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* year 2 Clinical Pathology > advanced micro > Flashcards

advanced micro Flashcards

1
Q

what 5 parts of a patients social history could be relevant to ascertain the causative organism of an infection?

A
  • travel
  • occupation
  • hobbies
  • animal contact
  • sexual history
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2
Q

at what temperature is someone deemed to have a definite fever?

A

38 degrees (or above)

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3
Q

FBC blood test: what types of blood cells are raised in:

  • bacterial infection?
  • viral infection?
A

bacterial = neutrophils

viral = lymphocytes

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4
Q

what colour does:

  • gram positive stain?
  • gram negative stain?
A

gram positive = purple

gram negative = pink/red

“stuff that’s red is bad”

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5
Q

what is the difference between an antibiotic and an antibacterial agent?

A

antibiotic
- chemical PRODUCTS OF MICROBES that inhibit/kill bacteria

antibacterial agent
- ANY chemical that inhibits/kills bacteria (irregardless of source)

nb often used interchangably in practise

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6
Q

what does minimum inhibitory concentration (MIC) or minimum bactericidal/fungicidal concentration (MBC/MFC) mean?

what does it mean if there is a low MIC?

A

MIC = minimum conc of antimicrobial agent at which visible growth is inhibited

MBC/MFC = minimum conc of antimicrobial agent at which most organisms are killed

a low MIC (or MBC/MFC) means that the bacteria (or fungi) is killed by a very small amount of antimicrobials - ie it’s sensitive

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7
Q

what type of cell mechanics tend to be targetted in:

  • bacteriostatic antibiotics?
  • bacteriocidal antibiotics?
A

bacteriostatic
- eg protein synthesis inhibitors

bacteriocidal
- eg attack cell wall or membrane

nb in vivo little difference, mainly terms used in lab

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8
Q

in terms of antimicrobial interactions, define the following terms:

  • synergism?
  • antagonism?
  • indifference?
A

synergism
- activity of 2 antimicrobials given together is greater than the sum of their activity if given seperately

antagonism
- one agent diminishes the activity of the other

indifference
- activity unaffected by the addition of another agent

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9
Q

what is the component of the fungal cell wall which a lot of anti-fungals target?

what is another component of the fungal cell wall?

A

beta-1,3-glucan

chitin - antifungals don’t currently target this

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10
Q

what classes of antimicrobials are cell wall synthesis inhibitors:

  • in bacteria? 2
  • in fungi? 1
A

antibacterial agents:

  • B-lactams
  • glycopeptides

antifungal agents:
- echinocandins

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11
Q

what is an anti-tuberculous agent which targets the cell wall of TB?

A

cycloserine

“need lots of cycles of treatment to treat drug-resistant TB”

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12
Q

in terms of drug delivery, what does parenterally mean?

A

injection or infusion
- eg IM, IV, subcutaneous

(ie NOT orally)

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13
Q

how do B-lactam antibiotics kill bacteria?

A

interfere with function of ‘penicilin binding proteins’

  • these are transpeptidase enzymes involved in peptidoglycan cross-linking
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14
Q

what three types of drug name suffixes or prefixes indicate that an antibiotic is a B-lactam antibiotic?

why is this important to know in clinical practise?

what are the 2 main exceptions to this?

A

suffixes:
= -cillin (penicillins)
= -penem (carbapenems)

prefixes:
= cef- (cephalosporins)

people with ‘penicilin allergies’ are allergic to ALL B-lactam antibiotics

other B-lactams:

  • aztreonam (a monobactam)
  • co-amoxiclav (combination of an antibiotic and an acid)
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15
Q

name 4 different types of penicillins (with at least one example for each)

A

penicillins

  • benzylpenicillin
  • phenoxymethylpenicillin

broad spectrum penicillins

  • amoxicillin
  • pivemecillinam

penicillinase-resistant penicillin:
- flucloxacillin

beta lactam-betalactamase inhibitor combinations

  • amoxicillin-clavulanic acid (aka co-amoxiclav
  • piperacillin-tazobactam
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16
Q

name 3 different classes of B-lactam antibiotics (with at least one example for each) which AREN’T penicillins!

A

monobactam
- aztreonam

cephalosporins

  • cephalexin
  • cefuroxime
  • cefotaxime
  • ceftriaxone
  • ceftazidime

carbapenems

  • ertapenem
  • imipenem
  • meropenem
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17
Q

what enzymes do penicillin-resistant bacteria produce?

what is their mechanism of action?

A

B-lactamase enzymes

enzyme hydrolyses, thus inactivating, B-lactams

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18
Q

what does BLBLI stand for?

name 2

why are they used?

what problems can they cause? 2

A

B-lactam/B-lactamase inhibitor combinations

amocixillin-clavulanate

  • aka augmentin
  • aka co-amoxiclav

piperacillin-tazobactam
- aka tazocin

increases the spectrum of antibiotics by deactivating B-lactamases produced by the bacteria

  • very broad spectrum (predispose to C. diff infection)
  • names don’t have -illin/cef- so importance of penicillin allergy may be missed
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19
Q

what is another class of antibacterial agents (bar B-lactams) which targets bacterial cell walls?

give 2 examples.

when are they used?

A

glycopeptides

  • vancomycin
  • teicoplanin
  • penicillin resistance
  • penicillin allergy
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20
Q

name a class of antifungals which target fungal cell walls.

give at least one example (what is the suffix?)

what is the mode of action?

A

echinocandins

  • anidulafungin
  • caspofungin
  • micafungin

-fungin suffix

inhibition of B-1,3-glucan synthase

nb very good as few side effects

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21
Q

name 5 classes of anti-bacterial agents which work by targetting protein synthesis

give at least one example for each

A

aminoglycosides

  • gentamicin
  • amikacin

Macrolides

  • erythromycin
  • clarithromycin (fewer side effects than erythromycin)
  • azithromycin

lincosamide
- clindamycin

tetracyclines

  • tetracycline
  • doxycycline
  • tigecycline (more broad, active against gram -ve)

oxazolidionones
- linezolid (used against MRSA + nasty infects but lots of side effects)

(nb also fusidic acid)

nb macrolides and aminoglycosides are ones used most in practise

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22
Q

name 2 antiobiotics which are DNA synthesis inhibitors

mehanism of action:
- both agents inhibit folate synthesis (act at different steps in pathway)

A

trimethoprim

sulfonamides

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23
Q

name a combination treatment of an anti-fungal and an anti-biotic which are normally given together as an antibacterial agent but is also effective a type of fungal pneumonia seen in immunosuppressed patients

A

co-trimoxazole

trimethoprim-sulfamethoazole

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24
Q 
name a class of antibiotics which are DNA synthesis inhibitors
- give 2 examples (suffix?)

mechanism of action:
- inhibit remodelling of DNA during DNA replication

A

quinolones
- nb most in clinical use are actually fluoroquinolones (incl egs below)

  • ciprofloxacin
  • levofloxacin

-oxacin suffix

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25
Q

name an anti-biotic which is a RNA synthesis inhibitor

what infection is it predominately used against?

