Mycobacterium leprae

Mycobacterium leprae is a gram-positive, acid-fast, rod-shaped bacterium that causes leprosy (Hansen's disease), a chronic infectious disease primarily affecting the skin and peripheral nerves.[1][7][13] It is an obligate intracellular parasite incapable of growth on artificial media due to extensive genome reduction, with only about half of its 3.3 million base pair genome encoding functional proteins, leading to reliance on host nutrients and a slow replication rate of approximately 12-13 days.[1][4][7] The bacterium prefers cooler temperatures (below 35°C), explaining its tropism for cooler skin areas and Schwann cells in peripheral nerves, where it invades and multiplies, often forming granulomas or globi clusters.[1][10] Pathogenesis involves a spectrum from tuberculoid (paucibacillary, cell-mediated immunity limiting growth) to lepromatous (multibacillary, impaired immunity allowing massive proliferation), with incubation periods of 9 months to 20 years and potential for severe nerve damage, disfigurement, and disability if untreated.[1][3] Leprosy is treated with WHO-recommended multidrug therapy (dapsone, rifampicin, clofazimine), though challenges include drug resistance, lengthy regimens, and incomplete nerve protection.[2][8] Ongoing research explores new antibacterials targeting enzymes like alanine racemase and potential vaccines, but M. leprae itself is not a molecular therapeutic target such as a receptor or enzyme; rather, it is the pathogenic organism killed by antibiotics.[2][11] Diagnostic tools detect its DNA/RNA for viability and confirmation, aiding paucibacillary/multibacillary classification.[5][6]

Other names

M. lepraeHansen's disease bacterium

Folate synthesis inhibition (dapsone); RNA polymerase inhibition (rifampicin); DNA binding and potassium channel inhibition (clofazimine); Protein synthesis inhibition (clarithromycin, minocycline); DNA gyrase/topoisomerase inhibition (levofloxacin, ofloxacin); ATP synthase inhibition (bedaquiline); Unknown bactericidal activity (R207910)