Related Experiment Videos
Mouse footpad pathogenicity of leprosy derived nocardioform bacteria cultivated in vitro
A N Chakrabarty1, N K Pal, S G Dastidar
1Dept. of Medical Microbiology and Parasitology, University College of Medicine, Calcutta University.
Abstract:
In vitro cultures of the nocardioform bacteria from leprosy-infected tissues consisted of granules and bacilli. Inoculation of these granules into mouse footpads (MFP) produced a mild, localised, inflammation for 4-6 weeks. The granules evoked typical granulomatous response in the subcutaneous tissue and showed gradual disintegration. Infiltration of muscles, connective tissue and epithelial cells by bacillary/mycelial masses was seen very frequently, and that of nerve bundles occasionally. Plenty of mycelial tufts emanated from many 'macrophage globi'. By 6-8 months, the granules disintegrated nearly completely releasing a large number of acid-fast bacilli (AFB), single layered rings of AFB, small globi and some residual mycelia. These AFB, harvested from the MFP, were similar to or indistinguishable from the bacillary preparations from the in vitro cultures and from the leprosy bacillus obtained directly from humans or as passaged into the MFP, on the basis of many criteria studied, including the 36k gene positivity.
Insights
Nocardioform bacteria from leprosy cultures formed granules and bacilli. When inoculated into mouse footpads, these granules released acid-fast bacilli (AFB) indistinguishable from human leprosy bacilli.
Area of Science:
- Microbiology
- Infectious Diseases
- Immunology
Background:
- Leprosy is caused by Mycobacterium leprae, a complex bacterium.
- Nocardioform bacteria isolated from leprosy tissues present unique morphological forms, including granules and bacilli.
Purpose of the Study:
- To investigate the in vivo behavior and infectivity of nocardioform bacteria from leprosy.
- To characterize the acid-fast bacilli (AFB) released from in vivo cultures.
Main Methods:
- In vitro culture of nocardioform bacteria from leprosy-infected tissues.
- Inoculation of bacterial granules into mouse footpads (MFP).
- Histopathological examination of infected tissues and characterization of released AFB.
Main Results:
- In vitro cultures yielded granules and bacilli.
- MFP inoculation caused localized inflammation and granulomatous response.
- Granules gradually disintegrated, releasing numerous AFB, rings of AFB, and residual mycelia.
- Harvested AFB were morphologically and genetically similar to in vitro preparations and human leprosy bacilli.
Conclusions:
- Nocardioform granules from leprosy are viable in vivo and release acid-fast bacilli.
- The mouse footpad model supports the study of leprosy pathogenesis and bacterial forms.
- The released AFB share key characteristics with Mycobacterium leprae, supporting their etiological role.