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Revision lecture Flashcards

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1
Q

Treatment of staph aureus

A

MSSA – methicillin sensitive
• Flucloxacillin 1st line

MRSA – methicillin resistant
• Vancomycin 1st line

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2
Q

Staph aures causes…

A

Skin and soft tissue infections

Deep infection
• Initial abrasion in skin
• Haematogenous spread to deep sites (Endocarditis, Septic arthritis, Osteomyelitis)

Line infections

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3
Q

Gram positive cocci in chains, catalase negative. What’s the next step?

A

MacConkey agar
- positive -> enterococci

Haemolysis

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4
Q

How do you diagnose based on haemolysis?

A

Alpha (partial, blood agar green)
Optochin:
Sensitive: Strep. pneumo
Resistant: Strep. viridans

Beta (complete)
Lancefield groups A-H

Gamma (no haemolysis)
enterococcus

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5
Q

Strep pyogenes causes….

A

Strep throat
Cellulitis

Immune mediated complications:

  • Rheumatic fever
  • Glomerulonephritis

Toxin mediated complications:

  • Scarlet fever (erythrogenic toxin)
  • Necrotizing fasciitis
  • toxic shock
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6
Q

Aerobic spore forming gram positive rods

A

– Bacillus anthracis (anthrax)

– Bacillus cereus (food poisoning)

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7
Q

Aerobic non spore forming gram positive rods

A

– Listeria (meningitis
(old/infants/preg)
– Corynebacterium
(diphtheria/skin commensals)

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8
Q

Anaerobic spore forming gram positive rods

A 
– Clostridia
• C.botulinum
• C. tetani
• C. difficile
• C. perfringens (gas gangrene)
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9
Q

Anaerobic non spore forming gram positive rods

A

– Propionibacterium (skin commensal)

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10
Q

Gram negative cocci

A

Neisseria meningitidis

Neisseria gonorrhoea

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11
Q

What does neisseria meningitidis cause?

A

Meningitis
Septicaemia (purpuric
rash)

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12
Q

How do you diagnose neisseria meningitidis?

A

Blood/CSF culture

PCR

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13
Q

Treatment for neisseria meningitidis?

A

Ceftriaxone

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14
Q

What does neisseria gonorrhoea cause?

A

Gonorrhoea:
• Asymptomatic/ Discharge/ PID
• Septic arthritis

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15
Q

Treatment for neisseria gonorrhoea?

A

Ceftriaxone but resistance increasing

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16
Q

Syndromes caused by gut commensals (enterobacteriacae

A

Escherichia coli – UTI, biliary sepsis, neonatal meningitis, HUS

Klebsiella – UTI, biliary, LRTI(elderly)

Salmonella
• Non-typhoidal – Gastroenteritis, sepsis, oesteomyelitis in sickle cell
• S.typhi/paratyphi – enteric fever

Shigella

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17
Q

ESBL

A

Extended-spectrum beta-lactamases

Resistance to 3rd gen Cephalosporin so Carbapenems (eg Meropenem) drug of choice

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18
Q

CPE

A

Carbapenemase-producing enterobacteriaceae

Resistant to carbapenems

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19
Q

Things caused by Haemophilus influenzae

A
  • Meningitis/Epiglotitis (uncommon now as HiB vacc)

* Exacerbation of COPD (non-capsulated org more common)

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20
Q

Things caused by Pseudomonas aeruginosa

A

HAI
LRTI (cystic fibrosis)
catheter UTI

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21
Q

Treatment for anaerobes

A

Metronidazole

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22
Q

India ink stain

A

Cryptococcus

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23
Q

Ziehl Neelsen

A

TB

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24
Q

Giemsa

A

Malaria

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25
Q

Antibiotics targeting cell wall

A

Beta lactams

vancomycin

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26
Q

Antibiotics targeting DNA/RNA

A

Fluroquinolones

Rifamycins

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27
Q

Antibiotics targeting folate synthesis

A

Trimethoprim

Sulfonamides

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28
Q

Antibiotics targeting protein synthesis

A

Tetracyclines
Aminoglycosides
Macrolides
Linezolid

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29
Q

How do Beta lactams work?

A

Prevent transpeptidation of peptidoglycan cell wall – Bind Penicillin Binding protein

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30
Q

Examples of beta-lactams

A
  • Penicillin – Pen, Amox, Fluclox, Pipericillin
  • Cephalosporin – Cephalexin, Ceftriaxone
  • Carabapenem – Meropenem
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31
Q

Mechanisms of resistance to beta-lactams

A

– Betalactamase – enzyme hydrolyses ring

– Alteration of PBP – eg MRSA

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32
Q

Treatment of betalactamase producing bacteria

A

• Betalactamase inhibitor – Clavulanate (Co-amoxiclav - Augmentin),
Tazobactam (Piptazobactam - Tazocin)
• Extended Spectrum Beta Lactamase (ESBL), Carbapenemase
Producing Enterobacteriaciae (CPE)

