A 43-year-old man with a 20-year history of alcohol use disorder presents to the hospital with acute pancreatitis complicated by sepsis. On hospital day 3, he develops a high fever (39.5°C), productive cough with purulent sputum, and worsening hypoxia requiring supplemental oxygen. Sputum culture is obtained. Gram staining of the sputum reveals gram-positive cocci in clusters. Culture on blood agar grows golden-yellow colonies within 24 hours. The isolate is catalase-positive, coagulase-positive, and ferments mannitol. Which of the following characteristics of this organism's cell wall composition best explains its gram-positive staining pattern?
- A)High concentration of peptidoglycan in a thick, multilayered cell wallGABARITO
- B)Presence of lipopolysaccharide in the outer membrane
- C)High content of mycolic acids with branched hydrocarbon chains
- D)Extensive lipoteichoic acid anchoring to the peptidoglycan layer
- E)Presence of porins that facilitate crystal violet uptake
Explicação
Staphylococcus aureus is a gram-positive coccus with a thick peptidoglycan cell wall (20-80 nm). Gram-positive bacteria retain the crystal violet-iodine complex in the thick peptidoglycan layer because the complex is too large to be extracted by acetone-alcoho... Ver explicação completa e trilha adaptativa →