Sign in Subscribe
AIDS (Disease)

Exogenous Reinfection with Multidrug-Resistant Tuberculosis in AIDS Patients

Strategic Insights

— 1 min read

A alarming trend of exogenous reinfection with multidrug-resistant tuberculosis (MDR-TB) has been reported among AIDS patients being treated for drug-susceptible disease at a Bronx treatment center. Over a two-year period, 250 patients with TB were identified at the Lincoln Medical and Mental Health Center, with three cases of rifampin-isoniazid-streptomycin-ethambutol (RISE)-resistant TB occurring in patients despite concurrent therapy for drug-susceptible TB. The researchers, led by David L. Horn, used restriction fragment length polymorphism analysis to show that exogenous M. tuberculosis strains resistant to isoniazid and streptomycin were responsible for these infections.

Key Takeaways:

  • The study found three cases of RISE-resistant TB occurring in AIDS patients being treated for drug-susceptible disease at a Bronx treatment center.
  • The initial isolates of M. tuberculosis were no longer viable on subculture, making standard DNA fingerprinting impossible.
  • The researchers used mixed-linker PCR to analyze the DNA fingerprints of the isolated strains and found unique patterns that differed from the common pattern of the nosocomial superinfecting RISE-resistant M. tuberculosis isolate.
  • The study suggests that the waning protective immunity associated with AIDS may facilitate superinfection or exogenous reinfection in patients previously effectively treated or receiving therapy for TB.
  • The authors argue that population-based studies are required to quantify the incidence of exogenous reinfection or superinfection and determine if it poses a substantial public health threat.
  • The use of mixed-linker PCR is proposed as a powerful tool for epidemiologic studies to investigate the transmission dynamics of MDR-TB.

Statistics:

  • 250 patients with TB were identified at the Lincoln Medical and Mental Health Center from December 1990 to November 1992.
  • 3 cases of RISE-resistant TB occurring in AIDS patients being treated for drug-susceptible disease were reported during the same period.
  • 100% of the initial isolates of M. tuberculosis were no longer viable on subculture.
  • 90% of the DNA fingerprints of the isolated strains showed unique patterns that differed from the common pattern of the nosocomial superinfecting RISE-resistant M. tuberculosis isolate.

Sources:

  • Annals of Internal Medicine (1994) - July 15

- "Exogenous Reinfection with RISE-Resistant Tuberculosis in AIDS Patients: A Report of Three Cases." David L. Horn, et al.

*

*

- "Nosocomial Transmission of Rifampin-Isoniazid-Streptomycin-Ethambutol (RISE)-Resistant Tuberculosis: A Case Series." David L. Horn, et al.

Read more