Lecture 22 - Antimicrobial Resistance (Global Challenges) Flashcards
What are the main causes of resistance?
poor compliance
inadequate treatment and diagnosis
poor health care infrastructure
lack of education and knowledge
global location causes severe logistical issues
How many deaths annually does tuberculosis cause?
1.5 million
> 40 million deaths in the next 20 years
How is tuberculosis spread?
from inhaling droplets from a cough or sneeze by an infected person
What is there a strong epidemiological co-existance between?
HIV and TB as patients who are immunocompromised easily catch TB
What is the structure of the TB cell wall?
very complicated
have long fatty acids called mycolic acids
What is very unique with TB?
persistance - after you become ill with TB bacteria can lie dormant in the body
you can be infected with TB but never full develop the disease
Why is treatment of TB difficult?
the disease causes many complex systems
mycobacterium tuberculosis has a very complex cell wall
reactivation of dormant or persistent bacteria
Bacterial persistence of TB?
after treatment a small % may remain in a dormant state in macrophage
these can become reactivated many years later
patients can show no symptoms - carriers
What is the % of risk of reactivation to secondary TB?
2-23% lifetime risk
What is risk of reactivation increased by?
10% if immunosuppressed
What are the 2 phases of treatment?
initial phase and the continuation phase
What is the initial phase of TB treatment?
4 drugs given together daily
isoniazid
rifampicin
pryazanimide
ethambutol
(first 3 as rifater)
How long is the initial phase?
2 months
can be extended until sensitivity testing is complete
What is the initial phase for?
to reduce the bacterial population as rapidly as possible
prevents resistance
What is pyrazinamide used for?
helps to reduce the chance of reactivation
PZA is only active during the initial phase
Why is PZA only active during the initial phase?
due to host immune response lowering pH in macrophages
What is the continuation phase of TB treatment?
rifampicin and isoniazide used together as Rifinah
How long is the continuation phase?
4 months
What does the continuation phase do?
helps destroy remaining bacteria left from initial phase
When is the treatment of TB extended?
for meningitis or resistant TB
What is directly observed treatment?
necessary for patients who cannot comply with their regime
ensures the best chance of fighting the infection
What needs to be changed in DOT?
regime and doses
How often is supervision given in DOT?
3 times per week
Why is treatment of TB so critical?
because of the complex nature of TB all drugs need to be taken and the treatment must be completed
