bacterial pathogens Flashcards

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1
Q

bacterial flora is

A

endogenous

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2
Q

endogenous bacteria

A

bacteria that naturally reside in a closed system

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3
Q

when does disease occur

A

when microbes including in normal bacterial flora enter a sterile area of the body such as the brain or muscle- endogenous infection

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4
Q

example of endogenous infection

A

when E.coli of GI tract enters urinary tract- uti

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5
Q

exogenous bacteria

A

microorganisms introduced to closed systems from the external world- can either be benign or pathogenic e.g. cholera

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6
Q

clostridium in being exogenous

A

can be introduced into a closed ecosystem as well, having mutualist benefits for both the microbe and the host

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7
Q

what can control the spread of infection

A

social and environmental factors; vector control, chemoprophylaxis, outbreak investigation, food safety, health education

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8
Q

examples of HCAI- hospital acquired infections

A

-intravenous canulae; surgery; skin infection; urinary catheter; Gastrointestinal infection

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9
Q

gram negative bacteria

A

thin peptidoglycan- stay red since cant retain dye

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10
Q

all proteobacteria are

A

gram negativw

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11
Q

Neisseria meningitidis- type of bacteria

A

beta proteobacteria

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12
Q

Neisseria meningitidis

A

carried in the nasopharynx in 10-15% of population- epidemics occur every 10-12 years. classified by serogroup

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13
Q

serogroup

A

these microorganisms, viruses or cells are classified together based on their cell surface antigens, allowing the epidemiological classification of organisms to the sub-species level
-reactivity to a bacterial polysaccharide capsule

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14
Q

how many serogroups of N-meningitidis

A

12, 6 of which (ABCWXY) can cause epidemics

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15
Q

serogroups are based on

A

cell surface antigens

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16
Q

vaccines available for Neisseria meningtidis

A

a meningococcal A conjugate vaccine, tetravalent A, C, Y and W conjugate vaccine and meningococcal polysaccharide vaccine

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17
Q

gram positive bacteria

A

these bacteria retain the crystal violet dye (one of the main chemicals used for gram staining

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18
Q

example of a gram positive bacteria

A

Corynebacterium diptheriae

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19
Q

Corynebacterium diphtheria causes

A

diptheria

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20
Q

diphtheria was first reported in

A

4th century

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21
Q

corynebacterium diphtheria

A

-immotile rod

22
Q

where does corynebacterium diphtheria colonize

A

upper respiratory tract

- route of infection: droplets, person to person e.g. from coughing and sneezing

23
Q

how does corynebacterium diphtheria cause damage

A

releasing exotoxins- killing host cells. these spread systematically and principally effects the lungs and the heart

24
Q

main cause of mortality in diphtheria is

A

toxin spread

25
Q

emerging infections

A

infections the are rapidly increasing in incidence or geographic range.

26
Q

reasons for a pathogen to appear in a list of ‘new species’ (5)

A

(1) both pathogen and disease it causes didn’t occur before 1980
(2) disease was already recognised but the pathogen was not identified as the etiological agent before 1980
(3) the pathogen was already recognised but not associated with human disease before 1980
(4) neither the pathogen or disease it causes were recognised before 1980, but they dd occur
(5) what was considered to be a single pathogen before 1980 was subsequently recognise as comprising two or more species

27
Q

the process of disease emergence can be divided into 2 steps

A

(1) introduction- where “andromeda- like” infections come from
(2) establishment and dissemination- which is much harder for most of these agents to achieve

28
Q

basic lesson on the pathogens that cause epidemics

A

many may be called, but few are chosen.

29
Q

main virulence factor of diptheria

A

AB toxin- controlled by immunisation (DTaB)

30
Q

vaccines for diptheria

A

all babies are vaccine against it in a 5 in 1 vaccine given when they are two, three and four months old.
- vaccine known a DTaP/ IPV/ Hib vaccine

31
Q

AB toxin and diptheria

A

AB toxin release by bacteria. Receptor in membrane of cell attaches to the toxin. a vesicle forms around the complex. As the now endosome goes further into the cell, it is acidified by a hydrogen pump. This causes the receptor to release the AB toxin and the complex leaves the endosome. The A part of the attaches to the EF-2 of the EF2/ADP molecule..

32
Q

before/ after vaccine for diphtheria, tetanus, pertussis, polio, Hib disease

A

deaths before: 6430 deaths; deaths after: 3

33
Q

zoonotic diseases

A

Zoonoses are infectious diseases of animals (usually vertebrates) that can naturally be transmitted to humans

34
Q

how many species can be capable of infection animal hosts and humans

A

800

35
Q

relatively few human pathogens are solely know was

A

human pathogens

36
Q

why may zoonotic diseases becoming more occurrent

A

increased production of food to satisfy future and present demand, agriculture is ow in previously untouched areas of native environment

37
Q

the impact of climate change has resulted in

A

disturbances in ecosystems and re-distribution of disease reservoirs and vectors.

38
Q

what has increased the chance of transmission of zoonotic disease

A

increased globalisation and trail as increased the chance, extent and spread at which disease transmission occurs

39
Q

how diseases present themselves in diff animals

A

many zoonotic agents cause little or no signs of disease in their natural hosts, such as wild birds and bats, but transmission hosts might present with disease symptoms ranging from moderate to sevre

40
Q

there terminal or spill over cost can present with

A

severe symptoms and high mortality rate ( e.g. in the case of humans infected with H5N1 influenza)

41
Q

example of humans transmitting pathogens to animals

A

MRSA

42
Q

Streptococcus suis- zoonotic disease

A

S.suish is a pathogenic gram positive bacterial strain that represents a primary health problem in the swim industry,

43
Q

key facts on S.suis

A
  • spread over 30 countries, 1,300 human cases
  • 35 serotypes based on capsular antigen. Most common in china (epidemics in 1998 and 2005).
  • reason for few cases in N.America could be misdiagnosis
44
Q

chinese serogrpup 2 strain 055zyH33 Streptococcus suis

A

Contains a system similar to a Type 4 secretion system which thought to stimulate the host immune reaction observed with streptococcal toxic shock like syndrome (STSLS)

45
Q

AB toxins

A

The AB toxins are two-component protein complexes secreted by a number of pathogenic bacteria. They can be classified as Type III toxins because they interfere with internal cell function.

46
Q

detailed AB TOXIN

A

1) B part of AB toxin attaches to the receptor on the outside of the cell
2) receptor mediated endocytosis
3) phagosome is acidified
4) causes AB toxin to separate
5) A part of the town binds to EF2 causing conformational change
6) prevents translation- causes cell death

47
Q

AB toxin is a Type..

A

III

48
Q

type III AB toxins

A

disrupt internal cell function

49
Q

B part

A

attaches to receptor

50
Q

A part

A

causes inactivation of EF2

51
Q

EF2

A

elongation factor- needed for attachments of new a.a. sequences