Infection Session 8 Flashcards Preview

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Flashcards in Infection Session 8 Deck (51):
1

Can a vector be inanimate?

Yes

2

What are the three communicable natures of infections?

Common source
Person-to-person direct
Person-to-person indirect

3

Give some examples of common source infections.

Legionella pneumophilia
Food poisoning
Rabies

4

Give some examples of person-to-person direct communicable infection causative agents

Influenza
Norovirus
Neisseria gonorrhoea

5

What are the consequences of transmission of infection?

Endemic disease
Outbreak
Epidemic
Pandemic

6

What is endemic disease?

Usual background rate of a disease

7

What is the definition of an outbreak in infection?

>/= 2 cases linked in time and place

8

What is the definition of an epidemic?

Rate of infection > usual background rate (strictly defined for some infections)

9

What is the definition of a pandemic?

V. high rate of infection spreading across many regions, countries and continents

10

What is basic reproduction number?

The average number of cases one case of infection generates over the course of its infectious period in an otherwise uninflected, non immune population

11

What is seen when basic reproduction number (R0) is >1?

Increase in cases --> ourtbreak

12

How does the R0 of measles compare to that of influenza?

Much higher

13

What pathogen factors can cause outbreaks, epidemics and pandemics?

Antigenic drift
Antigenic shift
Toxin production --> environmental contamination

14

What patient factors can contribute to outbreaks, epidemics and pandemics?

New hosts
Immunosuppressed population
Healthcare

15

What practice factors can contribute to outbreaks, epidemics and pandemics?

Social practice e.g. Sexual behaviour, drug use
Healthcare practice e.g. High bed occupancy

16

What place factors can contribute to outbreaks, epidemics and pandemics?

Migration introducing new pathogens of native infection to unexposed populations

17

What factor determining transmissibility varies by microorganism, it's presentation and immunity of potential host?

Infectious dose

18

Give some examples of high and low infectious dose microorganisms.

High: salmonella, cholera, bacillus anthracis
Low: C. Parvum, E.coli

19

What does small scale outbreaks being stochastic in nature mean?

Cases show random distribution leading to a normal epidemic curve shape which can alter position

20

What is the implication of small scale outbreaks being stochastic in nature?

Interventions can only be proven to work if they are effective in more than one outbreak

21

What non-biological factor might cause an increase in the number of lab reports of an infection?

Change in ascertainment (how infection is reported)

22

What three stages cause the normal shape of an epidemic curve?

Susceptible (lots of secondary cases) --> infected --> recovered/increased immunity/death

23

What patient interventions can be used to prevent infection?

Improve health of population
Passive immunity
Active immunity
Herd immunity

24

What does the proportion of people needed to vaccinate for effective herd immunity depend on?

R0 (higher it is, greater % need vaccinating)

25

What practice interventions can be used to prevent infection?

Avoid pathogen/vector geographically, PPE and behaviourally (safe sex, safe disposal of sharps, food and drink prep)

26

What place interventions can be used to prevent infection?

Environmental engineering to provide safe water and air
Good quality housing
Well designed care facilities

27

What aids local infection control to reduce risk?

Surveillance to monitor local, global and future trends

28

What are the consequences of good infection control?

Decreased incidence or elimination of disease

29

What are the consequences of poor infection control?

Decreased exposure to pathogen --> decreased immune stimulus --> lack antibodies --> increased number of susceptibles --> outbreak
Later average age of exposure due to decreased environmental levels leads to greater severity of disease experienced

30

Why is Abx resistance almost as old as the Abx themselves?

Produced naturally by bacteria and moulds for evolutionary advantage

31

What is the implication of carbapenem-resistant enterobacteriaceae?

It has genes which code for carbapenamase which also confer resistance to other Abx therefore the last resort Tx for G-ve bacteria is ineffective

32

Is it just inappropriate prescribing of Abx that causes antimicrobial resistance?

No, any exposure of bacteria to antimicrobials can

33

What is the implication for using empirical Abx therapy in antimicrobial resistance?

Much more likely to get empirical Abx estimate wrong and hence increase mortality

34

What is the definition of a multi-drug resistant (MDR) microbe?

Non-susceptibility to =/>1 agent in =/>3 antimicrobial categories

35

What is the definition of an extensively drug resistant (XDR) microbe?

Non-susceptibility to at least 1 agent in all but 2 or fewer antimicrobial categories

36

What is the definition of a pan-drug resistant (PDR) microbe?

Non-susceptible to all agents in an antimicrobial category

37

What does laboratory evidence provide to indicate antibacterials causes resistance?

Biological plausibility

38

What evidence do ecological studies provide to indicate antibacterials cause resistance?

Overall high levels of antibacterial use lead to more resistance

39

What individual level data provides evidence that antibacterials cause resistance?

Abx prescribed in UTI --> increased rates of carriage of resistant bacteria in recipients --> longer durations and multiple courses --> increased resistance rates

40

What is the smallest change necessary to give rise to antimicrobial resistance in a bacteria?

Single nucleotide

41

Can legionella pneumophilia cause inward transmission after infecting a human host from the environment?

No

42

What are the 5 objectives of antimicrobial stewardship?

Appropriate use of antimicrobials
Optimal clinical outcomes
Minimise toxicity and adverse events
Decrease costs of healthcare for infections
Limit selection for microbial strains

43

How are the 5 objectives of antimicrobial stewardship achieved?

Use of an MDT
Surveillance of process
Surveillance of outcome
Measures of interventions

44

Give some examples of persuasive interventions in antimicrobial stewardship.

Education
Consensus of best practice
Opinion leaders
Reminders
Audit feedback

45

Give some examples of restrictive intervention in antimicrobial stewardship.

Restricted susceptibility reporting
Formulary restriction
Validation codes
Automatic stop orders

46

Give some examples of structural interventions in antimicrobial stewardship.

Computerised records
Rapid lab tests
Quality monitoring

47

Which type of intervention in antimicrobial stewardship is slower to take effect but long-term is as effective as restrictive interventions?

Persuasive

48

What process measures can be used in antimicrobial stewardship?

Look at trends in antibacterial use and consider defined daily doses per 1000 bed days, classes and appropriateness over time +/- other institutions

49

What outcome measures can be used in antimicrobial stewardship?

Pt outcomes
Emergence of resistance
C.diff infection rate

50

What is needed for successful antimicrobial stewardship?

Long term confirmed and appropriate resources supported by leadership w/delegated leadership for challenge integrated into organised pt safety and QoL care

51

Give an example of an effective antimicrobial stewardship case.

Cephalosporins control on CDI in Leicester:
Introduced restoration codes first (quantitative restriction) followed by physical removal of cephalosporins from wards (qualitative restriction) --> marked decrease in total C.diff cases