Shewanella baltica and other TMA producing bacteria in the gut

Nigel Manning
Principal Clinical Scientist
Dept. Clinical Chemistry
Sheffield Children's Hospital
Sheffield
email : Nigel.Manning@sch.nhs.uk

Excerpts from Part 2 of Interview with Nigel Manning
March 2009

The bacteria possibly responsible for the production of trimethylamine in the gut

Do we know what bacteria is responsible for gut Trimethylamine (TMA) production ?

NM: There are more than 400 species of bacteria in the colon but only a few described as TMA-producing. The fishing industry’s research microbiologists have published many papers on TMA and ‘fish-spoiling’ and cite species such as Vibrio harveyi, Vibrio fischeri, Photobacterium leiognathi and Shewanella baltica. The last of these is also know to generate hydrogen sulphide – or ‘ rotten egg’ gas. Whether these microbes are those responsible for human TMA production is a good question, but they may represent a small portion of the total.

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[Shewanella baltica]...is also known to generate hydrogen sulphide - or 'rotten egg' gas.Shewanella baltica: Shewanella baltica (baltica of the Baltic Sea) is both an aerobic and anaerobic bacterium. Shewanella is the sole genus in the Shewanellaceae family of marine bacteria. Shewanella baltica are H2S-producing [hydrogen sulphide-producing] bacterial isolated from marine fish (mainly cod, plaice, and flounder) caught from the Baltic Sea. In aerobic conditions, the Black Sea strains of S. baltica absorbed significant quantities of Fe(III) from its medium, then reducing it to Fe (II) in anaerobic conditions. Under anaerobic conditions, S. baltica also oxidizes organic matter from the reduction of nitrate and sulfur compounds as well. S. baltica also has putrefaciens capable of high-rate azoreduction and humus reduction under anaerobic conditions. S. baltica produces a black precipitate of FeS when grown on TSI agar medium...(1)

Vibrio harveyi: Vibrio harveyi is a species of Gram-negative, bioluminescent, marine bacteria in the genus Vibrio. V. harveyi are rod-shaped, motile (via polar flagella), facultatively anaerobic, halophilic, and competent for both fermentative and respiratory metabolism. The do not grow at 4°C or above 35°C. V. harveyi can be found free-swimming in tropical marine waters, commensally in the gut microflora of marine animals, and as both a primary and opportunistic pathogen of marine animals, including Gorgonian corals, oysters, prawns, lobsters, the common snook, barramundi, turbot, milkfish, and seahorses[1]. V. harveyi is responsible for luminous vibriosis, a disease that affects commercially-farmed penaeid prawns[2]. Additionally, based on samples taken by ocean-going ships, V. harveyi is thought to be the cause of the milky seas effect, in which, during the night, a uniform blue glow is emitted from the seawater. Some glows can cover nearly 6,000 square miles. (2)

Vibrio fischeri: Vibrio fischeri is a gram-negative rod-shaped bacterium found globally in the marine environments. V. fischeri has bioluminescent properties, and is found predominantly in symbiosis with various marine animals, such as the bobtail squid. It is heterotrophic and moves by means of flagella. Free living V. fischeri survive on decaying organic matter (see saprotroph). The bacterium is a key research organism for examination of microbial bioluminescence, quorum sensing, and bacterial-animal symbiosis.(3)
See image results for Vibrio Fischeri (4)

Photobacterium leiognathi: Since ancient times mariners have reported seeing glowing seas as their ships sailed through the night. More recently, satellites have recorded pictures of glowing seas off the eastern coast of Africa. The bioluminescent microbes responsible for such phenomena require specific conditions and high concentrations to achieve this effect, but it is similar to the algae blooms that cause red tide. There are many varieties of bacterium that can emit light, and some of them have developed symbiotic relationships with animals. Photobacterium leiognathi is one such species...(5)

References:
(1) http://microbewiki.kenyon.edu/index.php/Shewanella_baltica
(2) http://en.wikipedia.org/wiki/Vibrio_harveyi
(3) http://en.wikipedia.org/wiki/Vibrio_fischeri
(4) http://images.google.com
(5) http://web.mst.edu/~microbio/BIO221_2006/P_leiognathi.htm