A

rifampicin

cornerstone of anti-tuberulous chemotherapy

  • ie used against TB
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26
Q

name a class of antibacterial agents which target bacterial cell MEMBRANES

give 2 examples
(gram -ve or +ve?)

A

cyclic lipopeptides

  • colistin (gram -ve)
  • daptomycin (gram +ve)

nb these are old but having to use them more + more due to anti-biotic resistance

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27
Q 
name 1 class of antifungal agents which target fungal cell MEMBRANES
- and 2 other different antifungals (that target cell membranes)

what specific component of fungal cell membranes do these drugs target?

A

azoles

  • clotrimazole
  • fluconazole

terbinafine

nyacin

target: ergosterol

nb ergosterol is only in fungal cell membranes, not human cell membranes!

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28
Q

metronidazole:

  • how it targets bacteria?
  • what other type of organism does it target?
A

targets DNA replication

protazoa

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29
Q

give 4 examples of groups of bacteria which have innate resistance to specific antibacterial agents

A

nb remember this is what DOESN’T work!

gram-negatives:

  • glycopeptides (vancomycin, teicoplanin)
  • daptomycin

gram-positives:

  • aztreonam
  • colistin

anaerobes:
- aminoglycosides (amikacin, gentamicin)

streptococci:
- aminoglycosides (amikacin, gentamicin)

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30
Q

name two methods by which bacteria can acquire genes, which encode an antibiotic resistance mechanism.

A
  • new mutation

- horizontal transfer (genetic exchange between bacteria, via plasmids)

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31
Q

name the 5 possible types of resistance mechanisms (can be innate or acquired)

A
  • absent target
  • decreased permeability
  • target modification
  • enzymatic degradation
  • drug efflux
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32
Q

what is the most common acquired resistance mechanism found in anti-fungal-resistant candida?

A

drug efflux

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33
Q

what mechanism is present in MRSA which results it being resistant to many antibiotics?

which antibiotics is it resistant to?

A

target modification
- altered penicillin-binding protein (encoded by MecA) does not bind B-lactams

resistant to ALL B-lactams!

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34
Q

what is the most common mechanism of resistance to B-lactams?

A

enzymatic degradation

- bacteria produce penicillinases (inactivate penicillin etc)

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35
Q

what does ESBL stand for? what are they?

A

extended-spectrum B-lactamases

enzymes produced by B-lactam resistant bacteria which inactivate penicillins AND cephalosporins

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36
Q

what does VRE stand for?

what method of resistance is found in these organisms?

A

vancomycin resistant enterococci

target modification
- mutation results in reduction of binding to vancomycin 1000-fold

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37
Q

what does minimum inhibitory concentration (MIC) mean?

A

the lowest concentration of an antimicrobial drug (antibiotics/antifungals/etc) that will inhibit the visible growth of a microorganism after overnight incubation

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38
Q

which types of viruses tend not to have lipid envelopes?

A

ones that replicate in the gut

eg:

  • adenoviruses
  • enteroviruses
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39
Q

what type of DNA/RNA to acute/chronic viruses tend to have?

give at least 4 examples of each

A

acute - RNA

  • influenza
  • measles
  • mumps
  • hep A

chronic - DNA

  • latent with/without recurrences:
    • herpes simplex
    • varicella zoster
    • cytomegalovirus
  • persistent:
    • HIV
    • HTLV
    • hep B
    • hep C
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40
Q

rashes:

  • difference between vesicular and non-vesicular rash?
  • examples of 5 viruses which cause non-vesicular rashes?
  • examples of 3 viruses which cause vesicular rashes?
A

vesicular just means vesicles are present

non-vesicular rashes:

  • measles
  • rubella
  • parvovirus
  • adenovirus
  • HHV6 (human herpes virus 6)

vesicular rashes:

  • chicken pox (HHV3)
  • herpes simplex (HHV1/2)
  • enteroviruses
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41
Q

name 6 viruses which can cause respiratory infections

A
  • influenza A/B
  • respiratory syncitial virus
  • parainfluenza virus
  • human metapneumovirus
  • rhinovirus
  • coronavirus (incl SARS)
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42
Q

name 5 viruses which can cause gastroenteritis

A
  • rotavirus
  • norovirus
  • astrovirus
  • sapovirus
  • adenovirus (group F)
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43
Q

name 5 viruses which can cause encephalitis/meningitis

A
  • HSV (reactivation)
  • enteroviruses
  • rabies
  • japanese encephalitis virus
  • nipah virus
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44
Q

when would you use antivirals for acute infections in general population? 4

A
  • primary HSV + herpes simplex encephalitis
  • chickenpox in adolescents + adults
  • shingles in eye
  • elderly (shingles, influenza)

nb 99% of people with viral infections won’t need antivirals

nb many viruses don’t actually damage the host cell, it’s the immune response to the virus which causes the damage

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45
Q

what is AZT (azidothymidine)?

what’s it used for?

A

a nucleoside reverse transcriptase inhibitor (NRTI)

  • inhibits reverse transcriptase (used by retroviruses to transform RNA -> DNA)

used against the reterovirus HIV
- inhibits its replication

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46
Q

what are the two types of NRTIs used to treat HIV?

give 2 examples of each

A

NRTI = nucleoside reverse transcriptase inhibitor

pyrimidine analogues:

  • zidovudine (thymidine analogue)
  • lamivudine (cytosine analogue)

purine analogues:

  • abacavir
  • tenofovir
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47
Q

which NRTIs are effective against hep B?

A
  • lamividine

- tenofovir

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48
Q

name 2 herpes virus polymerase inhibitors.

give 2 strains of herpes virus which each is effective against

A

aciclovir

  • herpes simplex
  • varicella zoster

ganciclovir
- cytomegalovirus
- HHV6 (human herpes virus 6)
(- as well as HSV + VZV)

nb MUST KNOW THESE!

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49
Q

name an antiviral used to treat hep C

how does it work?

A

sofosbuvir

hep C RNA polymerase nucleotide inhibitor

“people with hep C tend to be sat on their SOFAS taking drugs”

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50
Q

apart from NRTIs, what is another type of anti-viral drug used to treat HIV?

give 2 examples

A

non-nucleotide reverse transcriptase inhibitors (NNRTIs)

(work the same as NRTIs but structure is not based on nucleotides)

  • efavirenz
  • nevirapine
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51
Q

what is another type of antiviral which is used to treat both HIV and hep C?

give some examples

A

protease inhibitors (PI)

HIV

  • atazanavir
  • darunavir
  • ritonavir

Hep C

  • paritaprevir
  • grazoprevir
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52
Q

what does HAART stand for?

what’s it used to treat?

what does it consist of?

A

highly active antiretroviral therapy

HIV

  • started when CD4 count falls
  • aims to switch off virus replication
  • taken lifelong
  • 2 NRTIs + NNRTI
  • 2 NRTIs + boosted PI

nb now problems with toxicity

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53
Q

what are exogenous interferons used to treat? 6

A
  • some leukaemias
  • AIDS related Kaposi’s sarcoma
  • chronic hep B
  • chronic hep C
  • MS
  • genital warts (caused by HPV)
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54
Q

what are two anti-virals used in the treatment of influenza?

what is the mechanism?

