Page 127 - Journal of Special Operations Medicine - Winter 2015

Discussion
Figure 6 Gram stain E. cloacae and T. asahii have both been associated with
of an Enterobacter superficial skin infections. 20,21 However, coinfection of a
species. wound site with these two organisms has not been pre-
viously reported in the literature. Interestingly, members
of the Trichosporon genus have been sporadically impli-
cated in cases of synergistic infection with bacteria. 21,22
A synergistic wound infection is one in which two or
more organisms colonize a wound site and initiate a
web of interaction in which each organism cooperates
to support the growth, spread, or pathogenicity of the
others. Further, it has been shown that certain species
of Enterobacter are capable of locally blocking the im-
However, definitive identification of this organism re- mune response and inhibiting wound healing. 22,23 It is
quires more extensive biochemical testing. This is often tempting to speculate that the presence of E. cloacae at
accomplished with the aid of an automated identifica- the wound site allowed co-colonization with T. asahii,
tion system such as the Vitek 2 or the Microscan by and that when the viability of E. cloacae was disrupted
Siemens (http://www.siemens.com). These systems are by antimicrobial treatment, T. asahii was eliminated by
available in certain field-deployable laboratories, espe- host immunity allowing the wound to resolve.
cially those that are co-located with combat support
hospitals.
The present case serves as a reminder that both bacte-
rial and fungal pathogens are present in the external en-
Distinguishing Features of T. asahii vironment and that the small cuts and abrasions that
are often sustained by military personnel in the field can
T. asahii can be grown from clinical specimens on basic 24
blood agar medium or on a variety of media that have serve as portals of entry. In addition, this case is il-
been specifically designed for the recovery of fungi. lustrative of the fact that under certain circumstances,
17
Media capable of supporting fungal isolation are often unusual fungal pathogens can interact with common
available in field-deployed laboratories. T. asahii colo- bacterial pathogens, resulting in an exacerbated disease
nies range in color from yellow to cream and range in state. Laboratory support is essential for the diagnosis
texture from smooth to wrinkled. Biochemically, the and treatment of bacterial-fungal coinfections, since
most distinguishing feature of this organism is that it they cannot be identified based on clinical symptoms
is relatively unreactive. T. asahii is not capable of us- alone. Routine microscopy and basic stains are typi-
ing urea as a nitrogen source and or of fermenting the cally available in the microbiology section of the com-
sugars glucose, sucrose, lactose, galactose, or trehalose. bat support hospital. More extensive diagnostic systems
These data can be obtained with the aid of an auto- can augment these laboratories based on clinical need
mated microbial identification system. However, in the and knowledge of the local endemicity levels of environ-
deployed setting, presumptive identification will most mental pathogens derived from the medical intelligence
likely be obtained by microscopic evaluation of fungal preparation of the battlefield.
morphology. There are two primary stains that can be
used to identify this organism by microscopic morphol- References
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19
Budding yeasts are the single-celled form of the patho- 177:681–685.
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Recovery of Bacteria and Fungi From a Leg Wound 115