Streptococcus uberis

from Wikipedia, the free encyclopedia
Streptococcus uberis
Systematics
Department : Firmicutes
Class : Bacilli
Order : Lactobacillales
Family : Streptococcaceae
Genre : Streptococcus
Type : Streptococcus uberis
Scientific name
Streptococcus uberis
Diernhofer 1932

Streptococcus uberis is a bacterium belonging to the Bacilli class. In the dairy farming plays Streptococcus uberis as a mastitis a significant role.

features

Like all streptococci , Streptococcus uberis forms coccoidal , that is, spherical cells that cling to one another in long chains. The morphological differentiation of Streptococcus uberis from other streptococci, especially from enterococci , is not possible. But there are a number of differentiation possibilities in the physiological - chemical area for the diagnosis of the species.

Streptococcus uberis is one of the aesculin- positive environmental germs, which means that aesculin breakdown by the microorganisms takes place on aesculin-containing culture media. The bacterium is gram-positive and can usually be assigned to Lancefield group E. Streptococcus uberis does not produce any hemolysins, therefore only greenish zones are formed on blood agar plates . This property is known as α-hemolysis, or greening.

In Streptococcus uberis different genetically distinct occur tribes , which make a unique identification difficult at times. Some of these strains have a gene that enables individual bacteria to be encapsulated . There appears to be a connection between capsule formation and phagocyte ( neutrophil granulocyte ) resistance . The relationships between the possibility of encapsulation and virulence as a pathogen have not yet been adequately researched.

The complete genome of the Streptococcus uberis strain 0140J was sequenced in 2009 . The bacterium has 1,852,352 base pairs in its single, circular chromosome . The genetic information content is therefore at the lower end of the genomes that have so far been decoded for Streptococcus species, in the range of 1.8 to 2.3 megabytes.

Occurrence

Streptococcus uberis is ubiquitous all over the world. The bacteria are found everywhere around cattle herds, be it in the UK or Australia . They live in the grass in the pastures or in the straw in the stables. When taking samples in stables, more than one million individuals per gram of straw were found in 36 percent of all cases. The bacterium was also detected in the cattle's droppings . Genetic research has shown that Streptococcus uberis is less metabolic than most other Streptococcus species. The bacterium can also store energy in long polyphosphate chains. There are a number of ecological niches available to him. These also include specialized habitats within the animals, to whose commensals they belong, for example in the digestive tract and in the mammary glands of cows, where the infestation can lead to diseases.

Mastitis pathogen

Mastitis is inflammation of the mammary glands that is observed primarily in milk-producing pets. Different types of bacteria can be considered as causative agents. Streptococcus uberis is one of the constitutional or environmentally associated mastitis pathogens in cattle. Such pathogens only lead to the presence of a certain germ pressure or other predisposing factors, such as B. low immune defense of the animal, to a mostly subclinical or chronic course mastitis. Catarrhal mastitis with fever and changes in secretion also occur less frequently. Diseases caused by pathogens associated with the environment are more difficult to avoid than diseases that are transmitted from animal to animal via certain infection routes, such as mastitis caused by Streptococcus agalactiae .

Streptococcus uberis infections occur more frequently around birth (peripartum).

supporting documents

literature

  • Petra Winter (Ed.): Practical Guide to Mastitis . Parey at Mvs, 2008, ISBN 978-3-8304-4168-7
  • S. McDougall, TJ Parkinson, M. Leyland, FM Anniss, and SG Fenwick: Duration of infection and strain variation in Streptococcus uberis isolated from cow's milk . Journal of Dairy Science, 87, pp. 2062–2072, 2004 (full text) (English)

Individual evidence

  1. ↑ R. Tschischkale, Th. Peters, J. Ramm: Streptococci from the environment as mastitis pathogens . MBFG, 2009 p. 10 (PDF presentation, German; 3.2 MB)
  2. ↑ Tracey J. Coffey, Gillian D. Pullinger, Rachel Urwin, Keith A. Jolley, Stephen M. Wilson, Martin C. Maiden, and James A. Leigh: First insights into the evolution of Streptococcus uberis: a multilocus sequence typing scheme that enables investigation of its population biology. Applied and Environmental Microbiology, 72, 2, pp. 1420-1428, February 2006 doi : 10.1128 / AEM.72.2.1420-1428.2006 PMID 16461695 .
  3. ↑ James A. Leigh, TR Field: Streptococcus uberis resists the bactericidal action of bovine neutrophils despite the presence of bound immunoglobulin. In: Infection and Immunity , 62, 5, pp. 1854-1859, May 1994
  4. ↑ TR Field, PN Ward, LH Pedersen, James A. Leigh: The Hyaluronic Acid Capsule of Streptococcus uberis Is Not Required for the Development of Infection and Clinical Mastitis. Infect. Immune. 71, pp. 132-139, 2003
  5. ↑ Streptococcus uberis whole genome sequencing data at the Wellcome Trust Sanger Institute, Cambridge, England, 2009
  6. ↑ a b Philipp N. Ward et al .: Evidence for niche adaptation in the genome of the bovine pathogen Streptococcus uberis. BMC Genomics, 10, 54, 2009 doi : 10.1186 / 1471-2164-10-54 full text (English)
  7. ^ A. John Bramley: Sources of Streptococcus uberis in the dairy herd: I. Isolation from bovine faces and from straw bedding of cattle. Journal of Dairy Research, 49, 3, pp. 369-373, 1982
  8. ↑ James A. Leigh: Streptococcus uberis: A Permanent Barrier to the Control of Bovine Mastitis? The Veterinary Journal, 157, 3, pp. 225-248, 1999

Web links