While it is common practice to take a swab of a wound for bacteriological analysis, often a specimen of purulent discharge or exudate is more helpful in obtaining an accurate diagnosis.
Purulent discharge can be sent on a swab or in a sterile universal container. Exudate should be sent in a sterile universal container. The request form should be clearly marked with the source of the purulent discharge or exude, eg
purulent discharge from sacral wound
exudate from abdominal wound
purulent discharge from a wound drain, etc
When a swab is taken, the following method should be employed:
A cotton tipped transwab should be lightly rubbed across the wound surface in a zigzag manner, simultaneously rotating the swab over the entire surface. The swab should then be returned to the swab container with the transport medium in it.
DO NOT SEND DRY SWABS
Where the wound is dry, the swab should be moistened with 0.9% sodium chloride (normal saline) or transport medium prior to swabbing the wound
The specimen should be taken as close to specimen collection times as possible. Take the specimen the next morning rather than store overnight.
All relevant information should be included on the request form including:
patient name, DOB, address, location (eg ward, POD, health Centre etc), wound site, cause of wound, systemic antibiotic therapy etc
On receipt of the specimen result it is important to remember that the result should not be interpreted in isolation, but used in conjunction with other clinical findings. If in doubt, contact your Infection Control Nurse or Microb iologist.
It is important to be aware of the different types of swabs and media available:
Trans swabs - common cotton tipped swab with transport medium.
Thin wire laryngeal/urethral swab - for specialist use
Charcoal swabs - where gonococcus is suspected.
Chlamydial swabs - where chlamydia is suspected.
Viral swabs - where a viral infection is suspected. Use a normal cotton tipped transwab to take the specimen, but place the tip of the swab into viral transport medium. This can be obtained from Bacteriology
References
Donovan S (1998), Wound Infection and wound swabbing. Professional Nurse, vol 13 no.11.
Wilson J (1995), Infection Control in Clinical Practice. Balliere Tindall, London
