Review lectures Flashcards
List of things that cause opportunistic infections
Main ones:
Candida Albicans
Aspergillus fumigatus
Cryptococcus neoformans
Mucormycosis
Pneumocystis jiroveci
Others: Pseudomonas aeruginosa, JC polyomavirus, Acinetobacter baumanni, Toxoplasma gondii, Cytomegalovirus (HHV5), HHV8 Kaposi’s sarcoma, Cryptosporidium, Paecilomyces
Risk Factors for opportunistic Infections
– Acquired defects in cell-mediated immunity
– ->HIV/AIDS
– ->Anti-rejection therapies
–—–> Solid organ transplantation
–—–> Bone marrow transplantation
-–> Corticosteroids
– Neutropenia
–>Cancer patients following cytotoxic chemotherapy
–>Greatest risk in hematologic malignancies
– Inherited immunodeficiency disorders
–>Hyper-IgE syndrome
Candida Albicans as an opportunistic infection morphology
Germ Tubes, budding yeasts, pseudohyphae
Candida albicans opportunistic infection clinical manifestation
Thrush in immunocompromised (neonates, steroids, diabetes, AIDS),
vulvovaginitis (high pH, diabetes, use of antibiotics),
disseminated candidiasis (to any organ),
chronic mucocutaneous candidiasis.
Candida Albicans opportunistic infections treatment
Fluconazole
Aspergillus Fumigatus morphology opportunistic infection
45 angle branching septae
rare fruiting bodies
Mold with septate hyphae that branch at acute angles (. Not dimorphic.
Aspergillus Fumigatus clinical presentation immunocompromised infection
Ear fungus, lung cavity aspergilloma (“fungus ball”), invasive aspergillosis.
Cryptococcus Neoformans morphology
Heavily encapsulated yeast. Not dimorphic.
Narrow based unequal budding
Cryptococcus Neoformans clinical presentations in immunocompromised people
Cryptococcal meningitis, cryptococcosis.
Found in soil, pigeon droppings. Culture on Sabouraud’s agar. Stains with India ink. Latex agglutination for polysaccharide capsular antigen is more specific.
Cryptococcus Neoformans diagnosis
Culture on Sabouraud’s agar. Stains with India ink. Latex agglutination for polysaccharide capsular antigen is more specific.
Treat cryptococcal meningitis caused by cryptococcus neoformans
DOC is amphotericin B and flucytosine
Mucormycosis morphology
Mold with irregular nonseptate hyphae branching at wide angles (≥ 90°).
Clinical presentation of mucormycosis
Disease mostly in ketoacidotic diabetic and leukemic patients. Proliferates in blood vessels and enters brain. Rhinocerebral, brain abscesses. Headache, facial pain, potential CN involvement.
Pneumocystis jiroveci morphology
Yeast (originally classified as protozoan).
Pneumocystis jiroveci diagnosis
Silver stain of lung tissue shows sphorozites inside cysts.
Pneumocystis Jiroveci clinical presentation
Causes pneumonia (PCP). Most infections asymptomatic.
Immunosuppression (e.g. AIDS) predisposes to disease.
Pneumocystis Jiroveci treatment
Treat with TMP-SMX, pentamidine. Start prophylaxis when CD4 drops below 200 cells/mL in HIV patients.
Opportunistic infections with aids T cell counts
PCP
Toxoplasma, esophageal candidiasis, cryptococcal meningitis
CMV (typically retinitis), MAI complex
List of Agents of Bioterrorism
Bacillus anthracis (anthrax)
Clostridium botulinum
Yersinia pestis (plague)
Francisella tularensis (tularemia)
Variola major (smallpox)
Filoviruses (Ebola, Marburg)
Bacillus Anthrax morphology
Gram-positive spore-forming bacillus, facultative anaerobe
Bacillus Anthrax virulence factors
Only polypeptide capsule (D-glutamate).
Bacillus Anthrax clinical presentation
MCC of death: Inhalational anthrax –> two stages, inhalation of spores; flu-like sx rapidly progressing fever, pulmonary hemorrhage, mediastinitis, and shock
**Need to distinguish from pneumonia on clinical presentation!**
MCC of natural infection: Cutaneous anthrax –> results from deposition of organism onto non-intact skin; painless lesions, black eschar –> can progress to bacteremia and death
GI anthrax: results from ingestion of spores
Bacillus Anthrax epidemiology
Spores (inhaled, through broken skin, ingested), NO P2P. Wool-sorter’s disease. Patients in contact with animal skins from Africa.
Bacillus Anthrax treatment
Prompt antibiotic treatment (within 24 hrs)- PCN or Cipro or 90% mortality (in PNA)
Military personnel vaccinated
Yersenia Pestis Morphology
Gram negative rods; catalase (+), lactose (-), oxidase (-), safety pin appearance on peripheral blood smear
Yersenia Pestis clinical presentation
Plague: Bubonic (from flea or animal bite –> lymphadenopathy), Pneumonic (secondary to bubonic, septicemic or person to person), septicemic, meningitis, pharyngeal; 2-6 day incubation period
Pneumonic most likely in attack (P2P): fever, cough, dyspnea, bloody sputum
Yersenia pestis epidemiology
Resp droplets, flea bites, animal reservoirs (avoid animal tissue). Rats, prairie dogs
Yersenia Pestis treatment
Prompt antibiotic treatment within 24 hrs or 90% mortality (in pneumonia)
Variola Smallpox morphology
DNA virus; Orthopoxvirus family, Pox in Box
Infectious properties smallpox
Small inoculum; Aerosol spread
Clinical presentation of smallpox
Oral or respiratory mucosa –> Lymph Nodes –> asymp viremia to lymph organs (day 3 or 4) –> 2nd viremia (day 8) –> fever, malaise, delirium; 15-40% mortality
Smallpox diagnosis
Not chicken pox; all pustules are at the same stage
Smallpox epidemiology
Eradicated; 1 case is EMERGENCY –> disease eradicated in 1977
Not contagious until onset of rash (face/arms first)
treatment of smallpox
- Vaccine (vaccinia/cowpox) no longer given (can vaccinate up to 4 days post-exposure)
- Supportive care
TORCHES infections
Toxoplasma
Others: VZV, Parvovirus, HIV, HBV, HCV, and Bacterial sepsis (GBS, Listeria, E.coli)
Rubella
Cytomegalovirus
Herpes simplex
Enterovirus
Syphilis
