Overview
MDL Test Name
Wound Culture – Aerobic, Gram Stain
MDL Test Code
WNDA_CULT
Ask at Order Questions
Was the wound specimen collected during surgery?
Specimen Source
Wound (specify source/site)
Specimen Requirements
Container/Tube
ESwab - all swab collections
Sterile Container - all aspirations/drainage
Specimen Volume (minimum)
ESwab
N/A (swab specimen)
Must have swab present in container
Sterile Container
0.5mL
Sample Stability Time
48 hours
Transport/Storage Conditions
Refrigerated (2 – 8°C)
Ambient (20 – 25°C)
Patient Preparation / Collection Instructions
Cleanse skin or mucosal surfaces. For closed wounds and aspirates, disinfect as for a blood culture collection with 2% chlorhexidine or 70% alcohol followed by an iodine solution. Remove iodine with alcohol prior to specimen collection. For open wounds, debride (if appropriate), and thoroughly rinse with sterile saline prior to collection. Sample viable infected tissue, rather than superficial debris.
Gently roll the swab over the wound's surface approximately five times, focusing on the area where there is evidence of pus or inflamed tissue. Abscesses that are closed off and not yet draining externally should be aspirated and the pus (purulent fluid) sent for culture. Aspirate infected material with a needle and syringe.
Drainage fluids for culture should not be collected from the bag (due to organism overgrowth), it should be collected by direct aspiration of fluid from the area being drained or by aspiration of fresh fluid in the drainage tube after decontaminating the surface of the device.
Performance
Days Performed
Daily; Monday – Sunday
Report Available (TAT) – (Once received at MDL)
4 – 6 days
Specimen Retention Time
7 days
Method Description
Conventional aerobic bacterial culture technique with selective and non-selective media.
Identification methods (when appropriate) may include any of the following: conventional biochemical testing, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, and commercial identification panels.
Susceptibility testing (when appropriate) may include minimal inhibitory concentration (MIC) (broth microdilution or gradient strip diffusion) or disk diffusion.
Reference Values
No growth of pathogens.
Cautions
Antibiotics administered prior to sample collection may negatively affect the recovery of organisms associated with infection. Preferably collect specimen prior to initiation of therapy and only from wounds that are clinically infected or deteriorating or that fail to heal over a long period.
Many wound infections are polymicrobic and the isolation of an organism in culture may or may not correlate with infection of the wound.