Fungal Infections Flashcards
Name three fungal pathogens
Candida
Cryptococcus
Aspergillus
In what kinds of patients do fungi cause pathos?
It is an opportunistic species.
Immunocompromised patients-transplant, steroid, HIV, neonates and malignancy
ICU patients
Chronic lung disease patients
Which fungi species cannot get into the blood?
Aspergillus
What is mucocutaneous candidiasis?
Skin infection of candida mainly found in antibiotic use
Likes moist skin areas
Neonates under three months are prone to this infection as they don’t have a fully developed immune system. If it happens after three months old then it can be an indication of an immunological deficiency.
What tests are used to diagnose invasive candidiasis?
Blood culture or culture from normally sterile site β-d-glucan
PCR assays in development
In infants and children performance lower due to sampling issues
How is aspergillus transferred?
Spores in the air that are inhaled
What are three types of invasive aspergillus and in what type of patients are they found?
Acute pulmonary-neutropenic, post transplant and phagocyte defect patients
Chronic Pulmonary- chronic respiratory patients
Allergic Pulmonary- CF and asthma patients
What are the features of acute invasive aspergillosis?
Rapid and extensive hyphal growth
Thrombosis and haemorrhage
Angio-invasive and dissemination
Absent or non-specific clinical signs and symptoms
Persistent febrile neutropenia despite broad-spectrum antibiotics
In what conditions can pulmonary aspergilloma be found?
Conditions that leave cavities within the lungs Tuberculosis Sarcoidosis Bronchiectasis S. Aureus Pneumonia
What tests can be done to diagnose pulmonary aspergillosis?
Bronchi lavage or biopsy
Sputum Culture
Aspergillus specific IgG and IgE in chronic and allergic pulmonary aspergillosis
High resolution CT-chest
Molecular markers in blood: galactomannan and PCR-Aspergillus
How is Cryptococcus spread and where does it originate from?
Spread via air and inhaled
Found in bird faeces, organic matter and tree bark
In what patients is Cryptococcus common?
HIV patients
What is the presentation of Cryptococcus infection?
Ranges from asymptomatic to pneumonia
Meningoencephalitis in HIV patients
What are tests that can be done to diagnose Cryptococcus?
Cerebrospinal fluid: Indian Ink preparation (80% sensitivity), culture, high protein and low glucose, Cryptococcus antigen (lateral flow assay)
Blood: culture, Cryptococcus antigen
What are four types of antifungals and how do they work?
Amphotericin B formulations (iv)-acting on ergosterol> lysis
Azoles (iv, oral) - inhibiting ergosterol synthesis Echinocandins (iv) -inhibiting glucan synthesis Flucytosine (iv, oral) -inhibiting fungal DNA synthesis
