Difference between revisions of "Category:Corynebacterium species"

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(Created page with '===Overview=== *Common inhabitants of skin and mucous membranes of animals *Opportunistic infections *Cause pyogenic infections *Most species host specific ===Characteristics=…')
 
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===''Corynebacterium pseudotuberculosis''===
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===''[[Corynebacterium pseudotuberculosis]]''===
  
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*Caseous lymphadenitis:
 
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**''C. pseudotuberculosis'' carried on skin of sheep
 
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**Non-nitrate-reducing biotype
 
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**Infection follows tissue trauma such as shearing wounds
 
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**Incubation period 3 months
 
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**Chronic suppurative infection of sheep, goats and occasionally cattle
 
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**Abscessation of superficial and internal lymph nodes if haemtogenous spread occurs
 
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**Caseous abscesses with green colour and onion ring appearance
 
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**Ill thrift and pneumonia may occur
 
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**Condemnation of carcasses and hides
 
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**Infection spread by pus from abscesses, and oculonasal secretions
 
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**Organism survives in environment for several months
 
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**Sandwich ELISA detects circulating antibodies to phospholipase toxin
 
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**Control: importation measures including screening; culling of infected sheep, stict hygiene; inactivated vaccine
 
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*Ulcerative lymphangitis:
 
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**Nitrate reducing biotype
 
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**Disease in horses and cattle
 
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**Infection through skin wounds
 
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**Lymphangitis of lower limbs or abscessation in pectoral region
 
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**Slow onset, usually becomes chronic
 
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**Affected lymphatic vessels swollen and firm with nodules
 
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**Oedema in affected limbs
 
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**Ulcerative nodules exude thick green pus
 
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**Lymphangitis and lymphadenitis in cattle with abscesses as well as coronary band lesions causing lameness
 
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**Antibiotic treatment and topical iodophore shampoo
 
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*May cause [[Muscles Inflammatory - Pathology#Abscesses|myositis]]
 
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*Involved in [[Bacterial skin infections - Pathology#Deep pyoderma|deep pyoderma]]
 
  
  

Revision as of 12:31, 12 May 2010

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

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

Pages in category "Corynebacterium species"

The following 5 pages are in this category, out of 5 total.

A

C

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