Systemic candidiasis

Candida species are present as normal flora in humans. Therefore, systemic candidiasis often has an endogenous source of infection, primarily the gastrointestinal (GI) tract. Although mucocutaneous disease is common, invasive disease is not, and the primary reason is that Candida species in general are unable to traverse intact epithelium. C glabrata and C tropicalis are known to colonize the GI tract, whereas C parapsilosis tends to colonize skin and intravascular catheters. C parapsilosis can also be found on the hands of healthcare workers.

Common Candida species associated with candidemia and systemic candidiasis include:

• C albicans

• C glabrata

• C tropicalis

• C parapsilosis

• C dubliniensis

• C krusei

• C kefyr

• C lusitaniae

• C auris.

Candida species have specific receptors that assist in binding to mucosal surfaces.[2]Pappas PG. Invasive candidiasis. Infect Dis Clin North Am. 2006 Sep;20(3):485-506. http://www.ncbi.nlm.nih.gov/pubmed/16984866?tool=bestpractice.com The primary event in the transition from superficial infection to systemic, invasive infection or colonization is a disruption of the epithelial barrier, usually through insertion of an intravascular catheter. Other routes of infection include disruption of the gut mucosa, for instance through ulceration due to chemotherapy in patients with neutropenia and, rarely, from focal infections such as pyelonephritis secondary to an ascending urinary tract infection. The alteration of normal flora by administration of broad-spectrum antibiotics allows the yeast to proliferate in high numbers during invasion.