A

osteltamivir
- “TAMI flu”

zanamavir

  • both are neuramididase inhibitors
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55
Q

what is the antiviral used for the treatment of RSV, hep C and hep E?

A

ribavirin

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56
Q

when would you deliberately use bacteriocidial antibacterial agents (as opposed to bacteriostatic)?

A

if the patient had a compromised immune system

- as bacteriostatic drugs require endogenous immmune system to ‘finish off the job’

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57
Q

what is the difference between:

  • sepsis?
  • severe sepsis?
  • septic shock?
A

sepsis
= presence (probably/definite) of infection with systemic manifestations of infection

severe sepsis
= sepsis-induced tissue hypoperfusion or organ dysfunction

septic shock
= sepsis-induced hypotension, persisting despite adequate fluid resuscitation

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58
Q

what does SIRS stand for?

what can it be due to?

what are the most common/obvious acute clinical signs? 3

A

systemic inflammatory response syndrome

  • may be due to an infection but can also be autoimmune etc
  • low BP
  • high RR
  • altered mental state
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59
Q

what is seen as a more specific biochemical marker for systemic bacterial infection than CRP?

A

procalcitonin
- doesn’t react to viral/fungal malignancy

nb CRP has a 24hr time lag

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60
Q

what happens to platelet levels in infection?

A
  • platelets can go UP in chronic inflammation

- but can go down in severe acute infection (DIC)

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61
Q

what is the ‘sepsis 6’?

A

BUFALO

B - take Blood cultures
U - measure Urine output
F - give IV Fluid
A - give broad-spectrum Antibiotics
L - measure serum Lactabe + Hb
O - give high-flow Oxygen

take 3 things:

  • blood cultures
  • lactate/Hb
  • urine

give 3 things:

  • fluid
  • antibiotic
  • oxygen

nb start antibiotics within ONE hour of severe sepsis/septic shock

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62
Q

why are nitrites present on urine dipstick test if infection is present?

A

nitrAtes are excreted by kidney normally, some bacteria will reduce them to nitrItes -> nitrites in urine

  • so useful test, but not: not all bacteria do this!!
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63
Q

what are the 3 main groups of bacterial flora in the gut?

what is the likelihood of each causing a UTI?

what is a group of bacteria of skin flora which can, rarely, cause UTIs?

A

gram negative bacilli
- almost always (mainly e coli)

anaerobes

  • very rarely
  • if see, suspect something like fistula

enterococci
- can see, but uncommon

from skin flora
= staphylococci

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64
Q

what type of staphylococcus if commonly the cause cystitis in younger women?

A

staph saprophyticus

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65
Q

what is urine likely to look like macroscopically if there is a UTI?

A

cloudy

nb ‘smelly’ urine does not necessarily mean an infection, more to do with what you’ve eaten

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66
Q

which 3 antibiotics are most likely to result in C. diff infection?

A
  • ciprofloxacin (a fluoroquinolone)
  • cefuroxime (a cephalosporin)
  • co-amoxiclav
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67
Q

what is the treatment time for an uncomplicated UTI?

A

3 days of Abx

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68
Q

what factors should influence your choice of antibiotics:

  • related to Abx? 6
  • related to the patient? 6
A

Abx related:

  • spectrum
  • bacteriostatic/cidal
  • tissue penetration
  • does it need to be monitored?
  • side-effects
  • route of administration

patient related:

  • severity of illness
  • site of infection
  • immunosuppresed?
  • co-morbidities
  • co-medications
  • allergies
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69
Q

what sort of empirical Abx should be given in:

  • local infection?
  • sepsis?
A

local infection
- ‘educated guess’, treat for most likely pathogen

sepsis
- give broad spectrum antibiotics

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70
Q

what broad types of cocci are:

  • gram positive? 3
  • gram negative? 2
A

gram positive:

  • staphylocci
  • streptococci
  • enterococci

gram negative:

  • meningococci
  • gonococci (cause of gonorrhoea)
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71
Q

how are streptococci classified?

A

alpha haemolytic strep
- eg pneumococci

beta haemolytic streptococcus
- further categorised into group A, B, C or… etc strep

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72
Q

what type of organisms are seen as part of normal skin flora?

A

staphylococci

  • coagulase negative staph (v unlikely to cause infection, only in immunosuppressed patients or something like central lines)
  • staph aureus

streptococci

  • alpha haemolytic
  • beta haemolytic
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73
Q

what type of organisms commonly cause skin + soft tissue infections (SSTIs)?

A

staph aureus

  • MSSA (methicilling sensitive…)
  • MRSA

beta haemolytic strep

  • group A strep
  • strep pyogenes
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74
Q

what sort of normal colonising flora are seen in the:

  • mouth/URT? 2
  • nasopharynx? 5
A

mouth/URT:

  • streptococci
  • anaerobes
    (also: gram -ve cocci, candida, staphylococci)

nasopharynx:

  • strep pneumoniae
  • haemophilus influenzae (gram -ve cocci)
  • moraxella catarrhalis (gram -ve cocci)
  • other gram negative cocci
  • staph aureus

nb majority of URTI are caused by viruses

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75
Q

common causes of sore throat/tonsillitis:

  • viral? 2
  • bacterial? 2
A

viral:
- epstein barr virus
- rhinovirus
( and others)

bacteria:

  • group A strep
  • anaerobes
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76
Q

common causes of sinusitis:

  • acute? 2
  • chronic? 1
A

acute sinusitis:

  • strep pneumoniae
  • haemophilus influenzae

chronic:
- anaerobes

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77
Q

what are the common causes of pneumonia:

  • bacterial CAP? 3
  • bacterial HAP? 2
  • atypical bacteria? 3
  • viral? 2
A

bacterial CAP:

  • STREP PNEUMO
  • haemophillus influenzae (GNC)
  • moraxella catarrhalis (GNC)

bacterial HAP:
- gram -ve bacilli
- staph aureus
(+ ones that cause CAP)

atypical bacteria:

  • mycoplasma
  • chlamydia
  • legionella

viruses:

  • influenza
  • respiratory syncitial virus

nb virus can causes pneumonia by themselves but commonly just damage the mucosa -> secondary bacterial infection

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78
Q

what is a common cause of ventilator-associated pneumonia?

A

pseudomonas (a gram negative bacillus)

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79
Q

what are the two commonest causes of encephalitis?

A

herpes simplex viruses

enteroviruses

nb encephalitis almost always viral

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80
Q

common bacterial causes of meningitis:

  • in all ages? 3
  • neonates? 3
  • immunosuppressed? 2
  • post-neuro op? 1
A

in all ages:

  • neisseria meningitis
  • strep pneumoniae
  • haemophilus influenzae

neonates:

  • group B strep
  • gram neg bacilli
  • listeria

immunosuppressed:

  • gram neg bacilli
  • listeria

post neuro op
- + skin organisms (eg staph)

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81
Q

what type of bacteria tend to cause cerebral abscesses? why?

A

normally occur secondary to a local infection so tend to be caused by resp tract flora

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82
Q

what are the three main types of blood stream infections?

what are they often caused by?