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33
Q

What to use when patient has a penicillin allergy

A

– Mild – Consider Cephaosporin/Carbapenem

– Severe – Avoid all Betalactams – Choose another class

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34
Q

Treatment for streps

A

– Penicillin/Amoxicillin

Invasive group A strep + Clindamycin
Infective endocarditis + gentamicin

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35
Q

Treatment for listeria

A

Amoxicillin

NOT cephalosporins

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36
Q

Treatment for neisseria

A

Pen -> ceftriaxone

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37
Q

Treatment for enterobacteriacae

A

Increasing resistance

Amox -> augmentin -> gent -> mero (for ESBL)

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38
Q

Treatment for pseudomonas

A

Cipping (!) chocolate milk together great

Ciprofloxacin (oral)
Ceftazidime
Meropenem
Tazocin
Gentamicin
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39
Q

Treatment for anaerobes

A

Metronidazole

Penicillin above the diaphragm

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40
Q

Common species causing endocarditis in people with native valves

A

Viridans strep
Enterococci
Staph aureus

41
Q

Common species causing endocarditis in IVDUs

A

Staph aureus often on right valve

42
Q

Common species causing endocarditis in people with prosthetic valves

A

S. aureus

Skin flora

43
Q

Common species causing endocarditis in people with bowel cancer

A

Streptococcus bovis

44
Q

Causes of culture negative endocarditis

A 
prior antibiotics
Q fever (coxiella burnetti)
bartonella
chlamydia
HACEK group
45
Q

HACEK

A 
Haemophilus
Aggregatibacter
Cardiobacterium
Eikenella
Kingella
46
Q

Treatment for endocarditis

A

– Depends on bug (species and sensitivity), valve (native vs prosthetic)
– Usually B lactam + Gentamicin (synergy)
– Duration 2-6 weeks, high dose, IV
– +/- surgery

47
Q

Causes of CAP

A

Typical – S.pneumo, S.aureus, Haemophilus influenzae, Klebsiella
pneumomoniae
– Atypical – Mycoplasma, Chlamydia, Legionella,
– Viral – Influenza

48
Q

What is augmentin?

A

Amoxicillin + clavulanic acid

Co amoxiclav

49
Q

Treatment of CAP

A

Mild: Amoxicillin
Mod: Amox + Clary
Severe: Augmentin + Clary (severe)

Severe penicillin allergy: Moxifloxacin or Clary

50
Q

Causes of HAP

A

Pseudomonas
Klebsiella

If severe treat with anti pseudomonal

51
Q

Complication of pneumonia

A

Empyema (infected pleural fluid)

52
Q

Presentation of Encephalitis (Brain Inflammation)

A

Fever
low GCS
seizure
confused

53
Q

Common cause of encephalitis and treatment

A

HSV

Aciclovir

54
Q

Presentation of Meningitis (Meningeal inflammation)

A

Fever
neck stiffness
photophobia

55
Q

Causes of meningitis

A

Bacterial
• Infants - GBS, E.coli
• Children/Adults – N.meningitidis, S.pneumonia
• Elderly/Pregnant/Immunocompromised - + Listeria (add Amoxicillin)
• CSF – Poly++, Protein ++, low gluc
• Treatment – Cetriaxone +/- Amoxicillin +/- Steroids

Viral
• Enterovirus, HSV, VZV, HIV
• Usually self limiting

Other
• TB (Lymphocytic/high protein), Cryptococcus (HIV – high opening pressure)

56
Q

What would you see in the CSF of a patient with bacterial meningitis?

A

Polymorphs
Protein
Low glucose

57
Q

Feature of cryptococcus meningitis

A

High opening pressure

58
Q

Hydrocephalus with basal meningeal enhancement

A

TB

59
Q

Appearance of CSF: clear but small spidery clot on standing

A

Cryptococcus or TB

60
Q

Lymphocytic meningitis

A

Listeria

61
Q

Who is at risk of listeria?

A

Pregnant women
Older people
Alcoholics
Malignancy

62
Q

Antibiotics contraindicated in pregnancy

A

Trimethoprim (antifolate. Don’t give in first trimester)
Coamoxiclav (link to cerebral palsy and necrotising enterocolitis)
Quinolones (ciprofloxacin) teratogen
Gentamicin- ototoxic

63
Q

Antibiotic that is safe to use in pregnancy

A

Cephalosporins

64
Q

What is Cholecystitis and the symptoms?

A

Inflammation of the gall bladder

– RUQ pain, inflamed GB

65
Q

What is Cholangitis and the symptoms?

A

Inflammation of the common bile duct

RUQ, jaundice, deranged LFT (CBD obstruction)

66
Q

Treatment for intra abdominal infection

A

– Imaging
– Source Control + sampling
– Antibiotics (Aug +/- met +/- gent)

67
Q

Commonest cause of D+V in children

A

Rotavirus

68
Q

Commonest cause of D+V in adults

A

Norovirus

69
Q

Bacterial causes of GI infection

A

Preformed Toxin – S.aureus, B.cereus (less common – rice)
• Rapid onset 4-6 hours, vomiting predominates

In-vivo toxin production – V.cholera (watery stool), C.diff (inflammatory)
– Invasive – Salmonella, Shigella, Campylobacter
• Incubation 16-48 hours
• Diarrhoea + Abdo pain predominates, can be bloody
• Treat only if severe, extremes of age, immunocompromised
– Tx - Azithromycin

Haemolytic Uraemic Syndrome
• Commonly preceded by E.coli 0157 (bloody diarrhea) -> Shiga toxin
• 5 days later anaemia (haemolytic with RBC frag), thrombocytopenia and renal failure develop
• Supportive treatment

70
Q

Treatment of invasive GI bugs

A

Only treat extremes of age

Azithromycin

71
Q

Protozoa that cause GI upset. How do you distinguish them and treat them?

