lecture 29- lower respiratory tract infections II

Question 1

main atypical bacterial pneumonia- which are considered “walking” and which are considered toxic

Answer 1

• mycoplasma pneumoniae- walking
• chlamydophila pneumoniae-walking
• legionella pneumophila -toxic

Question 2

treatment of atypical pneumonia

Answer 2

-tetracycline or erythromycin

Question 3

what are some key characteristics of mycoplasma pneumoniae

Answer 3

• smallest free living bacteria
• no peptidoglycan!- no SHAPE- not responsive to antibiotics that target peptidoglycan*****
• membrane contains sterols
• restricted to humans
• causes tracheobronchitis
• low infectious dose transmission by respiratory droplets

Question 4

how does mycoplasma pneumoniae infect

Answer 4

• does so via P1 adhesion
• binds to celia and prevent their movement, epithelial death, defect in mucocilliary escalator -mucus accumulation and pneumonia

Question 5

what is a sign that you have a mycoplasma pneumoniae infection?

Answer 5

• have an IgM response crossreacting with RBCs =anemia

Question 6

diagnosis and treatment of mycoplasma pneumoniae

Answer 6

-diagnosis- NOT culture since it’s so small, do cold agglutinin, PCR, serology
-Treatment: erythromycin and tetracyclin
NOT BETA LACTAMS BECAUSE THEY TARGET PEPTIDOGLYCAN AND MYCOPLASMA PNEUMONIAE DOESN’T HAVE ONE

Question 7

if left untreated, what occurs most of the time with mycoplasma pneumoniae? Prevention?

Answer 7

• it’s self limiting and goes away in 2 wks

- prevention- just avoid places with it- no vaccine

Question 8

chlamydophila pneumoniae

• structure
• conditions it’s implicated with?

Answer 8

• small gram neg

- implicated with atherosclerotic plaque formation, asthma, multiple sclerosis and rheumatoid arthritis

Question 9

diagnosis of chlamydophila pneumoniae

treatment

Answer 9

PCR, microimmunofluorescence

treat- macrolide (erythromycin) or tetracycline

Question 10

legionella pneumophila

Answer 10

• toxic atypical pneumonia
• first found in American legion convention
• targets old people and immunosuppressed
• can cause PONTIAC FEVER (old people like Pontiacs)

Question 11

legionella
type of bacteria-
grows where?

Answer 11

gram negative coccobacilli in cells, pleomorphic (variable) outside
can exist as a parasite to amoeba
grows in- streams lakes, ground watter, mud, potting soil, riverbanks

Question 12

how is legionella transmitted

Answer 12

-via aerosols of manmade water supplies like misters, humidifiers, ACs, respiratory therapy devices, shower heads, supermarket produce misting systems

Question 13

how does legionella infect

Answer 13

• target and attach to alveolar macrophage using pili, flagella and other proteins
• it enters alveolar macrophage and causes a coiling phenomenon
• hijacks cell and prevents lysosome fusion and uses its ER, Ribosomes, and mitochondria to replicate in the legionella vacuole
• cell lyses and process starts over
• note= many bacterial and host enxymes released in this process that cause lung necrosis, systemic toxicity and inflammation

Question 14

what are some symptoms specific for legionella that you don’t see with other atypical pathogens like mycoplasma and chlamydophila

Answer 14

• ALWAYS WBC elevation
• pt gets progressively worse over 3-6 days and results in shock and respiratory failure
• delirium and dry cough that may be productive

Question 15

Diagnosis and treatment of legionella?

Answer 15

diagnosis- culture, direct fluorescent antibody, PCR

treatment- NOT beta lactams (b/c have beta lactamases), use macrolide or a floroquinolone