Streptococcus zooepidemicus: Difference between revisions
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==Pathology== | ==Pathology== | ||
===Animals=== | |||
''Streptococcus zooepidemicus'' is a pathogen of animals primarily affecting horses, in whom it can cause diseases in the upper respiratory tract, uterus, umbilicus, and wounds (5). In cows, ''S. zooepidemicus'' can cause mastitis (3), an inflammation in mammalian breast. As for other animals such as rabbits and swine, it can cause septicemia (3), which is a systematic inflammatory response to infections. This microorganism has also caused fibrinous pericarditis, fibrinous pleuritis, and pneumonia in sheeps. The overall symptoms of infections caused by S. zooepidemicus include pyrexia (fever), serous to mucopurulent nasal discharge, dyspnea (short of breath). | |||
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===Humans=== | |||
In general, this pathogen rarely causes human infections (3, 4, 24). However, ''Streptococcus zooepidemicus'' has been reported to have caused a broad range of diseases, including septicemia and endocarditis (6), respiratory tract infection leading to nephritis (7), cervical lymphadenitis (8), septic arthritis and pneumonia (9), and meningitis (10, 11). Severe condition of these infections has caused deaths in some cases (9, 11, 18). In this one rare case, there is evidence of ''S. zooepidemicus'' involving in superantigen production, which contributed to the death of a 63-year-old man who died shortly after suffering from toxic shock-like syndrome (18). | |||
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''Streptococcus zooepidemicus'' has also been reported to have caused poststreptococcal glomerulonephritis (PSGN), which is an acute inflammatory disorder of the glomerulus (24, 25). PSGN is usually developed in the aftermath of an acute throat or skin infection with a GAS strain; in this case, this disease caused by group C ''S. zooepidemicus'' was due to ingestion of food products made from unpasteurized milk. Interestingly, this disorder caused by subspecies ''zooepidemicus'' occurs predominantly in adults, whereas PSGN caused by GAS occurs in children (24, 25). Some of the clinical syndroms may include fever, edema, pharyngitis, hypertension, reduced renal function, and an increase in microalbuminuria (25, 26), a small amount of albumin present in urine. | |||
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Several theories have been proposed as an explanation for the initiation of PSGN; however, the main cause is still left undetermined (25). By activating the complement cascade via alternative pathway, PSGN causes glomerular inflammation by affecting the mesangial and endothelial cells. This activation will lead to an accumulation of fibrin in the glomeruli and a proliferation of parietal epithelial cells in Bowman’s capsule; it will also increase the entry of inflammatory cells, causing acute glomerular crescent formation. The glomerular capillaries will also be clogged due to the permeation of leukocyts and platelets. Along with the tissues being damaged and the filtration barrier of basement membrane being altered, these immune complexes may accumulate and fluid retention may occur, causing edema and vascular congestion (26). | |||
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==Application to Biotechnology== | ==Application to Biotechnology== | ||
''Streptococcus zooepidemicus'' is used in bacterial fermentation for producing hyaluronic acid, which is a component that is widely used in ophthalmic surgery and as an ingredient in cosmetics (15). Derivatives of this mucopolysaccharide are used mainly as a source of skin filler for anti-aging and lip augmentation due to its ability to “form a gelatinous materials in the tissue space, acting as a lubricant and shock absorbent” (16, 17) and high water retention capacity (27). Hyaluronic acid has also been used in viscosurgery and as a lubricating supplement in arthritic joints. | |||
==Current Research== | ==Current Research== | ||
Revision as of 02:41, 29 August 2007
A Microbial Biorealm page on the genus Streptococcus zooepidemicus
Classification
Higher order taxa
Bacteria; Firmicutes; Bascilli; Lactobacillales; Streptococcaceae; Streptococcus
Species
|
NCBI: Taxonomy |
Streptococcus equi
Subspecies
zooepidemicus
Other names
“Animal pyogenes, type A” [Edwards 1934]
“Streptococcus pyogene animalis” [Seelemann 1942]
“Streptococcus equi subsp. zooepidemicus” [Farrow and Collins 1985]
Type Strains
ATCC 43079
DSM 20727
NCDO 1358
Description and significance
Streptococcus zooepidemicus is one of the two subspecies of Streptococcus equi; it is suggested to be the species from which subspecies equi has been derived (5). Subspecies zooepidemicus is a normal bacterial flora in horses. It is isolated from wound infections of horses, and it has been isolated from other mammals such as cows, rabbits, and swine (3). In some cases, subspecies zooepidemicus is also isolated from humans through throat swabs (4). It occasionally causes human infection that can be traced back to contact with horses or consumption of unpasteurized dairy products (4).
Like other streptococci, Streptococcus zooepidemicus is a non-motile, non-sporulating, encapsulated, gram-positive, catalse-negative, and coccoid bacterium. It is a beta hemolytic streptococcus that produces hyaluronic acid but not streptolysin O and occurs in pairs or long chains (2). It is also lactose positive and is capable of fermenting sorbitol but not trehalose (3, 28).
