Streptococcus bovis

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Streptococcus bovis
Scientific classification
Kingdom: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Streptococcaceae
Genus: Streptococcus
Species: S. bovis
Binomial name
Streptococcus bovis
Orla-Jensen 1919

Streptococcus bovis (S. bovis) is a species of bacteria that in humans is associated with endocarditis[1] and colorectal cancer.[2] S. bovis is commonly found in the alimentary tract of cows, sheep, and other ruminants,[3] and may cause ruminal acidosis or feedlot bloat.[4][5]

Classification[edit]

S. bovis is a catalase- and oxidase-negative, non-motile, non-sporulating, Gram-positive lactic acid bacterium that grows as pairs or chains of cocci.[6] It is a member of the Lancefield group D streptococci. Most strains are non- or gamma-hemolytic, but some also display alpha-hemolytic activity on ovine blood agar plates.

Human infection[edit]

Entry[edit]

The main portal of entry for human infection of S. bovis bacteremia is the gastrointestinal tract, but in some cases entry is through the urinary tract, the hepatobiliary tree, or the oropharynx.[7]

Role in disease[edit]

S. bovis is a known human pathogen that has been implicated as a causative agent of endocarditis,[1] and, more rarely, neonatal septicemia and meningitis.[8][9][10]

Streptococcus bovis has long been associated with colorectal cancer (CRC),[2] however, not all genospecies are as closely related to CRC. A recent meta-analysis on the association between S. bovis biotypes and colonic adenomas/carcinomas revealed that patients with S. bovis biotype I infection had a strongly increased risk of having CRC (pooled odds ratio: 7.26; 95% confidence interval: 3.94–13.36), compared to S. bovis biotype II-infected patients.[11] This analysis clearly indicates that S. bovis should no longer be regarded as a single bacterial entity in clinical practice. Only Streptococcus gallolyticus (the new name of S. bovis biotype I) infection has an unambiguous association with colonic adenomas/carcinomas (prevalence range: 33–71%) that markedly exceeds the prevalence of colonic (pre-)maligancies in the general population (10–25%). Nonetheless, research has not yet determined if Streptococcus gallolyticus is a causative agent of colorectal cancer, or if pre-existing cancer makes the lumen of the large intestine more hospitable to its outgrowth.[12]

Ruminal effects[edit]

When ruminants consume diets high in starch or sugar, these easily fermentable carbohydrates promote the proliferation of S. bovis in the rumen. Because S. bovis is a lactic acid bacterium, fermentation of these carbohydrates to lactic acid can cause a dramatic decline in ruminal pH, and subsequent development of adverse conditions such as ruminal acidosis or feedlot bloat.[4][5]

References[edit]

  1. ^ a b Ryan K.J. and C.G. Ray CG (editors). 2004. Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
  2. ^ a b Klein RS, Recco RA, Catalano MT, Edberg SC, Casey JI, Steigbigel NH (13 October 1977). "Association of Streptococcus bovis with carcinoma of the colon". N. Engl. J. Med. 297 (15): 800–2. doi:10.1056/NEJM197710132971503. PMID 408687. 
  3. ^ Ghali M.B., Scott P.T., Al Jassim R.A.M. (2004). "Characterization of Streptococcus bovis from the rumen of the dromedary camel and Rusa deer". Lett. Appl. Microbiol 39 (4): 341–346. doi:10.1111/j.1472-765X.2004.01597.x. 
  4. ^ a b Asanuma N, Hino T (2002). "Regulation of fermentation in a ruminal bacterium, Streptococcus bovis, with special reference to rumen acidosis". Animal Sci. J. 73 (5): 313–325. doi:10.1046/j.1344-3941.2002.00044.x. 
  5. ^ a b "Subacute Ruminal Acidosis". The Merck Veterinary Manual. Retrieved 2008-09-10. 
  6. ^ Schlegel L., Grimont R., Ageron E., Grimont P.A.D., Bouvet A. (2003). "Reappraisal of the taxonomy of the Streptococcus bovis/Streptococcus equinus complex and related species: description of Streptococcus gallolyticus subsp. gallolyticus subsp. nov., S. gallolyticus subsp. macedonicus subsp. nov. and S. gallolyticus subsp. pasteurianus subsp. nov". Int. J. Syst. Evol. Microbiol 53 (3): 631–645. 
  7. ^ Streptococcus Group D Infections from Medscape. Author: Christian P Sinave. Updated: Jan 12, 2012
  8. ^ Headings DL, Herrera A, Mazzi E, Bergman MA (February 1978). "Fulminant neonatal septicemia caused by Streptococcus bovis". J. Pediatr. 92 (2): 282–3. doi:10.1016/S0022-3476(78)80026-2. PMID 413898. 
  9. ^ White BA, Labhsetwar SA, Mian AN (November 2002). "Streptococcus bovis bacteremia and fetal death". Obstet Gynecol 100 (5 Pt 2): 1126–9. doi:10.1016/S0029-7844(02)02206-8. PMID 12423832. 
  10. ^ Grant RJ, Whitehead TR, Orr JE (1 January 2000). "Streptococcus bovis meningitis in an infant". J. Clin. Microbiol. 38 (1): 462–3. PMC 88753. PMID 10618145. 
  11. ^ Boleij, A; van Gelder, MM, Swinkels, DW, Tjalsma, H (November 2011). "Clinical Importance of Streptococcus gallolyticus infection among colorectal cancer patients: systematic review and meta-analysis.". Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 53 (9): 870–8. doi:10.1093/cid/cir609. PMID 21960713. 
  12. ^ zur Hausen H (November 2006). "Streptococcus bovis: causal or incidental involvement in cancer of the colon?". Int. J. Cancer 119 (9): xi–xii. doi:10.1002/ijc.22314. PMID 16947772. 

External links[edit]