Contamination with overlying colonizing organisms:
(1) failure to decontaminate surface
(2) failure to protect specimen collection device from adjacent surfaces
(2a) use of a swab with a diameter too large for the opening
(2b) failure to aspirate available material with a protected catheter or needle
(3) contamination of sterile collection device (failure to maintain sterile collection system)
Failure to culture causative organism:
(1) failure to collect material from the abscess
(2) failure to perform anaerobic culture
(3) failure to perform mycobacterial culture
(4) failure to perform fungal culture
(5) exposure to chemical used for surface decontamination
Correlation of culture results with the direct specimen Gram stain (a smear made at the time of specimen collection) can be very helpful in determining the quality of the specimen and the significance of the isolates.
