Chromobacterium violaceum
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| Chromobacterium violaceum |
Chromobacterium violaceum is a Gram-negative, facultative anaerobic, non-sporing coccobacillus. It is part of the normal flora of water and soil of tropical and sub-tropical regions of the world. It produces a natural antibiotic called violacein. It grows readily on nutriet agar, producing distinctive smooth low convex colonies with a dark violet metallic sheen (due to violacein production). It is the only member of the genus Chromobacterium. Its full genome was published in 2003.[1]
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[edit] Biochemistry
C. violaceum ferments glucose, trehalose, N-acetylglucosamine and gluconate but not L-arabinose, D-galactose or D-maltose.
[edit] Medical significance
C.violaceum rarely infects humans, but when it does it causes skin lesions, sepsis and liver abscesses that may be fatal.[2] Care must be taken because Burkholderia pseudomallei is commonly misidentified as C. violaceum by many common identification methods.[3][4] The two are readily distinguished because B. pseudomallei produces large wrinkled colonies.
C.violaceum produces a number of natural antibiotics:
- Aztreonam is a monobactam antibiotic that is active against gram-negative aerobic bacteria including Pseudomonas aeruginosa. It is marketed as Azactam®.
- Violacein is active against amoebae and trypanosomes;
- Aerocyanidine is active against Gram-positive organisms;
- Aerocavin is active against Gram-positive and Gram-negative organisms.
[edit] Treatment
Infection caused by C. violaceum is rare, therefore there are no clinical trials evaluating different treatments. Antibiotics that have been used to successfully treat C. violaceum include pefloxacin,[5] ciprofloxacin, amikacin,[6] and co-trimoxazole.[7] Other antibiotics that appear to be effective in vitro include chloramphenicol and tetracycline.[8] For theoretical reasons, infection would not be expected to respond to penicillins, cephalosporins or aztreonam, although carbapenems like meropenem or imipenem may possibly work.[9]
[edit] References
- ^ Brazilian National Genome Project Consortium. (2003). "The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability.". Proc Natl Acad Sci U S A 100: 11660–5. PMID 14500782.
- ^ Sneath PH, Whelan JP, Bhagwan Singh R, Edwards D. (1953). "Fatal infection by Chromobacterium violaceum". Lancet 265 (6780): 276–7. PMID 13085740.
- ^ Inglis TJ, Chiang D, Lee GS, Chor-Kiang L (1998). "Potential misidentification of Burkholderia pseudomallei by API 20NE". Pathology 30 (1): 62–4. PMID: 9534210.
- ^ Lowe P, Engler C, Norton R. (2002). "Comparison of automated and nonautomated systems for identification of Burkholderia pseudomallei". J Clin Microbiol 40 (12): 4625–27.
- ^ (1999) "Two cases of Chromobacterium violaceum infection after injury in a subtropical region". J Clin Microbiol 37 (6): 2068–70.
- ^ Ray P, Sharma J, Marak RSK, et al. (2004). "Chromobacterium violaceum septicaemia from north India". Indian J Med Res 120: 523–26.
- ^ Moore C, Lane J, Stephens J (2001). "Successful treatment of an infant with Chromobacterium violaceum sepsis.". Clin Infect Dis 32 (6): E107–10. PMID 11247733.
- ^ Martinez R, Velludo MA, Santos VR, Dinamarco PV. (2000). "Chromobacterium violaceum infection in Brazil. A case report". Rev Inst Med Trop Sao Paulo 42 (2): 111–3.
- ^ Midani S, Rathore M (1998). "Chromobacterium violaceum infection.". South Med J 91 (5): 464–6. PMID 9598856.
