Fungemia-Introduction, Common fungi, Clinical Feature, Lab

Introduction

Table of Contents

Fungemia refers to the presence of fungi in the bloodstream, indicating systemic fungal infection. Candida species are most commonly responsible, but other yeasts and molds may also invade the bloodstream.

Fig. Blood fungal culture bottles containing a biphasic medium used for detecting fungal growth in fungemic patients

Fungemia is a medical emergency, especially in ICU patients, immunocompromised hosts, post-surgical cases, and neonates. Mortality rates can exceed 40% if diagnosis and treatment are delayed.

Common Fungi Causing Fungemia

Fungus	Features
Candida albicans	Most common; forms pseudohyphae
Candida glabrata	Less susceptible to azoles
Candida tropicalis	Common in neutropenic cancer patients
Candida parapsilosis	Catheter-associated infections
Candida auris	Emerging multidrug-resistant yeast
Cryptococcus neoformans	Seen in AIDS and transplant patients
Aspergillus spp.	Rare in blood cultures; usually seen in tissue
Fusarium spp.	May show true fungemia, especially in leukemia
Histoplasma capsulatum	Disseminates in AIDS, endemic areas

Clinical Features

Fever not responding to antibiotics
Chills, hypotension, tachycardia
Signs of sepsis or septic shock
Organ-specific signs: liver, kidney, CNS, retina, heart
Skin lesions (e.g., Candida tropicalis fungemia)
Dissemination in immunocompromised hosts

Laboratory Diagnosis

Test	Role
Blood culture (BACTEC, BacT/Alert)	Gold standard, but sensitivity is limited (~50%)
Fungal culture on SDA	Species identification from blood or catheter
Beta-D-glucan assay	Pan-fungal marker; elevated in many fungal infections
T2 Candida panel	Rapid, species-level detection directly from blood
MALDI-TOF MS	Rapid ID from positive culture
PCR-based panels	Detects fungal DNA; useful in early diagnosis
Antifungal susceptibility testing (AFST)	Guides targeted therapy

Fig. Various Candida species growth on Sabouraud dextrose agar (SDA)

Fig. Young Aspergillus colony morphology on Corn-meal agar (CMA)

Aspergillus structures in LPCB preparation of growth — Fig. Aspergillus structures in the LPCB preparation of growth

Treatment

Situation	Treatment
Stable, non-neutropenic	Fluconazole, if susceptible
Severely ill or neutropenic	Echinocandins (e.g., caspofungin, micafungin)
C. auris / resistant strains	Liposomal Amphotericin B, Echinocandins
Cryptococcal fungemia	Amphotericin B + Flucytosine, then Fluconazole
Aspergillus or Fusarium	Voriconazole or Amphotericin B

Duration: Continue antifungals for 14 days after the last positive blood culture and resolution of signs/symptoms.

Prevention

Strict catheter care and early removal of unnecessary lines
Judicious use of broad-spectrum antibiotics
Limit parenteral nutrition duration when possible
Use antifungal prophylaxis in high-risk ICU or neutropenic patients
Maintain good hand hygiene and hospital disinfection
Screen and isolate C. auris carriers to prevent outbreaks

Keynotes

Fungemia is a life-threatening condition, especially in critically ill patients.
Candida spp. are the leading cause; C. auris is an emerging global threat.
Early diagnosis, removal of the source, and prompt antifungal therapy are essential.
Culture and non-culture-based methods (T2, BDG) improve detection.
Prevention includes infection control, antifungal stewardship, and risk stratification.

Fungemia-Introduction, Common Fungi, Clinical Feature, Lab Diagnosis, Treatment, and Prevention