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Category:Corynebacterium species (view source)
Revision as of 12:31, 12 May 2010
, 12:31, 12 May 2010Created page with '===Overview=== *Common inhabitants of skin and mucous membranes of animals *Opportunistic infections *Cause pyogenic infections *Most species host specific ===Characteristics=…'
===Overview===
*Common inhabitants of skin and mucous membranes of animals
*Opportunistic infections
*Cause pyogenic infections
*Most species host specific
===Characteristics===
*Small, tough, Gram positive rods
*Pleomorphic
*Cluster together to resemble Chinese characters - coryneform morphology
*Known as diphtheroids
*Catalase positive, oxidase negative
*Facultative anaerobes
*Require enriched media for growth
*Non-motile
===Pathogenesis and pathogenicity===
*Pyogenic causing suppurative infections except for ''C. bovis''
*''C. pseudotuberculosis'':
**Facultative intracellular pathogen inside macrophages
**Cell wall lipid
**Produces a phospholipase toxin which hydolyses sphingomyelin in mammalian cell membranes
**Phospholipase may enhance survival and multiplication in host in early stages
*''C. renale''
**Urinary tract pathogens
**Produce urease and hydrolyse urea
**Possess fimbriae for attachment to urogenital mucosa
**Infection when immunity reduced or following tissue damage during parturition
===''Corynebacterium pseudotuberculosis''===
*Caseous lymphadenitis:
**''C. pseudotuberculosis'' carried on skin of sheep
**Non-nitrate-reducing biotype
**Infection follows tissue trauma such as shearing wounds
**Incubation period 3 months
**Chronic suppurative infection of sheep, goats and occasionally cattle
**Abscessation of superficial and internal lymph nodes if haemtogenous spread occurs
**Caseous abscesses with green colour and onion ring appearance
**Ill thrift and pneumonia may occur
**Condemnation of carcasses and hides
**Infection spread by pus from abscesses, and oculonasal secretions
**Organism survives in environment for several months
**Sandwich ELISA detects circulating antibodies to phospholipase toxin
**Control: importation measures including screening; culling of infected sheep, stict hygiene; inactivated vaccine
*Ulcerative lymphangitis:
**Nitrate reducing biotype
**Disease in horses and cattle
**Infection through skin wounds
**Lymphangitis of lower limbs or abscessation in pectoral region
**Slow onset, usually becomes chronic
**Affected lymphatic vessels swollen and firm with nodules
**Oedema in affected limbs
**Ulcerative nodules exude thick green pus
**Lymphangitis and lymphadenitis in cattle with abscesses as well as coronary band lesions causing lameness
**Antibiotic treatment and topical iodophore shampoo
*May cause [[Muscles Inflammatory - Pathology#Abscesses|myositis]]
*Involved in [[Bacterial skin infections - Pathology#Deep pyoderma|deep pyoderma]]
===''Corynebacterium renale''===
*''C. renale, C. pilosum, C. cystitidis''
*Found in the vulva, vagina and prepuce of normal cattle
*Bovine pyelonephritis
**Stress of parturition and short urethra predisposes cows to urinary tract infection
**Cystitis especially with ''C. cystitidis
**Ascending infection from bladder through ureters causes pyelonephritis
**Fever, anoexia, decreased milk production
**Restlessness; kicking of abdomen indicate renal pain
**Dysuria, arched back, bloody urine
**Chronic infection causes extensive renal damage
**Enlarged ureters and kidneys palpated per rectum
**Culture from urine; protein and red blood cells in urine
**Antibiotics e.g. penicillin for at least three weeks
*Ulcerative balanoposthitis (pizzle rot):
**Common in Merino sheep and Angora goats
**Ulceration around prepucial orifice with brown crust, and occasionally on vulva of ewes
**Bacteria hydrolyse urea to ammonia which causes mucosal irritation and ulceration
**High urine urea level, from high protein intake may predispose to condition
**High oestrogen levels in pastures also predisposes
**Castration and heavy wool around the prepuce are risk factors
===''Corynebacterium bovis''===
*Subclinical mastitis in cattle
*Found in teat cistern
*Causes mild neutrophil response in teat canal of healthy dairy cows and may protect against invasion from more pathogenic bacteria
===Diagnosis===
*Samples include pus, exudate, affected tissues and urine
*Presence of coryneform organisms in smears
*Culture on blood agar, selective blood agar and MacConkey agar
*Do not grow on MacConkey
*Colony characteristics:
**''C. bovis'': lipophilic bacterium; small, white, dry, non-haemolytic colonies on plates inoculated with bovine milk
**''C. kutscheri'': white colonies; occasionally haemolytic
**''C. pseudotuberculosis'': small, white coloniess surrounded by narrow zone of complete haemolysis; colonies become dry and cream-coloured
**''C. renale'': small, non-haemolytic colonies after 24 hours; pigment produced after 48 hours
*Biochemical reactions:
