% NaCl. The bacteria test positive for 3-day arylsulfatase reaction and have no color on iron uptake testing. These bacteria are aerobic and have variable nitrate reduction (8). These results are from tests intended to discriminate M. mucogenicum from other strains that instead were only able to reveal more about the bacteria’s metabolic processes. To determine between M. mucogenicum and M. chelonae, a close species, either cell wall analysis by high performance liquid chromatography (HPLC) of cell wall mycolic acid esters or molecular characterization can be utilized. Gene determinations must often be used to characterize the bacteria found in patients (8)
6. Ecology
Habitat; symbiosis; contributions to the environment.
7. Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
7. Key microorganisms
Include this section if your Wiki page focuses on a microbial process, rather than a specific taxon/group of organisms
8. Current Research
Include information about how this microbe (or related microbes) are currently being studied and for what purpose
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.
