Other Mycobacteria MCQs

The killed Mycobacterium indicus pranii vaccine has been developed in India in 2018. Trials have shown that if given in close contacts, cases can be brought down by 60% in 3 years Reference : Essentials of Medical Microbiology, byApurba Sastry and Sandhya Bhat, 3rd edition, page 538

The medial plantar nerve is never involved in leprosy. The most commonly involved nerve is ulnar followed by post auricular Reference : Essentials of Medical Microbiology, byApurba Sastry and Sandhya Bhat, 3rd edition, page 535

Since lepra bacilli grow in cooler areas, they invade cutaneous nerves first, hence thermal sensations are lost earlier. Reference- https://internationaltextbookofleprosy.org/chapter/neurological-manifestations-leprosy

Ans. is 'c' i.e., Post Rx surveillance of paucibacillary leprosy

Explanation: Mycobacterium leprae , the causative agent of leprosy (Hansen's disease) , is an obligate intracellular bacterium that cannot be grown on artificial culture media . It has never been consistently cultured in vitro. It is propagated in the footpads of mice or nine-banded armadillos for research purposes. Staphylococcus aureus, M. tuberculosis, S. pneumoniae a ll of these bacteria can be readily cultured on standard or enriched artificial laboratory media (e.g., blood agar, LJ medium, chocolate agar). (Options B, C and D ruled out) Key Takeaways: leprae is uncultivable on artificial media. Other notable uncultivable pathogens include Treponema pallidum and Rickettsia spp.

Mycobacterium paratuberculosis is known as Johne's bacilli Mycobacterium intracellulare is known as Battey's bacilli Mycobacterium leprae is known as Hansen's bacilli Reference: Essentials of Medical Microbiology, by Apurba Sastry and Sandhya Bhat, 3rd edition, page 34

Uniformly stained with parallel sides and round ends : Correct ; live bacilli display a uniform stain with distinct parallel sides and round ends, appearing five times longer than wide. Why Not Others : Irregularly shaped with fragmented ends : Incorrect; this description is typical of dead bacilli rather than live ones. Stained in clusters with irregular shapes : Incorrect; live bacilli should be uniform and not clustered or irregularly shaped. Invisible in the smear : Incorrect; live bacilli are visible and identifiable using the Ziehl-Neelsen stain. Key Takeaway : Live M. leprae bacilli are characterized by being uniformly stained with parallel sides and round ends , facilitating their identification under the microscope. Tags : inicet 2020 Reference: Shastri, A. (2021). Essentials of Medical Microbiology (3rd ed.). Publisher. Chapter-54-Leprosy , pp-536.

Mycobacterium avium complex : Correct ; this includes Mycobacterium avium and Mycobacterium intracellulare, which are associated with pulmonary infections in immunocompetent individuals. Why Not Others : Mycobacterium leprae : Misleading as it pertains only to leprosy, not respiratory issues. Mycobacterium tuberculosis : A known pathogen for tuberculosis, distinctly separate from NTM. Mycobacterium bovis : Primarily zoonotic and not typically linked to pulmonary disease in healthy individuals. Key Takeaway : The Mycobacterium avium complex is commonly linked to pulmonary infections in immunocompetent individuals, distinguishing it from other mycobacterial species. Tags : fmge 2021 Reference: Shastri, A. (2021). Essentials of Medical Microbiology (3rd ed.). Publisher. Chapter-63, pp-623.