Army Burn Center (2003–2008), approximately 25% of the isolates from patients newly
admitted are of this type. However, in no case were these organisms found to be invasive, and
in those who died, infection with this organism was not found to be the most likely cause of
death (22). Instead, it was the finding of invasive fungus orK. pneumoniae, which were the
likely cause of death in those who succumbed to burn wound infection. This is in congruence
with the findings of Wong et al in Singapore, who showed that acquisition ofAcinetobacterwas
not associated with mortality. They did note, however, that acquisition ofAcinetobacterwas
associated with the number of intravenous lines placed and length of hospital stay (23), which
increased hospital costs (24). If treatment is deemed necessary, oftentimes this will require
intravenous colistin, which has a high toxicity profile. It was recently shown to have a 79%
response rate when used in the severely burned withAcinetobacterinfection, however, 14% of
these developed renal insufficiency (25). Of other historical note, the isolation of vancomycin-
resistantEnterococcusspecies was common in burn centers in the 1990s, but again, these
organisms were not found to cause invasive wound infection and were at best associative with
burn death, which was much more likely to be due to other causes and other organisms.
DIAGNOSIS OF BURN WOUND INFECTION
It is essential to identify microbial invasion of the burn wound at the earliest possible time to
prevent extensive microvascular involvement and hematogenous dissemination of the
infecting organisms to remote tissues and organs. The entirety of the wound should be
examined at the time of the daily wound cleansing to record any change in the appearance of
the burn wound. The most frequent clinical sign of burn wound infection is the appearance of
focal dark brown or black discoloration of the wound, but such change may occur as a
consequence of focal hemorrhage into the wound due to minor local trauma. The most reliable
sign of burn wound infection is the conversion of an area of partial thickness injury to full
thickness necrosis. Other clinical signs that should alert one to the possibility of burn wound
infection include unexpectedly rapid eschar separation, degeneration of a previously excised
wound with neoeschar formation, hemorrhagic discoloration of the subeschar fat, and
erythematous or violaceous discoloration of an edematous wound margin. Pathognomonic of
invasivePseudomonasinfection are metastatic septic lesions in unburned tissue (ecthyma
gangrenosum) (Fig. 2) and green discoloration of the subcutaneous fat by the pyocyanin
produced by the invading organisms (Fig. 3).
Figure 2 Ecthyma gangrenosum. The dark staining viable organisms shown as a “cuff” around the vessel can
readily enter the circulation and spread hematogenously to form nodular foci of infection in remote tissues and
organs.
364 Wolf et al.