Week 8 Infection Prevention/ Antimicrobial resistance

Question 1

by what methods can infection spread?

Answer 1

contigeous- person to person - influenza, norovirus, neisseria gonorrhoea
inoculation
inhalation
ingestion
vector
vertical transmission

Question 2

what is the R0- reproduction number and how is it interpreted?

Answer 2

R0 is the average no. of cases one case generates over the course of its infectious period, in an otherwise uninfected, non-immune population
if R0>1 = increase in cases
if R0=1 = stable no. of cases
if R0

Question 3

what 4 Ps are the reason for outbreaks, epidemics and pandemics?

Answer 3

patient- new host- non-immunes, healthcare effects
pathogen- new pathogen- antigens, virulence factors, antibacterial resistance
place
practice- new practice- social and healthcare

Question 4

what are consequences of infection transmission?

Answer 4

endemic disease- normal usual background rate
outbreak- two or more cases linked in time and place
epidemic- rate of infection above usual background rate
pandemic- very high rate of infectious cases spread across many regions, countries and continents

Question 5

what are some common sources of infection?

Answer 5

environmental- lengionella pneumophilia
food/water- food poisoning- onward transmission possible
animals- rabies- onward transmission possible

Question 6

what is an infectious dose and what affects it (factors determining transmissibility)?

Answer 6

infectious dose is the number of microorganisms needed to cause infection
it varied by- microorganism, presentation of microorganism and the immunity of potential host

Question 7

describe the interventions affecting the 4 Ps and give examples

Answer 7

pathogen- reduction or eradication

• pathogens-antibacterials including disinfectants, decontamination, sterilisation;
• vectors- eliminate vector breeding sites

patient- improve health- nutrition and medical treatment, immunity passive eg maternal antibody and intravenous immunoglobin; active- vaccination

practice- behavioural change- safe sex safe disposal of sharps and food and drink prep, protective equipment- clothing, gloves downs
- avoid pathogen or vector

place- environmental, engineering- safe water, safe air, good quality housing, well designed healthcare facilities

Question 8

give examples of infections which can spread direct from person to person and indirectly from person to person?

Answer 8

direct- person to person- influenza, norovirus, neisseria gonorrhoea
indirect- person to person- mosquitos- malaria

Question 9

what are the good and bad consequences of controlling/preventing infection?

Answer 9

good- decreased incidence or elimination of disease/organism- smallpox, polio, dracunculiasis
bad- decreased exposure to pathogen- decreased immune stimulus- decreased antibody- increased susceptibility= outbreak
- later average age of exposure- increased severity- eg polio, Hep A, chicken pox, congenital rubella syndrome

Question 10

describe where resistance came from?

Answer 10

research analysing 30,000 year old bacteria has demonstrated genes coding for resistance to B lactams, tetracyclines and glycopeptide antibiotics

Question 10

how is it thought that resistance has developed?

Answer 10

increase in resistance could be due to incorrect and overuse of ABs

Question 11

what will the use of antimicrobials eventually lead to?

Answer 11

all exposure of bacteria to antimicrobials will always lead to antimicrobial resistance and resistance is irreversible

Question 11

what are the 3 consequences of antibacterial resistance?

Answer 11

treatment failure, prophylaxis failure, economic costs

Question 12

what does multi-drug resistant (MDR), extensively dug resistant (XDR) and pan-drug resistant (PDR) mean?

Answer 12

MDR- non susceptibility to at least 1agent in 3 or more antimicrobial categories
XDR- non susceptibility to at least 1agent but in all but 2 or less antimicrobial categories
PDR- non susceptibility to all agents in all antimicrobial categories

Question 13

what is the discovery void?

Answer 13

peak in new AB already passes, last new AB developed in 1987

Question 14

what is antimicrobial stewardship?

Answer 14

we have to look after what we have left- need to be careful with AB use as the way we are currently using them must not be effective

Question 15

what 3 kinds of studies evidence that antibacterials cause resistance?

Answer 15

1. lab evidence- provides biological plausibility- showing resistance can develop when exposed to low doses
2. ecological studies- related levels of antibacterial use in a population with levels of resistance- doesnt prove related in casual way
3. individual level data- relates prior antibacterial use in an indiviual with the subsequent presence of bacterial resistance- eg pt having ABs linked to increased rate of carriage of resistant bacteria in pts for up to 12 months- 2nd infection harder to treat for 1yr - longer duration or multiple courses= higher resistance rates

Question 16

what are the 2 ways that bacteria develop resistance?

Answer 16

mutations or acquisition of mutated genes

Question 17

what are the objectives of antimicrobial stewardship?

Answer 17

appropriate use of ABs,
optimum clinical outcomes
minimise toxicity and other adverse events
reduce cost for infection
limit selection for antimicrobial resistant strains

Question 18

what are the key elements of an antimicrobial stewardship programme?

Answer 18

1. MD team- medical microbiologist , antimicrobial pharmacist, infection control nurse
2. surveillance- process measure- what people are doing- how many prescribed to different wards, outcome measures- what results get as a consequence - pt outcomes, emergence of resistance, C dif infection rate
3. interventions- persuasive, restrictive, structural

Question 19

describe the 3 stewardship intervention types- examples

Answer 19

1. persuasive- education, consensus- make sure all doing the same, opinion leaders, reminders, audit- compare prescribing of others, feedback
2. restrictive- restricted susceptibility reporting- cannot get certain ABs in Leicester, formulary restriction, prior authorisation- pharmacy wont issue unless authorisation from microbiologist, automatic stop orders
3. structural- computerised records, rapid lab tests- confirm susceptibility before prescribing, expert systems, quality monitoring

Question 20

what are the potential risks of stewardship?

Answer 20

under-treating pts- increased risk of readmission