Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bacteriology > Mycobacteria > Flashcards

Mycobacteria Flashcards

1
Q

Mycobacteria description

A

Aerobic
Rod shaped
Non spore forming
Charact by large amounts of CW lipid incl mycolic acids
Acid fast bact
Sometimes form easily broken filaments showing similarity to actinomycetes
Virulent strains generally take longer to culture
Can be opportunist or obligate pathogens and some can only be grown in assoc with host cells
All thought to derive from single ancestor due to genetic similarities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mycobact bovis

A

Cause bovine TB and TB in pigs rarely in sheep dogs and horses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mycobact paratuberculosis

A

Cause Johnes dis in cattle sheep deer and goats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mycobact avium

A

TB in birds
Poultry v susceptible
Pigs suscept but no cattle
Sporadic horse dog and cat cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Mycobact leprae, lepraemurium, ulcerans, kansasii, fortuitum and chelonae

A

Cause leprosy and ulcerative lymphangitis in many species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mycobact tuberculosis

A

Cause human TB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Human TB and human co evolution

A

One of top 3 mortality worldwide dis
Evidence back to ape like ancestors
Bovine form first recorded with cattle domestication
Highly prevalent in third world assoc with poverty and high HIV incidence
Multi drug res strains are starting to emerge and some completely drug res strains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Human TB control

A

Major goal

BCC bacc not effective enough to eradicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why are human and bovine TB similar

A

Mtb and Mb are 99% similar on a genetic level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Mb human importance

A

Zoonotic can cause human TB

Pre milk pasteurisation many human TB cases caused by Mb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Bovine TB conseq

A

Major economic loss

80-100 mill per yr (UK gov cost)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Issue with bovine TB control

A

Incidence rising despite control measures though still geographically isolated in UK but endemic areas incr in size and now being found in previously TB free areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Attempt to control bovine TB

A 
5 pt plan
Improve detection and diagnosis
Incr research
Asses wildlife reservoir in badgers and how it affected dis spread
Dev vaccines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Control methods

A

TB skin test and slaughter policy

Other methods may be used as confirmatory test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

TB test used for

A

Detection of current or previous TB infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Confirmatory tests

A

Blood based detection

Culture and stain in lab

17
Q

TB test process

A

1.2.3.4 yr interval dep on freq of TB in area. Intradermally inject purified pro derivatives amd test for delayed type hypersensitivity after 72hr
comparative test with avium done as exposure to avium could hive false +ve to bovis
Animal ID, clip side of neck 2cm radius in 2 spots 13cm apart skin fold taken PPD inject usually avium in upper
Remeasure 72hr later

18
Q

TB test results

A

If bovis reaction is 4mm greater than avium it is a reactor

If 1-4mm then retest in 40-60d and rest of herd analysed using severe interp - 1mm

19
Q

What method being used to improve TB detection in low incidence areas ti maintain TB free status

A

Blood based detection method (cheaper and quicker) where spec IFN gamma resp to bovine PPD measured along with skin test. More animals test +ve so more culled. Tests a diff part of imm resp and can detect earlier after infection

20
Q

Factors affecting TB spread

A

High animal stocking densities
Immunosuppression
Cattle to cattle spread can occur
Role of wildlife reservoirs - controversial esp badger

21
Q

Countries without wildlife TB reservoirs

A

Australia, vigorous skin test and slaughter eradicated the dis

22
Q

Uk TB wildlife reservoir and methods to control

A

Badgers, evidence linking to bovine TB is compelling.
Can be Heavily infected with Mb and excrete large bacillus quantities that can survive on pasture for a long time
Cattle and badgers from similar location often infected with similar Mb substrain
But randomised badger culls have not decr TB incidence, it has cont to incr mabe due to disruption of badger grps that moved outside their normal area due to a key member of the grp being culled
Now trying BCG vacc of badgers at single site and monitoring neighbouring herds

23
Q

Other wildlife reservoirs and their locations

A

Possums NZ
White tailed deer USA
Wild boar Spain

24
Q

BCG vacc

A

Live Attenuated Mb derived from continual growtb on slices of potato over many yrs so caused a loss in many Mb genome regions
Administer subcut
Not always effective but unsure why
Has been trialled in cattle cam be used alone or in prime boost strategy (given 1st with boost of DNA or pro later) but these animals react +ve to skin test and gamma test so need DIVA test

25
Q

Conseq of being IC bact to imm resp

A

Cell med imm key to control esp macro act via IFN gamma released by stim T cells
Humoral imm and Ab secr not commonly seen in TB but can be observed in late stages and correlate with disease progression

26
Q

Imm resp to mycobact

A

Initiated via uptake macro or DC lining resp tractor in lungs induce cascade leading to granuloma form within tissues (lungs and lymph nodes)
Success assoc with cell med imm and secr of IFN gamma

27
Q

Granuloma

A

Aggregate of epitheloid hustiocytes

The cells have large vesicular nuclei, plentiful eosinophilic cytoplasm and are often elongated

28
Q

Cell types in granulomas

A

Macro (sometimes fuse to form giant cells)
Langhan’s giant cells are charct of TB with a horse shoe nulcei arrangement at one pole
B and T cells

29
Q

Necrosis of TB granuloma

A

Caseous necrosis

Gen large amount of released cellular matter

30
Q

Fibrin wall around granuloma formation

A

CD4+ T cells release TNF alpah and LT alpha 3 req for fibrin wall depositiony

31
Q

Virulence factors of mycobact

A

Protective glycolipid cont CW making bact hydrophobic resistant to lysis and helps resist O and N radicals
Also prod enz eg superoxide dismutase to res intermediates

32
Q

CW and CM structure

A

CW has a plasma mem cont pro, lipoarabinomannan, phosphatidylinositol
Peptidoglyc layer has 10% N glycolymuramic acid residue cov nattached to arabinogalactan with phophodiester bonds penultimate and final arabglyc are attached to mycolic acids of high molecular weight

33
Q

CW comp and fx

A

Mycolic acid- resist phago digest
Sulfatides- prev phagoso-lysoso fusion and phagocyte action
Cord factor- inhib phagocyte chemotax, activation and phag-lys fusion and digestion
LAM- prev phagocyt act and digestion within phag
Mycosides- prev IC killing and digestion

Bacteriology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions