Infection Patients with poorly controlled diabetes mellitus are prone to bacterial and fungal infections because of adverse effects of hyperglycemia on granulocyte and T-cell function. In addition to an overall increase in risk for infectious diseases, individuals with diabetes have an increased susceptibility to mucocutaneous fungal infections (eg, oral and vaginal candidiasis) and bacterial foot infections (including osteomyelitis), which are typically exacerbated by lower extremity vascular insufficiency and diabetic neuropathy.