A
  • infective endocarditis (native/prosthetic)
  • intracardiac device infections
  • graft infections
  • staphylococci
  • streptococci
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83
Q

what are the four antibiotics/types of antibiotics which are most likely to result in c diff infections?

A
  • clindamycin
  • co-amoxiclav
  • cephalosporins
  • fluoroquinolones (-floxacin)
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84
Q

Penicillin G + V

  • their other names?
  • routes of administration?
  • act well against? 1
  • act okay against? 2
  • not great against? 1
  • destroyed by B-lactamases?
A

Penicillin G

  • benzylpenicillin - “ben pen”
  • IV/IM

penicillin V

  • phenoxymethylpenicillin
  • oral

good for:
- streptococci

okay for:

  • many anaerobes
  • some GNC

bad for:
- staphylocci (as often produced b-lactamases)

yes, destroyed by b-lactamases

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85
Q

flucloxacillin:

  • route?
  • act well against? 2
  • act okay against? 2
  • don’t work for? 1
  • destroyed by b-lactamases?
A

oral/IV

good for:

  • streptococci
  • staphylcocci

okay for:

  • many anaerobes
  • some GNC

don’t work for:
- MRSA

NOT destroyed by b-lactamases

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86
Q

amoxicillin:

  • route?
  • act well against? 3
  • not great against? 1
  • destroyed by b-lactamases?
A

oral/IV

good for:

  • streptococci
  • enterococci
  • some GNB

not good for:
- staphylococci

yes, destroyed by b-lactamases

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87
Q

co-amoxiclav:

  • constituents?
  • act well against? 5
  • don’t work for? 2
A
  • amoxicillin
  • clavulanic acid (inhibits b-lactamases)

good for:

  • streptococci
  • staphylococci
  • most enterococci
  • many GNB
  • many anaerobes

don’t work for:

  • extended spectrum b-lactamase (EBSL) producers
  • MRSA
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88
Q

tazocin:

  • constituents?
  • act well against? 7
  • don’t work for? 2
  • problem with it? 1
A
  • piperacillin
  • tazobactam (inhibits b-lactamases)

good for:

  • staphylococci
  • most streptococci
  • most enterococci
  • anaerobes
  • PSEUDOMONAS
  • GNC
  • GNB

doesn’t work for:

  • ESBL producers
  • MRSA

doesn’t cross blood brain barrier!

nb not much stuff is active against pseudomonas!

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89
Q

macrolides:

  • examples? 3
  • effective against? 3
  • not great against? 1
A
  • erythromycin (lots of GI side effects)
  • clarithromycin (fewer GI side effects)
  • azithromycin (broader, also covers gram -ve stuff)

good for:

  • atypical organisms (chlamydia, gonorrhoea, mycoplasma, legionella)
  • staphylococci
  • streptococci

not good for:
- gram negatives

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90
Q

glycopeptides:

  • examples? 2
  • route?
  • good for? 3
  • don’t work for? 1
A
  • vancomycin
  • teicoplanin

IV
- except oral vancomycin, not absorbed but works in gut, used for c diff

good for:
- staphylococci
- streptococci
- enterococci
basically gram positive stuff

don’t work for:
- gram negative (intrinsic resistance)

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91
Q

clindamycin:

  • route?
  • good for? 3
  • problems with? 2
  • good things about it? 2
A

oral/IV

good for:
- staphylococci
- streptococci
- some anaerobes
basically gram positive

problems:

  • variable acquired resistance (do sensitivity test)
  • associated with c diff

good things:

  • anti-toxin action
  • good tissue penetration (good for SSTIs)
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92
Q

ciprofloxacin:

  • class?
  • route?
  • good for? 4
  • poor for? 2
  • problem? 1
  • good things? 2
A

fluoroquinolones

oral/IV

good for:

  • gram negatives
  • pseudomonas
  • staphylococci
  • atypicals

poor for:

  • streptococci
  • anaerobes

problem:
- associated with c diff

good things:

  • good absorption/tissue penetration
  • intracellular activity

nb aka early fluoroquinolones

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93
Q

levofloxacin:

  • class?
  • route?
  • good for? 3
  • poor for? 2
  • problem? 1
  • good things? 2
A

fluoroquinolones

oral/IV

good for:

  • gram positive
  • streptococci
  • atypicals

nb ‘respiratory FQ’ - tend to be used for pneumonias

poor for:

  • gram negatives
  • pseudomonas

problem:
- associated with c diff

good things:

  • good absorption/tissue penetration
  • intracellular activity
94
Q

aminoglycosides

  • examples? 2
  • route?
  • good for? 2
  • don’t work for? 2
  • problems? 2
A
  • erythromycin (only one that’s really used!)
  • amikacin

IV/IM/(topically)

good for:

  • gram -ve bacilli (incl pseudomonas)
  • staphylococci

don’t work for:

  • streptococci
  • anaerobes

problems:

  • need monitoring
  • nephrotoxic + ototoxic
95
Q

metronidazole:

  • route?
  • used for? 3
  • side effects? 3
A

IV/oral

good for:

  • anaerobes (bacteria)
  • protozoa (eg malaria)
  • some helminths

side effects:

  • can’t have with alcohol
  • GI upset
  • neurotoxicity
96
Q

what does necrotising fasciitis tend to be caused by? 2

A
  • group A strep

or:

  • mixed infection (in people who are immunosuppressed or have comorbidities)
97
Q

what antibiotics are used to treat MRSA? 4

A
  • doxycycline
  • clarithromycin
  • clindamycin
  • trimethoprim/co-trimoazole
98
Q

what is the empirical treatment for CAP?

A

co-amoxiclav

+clarithromycin if very unwell

99
Q

what are the two different types of immune response (relevant to vaccines)? and which Ig is predominately found in each?

A

primary immune response:

  • develops in weeks following first exposure to an antigen
  • slow and weak
  • mainly IgM
  • “I’m ill”

secondary immune response

  • reactivated when body encounters antigen again
  • fast and strong
  • mainly IgG
  • “I’m Gone”
100
Q

vaccinations which induce active immunity:

  • live vaccines? 4
  • inactivated organisms? 3
  • componenets of organisms? 2
  • inactivated toxins? 2
A

live vaccines:

  • MMR
  • BCG
  • yellow fever
  • varicella zoster (chicken pox/shingles)

inactivated organisms:

  • pertussis (whooping cough)
  • typhoid
  • polio

components of organisms:

  • influenza
  • pneumococcal

inactivated toxins:

  • diptheria
  • tetanus

nb the more ‘live’ the vaccine the stronger and longer-lasting the immunity
- but contraindicated in immunosuppressed

101
Q

vaccines which give passive immunity:

  • HNIG - what is it?
  • specific? 5
A

specific:

  • tetanus
  • botulism
  • hep B
  • rabies
  • varicella zoster

nb passive immunity is much shorter lived than active

102
Q

what is the ‘susceptible population’? 3

A

people who are at risk of infection from an infectious person:

