Introduction

Streptococcus constellatus is a species of Streptococcus

Streptococcus

Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...

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. DNA homology studies and 16S rRNA sequence analysis demonstrate S. constellatus is collectively known as the Streptococcus milleri group

Streptococcus milleri group

Streptococcus milleri group is a group of Streptococcus species.Members include:* Streptococcus anginosus* Streptococcus constellatus* Streptococcus intermedius...

 along with Streptococcus intermedius

Streptococcus intermedius

Streptococcus intermedius is a commensal bacterium and a member of the Streptococcus anginosus group. The S. anginosus group, occasionally termed “Streptococcus milleri group” display hemolytic and serologic diversity, yet share core physiological traits. Despite being commensal organisms, members...

and Streptococcus anginosus

Streptococcus anginosus

Streptococcus anginosus is a species of Streptococcus.Together with Streptococcus constellatus and Streptococcus intermedius they constitute the anginosus group, which is sometimes also referred to as the milleri group after the previously assumed single but later refuted species Streptococcus...

.

Morphology

S. constellatus are gram positive, non-sporing, non-motile, catalse negative cocci. The cells are small, normally 0.5-1μm in diameter and form short chains. Their cell wall peptidoglycan is composed of Lys-Ala_1-3 and has a DNA G+C content of 37-38%.

Metabolism and Growth

In the presence of CO₂ growth is enhanced, under aerobic

Aerobic

Aerobic is a word that means "requiring air", where "air" usually means oxygen.Aerobic may also refer to:* Aerobic exercise, prolonged exercise of moderate intensity* Aerobics, a form of aerobic exercise...

 conditions growth is reduced, and some strains require anaerobic

Anaerobic

Anaerobic is a word which literally means without oxygen, as opposed to aerobic.In wastewater treatment the absence of oxygen is indicated as anoxic; and anaerobic is used to indicate the absence of a common electron acceptor such as nitrate, sulfate or oxygen.Anaerobic may refer to:*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

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	+	-	+

Disease

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

Cystic fibrosis

Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...

 patients.

Subspecies

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

S. constellatus subsp. constellatus

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.

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

S. constellatus subsp. pharyngis

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

See also

• Streptococcus milleri group
  Streptococcus milleri group
  Streptococcus milleri group is a group of Streptococcus species.Members include:* Streptococcus anginosus* Streptococcus constellatus* Streptococcus intermedius...
  
  
• Streptococcus intermedius
  Streptococcus intermedius
  Streptococcus intermedius is a commensal bacterium and a member of the Streptococcus anginosus group. The S. anginosus group, occasionally termed “Streptococcus milleri group” display hemolytic and serologic diversity, yet share core physiological traits. Despite being commensal organisms, members...
  
  
• Streptococcus anginosus
  Streptococcus anginosus
  Streptococcus anginosus is a species of Streptococcus.Together with Streptococcus constellatus and Streptococcus intermedius they constitute the anginosus group, which is sometimes also referred to as the milleri group after the previously assumed single but later refuted species Streptococcus...