The most common means of transmitting the tubercle bacillus from one individual to another by...?

DHS 2018 shift 1st

Applied Microbiology & Infection control

Easy

Appeared in: DHS 2018 shift 1st

Explanation

The tubercle bacillus (Mycobacterium tuberculosis) is primarily transmitted through the airborne route.
Infected individuals with active pulmonary TB expel tiny infectious particles, known as droplet nuclei (less than 5 microns), when they cough, sneeze, speak, or sing.
These droplet nuclei can remain suspended in the air for several hours and, when inhaled by a susceptible person, can travel deep into the lungs to establish infection.
This is the most frequent and significant mode of transmission from person to person.

Option B: Tuberculosis is not transmitted via fomites (inanimate objects). The bacillus does not survive well on surfaces and infection requires inhalation into the respiratory tract.
Option C: This is not the most common route. Ingestion of unpasteurized milk can transmit Mycobacterium bovis (bovine TB), but this is rare due to pasteurization and because most human TB is caused by M. tuberculosis.
Option D: Similar to public toilets, eating utensils are fomites. TB is not spread by sharing utensils, food, or drinks.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mode of transmission for Tuberculosis (TB) as background academic context rather than a clinical decision trigger.
Understanding that TB is airborne is critical for implementing correct infection control measures, known as Airborne Precautions.
Nurses and healthcare providers must wear a fit-tested N95 respirator (or higher) when caring for patients with suspected or confirmed active pulmonary TB, as a standard surgical mask does not provide adequate protection against inhaling droplet nuclei.
Patients with active TB must be placed in a negative-pressure isolation room to prevent the spread of infectious particles to other areas of the healthcare facility.

How to Approach the Question

First, identify the key terms in the question: 'tubercle bacillus' (which is Tuberculosis) and 'most common means of transmitting'.
This is a factual recall question about the epidemiology of an infectious disease.
Recall the different modes of transmission: contact, droplet, airborne, and vehicle (like food/water).
Evaluate each option against your knowledge of TB. Recognize that TB is a classic example of a respiratory disease spread via the airborne route.
Eliminate the incorrect options. 'Using public toilet' and 'eating utensils' are fomites, which is not a route for TB. 'Milk products' is a rare route for a different species of mycobacterium (M. bovis), not the most common route for human TB.
Conclude that 'Air borne' is the only option that describes the primary and most common mode of transmission for Mycobacterium tuberculosis.

Concept Tested & Keywords

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