Identify wound infections and select targeted antibiotics through tissue cultures and laboratory analysis.
Wound cultures identify the specific bacteria causing infection and determine which antibiotics will be most effective. Without culture-guided therapy, antibiotic selection is guesswork—up to 40% of empiric (best-guess) antibiotics fail because they don't target the actual bacteria present. Cultures ensure you receive the right antibiotic the first time, avoiding treatment delays and antibiotic resistance.
A small piece of tissue is removed from the wound base using sterile technique. This provides the most accurate results because it samples bacteria deep in the tissue, not just surface contamination. Tissue cultures have 95% accuracy in identifying the true infecting organisms.
Best for: Deep infections, suspected osteomyelitis (bone infection), wounds not responding to antibiotics.
After cleaning the wound, a sterile swab is rotated over a 1cm² area while applying enough pressure to express fluid from deep tissue. More convenient than tissue biopsy and still provides good results when performed correctly. Accuracy is 75-85% when proper technique is used.
Best for: Routine wound surveillance, superficial infections, wounds with accessible wound bed.
Fluid is aspirated from the wound or surrounding tissue using a sterile needle and syringe. Useful for wounds with fluid pockets or abscesses. Provides better samples than surface swabs for deep infections.
Best for: Abscesses, wounds with purulent drainage, cellulitis evaluation.
Culture results typically take 48-72 hours and provide three critical pieces of information: (1) Organism identification—what bacteria, fungi, or other pathogens are present; (2) Quantitative bacterial count—infection is confirmed when >10⁵ (100,000) bacteria per gram of tissue; (3) Antibiotic sensitivity (susceptibility testing)—which antibiotics will kill the bacteria (sensitive), which won't work (resistant), and which are borderline (intermediate).
Gram-Positive:
Gram-Negative:
Not every wound requires a culture. Guidelines recommend cultures for: wounds with clinical signs of infection, wounds not healing despite appropriate treatment, wounds in immunocompromised patients, suspected osteomyelitis or deep tissue infection, wounds requiring antibiotic therapy, and post-surgical wounds with dehiscence or purulent drainage.
Medicare Part B covers wound cultures when medically necessary for diagnosing and treating wound infections. Coverage includes specimen collection, laboratory analysis, sensitivity testing, and interpretation. No prior authorization is required. The 20% coinsurance for wound culture is typically $10-30, fully covered by Medigap plans.