The significance of Candida in the human respiratory tract: our evolving understanding

Abstract

Candida is an opportunistic pathogen and the most commonly isolated fungal genus in humans. Though Candida is often detected in respiratory specimens from humans with and without lung disease, its significance remains undetermined. While historically considered a commensal organism with low virulence potential, the status of Candida as an innocent bystander has recently been called into question by both clinical observations and animal experimentation. We here review what is currently known and yet to be determined about the clinical, microbiological and pathophysiological significance of the detection of Candida spp. in the human respiratory tract.

Keywords: Candida; colonization; respiratory tract.

Figure 1.

Candida colonization of the airway potentiates bacterial pneumonia in a rat model. Pseudomonas aeruginosa (A), E. coli (B) and S. aureus (C) were instilled into the tracheas of rats with and without prior instillation of C. albicans. With all three pathogens, C. albicans significantly worsened both bacterial burden and lung injury. Figure reproduced from Roux et al.