Candida

Background

• Most common medically-important genus of yeast

Microbiology

• Budding yeast
• Human pathogens include:
  • Candida albicans
  • Candida dubliniensis
  • Candida glabrata
  • Candida tropicalis
  • Candida parapsilosis
  • Candida krusei
  • Candida guilliermondii
  • Candida auris
• Species that only rarely cause disease in humans include: Candida albidus, Candida catenulate, Candida chiropterorum, Candida ciferrii, Candida famata, Candida haemulonii, Candida humicola, Candida inconspicua, Candida kefyr, Candida lambica, Candida lipolytica, Candida norvegensis, Candida pelliculosa, Candida pintolopesii, Candida pulcherrima, Candida rugosa, Candida utilis and Candida zeylanoides

Clinical Manifestations

Fungemia

• See also candidemia
• Risk factors include colonization, gastrointestinal mucosal disruption, total parenteral nutrition, and immunosuppression

Oropharyngeal Candidiasis

• Risk factors include immunosuppression including diabetes, inhaled corticosteroids, and denture used

Esophageal Candidiasis

• Risk factors include immunosuppression

Vulvovaginal Candidiasis

• Risk factors include colonization from recent antibiotic use, immunosuppression including diabetes, use of oral contraceptives, and pregnancy

Candidal Infection of Skin and Nails

• Risk factors include moisture and occlusion, immersion in water, and peripheral vascular disease
• Candidal skin infections can occur in moist body parts especially where skin occludes, and presents as a pruritic, erythematous rash with a poorly-defined edge that may have vesicles or pustules
• Candidal onychomycosis is most commonly caused by Candida albicans and Candida parapsilosis, followed by Candida glabrata and Candida guilliermondii
• Paronychia can be caused by Candida albicans

Cutaneous Congenital Candidiasis

• Occurs in premature infants
• Presents as a generalized macular erythematous rash
• May become pustular, papular, or vescicular
• May desquamate

Chronic Mucocutaneous Candidiasis

• Occurs in people with T-cell defects, often related to primary immunodeficiency

Urinary Tract Infection

• Occurs in patients with diabetes, with indwelling urinary catheters, urinary obstruction, or recent urological procedures
• True infection most commonly occurs as a result of hematogenous dissemination rather than ascending infection or in patients who are immunocompromised
• Candida species are a common contaminant of urine cultures, especially in women with vulvovaginal candidiasis
• They can also asymptomatically colonize the urinary system, causing asymptomatic candiduria

Pulmonary Infections

• Can occur from hematogenous spread
• Primary, isolated candidal pneumonia is very rare, and is associated with aspiration pneumonia
• Empyema can occur in patients with severe underlying diseases
• Candidal mediastinitis can happen after thoracic surgery, and is associated with high mortality
• Laryngitis or epiglottitis is rare and life-threatening

Endocarditis

• Most common fungal cause of infective endocarditis
• Risk factors include cardiac surgery, prior endocarditis, valvular disease, prosthetic valve, long-term central line, and intravenous drug use
• Clinically presents like bacterial endocarditis, but has a higher risk of embolic events
• Most commonly involves aortic and mitral valves

Pericarditis and Myocarditis

• Risk factors include thoracic surgery or immunosuppression
• Myocarditis is rare, occuring via hematogenous spread in immunocompromised patients
  • Can have heart block and shock
• Pericarditis is also rare, often occurs after thoracic surgery, from hematogenous spread, or from contiguous spread

CNS Infections

• Occurs following neurosurgery or with ventricular shunt infection or with hematogenous spread
• Can cause brain abscess, meningitis, or stroke
• Meningitis can be difficult to diagnose, and requires a large volume of CSF for improved sensitivity

Ocular Candidiasis

• From direct inoculation after ocular surgery or trauma, or with hematogenous spread
• Includes keratitis, chorioretinitis, and endophthalmitis

Bone and Joint Infections

• Rare cause of osteomyelitis and septic arthritis
• Usually from hematogenous spread; other risk factors include surgery, trauma, intraarticular injection, or diabetic foot infection
• Symptoms may only become apparent months after initial hematogenous seeding, especially with vertebral osteomyelitis

Intraabdominal Infection

• Risk factors include abdominal perforation, abdominal surgery, solid organ transplantation, anastomotic leaks, pancreatitis, and peritoneal dialysis

Investigations

• Urine culture if concern for cystitis
• Blood culture
  • Never ignore candidemia!
  • Requires an ophthalmology consult to rule out endophthalmitis (1-3% of cases)
  • Echocardiogram if IVDU or prosthetic valve
• Germ tube test (GTT)
  • If positive, indicates Candida albicans or Candida dubliniensis
  • Identifies fluconazole-sensitive Candidae

Management

• Superficial infections involving skin or mucosa can be treated with either topical preparations or low-dose oral fluconazole
• Invasive infections should be treated with an echinocandin until species and susceptibilities are available
  • See also management of candidemia

Species	Resistance pattern
Candida albicans	Generally fluconazole-susceptible
Candida dubliniensis	Generally fluconazole-susceptible
Candida parapsilosis	Generally fluconazole-susceptible
Candida glabrata	Often fluconazole resistant, or dose-dependent
Candida tropicalis	Generally fluconazole-susceptible
Candida krusei	Inherent fluconazole resistance
Candida lusitaniae	Often amphotericin resistant but fluconazole-susceptible

• See also Antifungal spectrum of activity and Pharmacology of Systemic Antifungal Agents, CID 2006