Corynebacterium ulcerans

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Gram stain Culture

General information
- The pathogenic potential of coryneform bacteria has been underestimated
  
  C. ulcerans is , together with C. peudotuberculosis, the closest relative of C. diphteriae.
  
  Taxonomy
  Family: Corynebacteriaceae
  
  Natural habitats
  Part of the normal flora of humans and livestock.
  Is a veterinary pathogen that causes mastitis in cattle.
  
  Clinical significance
  Disease associated with C. ulcerans is rare, but if they are recovered from pseudomembranous material, the disease must be treated like a case of diphtheria.
  They can be transmitted from companion pets to humansa and cause significant infection.
Gram stain
- Gram positive rods,
  
  irregularly shaped (‘coryneforms”), they are arranged as single cells, in pairs, in V forms, in palisades, or in clusters with
  
  a so-called Chinese-letter appearance.
  
  Club-shaped rods are observed in true members of the genus Corynebacterium only
Culture characteristics
- Facultative anaerobic
  
  BA: colonies are some what dry, and gray-white, with some hemolysis, and are 1-2 mm in diameter after 24h.
  
  McConkey: no growth
  
  BBAØ: growth
Characteristics
References
- James Versalovic et al.(2011) Manual of Clinical Microbiology 10th Edition