Bifidobacterium choerinum

A Microbial Biorealm page on Bifidobacterium choerinum

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Classification

Higher Order Taxa

Bacteria; Actinobacteria; Actinobacteridae; Bifidobacteriales; Bifidobacteriaceae; Bifidobacterium choerinum

Species

Species of the Genus Bifidobacterium include: B. adolescentis;B. angulatum;B. animalis; B. asteroids; B. bifidum; B. boum;B. breve;B. catenulatum; B. choerinum; B. coryneforme;B. cuniculi;B. denticolens; B. dentium; B. gallicum; B. gallinarum; B. indicum;B. infantis;B. inopinatum;B. lactis;B. longum;B. magnum;B. merycicum;B. minimum;B. pseudocatenulatum;B. pseudolongum;B. pullorum;B. ruminantium; B. saeculare; B. subtile; B. suis;B. thermacidophilum;B. thermophilum.

Description and Significance

Members of the genus Bifidobacterium are some of the most common organisms in the human intestinal tract (5). Bifidobacterium choerinum is part of the B. pseudolongum group which is a branch of the Actinobacteria. Bifidobacterium bacteria are classified as anaerobes that are known to be beneficial to human health. This group is expected to prove highly valuable for use in milk products, health promotion, and treatment of intestinal disorders. However, their sensitivity to O2 limits probiotic activity to solely anaerobic habitats. Recent research has reported that the Bifidobacterium strains exhibit various types of oxic growth. Low concentrations of O₂ and CO₂ can have a stimulatory effect on the growth of Bifidobacterium strains (6).

Bifidobacterium choerinum is an autochthonous bifidobacterium species of the pig that is well adapted to the gut of pre-weaned piglets and shows potential probiotic properties (2).

Genome Structure

Bifidobacterium chromosomes are circular shape. ? bp in length with a 50% G-C content.

The particular species of Bifidobacterium can be easily detected by using the species-specific PCR method for identifying Bifidobacterium strains isolated from human feces (4).

Cell and Colony Structure

Bifidobacteria choerinum is a Gram-positive, anaerobic, branched rod-shaped bacterium. This particular type of bacteria are non-sporing and also non-motile. It is 10-12 μm and has a V or Y-like appearance. The optimal temperature for growth is 37-41°C, no growth occurs below 20°C and above 46°C. Bifidobacterium are acid-tolerant microorganisms, the optimal pH is between 6.5-7.3 with no growth occurring below 4 and above 8 (7). This bacterium has a hydrophobic character of bifidobacterium surface (3). Bifidobacterium accumulate iron when it is presented in the ferrous oxidation state. This form is expected under anaerobic conditions like the human colon or cattle rumen (3).

Metabolism

Bifidobacterium have been known to synthesize vitamins. It is an anaerobic microbe best grown in a TSA slant at 37°C. Significant amounts of polysaccharides normally galactose and glucose often associated with rhamnose (3). This bacterium is not considered to reduce nitrate (3). It also will not develop in the presence of CO₂. When residing in the intestines, they are able to ferment sugars to produce lactic acid. It has also been shown to be resistant to aminoglycoside antibiotics while being susceptible to Beta-lactams (3).

This type of bacterium ferments glucose via the phosphoketolase pathway and not via glycolysis. The typical fermentation end products are acetate and lactate.

Ecology

This bacterium is ubiquitous, endosymbiotic inhabitant.

Pathology

No known pathology.

References

1) Euzeby, J.P. List of Prokaryotic Names with Standing in Nomenclature- Genus Bifidobacterium. 12 March 2013. http://www.bacterio.cict.fr/b/bifidobacterium.html

2) Maxwell FJ., Duncan SH., Hold G., Stewart CS. Isolation, Growth on Prebiotics and Probiotic Potential of Novel Bifidobacteria from Pigs. Anaerobe. (2004) Online.

3) Whitman, William B., Goodfellow, Micahel., Kampfer, Peter., et. (2012) Bergey's Manual of Systematic Bacteriology. Vol. 5.

4) Matsuki, Takahiro., Watanabe, Koichi., Fukuda, Masafumi., and Oyaizu, Hiroshi. (1999) Distribution of Bifidobacterial Species in Human Intestinal Microflora Examined with 16S rRNA-Gene-Targeted Species-Specific Primers Applied and Environmental Microbiology. 65:10, 4506-4512; 25 April 2013. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91600/

5) Scardovi V. (1986). Genus Bifidobacterium Orla-Jensen 1924, 472al.. In: Sneath P.H.A., Mair N.S., Sharpe M.E., Holt J.G., eds, Bergey’s Manual of Systematic Bacteriology, Vol. 2, Williams and Wilkins, Baltimore, pp. 1418-1434.

6) Kawasaki, Shinji. (2011) Response of Bifidobacterium Species to Oxygen. Lactic Acid Bacteria and Bifidobacteria: Current Progress in Advanced Research. 25 April 2013. http://www.horizonpress.com/blogger/2011/03/response-of-bifidobacterium-species-to-oxygen.html

7) Biavati, B., Vescovo, M., Torriani, S., Bottazzi, V. Bifidobacteria: History, Ecology, Physiology and Applications. http://www.annmicro.unimi.it/full/50/biavati_50_117.pdf

8) Scardovi V., Trovatelli L.D., Biavati B., Zani G. (1979). Bifidobacterium cuniculi, Bifidobacterium choerinum, Bifidobacterium boum, and Bifidobacterium pseudocatenulatum: four new species and their deoxyribonucieic acid homology relationships. Int. J. Syst. Bacteriol., 29: 291-311.