Exogenous Reinfection with Multidrug-Resistant Mycobacterium tuberculosis in Patients with Advanced HIV Infection

1. Exogenous Reinfection with Multidrug-Resistant Mycobacterium tuberculosis in Patients with Advanced HIV Infection Celeste Nadal

2. Purpose • Determine the epidemiological connections between cases of multidrug-resistant tuberculosis (MDRT) • Prevention of future MDRT outbreaks Rationale

3. Outline • Background • Mycobacterium tuberculosis • Tuberculosis disease • HIV and Tuberculosis • Methods • Results • Conclusions

4. Mycobacterium tuberculosis • Characteristics • Obligate aerobe • Rod shaped • Acid fast • Mycolic acid cell wall

5. Tuberculosis Disease (TB) • Sites of infection • Mode of infection • Airborne

6. Pulmonary TB • Internal symptoms • Development of tubercles • Consumption • Sputum • External symptoms • Minor cough • Mild fever • Fatigue • Weight loss • Coughing up blood • Chest pain

7. TB and HIV • Increased susceptibility in immunosuppressed individuals • Infection in HIV positive individuals • 113 times more likely • 7 to 10% risk PER YEAR

8. Multidrug-Resistant Tuberculosis Infection • Primary drug resistance • Infection with multidrug-resistant TB • Acquired drug resistance • Development of resistance during therapy • Possibly due to inadequate treatment

9. Research Protocol • Trace M. tuberculosis transmission • Isolation and culture of bacterial sample • Evaluation of medical records • Follow-up studies • Radiometric broth method • Restriction-fragment-length polymorphisms analysis

10. Radiometric Broth Method • Determine susceptibility to • Isoniazid (0.1-0.2 mg/ml) • Rifampin (2 mg/ml) • Streptomycin (6.0 mg/ml) • Ethambutol (7.5 mg/ml) • Pyrazinamide (100 mg/ml)- testing began later in study • Tests for critical concentration • The level of a drug which distinguishes the strain from a strain that has never been in contact with the drug • 1% colony growth in presence of antibiotic

11. Restriction-Fragment-Length- Polymorphisms (RFLPs) Analysis • Form of DNA fingerprinting • Extract genomic DNA • Restriction enzyme digestion • PvuII • Southern blot • Gel electrophoresis • Transfer to nylon membrane • Hybridized with labeled probes

12. RFLP Patterns of Patients with Persistently Drug-Susceptible Isolates

13. RFLP Patterns of Patients with Increasingly Drug-Resistant Isolates

14. RFLP Patterns Indicating Exogenous Reinfection with New Multidrug-Resistant Strain in HIV+ Patients

15. Clinical Course of Four Patients with AIDS and Multidrug-Resistant Tuberculosis • Triangles • Out-patient visits • Circle • Negative TB culures • Boxes • Positive TB cultures • PCP • Pneumonia

16. Conclusion • RFLP Analysis • Confirmed acquired drug resistance • Demonstrated Third mechanism of developing Multidrug-resistant tuberculosis infection • Exogenous reinfection • Follow-up • Lack of acquired immunity to MTB in HIV pos patients are more likely to become reinfected with MDR-TB

17. Prevention • Routine skin testing for tuberculosis • Prompt and consistent treatment • Decrease open tuberculosis units