A 63-year-old woman comes to the office due to a new-onset cough, night sweats, and hemoptysis since last week. The patient grew up in Bangladesh and immigrated to the United States when she was 35 years old. Her only medical condition is polycystic kidney disease, for which she received a kidney transplant 8 months ago. Her temperature is 98°F (36.7°C), blood pressure is 122/75 mmHg, pulse is 85/min, and respirations are 16/min. On lung auscultation, inspiratory crackles are present. A chest radiograph is ordered and a new cavitary lesion is noted in the apical-posterior segment of her left upper lobe. Bacteria isolated from the lung tissue fail to decolorize with hydrochloric acid and alcohol after staining carbolfuchsin. Which of the following cell wall components is most likely responsible for this staining phenomenon?

Question

A 63-year-old woman comes to the office due to a new-onset cough, night sweats, and hemoptysis since last week. The patient grew up in Bangladesh and immigrated to the United States when she was 35 years old. Her only medical condition is polycystic kidney disease, for which she received a kidney transplant 8 months ago. Her temperature is 98°F (36.7°C), blood pressure is 122/75 mmHg, pulse is 85/min, and respirations are 16/min. On lung auscultation, inspiratory crackles are present. A chest radiograph is ordered and a new cavitary lesion is noted in the apical-posterior segment of her left upper lobe. Bacteria isolated from the lung tissue fail to decolorize with hydrochloric acid and alcohol after staining carbolfuchsin.  Which of the following cell wall components is most likely responsible for this staining phenomenon?

Quizplus · Accepted Answer

Eductional Objective: The acid-fast stain identifies organisms that have mycolic acid present in their cell walls, including Mycobacterium and some Nocardia species.  Acid-fast staining is carried out by applying an aniline dye (eg, carbolfuchsin) to a smear and then decolorizing with acid alcohol to reveal whether the organisms present are "acid fast."

A 63-Year-Old Woman Comes to the Office Due to a New-Onset