Skip to Main Content

++

Chapter 23: Mycobacteria

++
++
++

A 60-year-old man has a 5-month history of progressive weakness and a weight loss of 13 kg along with intermittent fever, chills, and a chronic cough productive of yellow sputum, occasionally streaked with blood. A sputum specimen is obtained, and numerous acid-fast bacteria are seen on the smear. Culture of the sputum is positive for M tuberculosis. Which treatment regimen is most appropriate for initial therapy?

++
++
++

(A) Isoniazid and rifampin

++
++

(B) Sulfamethoxazole–trimethoprim and streptomycin

++
++

(C) Isoniazid, rifampin, pyrazinamide, and ethambutol

++
++

(D) Isoniazid, cycloserine, and ciprofloxacin

++
++

(E) Rifampin and streptomycin

++
++
++

A 60-year-old man has a 5-month history of progressive weakness and a weight loss of 13 kg along with intermittent fever, chills, and a chronic cough productive of yellow sputum, occasionally streaked with blood. A sputum specimen is obtained, and numerous acid-fast bacteria are seen on the smear. Culture of the sputum is positive for M tuberculosis.

++

If the patient’s M tuberculosis isolate to be resistant to isoniazid, the likely mechanism for resistance is

++
++
++

(A) β-Lactamase

++
++

(B) Mutations in the catalase-peroxidase gene

++
++

(C) Alterations in the β subunit of RNA polymerase

++
++

(D) Mutations in the DNA gyrase gene

++
++

(E) Mutations in the genes encoding the S12 protein and 16S rRNA

++
++
++

A 47-year-old woman presents with a 3-month history of progressive cough, weight loss, and fever. Chest radiography shows bilateral cavitary disease suggestive of tuberculosis. Sputum culture grows an acid-fast bacillus that is a photochromogen (makes an orange pigment when exposed to light). The organism most likely is

++
++
++

(A) Mycobacterium tuberculosis

++
++

(B) Mycobacterium kansasii

++
++

(C) Mycobacterium gordonae

++
++

(D) Mycobacterium avium complex

++
++

(E) Mycobacterium fortuitum

++
++
++

A 31-year-old Asian woman is admitted to the hospital with a 7-week history of increasing malaise, myalgia, nonproductive cough, and shortness of breath. She has daily fevers of 38–39°C and a recent 5-kg weight loss. She had a negative chest radiograph when she entered the United States 7 years ago. The patient’s grandmother died of tuberculosis when the patient was an infant. A current chest radiograph is normal; results of other tests show a decreased hematocrit and liver function test abnormalities. Liver and bone marrow biopsies show granulomas with giant cells ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.