Background: A substantial proportion of patients become colonized with Candida spp. after
surgery, but only a minority subsequently develop invasive candidiasis. However, clinical
signs of severe infection manifest only late, presenting a challenge for diagnosis. Better knowledge
of the pathogenesis of candidiasis and new compounds have improved the prognosis
but also encouraged the emergence of non-albicans strains of Candida.
Diagnosis: Genotyping has confirmed that colonization from endogenous sources is responsible
for the majority of cases of invasive candidiasis. Nevertheless, even if a large proportion
of surgical patients becomes colonized, only a minority develop invasive candidiasis.
This subgroup is difficult to identify, and many clinicians treat systematically all colonized
patients, a practice that may select resistant strains. Biological tools have not improved the
diagnosis, and the threshold between colonization and infection remains to be determined.
The colonization index, defined as the ratio of the number of sites colonized by Candida
strains to the number of sites tested, is a useful tool.
Conclusions: After surgery, empiric treatment must be restricted to patients in whom the
dynamics of Candida colonization predict a very high risk of invasive candidiasis. Prophylaxis
should be limited to the small group of patients in whom its efficacy is proven.
