Organism, chronology | Characteristics |
Commensal skin organisms (gram positive) result in early colonization of burns | - Streptococcus and Staphylococcus species primarily
- Other sources are upper respiratory tract and environment
- Topical antimicrobials help decrease colonization
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Gram-negative species dominant >5 days | - 2 to 4 days post-burn, gram-negative bacteria colonize wound
- Patient skin, upper respiratory tract, gastrointestinal tract, and hospital environment are typical sources
- Pseudomonas aeruginoasa, Acinetobacter baumannii, Escherichia Coli, Klebsiella pneumoniae, Enterobacter cloacae
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If gram-negative cover is initiated, yeast often appears | - Yeast and fungi colonization follows
- Majority are Candida species, other fungi are increasing in frequency
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Finally, more resistant bacteria and fungi invade the wound | - MRSA, VRE, multi-drug-resistant Pseudomonas and Acinetobacter species, and fungi
- Usually secondary to broad-spectrum antibiotics, or inadequate host response or therapeutic measures (excision burn, topical and systemic antibiotics)
- Transition from colonization to invasion
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