Streptococcus constellatus

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Streptococcus constellatus
Scientific classification
Kingdom: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Streptococcaceae
Genus: Streptococcus
Species: S. constellatus

Introduction[edit]

Streptococcus constellatus is a species of Streptococcus [1] part of the normal flora in the oral cavity, urogenital region, and intestinal tract. However, it can frequently cause purulent infections in other parts of the body.[2] DNA homology studies and 16S rRNA sequence analysis demonstrate S. constellatus is collectively known as the Streptococcus milleri group along with Streptococcus intermedius and Streptococcus anginosus. [3]

Morphology[edit]

S. constellatus are gram positive, non-sporing, non-motile, catalase negative cocci. The cells are small, normally 0.5-1μm in diameter and form short chains. Their cell wall peptidoglycan is composed of Lys-Ala1-3 and has a DNA G+C content of 37-38%.[4]

Metabolism and Growth[edit]

In the presence of CO2 growth is enhanced, under aerobic conditions growth is reduced, and some strains require anaerobic conditions to grow.

“S. constellatus” produces major amounts of lactic acid, fermented glucose, maltose and sucrose, but not lactose and hydrolyzed aesculin.

Biochemical Characteristics[edit]

The typical species is Lancefield Groups A,C, G, and F, with the remaining NG (non-groupable) and haemolysis on blood agar is β-haemolytic and NH (non-haemolytic).

Enzyme S. constellatus S. anginosus S. intermedius
Beta-D-fucosidase - - +
Beta-N-acetylglucosaminidase - - +
Beta-N-galactosaminidase - - +
Sialidase - - +
Beta-galactosidase - - +
Beta-glucosidase - + +/-
Hyaluronidase + - +

[5]

Disease[edit]

Clinically it is associated with abscess formation in the upper body and respiratory tract. It is the most common cause of brain and liver abscesses. It has also been found to be involved with pulmonary exacerbations in cystic fibrosis patients.[6]

Subspecies[edit]

Evidence supports the further subdivision of S. constellatus into two subspecies, S. constellatus subsp. constellatus and S. constellatus subsp. pharyngis.[4]

S. constellatus subsp. constellatus[edit]

Normally found in the oral cavities and upper respiratory tracts and isolated from purulent human infections, including appendicitis. Strains are frequently β-haemolyic and belong to Lancefield Group F or are nonhaemolytic (α and γ) and seologically ungroupable. However, a few strains react with Lancefield Group A, C, and G antisera.[7]

Most strains produce:

  • α-glucosidase, but very few produce: β-galactosidase and β-glucosidase

Most strains do NOT produce:

  • β-N-acetylglucosaminidase
  • β-D-fucosidase
  • α-galactosidase
  • β-glucuronidase
  • pyrrolidonylarylamidase
  • sialidase [7]

S. constellatus subsp. pharyngis[edit]

Normally found in infections of the human throat, patients with pharyngitis. Strains freqeuncty are β-haemolytic and belong to Lancefield C.

Most strains produce:

  • β-N-acetylgalactosaminidase
  • β-D-fucosidase
  • α-galactosidase
  • α-glucosidase
  • β-glucosdiase
  • β-N-acetylglucosaminidase

Most strains do NOT produce:

  • α-galactosidase
  • β-glucuronidase
  • pyrrolidonylarylamidase
  • sialidase[7]

See also[edit]

References[edit]

  1. ^ Jacobs JA, Schouls LM, Whiley RA (January 2000). "DNA-DNA reassociation studies of Streptococcus constellatus with unusual 16S rRNA sequences". Int. J. Syst. Evol. Microbiol. 50 Pt 1: 247–9. PMID 10826810. 
  2. ^ Whiley, R.A., Beighton, D., Winstanley, T.G., Fraser, H.Y. and Hardie, J.M. (1992) Streptococcus intermedius, Streptococcus constel- latus, Streptococcus anginosus(the Streptococcus milleri group): Asso- ciation with di¡erent body site and clinical infections. J. Clin. Micro- biol. 30, 243^244.
  3. ^ Whiley RA, Beighton D, Winstanley TG, Fraser HY, Hardie HM (January 1992). "Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus (the Streptococcus milleri group): Association with Different Body Sites and Clinical Infections". J. Clin. Microbiol. 30 (1): 243–4. PMC 265033. PMID 1734062. 
  4. ^ a b Whiley, R. A., Hall, L. M. C., Hardie, J. M., Beighton, D. A study of small-colony, {beta}-haemolytic, Lancefield group C streptococci within the anginosus group: description of Streptococcus constellatus subsp. pharyngis subsp. nov., associated with the human throat and pharyngitis Int J Syst Bacteriol 1999 49: 1443-1449
  5. ^ Stevens, D. and Kaplan, E. (2000). Steptococcal infections: clinical aspects, microbiology and molecular pathogenesis. Oxford University Press, Inc.: New York.
  6. ^ Sibley CD, Parkins MD, Rabin HR, Duan K, Norgaard JC, Surette MG. (September 2008). "A polymicrobial perspective of pulmonary infections exposes an enigmatic pathogen in cystic fibrosis patients.". Proc. Natl. Acad. Sci. U.S.A. 105 (39): 15070–5. doi:10.1073/pnas.0804326105. PMC 2567494. PMID 18812504. 
  7. ^ a b c Whiley, R. A., Hall, L. M. C., Hardie, J. M., Beighton, D. A study of small-colony, {beta}-haemolytic, Lancefield group C streptococci within the anginosus group: description of Streptococcus constellatus subsp. pharyngis subsp. nov., associated with the human throat and pharyngitis Int J Syst Bacteriol 1999 49: 1443-1449