Mycobacteria

Question 1

give 6 facts about mycobacteria

Answer 1

1. bacilli arranged in clumps
2. similar cell wall -> GNB but no LPS
3. lipid-rich cell wall- 60%
4. non-motile
5. Acid-Alcohol fast as-> impermeable to various basic dyes due to lipid- when dyes=combined with phenol can permeate + resist decolourization by acidified organic solvents

Question 2

properties associated with lipid rich cell wall x7

Answer 2

Resistant to-> drying, osmotic lyses, acid, alkalis, many antibiotics, many disinfectants + impermeable to stains

Question 3

Mycobacteria- survival strategies name main species + where it effects + outcome

Answer 3

all are intracellular, cell wall helps survive in macrophage resisting oxidative damage- Pulmonary TB infects alveolar macrophages - macrophage is unable to kill organism

Question 4

2 different species

Answer 4

Pathogenic + non-pathogenic

Question 5

Mycobacterium B causes? type of disease how is it transmitted

Answer 5

Bovis- Zoonosis- disease transmitted from animal to human and consumption of animal infected products

Question 6

M. TB discovered by who? describe its physiology? primarily a pathogen of otherwise known as x x

Answer 6

Robert Koch- highly aerobic requires high level of O2- prim pathogen of mammalian respiratory system obligate parasite

Question 7

2 types of Mycobacterium TB infections
Differentiate between infection vs disease of TB

Answer 7

Pathogenic + non-pathogenic
Infection- primary- usually from childhood and the immune system keeps it under control -non-infectious
whilst disease can be infections and happens when lesions form later in life

Question 8

M. TB transmission

Answer 8

transmitted through droplets/air- person becomes infected when inhalation of droplet nuclei occur- 15 microm in size- communicable disease- no highly contagious as must be in long contact [family] 8hours-6months. coughs, speak, laugh, sneezes- put into air by infected person with active TB- after 2 weeks of effective treatment person = no-longer contagious + can’t spread it. droplets can be suspended in air for several mins-hours

Question 9

Clinical Features of Pulmonary TB - in who does it progress more rapidly in

Answer 9

persistent cough, chest pains, low grade fever, weight loss, night sweats- person with AIDS-immunocompromised

Question 10

List 3 steps in Pathophysiology of TB

Answer 10

1. inhalation of droplet enters into lungs & deposits into alveolar
2. macrophages & T lymphocytes -try to contain infection by forming granulomas
3. in weaker immune system- wall loses integrity & bacilli escape + able to spread to other tissues / other alveoli

Question 11

Differentiate between healthy and unhealthy persons TB infection process

Answer 11

in unhealthy person- bacilli overwhelm immune system- break out of tubercles + infect other alveoli, organ & can flow through bloodstream [ACTIVE TB]
Healthy person -> initial infection= controlled by immune response bacilli REMAIN in tubercles for several years [LATENT TB]