  • has not encountered/been vaccinated against it
  • unable to mount an immune response
  • vaccination is contraindicated
103
Q

define term: decontamination

A

the destruction/removal of micro organisms from a surface/object

104
Q

define term: sterilisation

A

complete killing (or removal) of ALL types of micro-organisms

105
Q

define term: disinfection

A

removal or destruction of sufficient numbers of potentially harmful micro-organisms to make an item safe to use

nb almost always chemical

106
Q

sterilisation methods? 4

A

heat

  • moist (eg autoclave)
  • dry (eg oven)

chemical

  • gas
  • liquid

filtration

ionising radiation

107
Q

define term: antisepsis

A

removal/destruction of sufficient numbers of potentially harmful micro-organisms on damaged skin/living tissues

ie disinfectant applied to living tissues

nb requires a disinfectant with minimal toxicity

108
Q

what type of decontamination should be used on items/devices that:

  • will enter sterile body areas or break the skin?
  • will contact mucous membranes or that will be contaminated with bodily fluids?
  • thatonly contact intact skin (no bodily fluids)?
A

sterile body areas/break skin:
- sterilise

mucous membranes/bodily fluids:
- disinfect

intact skin:
- clean

109
Q

how are these things decontaminated:

  • reusable surgical instruments?
  • flexible endoscopes?
  • syringe needle?
  • central venous catheter (CVC) insertion site?
A

reusable surgical instruments:
- sterilisation by autoclave (moist heat)

flexible endoscopes:
- ‘high level’ disinfection via chemicals

syringe needle:
- sterilised by gamma irradiation before use (disposal after use)

CVC insertion site:
- antisepsis via chemicals (2% chlorhexidine in 70% isopropyl alcohol)

110
Q

when should you do a HIV test? 2

A
  • acute medical admission
  • new GP registration

nb leeds is an area of high prevalence

111
Q

lumbar puncture for meningitis:

    • normal findings?
    • viral findings?
    • bacterial findings?
    • fungal or TB findings?

categories are:

  • opening pressure
  • appearance of CSF
  • WBC count
  • WBC differentiation
  • protein (g/L)
  • glucose (CSF:blood ratio)
A

normal:

  • opening pressure: 5-20
  • clear CSF
  • WBC count <3
  • 0.2-0.5g/L protein
  • 0.6 glucose (CSF:blood)

viral:

  • opening pressure: normal/slight increase
  • clear CSF
  • WBC count medium
  • mainly lymphocytes
  • low/normal protein
  • high glucose

bacterial:

  • opening pressure: high
  • turbid CSF
  • WBC count high
  • mainly polymorphs
  • high protein
  • low glucose (bacteria eat it all!)

fungal/TB:

  • opening pressure: variable
  • variable CSF
  • variable WBC count
  • mainly lymphocytes
  • low/normal protein
  • low glucose (fungus/TB eats sugar)

basically:

  • viral: clear, lymphocytes, high glucose
  • bacterial: turbid, polymorphs, high protein, low glucose, high opening pressure
  • fungal/TB: lymphocytes, low glucose

“living organisms (ie not viruses) eat sugar!”

112
Q

other tests (bar LP) done for meningitis? 8

A
  • blood cultures
  • blood for bacterial PCR
  • FBC
  • CRP
  • clotting
  • U+Es
  • LFTs
  • blood glucose
113
Q

encephalitis:

  • normal cause?
  • diagnostic test?
A

viral (norm herpes)

lumbar puncture
- CSF requesting viral PCR specifically

114
Q

brain abscess:

  • diagnostic tests? 2
  • don’t do?
A

local sampling

  • pus, from surgical biopsy/drainage
  • – gram, culture, sensitivity

blood cultures

don’t do: LP!

  • high risk due to increased ICP
  • rarely positive anyway

nb normally spread from local source mof infection, eg ear or sinuses

115
Q

diagnosis of:

  • acute otitis media?
  • acute otitis externa?
A

otitis media:

  • clinical diagnosis
  • send pus if ear drum perforated

otitis externa:

  • ear swab to determine cause
  • do sensitivity testing on this

nb for both, beware of colonising bacteria, hard to interpret, often get false positive

116
Q

what is the diagnostic test for influenza?

who is this given to? 2

A

viral PCR from nose/throat swabs

  • those who may require treatment (ie antivirals)
  • those at risk of transmitting (eg in hosp/prisons/etc)
117
Q

what diagnostic interventions are required for pneumonia with:

  • a low CURB65 score? 1
  • a mod/severe CURB65 score? 3
A

low CURB65:
- CRP

mod/severe CURB65:

  • sputum
  • blood cultures
  • stypical screen
118
Q

what is involved in an ‘atypical screen’? 2

A
  • test urine for legionella antigen
  • nose/throat swab for mycoplasma PCR

(- may include serum)

119
Q

what is the diagnostic tests for:

  • exposure to TB? 2
  • symptomatic pulmonary TB?
A

exposure:
- mantoux
- IGRA (interferon G releasing assay)
nb both of these rely on intact immune system

pulmonary symtpms:

  • 3 sputum samples
  • microscopy + culture (for 8 weeks)
120
Q

less common causes of respiratory infection:

  • who would you test?
  • diagnostic tests? 3
  • type of sample needed?
A

consider in immunosuppressed

  • on chemo
  • post-transplant
  • HIV
  • on steroids
  • diabetes
  • CKD
  • viral (eg RSV, CMV) = viral PCR
  • fungal (eg aspergillus) = culture, aspergillus antigen
  • pnemocystis - pneumocyctis PCR

deep respiratory sample (lavage)

121
Q

h pylori infection:

  • 4 diagnostic tests?
  • best one?
A

h pylori antiBODY test
- doesn’t distinguish active from past infection

h pylori stool antiGEN test
- BEST ONE!!

urea breath test
- expensive (but gold standard for test of cure)

biopsy urease test
- invasive

nb with all of these should stop PPIs before testing!

122
Q

liver abscess

  • 3 main causes?
  • diagnostic tests? 5
A
  • pyogenic (bacteria)
  • hydatid parasite
  • amoebic
    history to guide aetiology
  • imaging (USS/CT)
  • pus (if safe to drain)
  • blood cultures (+ normal blood tests)
  • hydatid serology
  • stool for parasitic eggs
123
Q

diagnostic blood test for endocarditis?

A

blood cultures
- 3 should be taken, each at different time of day

(as bacterial loads in blood vary throughout day so may get false negative if only test once)

124
Q

what imaging techniques should be used for suspected endocarditis?

A

echocardiography (2 types:)

trans-thoracic echo (TTE)
- less invasive but more sensitive

trans-oesophageal echo (TOE)

  • more invasive but more sensitive
  • should always do in suspected prosthetic valve endocarditis
125
Q

how is viral hepatitis diagnosed?

A

serology +/- PCR

nb serology comprises antigen + antibody detection

126
Q

clostridium botulinum

  • what does it cause?
  • what sort of toxin does it produce?
A

a rare cause of food poisoning

an exotoxin

127
Q

what is the difference between an endotoxin and an exotoxin?

A

Exotoxins are usually heat labile proteins secreted by certain species of bacteria which diffuse into the surrounding medium.

