Bacteria;Firmicutes; Bacilli; Lactobacillales; Streptococcaceae; Streptococcus
This sample was cultivated from the edge of a fence wall in a subdivision in Austin, TX near a garden bed. The surrounding soil was moist from a sprinkler having been left on and rocky. This area was also frequented by dogs and household pets.
Description and Significance
Streptococcus bovis is a gram-positive bacterium that grows in pairs or chains of cocci and is a normal inhabitant of the gastrointestinal tract. It is both oxidase and catalase-negative and is a non-motile, non-sporulating, facultative anaerobe. S. bovis is classified as a group D streptococci, gamma-hemolytic species causing no hemolysis, accompanied only by the strain streptococcus equinus. S. bovis is associated closely with infective endocarditis and has links to colon cancer, liver diseases, neonatal septicemia, and more rarely, neonatal meningitis and adult meningitis.
Streptococcus bovis has antimicrobial susceptibility to penicillin, Ticarcillin, sulfisoxazone, Azlocillin and ceftazidime.
Comprised of a single circular chromosome of 2,362,241 bp. and does not contain any plasmids. There are 61 tRNA genes and five rRNA operons in each chromosomes, with most of the tRNA genes situated close to rRNA operons. A total of 2246 protein-coding genes are predicted in ATCC 43143, much similar to the recently sequenced S. gallolyticus UCN34 of the same biotype (3)
Cell Structure, Metabolism and Life Cycle
streptococcus bovis' cell surface has a variety of proteins and polysaccharides that are either covalently or non- covalently bonded to the cell wall, much like other gram-positive bacteria. The cell surface can be divided into four further categories: (1) LPXTG- like proteins, (2) pseudopili, (3) surface lipoproteins, and (4) capsule. The capsule is required in order for the organism to be resistant to phagocytosis. S. bovis is a ruminal bacterium that has very high rates of catabolism, and is a model of energy- spilling. "'S. bovis' regulates energy spilling via changes in the concentration of intracellular fructose -diphosphate." (4) Can rapidly ferment starch and produce lactic acid as the end result of fermentation.
Physiology and Pathogenesis
In a study performed in Naples, Italy, it was concluded that S. bovis was the second most common pathogen associated with endocarditis. There does seem to be some disagreement, however, about the different strains of S. bovis type I causing endocarditis and type II being a predisposing factor to gastrointestinal malignancy. The genetic diversity among the two biotypes most likely contributes to the type of disease the patient usually develops. S. bovis causes disease in both humans and animals alike. In humans it is the the causative agent of bacteremia which can lead to malignant and non-malignant gastrointestinal diseases. S. bovis presents itself as gastrointestinal lesions usually and is sometimes overlooked because s. bovis bacterium is a naturally occurring bacterium in the gastrointestinal tract. When looking to diagnose endocarditis, patients wil usually experience colonic polyps, perirectal abscess and rectal manipulations. In some cases the endocarditis presented itself before any symptoms of the colonic lesions had surfaced. Patients will usually come in experiencing fever, chills, and loss of appetite. Most often liver function becomes impaired and irritable bowel syndrome symptoms can be experienced.
1. Salah Shanan, Samia A. Gumaa, Gunnar Sandström, and Hadi Abd, “Significant Association of Streptococcus bovis with Malignant Gastrointestinal Diseases,” International Journal of Microbiology, vol. 2011, Article ID 792019, 5 pages, 2011. doi:10.1155/2011/792019
2. Accepted manuscript posted online 9 July 2008, doi: 10.1128/JCM.00078-08. J. Clin. Microbiol. September 2008 vol. 46 no. 9 2966-2972
3.Lin I-H, Liu T-T, Teng Y-T, Wu H-L, Liu Y-M, et al. (2011) Sequencing and Comparative Genome Analysis of Two Pathogenic Streptococcus gallolyticus Subspecies: Genome Plasticity, Adaptation and Virulence. PLoS ONE 6(5): e20519. doi: 10.1371/journal.pone.0020519
4.Clin Infect Dis. (2011) 53 (9): 870-878.doi: 10.1093/cid/cir609First published online: September 29, 2011
Page authored by Jessica Payne, student of Prof. Kristine Hollingsworth at Austin Community College.