1. Clinical Case Female, 27 years of age 3 rd year Internal Medicine resident at the Mexicali General Hospital Never smoked; does not ingest alcoholic beverages or use illicit drugs Used to run 5 km daily before being ill Single, no children; lives with parents

2. Previous medical history: non-relevant; no known allergies Contact with tuberculosis patients: extremely frequent at her hospital; assisted in bronchoscopy procedures several times during her 1 st year of residency Has never been diagnosed with TB or received TB treatment before

3. Started her symptoms –July 2005; right pleuritic chest pain; self-limited. Chest x-ray at that time normal –December 2005: Headache Malaise Hyporexia Dry cough Fever Dyaphoresis –She received 10 days of gatifloxacin (400 mg OD)

4. By the end of January 06 her symptoms persisted chest- x-ray Jan 29, 2006 showed two small cavities in the right lower lobe

7. She was started on the five available first- line drugs (IRZES), self-administered Five days later she underwent bronchoscopy (she could not produce any sputum for AFB exam) AFB from bronchoscopy: reported as positive with 354 AFB in 100 fields HIV test: non reactive (ELISA)

8. She feels better; fever and cough disappeared, gained weight (3 kg) Culture results are reported from Imperial Valley Laboratory –Resistant to ISRZ and ethambutol at 2.5; susceptible to ethambutol at 5 –Susceptible to capreomycin, ethionamide and levofloxacin A CT scan (03/29/06) shows persistence of the lung cavitations

9. March 06

11. On Dr. Laniado’s advise she stops all treatment on April 01, 2006 Examined by Dr. Laniado on April 10, 2006; she is asymptomatic and her physical examination is negative; does not expectorate Bronchoscopy performed on April 11, 2006 to perform BAL

12. AFB from BAL in the State Laboratory in Tijuana and the General Hospital in Mexicali are reported as negative. Culture pending PCR analysis of the BAL is reported as positive for Mycobacterium tuberculosis and the mutation for rifampin resistance is detected

13. She is started again on IRSZ while waiting for the binational conference