Microbiology Compilation Flashcards Preview

RB Y2 CLASP - Sepsis > Microbiology Compilation > Flashcards

Flashcards in Microbiology Compilation Deck (47):
1

commensals of the mouth 

  • strep viridans 
  • candida 
  • neisseria 
  • anaerobes 

2

bowel commensals 

  • Enterococci
  • Anaerobes: clostridium and bacteroides
  • Coliforms

3

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gamma haemolysis

4

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alpha haemolysis 

5

name 4 methods for detecting bacteria 

  • chromogenic media
  • MALDI-TOF 
  • PCR 
  • whole genome sequencing 

6

non/lactose fermenter enterobacteriaceae

  • Lactose fermenters: E. coli, Klebsiella, Enterobacter
  • Non-lactose fermenters: Salmonella, Proteus

7

what are 3 encapsulated bacteria 

  • h influenza b
  • pneumococcal 
  • neisseria meningitidis 

hyposplenism makes host susceptible to infections from encapsualted organisms 

8

name 2 spirochaetes 

treponema pallidum 

borrelia burgodorferi (lyme disease)

9

what are most false blood cultures due to 

contamination with skin commensals due to poor technique

10

how is influenza confirmed 

nasopahryngeal swab and doing PCR 

11

when is CSF examined 

  • when there is suspicion of possible meningitis - via lumbar puncture
  • wouldnt normally do this in the clinical setting 
  • check child with clotting screen first  

12

indications for urine dipstick 

  • avoid in the elderly 
  • avoid in catheterized patients as it is often colonised 
  • not the test of choice in sepsis 

13

indication for urine catheter samples 

  • do not send unless it is considered to be a source of infection and the patient appears infected 

14

indications for urine culture 

  • complicated infection 
  • male infection 
  • recurrent UTI in female 

15

what is the aim of antimicrobial stewardship 

optimal selection, dosage, and duration of treatment - prudent prescribing 

and explaining, reassuring and educating the large group of patients who dont need ABx

16

4Ds of antimicrobial therapy 

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17

what does de-escalation involve 

  • moving from IV to oral - IV therapy must be reviewed every 12-24 hours 
  • moving to a narrower spectrum 
  • watch microbiology results 

18

indications for IV route 

  • sepsis 
  • oral compromised 
  • post surgery 
  • ostemyelitis 
  • febrile with neutropenia or IS 

IV just gives faster systemic absorption 

19

define pharmacodynamics 

the relationship between infection outcome and drug outcomes 

20

define pharmacokinetics 

effect of body's processes on the drug 

21

minimum inhibitory concentration 

  • a measure of the potency of the drug against a given pathogen 
  • the concentration required to kill 99.9% of organisms within 18-24 hours (tube/well containing pathogen visually clear)

22

what type of dosing gives optimal outcomes 

  • high dosages for shorter duration 
    • longer increases risk for C diff and resistance 
  • keeping to recommended dose interval is important in effectiveness 

23

what can too high dosing cause 

harm 

resistance 

24

outline the start SMART then FOCUS diagram 

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25

action of beta lactams 

inhibit cell wall biosynthesis by binding to the enzymes that cross link peptidoglycans 

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26

are beta lactams bacteriostatic or cidal 

bacteriocidal 

27

what is penicillin allergy due to 

degradation product of beta lactams, true allergy exists in <0.05%

28

aztreonam 

  • beta lactam 
  • can be used in penicillin type 1 allergy 
  • active against Gram negative bacteria 
  • used in Gentamicin resistance 

29

how do bacteria develop resistance to beta lactams  

synthesise a beta lactamase, this breaks open the beta lactam ring and inactivates the drug 

eg MRSA 

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30

how can beta lactam resistance be overcome 

ABx are given with a beta lactamase eg clavulanic acid 

31

what are ESBL susceptible to 

carbapenems

32

how can resistance be acquried to an ABx

  • Organism specific rate of mutation, some are hypermutators
  • Random mutations that can be induced by antibiotics
  • Bacterial burden – mutation is more likely if there is a higher bacterial load
  • Efflux pumps

33

what sites are harder for ABx to get to 

in general, tight junctions eg CNS, eyes, prostate 

34

gentamicin toxicity 

kidneys and CNVIII - dizziness and deafness 

- contraindicated in renal problems - can only be given for a max of 24 hours 

35

how long in total can gentamicin be given for 

72 hours 

36

which ABx can cause tendonitis 

quinolones - achilles and extensor knee mechanism?

37

which ABx have anti toxin effects 

clindamycin and linezolid 

38

common adverse effects of ABx

nausea and vomiting 

39

C Diff causing ABx 

  • all ABx carry some risk 
  • 4 C's - Ciprofloxacin (fluoroquinolones), Clindamycin, Cephalosporins (Ceftriaxone) and Co-amoxiclav
  • remember levofloxacin 
  • kill off the normal gut bacteria and allow the overgrowth of C diff 
  • PPIs - reduce the acid produced in the stomach which is normally the first line of defence 

40

does treatment time influence the risk of C diff 

yes - longer treatment 

also hospitalization time 

IC 

41

how long after ABx may C diff occur 

up to 12 weeks 

42

C diff infection 

  • c diff are gram positive, spore forming, anaerobic rods that produce toxins A and B 
  • toxin A in an enterotoxin and toxin B causes bloody diarrhoea 
  • these cause an inflammatory response in the large intestine that leads to increased vascular permeability and pseudomembrane formation 

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43

clinical features of C diff infection  

range from mild diarrhoea to profuse, watery, haemorrhagic colitis 

abdominal pain and vomiting 

44

who tends to get C diff infections 

elderly women 

45

investigation of C diff 

stool toxin 

46

management of C diff infection 

mild: oral metronidazole 

severe: oral vancomycin ± IV meronidazole 

47

coverage of MRSA 

vancomycin - gram positive