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Microbiology

Notes

  • Lower limb ulcers will always be colonised with bacteria so a positive culture result will not distinguish clinical infection from colonisation
  • If specimens are taken from ulcers, the debris on the ulcer should be removed and the ulcer should be cleaned with saline. A biopsy or, preferably, a needle aspiration of the edge of the wound should then be taken.
  • A less invasive irrigation-aspiration method may be preferred. Place the tip of a small needleless syringe under the ulcer margin and irrigate gently with at least 1 mL sterile 0.85% NaCl without preservative. After massaging the ulcer margin, repeat the irrigation with a further 1 mL sterile saline. Massage the ulcer margin again, aspirate approximately 0.25 mL of the fluid and place in a 30mL sterile bottle.
  • For skin mycoses skin scrapes are required
  • For suspected Mycobacterial skin infection a biopsy is recommended

Sample requirements

Standard charcoal transport swab

Black top charcoal swab

Required information

  • Relevant clinical details
  • Site of lesion
  • Nature of wound e.g. bite, boil, burn, cellulitis post operative, ulcer
  • If infection is recurrent
  • Diabetes
  • History of immune compromise/immunosuppression treatment
  • Recent, current and intended antibiotics

Storage/transport

Store and transport at room temperature. Samples should be transported to the laboratory with minimal delay.

Turnaround time

2 - 3 days