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Primary dapsone-resistant leprosy in San Francisco
Summary
This study found that Mycobacterium leprae, the bacteria causing leprosy, remained highly sensitive to dapsone in most patients. Only one case showed minimal resistance, which was overcome by standard dapsone treatment levels.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Leprosy, a chronic infectious disease, is primarily caused by Mycobacterium leprae.
- Dapsone has been the cornerstone of multidrug therapy for leprosy for decades.
- Emergence of drug resistance in Mycobacterium leprae is a significant public health concern.
Purpose of the Study:
- To determine the in vivo dapsone sensitivity of Mycobacterium leprae strains.
- To assess the prevalence of dapsone resistance in untreated leprosy patients.
Main Methods:
- Mouse foot pad inoculation model was used to evaluate M. leprae growth.
- Drug sensitivity testing was performed using dapsone-infused diets.
- Mouse plasma dapsone levels were measured to ensure drug delivery.
Main Results:
- Mycobacterium leprae from 53 out of 54 patients were fully sensitive to dapsone.
- M. leprae from one patient exhibited resistance only to the lowest tested dapsone concentration (0.0001%).
- Higher, clinically achievable dapsone levels effectively inhibited the growth of M. leprae from the resistant case.
Conclusions:
- High dapsone sensitivity of Mycobacterium leprae strains was observed in this patient cohort.
- Dapsone remains an effective therapeutic agent for most leprosy cases.
- Minimal dapsone resistance was detected, suggesting continued efficacy of standard treatment regimens.