Zygomycetes Flashcards
What are the most common pathogens int he zygomycetes family?
Rhizopus
What is the common name for the infections caused by the zygomycetes family?
Mucormycosis.
What is the most common cause of rhino cerebral infections?
Rhizopus arrhizus
What are the distinguishing growth characteristics of Zygomycetes?
They have large diameter hyphae, and non-septate hyphae with 90 degree branching
How do zygomycetes sporulate?
Asexually in the sporangium.
What temp do zygomycetes grow well at?
Not at 37 C! This is important!
Where do zygomycetes grow in the environment?
On living and dead organic matter.
How are zygomycetes transmitted?
Inhalation of spores, traumatic implantation of spores, and ingestion of spores
What populations are at a high risk for zycomycosis?
Those that are immunocompromised: patients with uncontrolled diabetes, especially w/ ketoacidosis, neutropenic cancer puts, those that use long term steroids or long term VORICONAZOLE.
What conditions are risks for the GI form of zygomycosis?
Iron overload or extreme malnutrition.
What is the primary pathogenesis of zygomycetes?
ANGIOINVASION
What are the 5 different diseases caused by zygomycetes?
Rhinocerebral zygomycosis, pulmonary zygomycosis, disseminated zygomycosis, cutaneous zygomycosis, and GI zygomycosis
What is the most common presentation of zygomycosis?
Rhinocerebral zygomycosis.
What is the characteristic presentation of rhino cerebral zygomycosis
Involves the nose, eye, sinuses, brain, meninges.
Pt presents w/ fever, facial and/or eye pain, building of eye and progressive signs of involvement of orbital structures. black necrotic lesions in mouth.
What is a characteristic sign of rhino cerebral zygomycosis?
Black necrotic lesions on the hard palate and nasal mucosa.
What species can cause rhino cerebral disease in immunocompetent individuals?
Apophysomyces elegans
How does a patient present with pulmonary zygomycosis?
Fever, cough, chest pain, SOB, hemoptysis, segmental consolidation and possible cavitation
What are the complications of angioinvasion from disseminated mucormycosis?
tissue infarction and multigrain failure.
Where does disseminated zygomycosis spread?
Everywhere! Predominantly the CNS, but also the liver, spleen, heart, bone, kidneys and skin.
What is the pt presentation w/ GI zygomycosis?
Abdominal pain or distention, nausea, vomiting, and diarrhea. May mimic an intra-abdominal abscess.
Diagnosis of zygomycosis:
- obtain appropriate samples
- do direct microscopic examination and look for characteristic zygomycetes
- Do culture
No serological tests are available, Beta-glucan and galactomannan tests are negative
Treatment for zygomycosis
Aggressive surgical measures
Aggressive measures to control underlying conditions
Aggressive antifungal therapy
What drugs are zygomycetes inherently resistant to?
Azoles and echinocandins
What is the mainstay of anti fungal therapy for zygomycosis?
Lipid formulation of Ampho B + possibly posaconazole.
