Bacterial Pneumonias 1 Flashcards
What are 4 causitive agents of typical pneumonia?
S. Pneumo, H. Flu, K. Pneumoniae, S. Aureus
What are the three zoonotic pathogens of atypical pneumonia?
Chlamydia psittaci, francisella tularensis, coxiella burnetti
What are the three non-zoonotic pathogens of atypical pneumonia?
Chlamydia pneumoniae, mycoplasma pneumoniae, legionella pneumoniae
How does the typical bacterial pneumonia present?
Sudden onset, appears sick, higher fever (over 103), Chills and shaking, productive cough, frequent pleurisy, well-defined consolidation on a CXR, SOB
How does the atypical bacterial pneumonia present?
Gradual onset, appear well, lower fever (less than 103), Patchy infiltrates, non-productive cough, patchy infiltrates (diffuse), body aches, diarrhea, abdominal pain
What are the characteristics of S. Pneumo?
Gram positive lancet shaped diplococcus
alpha hemolytic
optochin sensitive
encapsulated=virulent
What is the major reservoir for s. pneumo?
asymptomatic carriers due to normal flora
What is the major virulence factor for s. pneumo, what is it the basis for, and how does it have its action?
The capsule, basis for serotyping and anti-pneumococcal vaccines, inhibits phagocytosis which interferes with complement activity by preventing opsonization of the bacteria by C3b
What are two virulence factors utilized by s. pneumo to enhance protection?
IgA protease, hydrogen peroxide (apoptosis in host cells and elimination of competing bacteria)
What are the two virulence factors that contribute to the binding capacity of s pneumo?
Pili (activate production of large quantities of TNF and help colonize UR tract) and surface proteins (choline binding proteins)
What is the role of peptidoglycan-teichoic acid complex in producing virulence for s. pneumo?
it is a potent immune modulator so it illicits a significant immune response
What is the virulence factor of s pneumo that activates complement by forming transmembrane pores?
Pneumolysin
What effect do neuraminidase and hyaluronidase have on s pneumo virulence?
They chew away tissue matrix to embed itself into the tissue to get away from abx
What is autolysin released in response to? What does it do as a virulence factor for s pneumo?
in response to abx tx and stationary phase as an attempt to dampen the host immune response by causing lysis of pneumococcus and release of pneumolysis and host cell apoptosis
What is a way to presumptively ID s. pneumo?
optochin sensitivity
What is a way to confirm s. pneumo?
bile solubility– bile will lyse s. pneumo but not other alpha hemolytic strep
What is used to observe s. pneumo capsules?
A Quellung reaction (agglutination test)
What is the name of the test that looks for s pneumo specific rRNA and is quick, accurate, and relatively inexpensive?
Genetic probe test
What is the DOC for s. pneumo?
PCN G, but it is becoming increasingly resistant so may have to replace with vancomycin and watch blood levels
What population is the 23-valent s. pneumo vaccine indicated for?
65+ and persons with predisposing factors
What population is the 13-valent s. pneumo vaccine used for?
children 6 years and under, it includes 75% of strains of penicillin-resistant s. pneumo
You find a non-motile, gram negative bacillus with a thick slimy capsule. What is it most likely to be and what populations should you watch out for it in?
Klebsiella pneumoniae,
ALCOHOLICS, DM, and homeless population
Where is Klebsiella found?
It is considered normal intestinal flora, but is important cause of nosocomial infections
What is the primary virulence factor for Klebsiella pneumo?
polysaccharide capsule which prevents MAC-mediated lysis
What is another virulence factor of klebsiella? What does it help to do?
adhesins, which are receptor specific and either fimbrial or non-fimbrial; once patient aspirates, it helps cause aggressive necrotizing CAP with lots of blood and severe illness with rapid onset.
What is the CP of Klebsiella? What is the outcome?
Acute onset of high fever and a productive cough with a thick, blood tinged, CURRENT JELLY sputum, often absess formation, cavitation, and pleuritic chest pain; Often fatal, even with antibiotic treatment