**Certain strains of ''C. pseudotuberculosis'' reduce nitrates
**All pathogenic strains except ''C. bovis'' produce urease
*Enhancement of haemolysis produced by ''C. pseudotuberculosis'' when inoculated across a streak of ''Rhodococcus equi''[[Category:Bacteria]][[Category:Gram_positive_bacteria]]
*Common inhabitants of skin and mucous membranes of animals
*Opportunistic infections
*Cause pyogenic infections
*Most species host specific
===Characteristics===
*Small, tough, Gram positive rods
*Pleomorphic
*Cluster together to resemble Chinese characters - coryneform morphology
*Known as diphtheroids
*Catalase positive, oxidase negative
*Facultative anaerobes
*Require enriched media for growth
*Non-motile
===Pathogenesis and pathogenicity===
*Pyogenic causing suppurative infections except for ''C. bovis''
*''C. pseudotuberculosis'':
**Facultative intracellular pathogen inside macrophages
**Cell wall lipid
**Produces a phospholipase toxin which hydolyses sphingomyelin in mammalian cell membranes
**Phospholipase may enhance survival and multiplication in host in early stages
*''C. renale''
**Urinary tract pathogens
**Produce urease and hydrolyse urea
**Possess fimbriae for attachment to urogenital mucosa
**Infection when immunity reduced or following tissue damage during parturition
===''Corynebacterium pseudotuberculosis''===
*Caseous lymphadenitis:
**''C. pseudotuberculosis'' carried on skin of sheep
**Non-nitrate-reducing biotype
**Infection follows tissue trauma such as shearing wounds
**Incubation period 3 months
**Chronic suppurative infection of sheep, goats and occasionally cattle
**Abscessation of superficial and internal lymph nodes if haemtogenous spread occurs
**Caseous abscesses with green colour and onion ring appearance
**Ill thrift and pneumonia may occur
**Condemnation of carcasses and hides
**Infection spread by pus from abscesses, and oculonasal secretions
**Organism survives in environment for several months
**Sandwich ELISA detects circulating antibodies to phospholipase toxin
**Control: importation measures including screening; culling of infected sheep, stict hygiene; inactivated vaccine
*Ulcerative lymphangitis:
**Nitrate reducing biotype
**Disease in horses and cattle
**Infection through skin wounds
**Lymphangitis of lower limbs or abscessation in pectoral region
**Slow onset, usually becomes chronic
**Affected lymphatic vessels swollen and firm with nodules
**Oedema in affected limbs
**Ulcerative nodules exude thick green pus
**Lymphangitis and lymphadenitis in cattle with abscesses as well as coronary band lesions causing lameness
**Antibiotic treatment and topical iodophore shampoo
*May cause [[Muscles Inflammatory - Pathology#Abscesses|myositis]]
*Involved in [[Bacterial skin infections - Pathology#Deep pyoderma|deep pyoderma]]
===''Corynebacterium renale''===
*''C. renale, C. pilosum, C. cystitidis''
*Found in the vulva, vagina and prepuce of normal cattle
*Bovine pyelonephritis
**Stress of parturition and short urethra predisposes cows to urinary tract infection
**Cystitis especially with ''C. cystitidis
**Ascending infection from bladder through ureters causes pyelonephritis
**Fever, anoexia, decreased milk production
**Restlessness; kicking of abdomen indicate renal pain
**Dysuria, arched back, bloody urine
**Chronic infection causes extensive renal damage
**Enlarged ureters and kidneys palpated per rectum
**Culture from urine; protein and red blood cells in urine
**Antibiotics e.g. penicillin for at least three weeks
*Ulcerative balanoposthitis (pizzle rot):
**Common in Merino sheep and Angora goats
**Ulceration around prepucial orifice with brown crust, and occasionally on vulva of ewes
**Bacteria hydrolyse urea to ammonia which causes mucosal irritation and ulceration
**High urine urea level, from high protein intake may predispose to condition
**High oestrogen levels in pastures also predisposes
**Castration and heavy wool around the prepuce are risk factors
===''Corynebacterium bovis''===
*Subclinical mastitis in cattle
*Found in teat cistern
*Causes mild neutrophil response in teat canal of healthy dairy cows and may protect against invasion from more pathogenic bacteria
===Diagnosis===
*Samples include pus, exudate, affected tissues and urine
*Presence of coryneform organisms in smears
*Culture on blood agar, selective blood agar and MacConkey agar
*Do not grow on MacConkey
*Colony characteristics:
**''C. bovis'': lipophilic bacterium; small, white, dry, non-haemolytic colonies on plates inoculated with bovine milk
**''C. kutscheri'': white colonies; occasionally haemolytic
**''C. pseudotuberculosis'': small, white coloniess surrounded by narrow zone of complete haemolysis; colonies become dry and cream-coloured
**''C. renale'': small, non-haemolytic colonies after 24 hours; pigment produced after 48 hours
*Biochemical reactions:
**Certain strains of ''C. pseudotuberculosis'' reduce nitrates
**All pathogenic strains except ''C. bovis'' produce urease
*Enhancement of haemolysis produced by ''C. pseudotuberculosis'' when inoculated across a streak of ''Rhodococcus equi''[[Category:Bacteria]][[Category:Gram_positive_bacteria]]