Lecture 10: Mycobacterium tuberculosis Flashcards
TB is caused by?
mycobacterium tuberculosis complex
How did TB first present
affected everyone, slow progression, thought to be hereditery, chronic disease, respectable symptoms
How was it discovered that TB was infectious
Robert Koch - infected peice of lung from human in rabbit - identified mycobateria reponsible
Describe the morphological features of M. tuberculosis
- complex lipid-rich cell wall
- acid fast bacilli (AFB)
- grows very slowly
- resistant to common ABs
- lives inside **macrophages **
How is Tb transmitted?
Airborne, bacilli released in droplets that survive in the air for house, indectious dose is <5 bacilli, droplets settle in alveolus - engulfed by alveolar macrophages
how do granulomas grow in TB?
infected macrophages recriuit additional macrophages and other immune cells to form organised structures - critical for restricting bacterial expansion
In TB most infections are ____ and ____ lead to active disease. The quartet of symptoms include ____ , ____ ,____, ____. Untreated TB progresses to ____ ____ and a ____ cough. Active disease is when bacteria are ____ . If untreated death rate is ____.
asymptomatic, 10%, weight loss, night sweats, fever, malaise, chest pains, bloody cough, infectious, 50%
Who gets the disease?
1/3 worlds population is infected
15-34 year old highest incidence
How are HIV and TB related
HIV impacts immune system
HIV patients are up to ____ x more likely to develop TB. ____% of TB cases are HIV+. In. 2021 TB accounted for ____ deaths of HIV/Aids patients. Most cases are in Africa with many in South Africa. Major benefits of Anti Retroviral Therapy (ART) in terms of TB risk and mortality
20, 10%, ~200,000
what sex is most likely to get TB
males, 6.8 rate
compared to females - 6.1
What age group is hospitalized most?
15-39
risk factors of TB
- born outside of NZ
- resident with person outside NZ
TB treatment
M. bocis Bacille Calmette Guerin (BCG)
derived from virulent isolate of bovine tuberculosis
BCG vaccination given >____ people but efficacy varies, ____% in trials. This is thougth to be due to ____ ____ to ____ ____. It is also only effective druing ____ . Risk of disseminated infection in ____
3 billion, 0-80%, prior exposure, environmental mycobacteria, childhood, HIV-infected infants
