Gomez - Pulmonary Infections Flashcards
What two acute phase reactants indicate bacterial PNA over viral?
CRP
procalcitonin
What are pts who have had splenectomies at risk for?
Increased risk of infection from encapsulated organisms
What is the most common organism that causes pneumonia?
Strep pneumoniae
What is the most common organism causing pneumonia in IV drug abusers?
Staph aureus
What is the most common infectious agent found in pts with COPD?
What is the second most common?
1st: Haemophilus influenzae (Gram -)
2nd: Moraxella catarrhalis (Gram -)
What type of organism must be covered for when treating suspected cases of Legionella?
Gram negative bacteria
In what pt populations will you typically see pneumonia from Pseudomonas aeruginosa?
Pts w/ cystic fibrosis
Pts w/ neutropenia (i.e. on chemotherapy)
What organism would you suspect if pt had pneumonia with presence of cold agglutinins?
Mycoplasma pneumoniae
What is important to remember about organisms causing pneumonia in immunocompromised individuals?
They can get pneumonia from ALL OF THE COMMON organisms IN ADDITION TO the more rare organisms.
Describe Strep pneumoniae
1 cause of bacterial pneumonia in adults
Gram(+) encapsulated diplococcus
α-hemolytic
Optochin sensitive
Describe Haemophilus influenzae
Gram(-) coccobacilli
Capsule is major viral factor
H.iB is most common cause of bacterial meningitis in children 6mos-2yrs
Describe Moraxella catarrhalis
Gram(-) diplococcus
Typically manifests as common cold, otitis media, sinusitis
Less commonly: bronchitis, laryngitis, pneumonia in children
Describe Staphylococcus aureus
Gram(+) cocci in clusters
Catalase(+)
Coagulase(+)
In addition to skin infections, can cause pneumonia, meningitis, endocarditis, toxic shock syndrome
Some strains resistant to PCN and vanco
Describe Legionella pneumophilia
Gram(-) bacilli
Grow in standing water
Causes lobar pneumonia with non-productive cough, fever, can lead to multi-organ failure and death
Describe Klebsiella pneumoniae
Gram(-) encapsulated bacilli
Ferment lactose (red on MacConkey agar)
Most common cause of nosocomial respiratory tract infections
Causes hemorrhagic pneumonia w/ red jelly-colored sputum
Describe Pseudomonas
Gram(-) rods
Oxidase(+)
Nonfermenter
Secretes antiphagocytic slime
Commonly present in lungs of pts w/ CF
Describe Mycoplasma pneumoniae
Lack a cell wall
Causes atypical “walking” pneumonia
Associated with cold agglutinin (anti-I) production
Describe Chlamydia ssp. with respect to respiratory disease
Gram(-) coccoid to rod
Produce infectious elementary bodies
Cannot produce ATP
- pneumoniae* strain causes atypical pneumonias (upper and lower)
- psittaci* strain causes bird fancier’s disease
Describe Coxiella burnetti
Gram(-) intracellular parasite
Found in farm animals and their products (ex. milk)
Has an endospore-like state resistant to environmental insult
Causes Q fever
Describe Bacillus anthracis
Gram(+) bacilli in chains
Describe Yersinia pestis
Gram(-) coccobacilli
Non-lactose fermenter, but does ferment glucose
Describe pneumonic plague
Occurs in crowded conditions
Spread by respiratory droplets
Shorter incubation period and greater mortality than bubonic
Describe Mycobacteria
Gram ambiguous (cell wall is (+), but (-) by DNA)
Acid fast - use Ziehl-Neelsen stain to ID
What is a Ghon complex?
Found in tuberculosis infection
Calcified parenchymal necrotic lesion and associated lymph node