Endotoxins are heat stable lipopolysaccharide-protein complexes which form structural components of cell wall of Gram Negative Bacteria and liberated only on cell lysis or death of bacteria.

ie exotoxins is stuff the bacteria actively produce and secrete, endotoxins are molecules in bacterial cell wall which is released when that cell lyses

128
Q

what is the name given to an organism which, when present, almost invariably causes disease?

A

primary pathogen

129
Q

which structures on the surface of bacteria facilitate bacterial adhesion?

A

fimbrae

130
Q

give 4 examples of common gram positive cocci species

A
  • staph aureus
  • staph epidermis
  • strep pneumoniae
  • strep pyogenes
131
Q

give 4 examples of gram positive rods (genuses)

A
  • clostridium (eg c diff)
  • bacillus
  • corynebacteria (eg c diptheria + c bovis)
  • listeria (eg L monocytogenes)
132
Q

give 2 examples of gram negative cocci species

A

neisseria meningitides

neisseria gonorrhoea

133
Q

give 7 examples of gram negative rod genuses

A
  • escerichia (eg e coli)
  • pseudomonas
  • salmonella
  • shigella (causes dysentry)
  • kleibsiella (eg k pneumoniae)
  • proteus (eg p vulgaris)
  • haemophilus (eg haemophilus influenzae)
134
Q

what antibiotic should you use to treat MRSA?

A

vancomycin

or any other glycopeptide

135
Q

out of the 3 main classes of B-lactams which are most and least broad spectrum?

A

penicillins = least

cephalosporins = middle

carbapenems = most broad spectrum

136
Q

give an example of a macrolide

what do these types of antibiotics target in bacteria?

A
  • erythromycin
  • azithromycin
  • clarithromycin

protein synthesis

137
Q

give an example of an aminoglycoside

what do these antibiotics target in clinical practise?

A

gentamycin

protein synthesis

138
Q

what is the first line treatment for anerobic bacteria?

A

metronidazole

139
Q

what antibiotic is first line for treatment of c diff infection?

A

metronidazole

nb c diff is an anaerobe

140
Q

what is (often) the first line treatment for UTIs?

what class is it?

what part of the bacteria does it target?

A

ciprofloxacin

fluoroquinolones

DNA replication

141
Q

which of these antibiotics ONLY work on gram negative or gram positive bacteria:

  • penicillin?
  • gentamicin?
  • vancomycin?
A

penicillin
= gram positive only

(nb amoxicillin + other broad spectrum penicillin derivatives have broader cover)

gentamicin
= gram negative only

vancomycin
= gram positive only (eg MRSA)

142
Q

which type of antibiotic can bacteria become resistant to, by the use of an efflux pump?

A

quinolones

143
Q

name a common:

  • broad-spectrum penicillin?
  • penicillinase-resistant penicillin?
A

broad-spectrum penicillin
= amoxicillin

penicillinase-resistant penicillin
= flucloxacillin
(nb this is still resistant against MRSA)

144
Q

what is the first line treatment for:

  • mild typical pneumonia?
  • serious typical pneumonia?

what criteria do you use to tell the difference between the two?

A

mild typical pneumonia
- amoxicillin

serious typical pneumonia
- co-amoxiclav AND clarithromycin

CURB-65 score

(confusion, urea, RR, BP, age >65)

145
Q

what is the most common cause of community acquired pneumonia?

what type of bacteria is it?

A

strep pneumoniae

gram positive diplococci

146
Q

which bacteria often causes pneumoniae in people who are recovering from influenza virus?

A

staph aureus

147
Q

which bacteria tend to cause hospital acquired pneumonia?

A

kleibsiella pneumoniae and other gram negatives

also MRSA

148
Q

signs/symptoms of:

  • lower UTI? 2
  • upper UTI? 4
A

lower UTI:

  • dysuria
  • frequency
upper UTI:
- fever
- loin pain
- tachycardia
- low BP
(+ lower UTI symptoms)
149
Q

name 2 antibiotics which are often used to treat lower UTIs

A
  • trimethoprim
  • amoxicillin

nb just give orally

150
Q

what is often the first line treatment for upper UTIs?

A

IV cefuroxime

151
Q

what is the most common cause of lower UTIs?

A

e coli

152
Q

meningitis:

  • most common cause in children/young adults?
  • most common cause in elderly?

what type of bacteria are these)

A

children/young adults:
- neisseria meningitides (gram neg diplococci)

elderly:
- strep pneumoniae (gram pos diplococci)

153
Q

what would the first line treatment be in a young adult with suspected meningitis?

A

IV ceftriaxone

154
Q

what is the difference between meningitis and meningococcal septicaemia?

A

meningitis
= CNS only

meningococcal septicaemia
= CNS + blood stream infection
- non-blanching rash
- low BP
- tachycardia
155
Q

what is SIRS?

criteria? 4

difference between that and sepsis?

A

systemic inflammatory response syndrome

2 of the following:

  • temp >38
  • pulse >90
  • RR >20
  • WBC >12

sepsis = SIRS AND a suspected focus of infection

ie SIRS is just saying that there is a systemic immune response but this doesn’t mean it necessarily has an infective cause
- eg could be a PE

156
Q

what is septic shock?

A

sepsis AND a low BP (<90/60)

ie body isn’t coping

157
Q

what does buffalo stand for?

A

blood cultures
- take 2 sets

urine output
- catheterise to measure

fluids
- 500ml IV saline over 15 mins

antibiotics

  • as per suspected infection, go broad
  • norm tazocin (piperacillin tazobactam)

lactate
- do ABG for lactate + pH

oxygen
- 15L/min via reservoir face mask

158
Q

cellulitis:

  • what is it?
  • normal causative organism?
A

skin + soft tissue infection

caused by gram positive cocci

almost always:

  • staph aureus
  • strep pyogenes
159
Q

necrotising fasciitis:

  • what is it?
  • normal causative organism?
  • treatment? 2
A

a SEVERE skin + soft tissue infection

a polymicrobial mix
- usually involving strep pyogenes

  • debridement
  • broad spectrum Abx (eg meropenem + clindamycin)

nb strep pyogenes is NOT normal skin flora

160
Q

what main group of antibiotics is the safest to use in pregnancy?

what is another drug that is safe in pregnancy?

A

ALL beta lactams are safe in pregnancy

also erythromycin

“erythromycin may cause GI problems but you probably already have morning sickness in pregnancy so not gunna make things any worse”

nb CAN’T use clarithromycin though!!

161
Q

which main 3 antibiotics should you avoid in pregnancy?

what effects do they have if taken?

A

quinolones (eg ciprofloxacin)
- damage to cartilage of foetus

trimethoprim
- is a folic acid antagonist (want folic acid in pregnancy to prevent neural tube defects)

tetracyclins
- deposits + stains bones/teeth of babies

162
Q

what is antimicrobial stewardship?

what are the 4 goals of it?

A

an organisational or healthcare-system-wide approach to promoting and monitoring judicious use of antimicrobials to preserve their future effectiveness

  • improve patient outcomes
  • improve patient safety (eg c diff)
  • reduce resistance
  • reduce healthcare costs
163
Q

when reviewing a patient who is on IV antibiotics, what are the 5 possible continuing management plans?

