Virulence Factors RT Microorganisms

Question 1

Strep pneumoniae. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 1

• Pneumonia, gram pos diplococci
• surface adhesins, IgA protease, pneumolysin (pore-forming), teichoic acid (inflammatory) and polysaccharide capsule (antiphagocytic)
• Tx: beta-lactam and macrolide

Question 2

Strep pyogenes. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 2

• Strep pharyngitis, gram pos cocci

Virulence factors: M-protein (antiphagocytic), +/- capsule, SPE

• Tx: beta-lactam and macrolide

Question 2

Haemophilus influenza. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 2

• Diseases: laryngitis, tracheitis, epiglottitis, conjunctivitis, sinusitis, otitis media, pneumonia, tracheobronchitis, meningitis
• gram neg coccobacilli
• LPS, IgA protease, PRP capsule (antiphagocytic)
• Tx: broad-spectrum beta-lactam

Question 3

Bordatella pertussis. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 3

• pertussis / whooping cough, gram neg coccobacilli
• pertussis toxin (increase cAMP = increased secretions in respiratory tract)
• Tx: macrolide

Question 4

Staph aureus. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 4

• pneumonia, gram pos cocci clusters
• exotoxins (multiple), coagulase (clots blood), protein A (binds Fc on Abs), PVL (pore-forming and implicated in necrotizing pneumonia)
• Tx: beta-lactam if sensitive OR linezolid OR vancomycin

Question 6

Corynebacterium diphtheriae. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 6

• Diphtheria, gram pos bacilli
• diphtheria exotoxin (blocks protein synthesis w/specific target of heart, kidney and nerve cells)
• Tx: beta-lactam and macrolide

Question 7

Pseudomonas aeruginosa. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 7

• pneumonia, gram neg bacilli
• Toxin A (halts protein synthesis), leukocidin (pore-forming), PLC (disrupts membrane), capsule, pyocyanin (toxic to cells), pyoverdin (iron uptake protein)
• Tx: aminoglycoside + antipseudomonal (ticarcillin / piperacillin)

Question 8

Klebsiella pneumonia. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 8

• pneumonia, gram neg bacilli
• LPS, capsule
• Tx: aminoglycoside and beta-lactam (if sensitive)

Question 9

Legionella pneumophila. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 9

• pneumonia, gram neg coccobacilli (intracellularly, EC = pleomorphic)
• pili/flagella, endocytic vacuole (LCV)
• Tx: macrolide of fluoroquinolone

Question 10

Mycoplasma pneumoniae. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 10

• pneumonia, no gram stain (wall-less)
• p1 adhesin (binds base of ciliated resp epithelium = ciliostasis)
• Tx: macrolide and tetracycline

Question 11

Mycobacterium tuberculosis. Major disease of RT, gram stain and morphology, virulence factors, treatment

Answer 11

• Tuberculosis, weakly G pos, but acid fast
• No virulence factors of note
• Tx: 4 drug cocktail - rifampin, isoniazid, ethambutol, pyrazinamide