Most cases of IC (and subsequent invasive infection) are seen in preterm infants and critically ill or immunocompromised individuals. Certain medications, such as antibiotics and steroids, can also increase the risk of developing IC.
Immature immune systems, permeable intestines, invasive surgical procedures, hospitalization, and the use of broad-spectrum antibiotics make premature infants more prone to IC and invasive infections.[1] (A suppressed immune system also increases the risk of oral and esophageal candidiasis in people with HIV or cancer, but whether this translates to IC is unknown.)
Emerging research suggests that people with diabetes may also be more prone to IC, but these findings are complicated by the participants’ use of antifungals, antibiotics, and steroids (to control inflammation). Intestinal Candida counts can also be elevated as a result of swallowing oral Candida, and oral candidiasis (overgrowth of yeast in the mouth and throat) can occur in people who wear dentures or take the aforementioned medications.[2][3][4]
Healthy people may experience a relative increase in Candida compared to bacteria while taking antibiotics, but the actual numbers of Candida may not reach abnormally high levels consistent with IC. This has been connected to antibiotic-associated diarrhea, but a causal relationship hasn’t been established. Early studies detected Candida in the stools of people with antibiotic-associated diarrhea, but they lacked a control group, so no conclusions could be drawn. Evidence from a small, uncontrolled study showed that antibiotic-associated diarrhea occurred in patients regardless of Candida colonization. Though antifungal medications resolved diarrhea in five of the seven colonized patients, diarrhea also resolved without treatment in two patients and didn’t resolve until after antibiotics were ceased in the non-colonized patients.[5][6]