A
  • continue on IV
  • OPAT (IV at home, out-patient antibiotic therapy)
  • change antibiotic
  • stop antibiotic
  • IV to oral switch
164
Q

what are the three different types of antibiotic therapy, describe when they are used?

A

empiric therapy:

  • based on:
  • – likely pathogen based on clinical history + exam
  • – local antimicrobial policies
  • likely to be relatively broad spectrum

targeted therapy:

  • based on:
  • – predicted susceptibility of organism found in culture
  • – local antimicrobial policies
  • likely to be more narrow spectrum

susceptibility-guided therapy:

  • based on:
  • – antimicrobial susceptibility testing results (ie on an agar plate)
  • as narrow spectrum as possible
165
Q

what is the 90-60 rule?

A

the range of correlations between susceptibility and outcome in studies of bacterial infections

infections due to susceptible isolates respond to therapy about 90% of the time

infections due to resistant isolates respond to therapy about 60% of the time

166
Q

if you give someone an antibiotic for an infection, they are much more likely to be resistant to that same antibiotic if you try to give it to them next time they have an infection.

how long does this resistance hang around for?

A

up to a year

so must always check what antibiotics patients have been prescribed in the past, if possible, when deciding what to prescribe them now

167
Q

what two classes of antibiotics often have synergistic effects when used together?

A

B-lactams and aminoglycosides (ie gentamicin)

1 + 1 = 3

eg in streptococcal endocrditis

168
Q

what two antibiotics have an antagonistic effect when used together?

A

sodium fusidate and flucloxacillin

nb sodium fusidate is rarely used now

169
Q

first line antibiotic used to treat staph aureus infection (not MRSA)?

A

flucloxacillin

170
Q

first line antibiotic used to treat strep pyogenes infection?

A

benzylpenicillin

171
Q

first line antibiotic used to treat gram-negative infections?

who should this use be cautioned in?

A

cephalosporins

caution in elderly (due to c diff)

172
Q

first line treatment for gram positive bacteria (incl MRSA)?

A

vancomycin

an glycopeptide

173
Q

what is the last line treatment for most conditions?

A

meropenem

a carbopenem

nb doesn’t work for MRSA

174
Q

what is the last option for multi-resistant gram-negatives?

side effect?

A

colistin

very nephrotoxic so rarely used

175
Q

which class of antibiotics has very good availability in the CSF?

which 2 classes of antibiotics have very poor availability in CSF?

A

very good availability:
- B-lactams

very poor availability:

  • aminoglycosides (gentamicin)
  • glycopeptides (vancomycin)
176
Q

which two classes of antibiotics have very good availability in urine? (ie good to treat UTIs)

which class of antibiotics has very poor availability in urine?

A

very good availability:

  • trimethoprim
  • B-lactams

very poor availability:
- macrolides (erythromycin, clarithromycin, azithromycin)

177
Q

what are the 2 main different types of pharmacodynamic considerations to take into account when deciding dosages of antibiotics to give?

how does this effect the dose and time between doses that you administer?

give an example of each

A

antibiotics which are CONCENTRATION dependent:

  • main determinant of bacterial killing is the factor by which cioncentration exceed MIC
  • administered at high doses but with long gaps between doses
  • eg aminoglycosides (gentamicin)

antibiotics which are TIME dependent:

  • main determinant of bacterial killing is the amount of time for which antibiotic concentration exceeds MIC
  • administered slightly lower doses but very frequently to keep above MIC
  • eg B-lactams
178
Q

what 3 main reasons are there for prescribing more than one antibiotic for an infection?

A

to increase efficacy
- synergistic combination (eg B-lactam + gentamicin)

to provide adequately broad spectrum

  • singl agent may not cover all required organisms
  • polymicrobial infection
  • empiric treatment of sepsis

to reduce resitance

  • organism would need to develop resistance to multiple agent simultaneously
  • eg antituberculous chemotherapy
179
Q

what are the reasons why you WOULDN’T prescribe an antibiotic orally? 6

ie would give by IV or another route instead

A
  • sepsis
  • deep seated infection (endocarditis, meningitis, osteomyelitis etc)
  • patient vomitting
  • patient very sick (as reduced perfusion to gut so reduced GI absorption)
  • compliance/adherance problems (eg therapy can be given intramuscular)
  • prone to GI side effects

nb always try and give antibiotics orally if possible!! better for everyone
- reduces risk of line infections etc and means can leave hosp earlier

180
Q

what three questions should you ask when taking an allergy history?

A
  • what allergic to?
  • what happened?
  • how long ago?
181
Q

who should ceftriaxone NOT be used in?

why?

A

neonates with jaundice

can displace bilirubin from albumin

182
Q

which two antibiotics should NOT be used in people with epilepsy?

why?

A

quinolones/fluroquinolones (ending -floxacin)

imipenem (an IV carbopenem)

can lower seizure threshold

183
Q

which class of antibiotics are contraindicated in children?

why?

A

quinolones/fluroquinolones (ending -floxacin)

can cause athropathy

184
Q

what is a major possible adverse effect of quinolones/fluroquinolones (ending -floxacin)?

A

can cause tendonitis/tendon rupture

use with caution in elderly

185
Q

who should tetracyclines not be used in?

why?

A

children under 12

can stain teeth

186
Q

which two main classes of antibiotics are at greatest risk of causing nephrotoxicity?

A
  • aminoglycosides (gentamicin)

- glycopeptides (vancomycin)

187
Q

which 2 antibiotics can cause bone marrow suppression?

A
  • chloramphenicol

- linezolid

188
Q

which 2 antibiotics can cause cholestatic jaundice?

A

nb this is indicated by change in LFTs

  • co-amoxiclav
  • flucloxacillin
189
Q

which antibiotic has an increased risk of leading to myopathy/rhabdomyolysis?

A

daptomycin

190
Q

why should you ALWAYS treat bacteruria in pregnancy?

A

as it’s linked with premature birth

191
Q

what drug do macrolides (ery,clary,azithromycin) and metronidazole interact with?

what is the effect?

A

warfarin

increase anticoagulant effect of warfarin

as these Abx are enzyme inhibitors

192
Q

what drug does clarithromycin interact with?

what is the effect?

A

simvastatin

increase the risk of myopathy

193
Q

which 2 types of antibiotics can antacids + calcium reduce the absorption of?

A
  • tetracyclines

- quinolones

194
Q

which antibiotic should you not consuem alcohol while on?

A

metronidazole

195
Q

which antibiotic has no bioavailability when given orally?

A

gentamicin

always given IV (or IM/topically?)

196
Q

how should you prescribe antibiotics to an obese person (as opposed to a patient with a normal BMI)?

A

may need larger doses (see guidlines)

197
Q

which infections typically need long courses of IV therapy? 7

A
  • osteomyelitis
  • liver abscess
  • meningitis
  • bacteraemia/sepsis
  • endocarditis
  • CF
  • infections in immunocompromised

consult relavent guidlines for these!

198
Q

how long should Abx typically be prescribed for UTIs in:

  • women?
  • men?
A

women = 3 days

men = 7 days

199
Q

how long should antibiotics typically be prescribed for in upper resp tract infections?

