Opportunistic fungal infections

Question 1

only an issue in

Answer 1

compromised immune systems

Question 2

Candida albicans

Answer 2

Native flora

-infections through things that penetrate skin

Question 3

different risks for candida albicans

Answer 3

intertriginous risk-> moisture, friction, heat, obesity, antibiotics
onychomycosis risk-> continuous wetting
vulvovaginal candidiasis risk-> low vaginal pH, dm, sexual contact, antibiotics
neonatal candidiasis risk-> low birth weight/age, antibiotic drugs
oesophageal risk-> AIDS, severe IC’s
gastrointestinal risk-> hematological malignant
peritionitis risk-> colonization of catheter
urinary tract candidiasis risk-> antibiotic candiduria treatment, prolonged catheterization with antibiotic treatment diabetes, glycosuria

Question 4

candida albicans diagnosis

Answer 4

skin scraping, mucosal scraping, vaginal secretions, culturing blood fluids

• observe budding yeast in gram stain
• Nystatin/miconazole (topical)
• itraconazole, fluconazole, amphotericin B

Question 5

candida albicans clinical

Answer 5

orophaygneal: thrush
-pseudomembranous oropharyngeal->white/gray plaques
-erythematous (atrophic)->hard palate, tongue
-angular cheilitis-> burning/dry mouth, loss of taste, different from HSV: mucocutaneous junction and vesicles
cutaneous candidiasis:
-intertriginous->axillae, groin, rash, satellite lesions on healthy skin
-diaper rash
-interdigitalis->skin/finger/ toe web spaces
-candidal onchomycosis->chronic-> anycholysis
-vulvovaginal candidiasis and balanitis
-chronic mucocutaneous candidiasis->skin, nails
-neonatal candidiasis->eyes, lungs, kidneys, CNS
-congenital candidiasis->abortion
-oesphageal candidiasis->dysphagia, speticemia
-gastrointestinal candidiasis->ulcerations in stomach
-broncopulmonary candidiasis->diffuse pneumonia
-peritonitis-> cloudy peritoneal dialysate
-urinary tract candidiasis->
-candidemia/dissemination-> yeast in blood

Question 6

Cryptococcus neoformans and bacillospora

Answer 6

• neoformans (A,D)-> birds excreta
• bacillospora (B,C)-> thick polysaccharide capsule and melanin in cell wall when grown on catechols (eucalyptus trees, tropical and subtropical climates)
• Inhale spores->pulmonary alveoli->phagocytosed by MQ-> anti-phagocytic capsule, melanin (oxidative protection)-> cellular and humoral immune reaction from host-> tissue destruction from organism burden
• CYSTS cluster in yeast
• Pulmonary, acute respiratory distress syndrome
• disseminated: CNS (meningitis, meningoencephalitis), skin
• detect under microscope with India ink
• serology: capsular antigen
• culture in a couple days
• fluconazole, itraconazole (IC’s)
• Immune deficient:amphotericin B, flu cytosine

Question 7

Aspergillus fumigatus

Answer 7

-90% present at A. fumigatus
minorly present as-> A. flavus, niger, terreus
-inhale conidia-> mucous layer of cilia respiratory tract, MQ, Neutrophils-> engulf->produce toxic metabolites
-IC’s-> granuloma (hyphae observed), vascular invasion-> hemorrhage/necrosis of lung tissue
-common in soil, insulating material, air conditioning, heating vents
-Allergic bronchopulmonary
-pulmonary aspergiloma (hyphae abundant)
-invasive pulmonary (severe pneumonia)

Question 8

Absidia, Rhizomucar,Rhizpus, Mucor

Answer 8

-sinuses, brain, lungs, in IC’s, or diabetics
-soil fungi, decaying vegetation
-spores inhaled-> germinate-> invade tissue/blood vessels-> tissue necrosis (face, lungs, GI, skin)-> rapid death
-Mucormycosis:
rhinocerebral mucormycosis (nose/sinuses)-> diabetics
pulmonary mucormycosis: severe pneumonia
cutaneous mucomycosis: hardened area skin with blackened center
-CT scan, MRI, tisue specimen analyzed for DX
-surgery

Question 9

Pneumocystis jiroveci

Answer 9

VERY COMMON IN THOSE WITH AIDS

• thick walled trophozoites, thick walled cysts
• torphozoite from asexual developemt-> replicate asexually via binary fission or sexually via conjugation (meosis then mitosis)-> precyst-> mature cysts with 8 spores
• corticosteroid therapy, transplant recipients, antineoplastic, transplant recipients
• Pneumocystis jiroveci pneumonia-> pneumonia
• trophozoies/sporozoites inhaled-> CD4 T cells need for control-> respiratory failure-> hypoxemia , respiratory alkalosis, changes in lung capacity

Question 10

Pneumocystis jiroveci diagnosis

Answer 10

aquire organism via bronchoalveolar lavage, lung biospy, induced sputum
-stain with giemsa, toludine blue, methenamine silver, calcofluor white
-X-ray of chest
-treatment: sulphamehoxazole (bactrim)-> block folic acid production
clotrimoxazole (septra) trimethorpim, (TMP-SMX)
pentamidine isothionate
prophylaxis-> TMP-SMX, aerolized pentamidine