A 45-year-old man with COPD presents to the emergency department with a 3-day history of productive cough with green sputum, dyspnea, and fever. Vital signs: BP 128/82 mmHg, HR 102/min, RR 24/min, temperature 38.9°C, SpO2 92% on room air. Chest X-ray shows left lower lobe consolidation. Sputum culture yields a gram-negative rod that is oxidase-positive with blue-green pigmentation on blood agar and optimal growth at 42°C. Which of the following virulence factors is most important for this organism's ability to evade host defenses and cause tissue destruction in respiratory infections?
- A)Exotoxin A (inactivates elongation factor-2) and elastase (degrades elastic fibers)GABARITO
- B)Lipopolysaccharide endotoxin and type IV pili for mucosal adherence
- C)Type III secretion system delivering cytotoxins directly into host epithelial cells
- D)Protein A binding immunoglobulin Fc regions and M protein molecular mimicry
- E)Streptolysins and hyaluronidase for tissue invasion and spread
Explicação
The clinical presentation and culture characteristics are diagnostic for Pseudomonas aeruginosa (gram-negative rod, oxidase-positive, green pigmentation, thermophilic at 42°C, common respiratory pathogen in COPD). P. aeruginosa's major virulence mechanisms inc... Ver explicação completa e trilha adaptativa →