Difference between revisions of "Corynebacterium species"

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#REDIRECT[[:Category:Corynebacterium species]]
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{{toplink
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|backcolour =
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|linkpage =Bacteria
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|linktext =BACTERIA
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|pagetype=Bugs
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}}
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<br>
 +
===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
 +
**Dysurea, 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 aroung 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''

Revision as of 16:04, 22 September 2008

Infectious agents and parasitesWikiBugs Banner.png
BACTERIA



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 myositis
  • Involved in 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
    • Dysurea, 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 aroung 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
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