A

Amoebic (acute), Giardia (chronic)

Metronidazole

72
Q

Risk factors for UTIs

A 
Age
sex
pregnancy
diabetes
obstruction
stones
catheter
73
Q

Cause of UTIs

A

– Community – Coliforms (E.coli, Proteus), Staph.saprophyticus
– Hospital – Coliforms (E.coli, Klebsiella), Pseudomonas, Candida

74
Q

When to treat UTIs

A

– Asymptomatic bacturia – No treatment (apart from pregnancy)
– Uncomplicated cystitis – Short course (3-5 days)
– Complicated/Pyelonehritis – Longer (7-14 days)

75
Q

What do you treat UTIs with

A

First line
– Nitrofurantoin
– Trimethoprim
– Cephalexin

Second line
– Coamoxiclav
– Ceftriaxone
– Ciprofloxacin

Cephadrine (preferred in pregnancy)
– Avoid Trimethoprim, gentamicin, cipro in pregnancy

76
Q

Purulent skin and soft tissue infections

A

Furuncle
Carbuncle
Abcess

77
Q

Non purulent skin and soft tissue infections

A

Erysipela
Cellulitis
Necrotizing fascitis

78
Q

Management of skin and soft tissue infections

A

– I+D if purlent, debridement if necrotizing (source control)
– Fluclox (Vanc if concerned re MRSA), Aug/Gent + clinda if severe

79
Q

Less common causes of skin and soft tissue infections

A 
Other infections (pseudomonas, C.perfringens, Fungal
(tinea/candida)

Viral (HSV/VZV)

80
Q

Osteomyelitis typically affects

A

the growth plate

81
Q

Common cause of osteomyelitis

A

Steph aureus

82
Q

Management of osteomyelitis

A

– Imaging
– Surgical sampling and debridment
– Prolonged antibiotics as dead fragments of bone with little blood supply

83
Q

What’s SIRS?

A

Systemic Inflammatory Response Syndrome

84
Q

Criteria for SIRS

A 
2 or more of:
Temp >38 or <36
RR > 20/min
HR > 90 bpm
WCC >12 or <4 x 10^9/L
85
Q

What is sepsis?

A

SIRS + clinical evidence of infection

86
Q

What is severe sepsis?

A

Sepsis + organ dysfunction

87
Q

Septic shock

A
  • sepsis with hypotension SBP <90 despite adequate fluid resuscitation
  • raised lactate (>4)
88
Q

Sepsis 6

A

Take

  • blood cultures
  • lactate
  • urine output

Give

  • antibiotics
  • oxygen
  • fluid
89
Q

HIV infections

A 
Bacterial skin infections
VZV, Kaposi's sarcoma
Oral candidiasis
PCP
Non-hodgkin lymphoma
Cryptococcal meningitis
HSV
CMV
Mycobacterium avium
90
Q

Diagnosing TB

A

Smear (60% sensitive)
GeneXpert (90% sensitive)
Liquid culture (gold standard but slow)

91
Q

If you have been back from travelling for more than 21 days what do you not have?

A

Ebola
Lassa
Marburg
Crimean congo HF

21 dy incubation period

92
Q

People at risk of HIV

A

4 Hs

Haemophiliacs
Heroin users
Homosexuals
Haitians

93
Q

HIV diagnosis

A

ELISA- detects anti-HIV antibodies

PCR but problems with false positives and negatives

94
Q

Treatment for PCP

A

Co-trimoxazole (septrin) 16 tablets/day!
(trimethoprim and sulfamethoxazole)

or IV pentamidine

95
Q

When do you treat for PCP?

A

Prophylactic treatment whe T cell count is below 200

96
Q

Targets for HIV therapeutics

A

Reverse transcriptase enzymes zidovudine
Protease enzyme ritonavir
Entry inhibitors (CCR5 and CXCR4)
Integrase inhibitors

97
Q

Treatment of malaria

A

Depends on species, severity and expected resistance

Uncomplicated P. falciparum:
Oral artemisinin combination therapy (ACT)

Severe P. falciparum
IV artesunate + PO secont agent (or ACT)

Non falciparum malaria
Chlorloquine or ACT
+ primaquine in vivaz/ovale if not G6PD

98
Q

Infection prevention and control for C. difficile

A 
Suspect
Isolate person
Gown and glove
Hand washing
Test (stool sample for toxin)
99
Q

Treatment for legionella pneumo.

A

Clarithromycin and rifampicin

or
Ciprofloxacin

Microbiology (4 decks)

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