A

5 days

200
Q

how long should TB be treated on Abx for?

A

6-9months

longer if drug resistant

201
Q

name two classes of antibiotics which have narrow therapeutic spectrums?

A

aminoglycosides (gentamicin)

glycopeptides (vancomycin, teicoplanin)

202
Q

what 3 different types of surgical procedure would prophylactic antibiotics be indicated for?

A
  • clean surgery involving placement of a prosthesis or implant
  • clean contaminated surgery
  • contaminated surgery (eg in bowel or abscess)

nb normally just give one dose before surgery, but give more if lng surgery or if lots of blood loss

203
Q

what is the algorithm of when to switch from IV to oral?

A

ACED

A - Apyrexial
C - Clinically improving
E - Eating
D - no Deep seated infection

204
Q

generally speaking, what sort of bacteria tend to cause:

  • infections ‘outside’ the body (skin + soft tissue)?
  • infections ‘inside’ the body (GI, genitals)?
A

‘Outside’ (skin, soft tissue)
- gram POSitive

‘inside’ (GI, genitals)
- gram NEGative

“you try and put a positive fact on the outside, even though you are feeling negative on the inside”

205
Q

which bacteria only tends to cause infections in association with plastics/man made material (eg central line, catheter, prostetic hip)

A

staph epidermis

is part of normal skin flora

206
Q

what do coagulase negative and positive staph mean?

give examples?

A

means how they respond to a coagulase test

staph aureus is coag positive

all other staphs are coag negative (eg s epidermis)

207
Q

what is alpha and beta haemolytic in reference to? what are the 2 subtypes of one of these?

A

alpha haemolytic and beta haemolytic are the two main groups of STREPTOCOCCI

beta- haemolytic is then further subcategorised into:

  • group A strep
  • group B strep
208
Q

give an example of a group A strep

what 3 conditions can it most commonly cause?

A

strep pyogenes

  • bacterial sore throat
  • necrotising fasciitis
  • rheumatic fever
209
Q

what is the commonest cause of bacterial meningitis?

type of bacteria?

A

strep pneumoniae

a beta-haemolytic strep

nb also most common cause of community acquired pneumonia

210
Q

what is the most common cause of bacteria; neonatal meningitis?

A

group b strep

nb this is a sub-type of beta haemolytic strep

211
Q

what are the possible consequences of contracting a listeria infection:

  • early in pregnancy?
  • late in pregnancy?
A

early in preg:
- miscarriage

late in preg:
- baby gets meningitis +/or sepsis

212
Q

name four anaerobic bacteria and the conditions they can lead to

A

all clostridium species

c. diff
- Abx associated diarrhoea/colitis

c. perfingens
- gas gangrene

c. tetani
- tetanus

c. botulism
- botulism

213
Q

what are the difference in effect in tetanus as opposed to botulism

A

tetanus
- rigid paralysis/lock jaw

botulism
- flaccid paralysis

214
Q

what is the stain for mycobacterium species?

A

ziehl-neelsen stain

nb this includes TB + leprosy

215
Q

what is the treatmetn for TB?

A

RIPE

R - rifampicin
I - Isoniazid
P - Pyrazinamide
E - Ethambutol

216
Q

what is the most common cause of endocarditis?

non-prosthetic valves, non IVDU

A

strep viridans

present in the mouth -> blood stream -> infection

217
Q

are herpes viruses DNA or RNA viruses?

A

all double-stranded DNA viruses

nb chronic/reactivating infections tend to be caused by DNA viruses, acute infections tend to be RNA (general rule, not always correct!)

218
Q

how are these types of herpes viruses transmitted:

  • HSV1 + 2?
  • VZV?
  • EBV?
  • CMV?
A

HSV1 + 2:

  • direct contact
  • kissing/sleeping with someone with a cold sore/genital herpes

VZV

  • respiratory droplets
  • “chicken pox parties”

EBV

  • saliva + genital secretions
  • “kissing disease”

CMV

  • saliva + genital secretions
  • infected blood/organ donation
  • “often occurs post transplant”
219
Q

what’s the difference being bronchitis and brochiolitis?

who gets which?

A

bronchitis:

  • inflammation of bronchi
  • a feature of COPD

bronchiolitis

  • inflammation of bronchioles
  • kids with RSV

“kids are smaller, as are bronchioles”

220
Q

who is more likely to develop chronic hepatitis from a hep B infection?

A

babies
- predominately vertical transmission

if get it congeitally, 90% chance -> chronic

if get it as an adult (eg via blood), 5% chance -> chronic

221
Q

who does rota virus tend to affect?

A

children

think of it as norovirus for kids

222
Q

parvovirus:

  • what does it cause?
  • symptoms?
  • who is it most dangerous in? 2
A

‘slapped cheek disease’

“if someone is being a PERV the SLAP them round the face”

  • fever
  • red rash to cheeks

people with high RBC turnover (eg sickle cell)
- can cause transient aplastic crisis

pregnancy:

  • if early -> miscarriage
  • if late -> hydrops fetalis
223
Q

what is hydrop fetalis?

A

severe foetal anemia -> oedema, ascites + heart failure

nb also caused by rhesus incompatibility

224
Q

enteroviruses:

  • examples?
  • clinical presentation?
A
  • coxsackie A + B
  • enteroviruses
  • echoviruses

90% asymptomatic
- or just mild febrile illness (common cold like)

nb these viruses replicate in the gut (hence are called ENTERO viruses) but their clinical effects are on lung, cardiac +/or CNS, do NOT cause GI symptoms!!

  • hand, foot + mouth disease in kidss
  • meningitis (>50% viral meningitis)
  • encephalitis
  • other
225
Q

what antiviral is used for:

  • any herpes virus infection?
  • CMV infection?
  • inflenza? 2
  • hep C/RSV?
A

herpes
= aciclovir (can get cream for cold sores as well)

CMV
= ganciclovir

influenza
= ostelTAMIvir (tami flu)
= zanamavir (“has z in, as does influenza”)

hep C/RSV
= ribovirin

226
Q

what other, non-antiviral, drug can be used to treat hep B + C?

A

interferon

triggers immune response from body as well as interfering with viral replication

227
Q

where can candida albicans infect?

A

mucous membranes

and also systemically

but NOT skin (dermatophytes do skin)

228
Q

what is the 1st line antifungals for:

  • superficial (eg skin) infection? (topical)
  • deep (eg vaginal thrush) infection? (oral)
A

topical
= clotrimazole
(eg athletes foot + other dermatophytes)

oral
= fluclonazole
(eg vaginal candida infection)

nb fluclonazole is contraindicated in pregnancy
- a big issue as lots of pregnant women get thrush

229
Q

how would you describe the lesions in impetigo?

what are the ccommon causative organisms? 2

A

honey-crusted lesions

  • staph aureus
  • strep pyogenes (group A strep)
230
Q

what species of schistosoma is responsible for urinary disease?

A

s. haematobium

“causes HAEM in the urine”

these ones cause liver disease:

  • s. masoni
  • s intercallatum
  • s. japonicum
  • s. mekongi

* year 2 Clinical Pathology (11 decks)

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