Lower Resp. Micro- Debiel Flashcards
What is the most common cause of community acquired pneumonia?
Strep pneumoniae
Sudden onset of chills, fever, dyspnea, productive cough with purulent sputum, PLEURITIC chest pain, tachypnea, decreased breath sounds with dullness to percussion
Typical pneumonia
Gradual onset of non-productive cough, dyspnea, more prominent extra-pulmonary signs (headache, sore throat, diarrhea)
Atypical pneumonia
What are the four common causes of aytpical pneumonia?
Viruses (RSV and Influenza)
Mycoplasma
Chlamydia
Legionella
What type of pneumonia would intra-alveolar exudate indicate?
Lobar pneumonia
Usually bacterial
What type of pneumonia would diffuse patchy inflammation of interstitial areas/alveolar walls indicate?
Interstitial pneumonia/ Atypical
Usually caused by viruses, mycoplasma, chlamydia, legionella
What is the common causes of post-viral/ secondary?
S. aureus
Pneumonia causes associated with IV drug use
Staph aureus
Causes of pneumonia associated with post-viral/ secondary infections
Staph aureus
Causes of pneumonia commonly seen in alcoholics?
S. pneumoniae
Klebsiella pneumoniae
Anaerobes
Causes of pneumonia associated with gross aspiration?
Anaerobes
Causes of pneumonia associated with the immunocompromised?
Gram - rods S. pneumoniae Fungi Filamentous bacteria Pneumocystis jiroveci Viruses
Most common hospital acquired cause of pneumonia?
Gram - rods
Drug resistant staph aureus
Common cause of pneumonia for neonate (birth-6 weeks)
Group B strep
E. Coli
Most common causes of pneumonia in children (6 weeks - 18 years)
Viruses = RSV
Mycoplasma
Chlamydia
Strep Pneumo
Most common cause of pneumonia in Adults (18-40 years)
Mycoplasma
Chlamydia
Strep pneumo
Most common cause of pneumonia in adults (40-65 years)
Strep pneumo
H. Flu
Anaerobic bacteria
viruses
Most common cause of pneumonia in the elderly? (older than 65)
Strep pneum Viruses Anaerobic bacteria H. Flu Gram - rods
What is the most common cause of pneumonia in COPD patients? second most common cause?
1: H. Flu
2. M. catarrhalis
Why would you not use a b-lactam antibiotic to kill mycoplasma pneumoniae?
They have no cell wall!!! (does not gram stain!)
What is a complication of pneumonia with a mycoplasma pneumoniae infection?
B-cells may generate a response where autoantibodies react with RBCs = IgM cold agglutinins
A 1-day old infant developed pneumonia. Probable cause? why? how do you treat it?
Strep. agalactiae
It is carried in mother’s genital tract.
Treat with penicillin G
Gram +, B-hemolytic, bacitracin resistant
infects newborns
Can cause pneumonia, meningitis, and sepsis
Strep. Agalactiae = Group B strep!
What are the three B-hemolytic organisms?
Staph Aureus Strep Pyogenes (bacitracin sensitive) Strep Agalactiae (bacitracin resistant)
Gram + cocci
Catalase -
B-hemolysis
Bacitracin Resistant
Strep. Agalactiae
Group B-strep
Gram + cocci
Catalase -
B-hemolysis
Bacitracin Sensitive
Strep. Pyogenes
Group A-strep
Treatment for Chlamydiae pneumoniae
Doxycycline
What is the obligate intracellular parasite that can cause atypical pneumonia common in young adults?
Chlamydiae pneumonia
What stain do you need to use to visual intra-cytoplasmic inclusion during a chlamydiae pneumonia infection?
Giemsa stain
What are the two life-forms of chlamydiae?
Elementary body = infectious, enters cell via endocytosis, then transforms into reticulate body (extracellular)
Reticulate body: replicates by fission, and reorganizes into elementary bodies (intracellular)
What stain do you need to use to visual legionella?
Silver stain
What media do you need to culture legionella on?
Charcoal yeast extract with iron and cysteine
Where does legionella like to proliferate?
They get phagocytosed by alveolar macrophages, and survive and proliferate in there.
Virulence factors of RSV
G-surface protein for attachment
F protein causes infected cells to fuse
At what age group does Strep Pneumonia become the most common cause of pneumonia?
Age 40-65
Gram + diplococci Catalase - Alpha hemolytic Susceptible to optochin Quellung +
Strep Pneumonae
What causes “rust-colored” sputum?
Strep Pneumoniae
It does alpha hemolysis (only partially lysis RBCs)
What organism is associated with alcoholics and aspiration and shows up bright red because it is gamma hemolytic?
Klebsiella
What kind of agar do you grow H. influenzae on?
Chocolate agar
If someone has conjunctivitis and it feels like “grains of sand” what are you thinking?
Adenovirus
Multinucleated giant cells in pneumonia, crusted lesion on lip. What are you thinking?
HSV-1
What antibody opsonizes microorganisms once they arrive in the alveoli?
IgG
Does bronchitis cause inflammation in the alveoli?
No
Peak age for bronchiolitis?
2-8 months
When are adults infectious with influenza?
The day before symptoms begin through 5 days after onset of illness
Describe bordatella pertusis.
Gram - cocco-bacillus
With what bug do you see an increase in lymphocytes (rather than a typical increase in neutrophils with bacterial infection)?
B. Pertussis
What drug is given in pertussis?
Erythromycin
Tx for Moraxella catarrhalis?
Amoxicillin-clavulanate
How does B. pertussis adhere to cilia?
Filamentous hemagluttinin
Describe the pathogenesis of B. pertussis.
Binds epithelium via Filamentous hemagluttinin
AB toxin inactivates Gi proteins. This leads to an increase in cAMP.
Increase in cAMP impairs phagocytosis
Describe what happens from the B cell response to Mycoplasma pneumoniae.
B cells generate IgM antibodies that react with erythrocytes. Cold agglutination
Gram +
Aerobic
Beaded filaments
Weakly acid-fast
Pneumonia or abscesses.
Immunocompromised patients.
Nocardia asteroides
3 things that cause green sputum?
Pseudomonas
Haemophilus
Pneumococcal species
How can you differentiate between bronchitis and pneumonia?
CXR!!!!!!
Bronchitis will NOT have consolidations or infiltrates as seen in pneumonia
Most common cause of bronchiolitis?
RSV
Which antigenic types of flu cause the epidemics?
Type A and B!
Type C is mild disease, rarely causes epidemic, and by age 15 almost everyone has developed antibodies to it
What is one way to distinguish influenza infection from the common cold?
Common cold is afebrile
Influenza has abrupt onset high fever
Who should get a flu vaccine?
Everyone over 6 months of age
What does B. Pertussis need to be grown on?
Bordet-Gengou medium
When is someone with the flu infectious?
1 day BEFORE symptoms begin through 5 days after onset of illness
Describe the difference between antigenic drift and shift
Antigenic Drift: occurs when minor changes in antigens occur due to gene mutaiton in influenza virus
Antigenic Shift: occurs when MAJOR changes in antigens occur due to gene reassortment in influenza A virus
Which type of influenza virus undergoes antigenic shift?
Type A influenza virus
Which organism causes rust colored sputum?
Strep pneumonia due to the alpha hemolysis
Which organisms cause green sputum?
Pseudomonas
Haemophilus
Pneumococcal speices
Which organism produces red currant jelly sputum?
Klebsiella
Which organisms causes foul smell/ bad tasting sputum?
Anaerobic infections
