An evaluation of burn wound quantitative microbiology. I. Quantitative eschar cultures.

The reliability of quantitative data from burn wound biopsy cultures was investigated. This was done by comparing the recovery of microorganisms from a series of burn wound eschar biopsy specimens that were each divided into two approximately equal portions and cultured in parallel. The results indicate that a microorganism present in the burn wound site in any quantity has at least a 25% chance of being missed by a single quantitative eschar culture. For recovery levels corresponding to quantitative breakpoints that have been proposed to be predictive of burn wound sepsis, only 38% of paired quantitative results agreed within the same log10 unit, and 44% differed by +/- 2 log10 units or more. These findings indicate that quantitative results derived from burn wound biopsy cultures are unreliable and may be significantly misleading when used for decision-making relative to patient care.