Genome structure
Although the shotgun sequencing is complete with an available database of reads, the genome project of Streptococcus zooepidemicus is still in progress. At present, the genome size of this microorganism is about 2.3 Mb with a G+C content of approximately 41%, and 33,640 reads totaling 23.629Mb covering theoretically 99.99% of the genome (14). The similarity between the DNA of the two subspecies, zooepidemicus and equi, is over 92%. However, their biological behaviors in horses differ significantly. Subspecies zooepidemicus is a commensal of equine nasopharynx and external genitalia and causes infections in various areas, while subspecies equi is a contributing agent that causes strangles (3, 18). In addition, S. zooepidemicus has Szp proteins that may have an antiphagocytic role similar to the M proteins in group A streptococci (GAS) in the case of causing human infection. The Szp proteins not only share structural similarities with the M proteins but also stimulate opsonic antibodies just like the M proteins do (13).
Cell structure and metabolism
Cell wall
In general, Lancefield group C streptococci (GCS) have cell walls consisting of group-specific carbohydrate and mucopeptide polymer (20). The group-specific antigens of GCS are polysaccharides that are made up of hexoamine and rhamnose. Unlike group A streptococci (GAS), GCS carbohydrate has a terminal antigenic determinant of N-acetyl-galactosamine (3).
Metabolism
Ecology
Streptococcus zooepidemicus is facultively anaerobic and host-associated. Its optimal temperature for growth is 37° C. It is a commensal of horses, and its host range also includes swine, cattle, poultry, and human (21). This microorganism can be found in various parts of horses and cattle, including nasopharynx, tonsils, respiratory tract, and the genital muscous membranes (24). In fact, subspecies zooepidemicus is the one bacterium that is most commonly recovered from wounds and abscesses, guttural pouches, transtracheal washes (TTW), and uterus of horses (12).
Pathology
Animals
Streptococcus zooepidemicus is a pathogen of animals primarily affecting horses, in whom it can cause diseases in the upper respiratory tract, uterus, umbilicus, and wounds (5). In cows, S. zooepidemicus can cause mastitis (3), an inflammation in mammalian breast. As for other animals such as rabbits and swine, it can cause septicemia (3), which is a systematic inflammatory response to infections. This microorganism has also caused fibrinous pericarditis, fibrinous pleuritis, and pneumonia in sheeps. The overall symptoms of infections caused by S. zooepidemicus include pyrexia (fever), serous to mucopurulent nasal discharge, dyspnea (short of breath).
Humans
In general, this pathogen rarely causes human infections (3, 4, 24). However, Streptococcus zooepidemicus has been reported to have caused a broad range of diseases, including septicemia and endocarditis (6), respiratory tract infection leading to nephritis (7), cervical lymphadenitis (8), septic arthritis and pneumonia (9), and meningitis (10, 11). Severe condition of these infections has caused deaths in some cases (9, 11, 18). In this one rare case, there is evidence of S. zooepidemicus involving in superantigen production, which contributed to the death of a 63-year-old man who died shortly after suffering from toxic shock-like syndrome (18).
Streptococcus zooepidemicus has also been reported to have caused poststreptococcal glomerulonephritis (PSGN), which is an acute inflammatory disorder of the glomerulus (24, 25). PSGN is usually developed in the aftermath of an acute throat or skin infection with a GAS strain; in this case, this disease caused by group C S. zooepidemicus was due to ingestion of food products made from unpasteurized milk. Interestingly, this disorder caused by subspecies zooepidemicus occurs predominantly in adults, whereas PSGN caused by GAS occurs in children (24, 25). Some of the clinical syndroms may include fever, edema, pharyngitis, hypertension, reduced renal function, and an increase in microalbuminuria (25, 26), a small amount of albumin present in urine.
Several theories have been proposed as an explanation for the initiation of PSGN; however, the main cause is still left undetermined (25). By activating the complement cascade via alternative pathway, PSGN causes glomerular inflammation by affecting the mesangial and endothelial cells. This activation will lead to an accumulation of fibrin in the glomeruli and a proliferation of parietal epithelial cells in Bowman’s capsule; it will also increase the entry of inflammatory cells, causing acute glomerular crescent formation. The glomerular capillaries will also be clogged due to the permeation of leukocyts and platelets. Along with the tissues being damaged and the filtration barrier of basement membrane being altered, these immune complexes may accumulate and fluid retention may occur, causing edema and vascular congestion (26).
Application to Biotechnology
Streptococcus zooepidemicus is used in bacterial fermentation for producing hyaluronic acid, which is a component that is widely used in ophthalmic surgery and as an ingredient in cosmetics (15). Derivatives of this mucopolysaccharide are used mainly as a source of skin filler for anti-aging and lip augmentation due to its ability to “form a gelatinous materials in the tissue space, acting as a lubricant and shock absorbent” (16, 17) and high water retention capacity (27). Hyaluronic acid has also been used in viscosurgery and as a lubricating supplement in arthritic joints.
Current Research
Enter summaries of the most recent research here--at least three required
References
Edited by Jenny Chong, student of Rachel Larsen
