A 32-year-old Hispanic woman presented with a cough for several weeks and a 15-lb weight loss. She also had night sweats and subjective fevers and felt fatigued. Despite erythromycin treatment for suspected pneumonia given by her family physician, her fever and cough progressively got worse and she complained about coughing blood-tinged sputum. She had emigrated from Venezuela to the United States three years before her illness, but she frequently returned to Venezuela to visit relatives. Her vital signs reported a temperature of 38.6 degree C. pulse 96/min, resting 18/min and blood pressure 112/60 mmHg. On exam, bilateral rales and lymphadenopathy was noted. Laboratory studies showed a normal differential with a white blood cell count of 8500/mu L. Her hematocrit was 32%, her blood gases were p0_2 78 mmHg with normal serum chemistries. A chest x-ray revealed right upper lobe infiltrates (Figure 1). a PPD test was positive and a sputum smear was strongly positive for acid fast bacilli. What organism was most likely causing her infection? What risk factors did she have for infection with this organism? Describe the natural history of infections with this organism. What is a PPD test? What is its value in this patient? What additional tests are available for detecting latent infection with this organism? The organism isolated from the patient had the following susceptibility pattern: How would you classify this organism? What is the global distribution of these organism? What is the significance of her being from Venezuela? What recent technical development will, it is hoped, greatly enhance the control of this organism?