Pneumonia Causing Organisms Flashcards
What bugs are always regarded as significant or causative of pneumonia?
- Strept. pneumonia
- Legionella
- Influenza viruses
- Mycobacterium tuberculosis
- C. psittaci
- Agents of bioterrorism: B. anthracis, Yersinia pestis, Francisella tularensis, Coxiella burnetii, hanta virus
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Fungi:
- Histoplasma
- Blastomyces
- Coccidioides
What are the most common organisms of community acquired pneumonia?
- *Strept. pneumonia (most frequent)
- Mycoplasma pneumoniae
- Chlamydophilia pneumoniae
- Legionella
- Respiratory viruses
What are the most commonl pneumonia organisms when associated with…
- Prior influenza, antibiotic Rx, chronic pulmonary disease?
- ICU admision?
- Immunosuppressed?
- Staph. aureus, enterobacteriaceae, pseudomonas aeruginosa
- Strept. pneumoniae, enteric gram (-) bacilli, Staph. aureus, Legionella, H. influenza, respiratory viruses
- Same as in 2 + pneumocystis jirovecii, CMV, invasive fungi (aspergillus, candida, cryptococcus, mucor speicies, nocardia), mycobacteria, parasites, and tons more
What is the most common viral cause of community acquired pneumonia in adults?
In kids?
What’s the best way to diagnose viral pneumoniae?
- Influenza A and B
- Respiratory syncytial virus
- PCR
Strept. pneumoniae
- Is this capable of killing an adult?
- How do you diagnose this infection?
- Is there a vaccine?
*Strept. pneumoniae = most common cause of bacterial pneumoniae!
- Yes, it can kill an adult quickly
- Sputum culture, blood culture, pleural fluid culture, or urine antigen test
- Yes there is a vaccine for high risk patients (recognizes sugar surface proteins)
H. influenza
- Is there a vaccine for this?
- What are the two different forms of this bug and what is the most infectious form?
- This is the most common bug to cause pneumonia in what group of patients?
- Yes, Hib vaccine (for H. influenza type B (non-typable))
- There is typeable (encapsulated) and non-typeable (non-encapsulated) . Non-typeable is the most infectious
- COPD patients that develop pneumonia usually get it from H. influenza.
Mycoplasma pneumoniae
- Does this bacteria have a cell wall?
- What age groups are most susceptible?
- How is the bacteria transmitted?
- Is there a diagnostic test? What does this mean for treatment?
- No cell wall (acidfast bacteria)
- Children and young adults are especially susceptible to this bug
- Person-person direct transmission
- No rapid diagnostic tests (only culturing which takes a lot of time) so don’t wait to diagnose before you treat.
Chlamydophilia pneumoniae
- Where does this bacteria go to replicate?
- What age group typically gets this bug?
- What diagnostic tests are available for this bug?
- It is an intracellular bacteria (outside it’s Really Cold = Rickettsia rieckettsi and Chlamydia)
- Elderly
- Only slow serological diagnosis (starting to make new methods using antigen and PCR testing though)
Legionella pneumophilia
- How does this bacteria travel and what environments is it found in?
- Should you be worried about a travel history with this organism?
- Is this a dangerous infection?
- How do you diagnose this bug?
- What is its significant association?
- Legionella travels by water droplets that have become aerosolized from water reserves. You can get this from artificial aquatic environments (pool, water parks, humidifier, etc.)
- Yes because it often occurs in epidemics. Check if th patient has traveled to an endemic nation.
- Yes, fatality rates up to 50%
- Urinary antigen test or growht on selective media
- Hyponatremia
What is type of bacteria is typically the cause of nosocomial pneumonia?
When are patient’s at highest risk for these infections?
Are these severe diseases?
Gram - bacilli commonly are the main cause of nosocomial infections
Patients on mechanical ventilators are at greatest risk
Yes the diseases are very severe
What gram - bacilli are found in…
- Patients with alcohol abuse or diabetes?
- Patients with chronic lung disease (cystic fibrosis, COPD, pulm fibrosis, etc.)
- COPD + immunocompromised
- Klebsiella pneumonia
- Pseudomonas aeruginosa
- Moraxella catarrhalis
When do we see anaerobic bacteria causing pneumonia?
What frequently forms in aspiration pneumonia?
Aspiration of gastric contents
Abscess formation
What bacteria are you at high risk of getting as a secondary infection after an initial Influenza infection?
Staph. aureus
What is the most common cause of lower respiratory tract infections (bronchiolitis) in kids < 1 year od?
What virus favors the immunocompromised for creating pneumoniae?
What virus is found in southestern USA and gives flu-like symptoms + pulmonary edema?
What is the most frequent complication of a varicella infection in a healthy adult?
Respiratory Syncytial Virus (RSV)
Parainfluenza virus
Hanta virus
Varicella pneumonia
Fungi are regionally endemic: what fungi are found in…
- Minnesota/midwest?
- Caves and bat guano especially in the Ohio river valley?
- In dusty soil in southwestern USA (pheonix)?
- Blastomycosis
- Histoplasmosis
- Coccidioidomycosis
- How do fungi infect the respiratory system? Do they stay in the lungs?
- What is a key clinical feature in differentiating a fungal infection from a bacterial infection?
- What do you see in imaging studies with a fungal infection (CXR, CT scan)?
- What is the histological pathology of fungal infections?
- Fungi first enter as spores then enter the blood and go systemic. They do not always stay in the lungs –> possible skin, bone, CNS infections as well!
- Key feature = patient keeps failing an antibiotic regimen
- CXR and CT scan can show ordinary pulmonary infiltrates or a tumor-like mass
- Necrotizing granuloma
Histoplasmosis
- what region is this fungi endemic to?
- What are the symptoms of histoplasmosis pneumoniae?
- What does this look like on CXR?
- How do you diagnose histoplasmosis?
- Is this a yeast or a mold? Where does it live inside the human body?
- Ohio/mississipi river valleys (bat/bird droppings contain it)
- Flu-like symptoms with pulmonary complaints
- CXR mimics sarcoidosis, TB, or a malignancy
- Diagnosis is through respiratory secretions or tissue biopsy
- Can also do urine antigen test or serology - Smallest yeast form. Lives inside the macrophage
Blastomycosis
- Where is this fungi endemic to?
- What is the form of this fungus?
- What are the symptoms like for a blasto infection?
- Where does this fungus disseminate to?
- How is this fungus diagnosed?
- Central and southeastern USA (Great Lakes Region)!
- Broad based budding yeast
- Symptoms: non-specific (cough, fever, sputum production)
- Common dissemination: Blood –> skin, bones/joints, GU! Can present as a disease at multiple sites
- Dx: respiratory secretions (sputum/bronchoscopic) and tissue biopsy
