Specimen Collection

Acceptable Specimens for Bacteriologic Analysis of Wounds

Superficial Wounds: order "wound culture"

Appropriate samples:

  • Aspiration of pus, or local irrigation fluid (using non-bacteriostatic saline), swab of purulence originating beneath the dermis
  • If swabs must be used, collect two, one for culture and one for Gram staining.

Inappropriate samples:

  • Swabs of surface material or specimens contaminated with surface material, irrigation fluid with saline containing preservative

Deep Wounds: order "abscess culture"

Appropriate samples:

  1. Tissue obtained by biopsy following cleansing of superficial debris using aseptic approach (3-4 mm punch biopsy specimen is optimal when quantitative cultures are ordered).
  2. Superficial necrotic tissues removed by curettage
  3. Deep tissues obtained by non-invasive method such as dermabrasion
  4. Deep aspirate of surface ulcer, sinus tract obtained by needle and syringe.

Inappropriate samples:

  • Specimens contaminated with surface material

Anaerobic culture: order "anaerobic culture"


  1. Aspirate/abscess:
    1. Clean site by wiping with sterile saline or 70% alcohol.
    2. Aspirate the area containing fluid, pus, or exudates by needle and syringe. Irrigation with a small amount of sterile non-bacteriostatic saline may be necessary.
    3. Aspirate saline into syringe and expel into a sterile screw cap tube.
  2. Tissue:
    1. Clean and debride the wound.
    2. Clean surface with sterile saline
    3. Obtain tissue sample from the deep part of the wound or base of the lesion/wound/ulcer.
    4. Never submit swab that has been rubbed over surface of the tissue.


  1. Tissue is placed into a sterile screw cup container. You can add several drops of sterile saline to keep small pieces of tissue moist. Alternatively, very small pieces of tissue can be placed into a small square of moist sterile gauze.
  2. Aspirate is placed into a sterile container.
  3. For anaerobic culture: Samples should be placed into oxygen free environment using anaerobic transport media. Large piece of tissue (< 1 cm3) can be placed only in sterile container without anaerobic transport media.