Revision lecture Flashcards
(99 cards)
1
Q
Treatment of staph aureus
A
MSSA – methicillin sensitive
• Flucloxacillin 1st line
MRSA – methicillin resistant
• Vancomycin 1st line
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
3
Q
Gram positive cocci in chains, catalase negative. What’s the next step?
A
MacConkey agar
- positive -> enterococci
Haemolysis
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
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
6
Q
Aerobic spore forming gram positive rods
A
– Bacillus anthracis (anthrax)
– Bacillus cereus (food poisoning)
7
Q
Aerobic non spore forming gram positive rods
A
– Listeria (meningitis
(old/infants/preg)
– Corynebacterium
(diphtheria/skin commensals)
8
Q
Anaerobic spore forming gram positive rods
A
– Clostridia • C.botulinum • C. tetani • C. difficile • C. perfringens (gas gangrene)
9
Q
Anaerobic non spore forming gram positive rods
A
– Propionibacterium (skin commensal)
10
Q
Gram negative cocci
A
Neisseria meningitidis
Neisseria gonorrhoea
11
Q
What does neisseria meningitidis cause?
A
Meningitis
Septicaemia (purpuric
rash)
12
Q
How do you diagnose neisseria meningitidis?
A
Blood/CSF culture
PCR
13
Q
Treatment for neisseria meningitidis?
A
Ceftriaxone
14
Q
What does neisseria gonorrhoea cause?
A
Gonorrhoea:
• Asymptomatic/ Discharge/ PID
• Septic arthritis
15
Q
Treatment for neisseria gonorrhoea?
A
Ceftriaxone but resistance increasing
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
17
Q
ESBL
A
Extended-spectrum beta-lactamases
Resistance to 3rd gen Cephalosporin so Carbapenems (eg Meropenem) drug of choice
18
Q
CPE
A
Carbapenemase-producing enterobacteriaceae
Resistant to carbapenems
19
Q
Things caused by Haemophilus influenzae
A
- Meningitis/Epiglotitis (uncommon now as HiB vacc)
* Exacerbation of COPD (non-capsulated org more common)
20
Q
Things caused by Pseudomonas aeruginosa
A
HAI
LRTI (cystic fibrosis)
catheter UTI
21
Q
Treatment for anaerobes
A
Metronidazole
22
Q
India ink stain
A
Cryptococcus
23
Q
Ziehl Neelsen
A
TB
24
Q
Giemsa
A
Malaria
25
Antibiotics targeting cell wall
Beta lactams
| vancomycin
26
Antibiotics targeting DNA/RNA
Fluroquinolones
| Rifamycins
27
Antibiotics targeting folate synthesis
Trimethoprim
| Sulfonamides
28
Antibiotics targeting protein synthesis
Tetracyclines
Aminoglycosides
Macrolides
Linezolid
29
How do Beta lactams work?
Prevent transpeptidation of peptidoglycan cell wall – Bind Penicillin Binding protein
30
Examples of beta-lactams
* Penicillin – Pen, Amox, Fluclox, Pipericillin
* Cephalosporin – Cephalexin, Ceftriaxone
* Carabapenem – Meropenem
31
Mechanisms of resistance to beta-lactams
– Betalactamase – enzyme hydrolyses ring
| – Alteration of PBP – eg MRSA
32
Treatment of betalactamase producing bacteria
• Betalactamase inhibitor – Clavulanate (Co-amoxiclav - Augmentin),
Tazobactam (Piptazobactam - Tazocin)
• Extended Spectrum Beta Lactamase (ESBL), Carbapenemase
Producing Enterobacteriaciae (CPE)
33
What to use when patient has a penicillin allergy
– Mild – Consider Cephaosporin/Carbapenem
| – Severe – Avoid all Betalactams – Choose another class
34
Treatment for streps
– Penicillin/Amoxicillin
Invasive group A strep + Clindamycin
Infective endocarditis + gentamicin
35
Treatment for listeria
Amoxicillin
NOT cephalosporins
36
Treatment for neisseria
Pen -> ceftriaxone
37
Treatment for enterobacteriacae
Increasing resistance
Amox -> augmentin -> gent -> mero (for ESBL)
38
Treatment for pseudomonas
Cipping (!) chocolate milk together great
```
Ciprofloxacin (oral)
Ceftazidime
Meropenem
Tazocin
Gentamicin
```
39
Treatment for anaerobes
Metronidazole
| Penicillin above the diaphragm
40
Common species causing endocarditis in people with native valves
Viridans strep
Enterococci
Staph aureus
41
Common species causing endocarditis in IVDUs
Staph aureus often on right valve
42
Common species causing endocarditis in people with prosthetic valves
S. aureus
| Skin flora
43
Common species causing endocarditis in people with bowel cancer
Streptococcus bovis
44
Causes of culture negative endocarditis
```
prior antibiotics
Q fever (coxiella burnetti)
bartonella
chlamydia
HACEK group
```
45
HACEK
```
Haemophilus
Aggregatibacter
Cardiobacterium
Eikenella
Kingella
```
46
Treatment for endocarditis
– Depends on bug (species and sensitivity), valve (native vs prosthetic)
– Usually B lactam + Gentamicin (synergy)
– Duration 2-6 weeks, high dose, IV
– +/- surgery
47
Causes of CAP
Typical – S.pneumo, S.aureus, Haemophilus influenzae, Klebsiella
pneumomoniae
– Atypical – Mycoplasma, Chlamydia, Legionella,
– Viral – Influenza
48
What is augmentin?
Amoxicillin + clavulanic acid
| Co amoxiclav
49
Treatment of CAP
Mild: Amoxicillin
Mod: Amox + Clary
Severe: Augmentin + Clary (severe)
Severe penicillin allergy: Moxifloxacin or Clary
50
Causes of HAP
Pseudomonas
Klebsiella
If severe treat with anti pseudomonal
51
Complication of pneumonia
Empyema (infected pleural fluid)
52
Presentation of Encephalitis (Brain Inflammation)
Fever
low GCS
seizure
confused
53
Common cause of encephalitis and treatment
HSV
| Aciclovir
54
Presentation of Meningitis (Meningeal inflammation)
Fever
neck stiffness
photophobia
55
Causes of meningitis
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
What would you see in the CSF of a patient with bacterial meningitis?
Polymorphs
Protein
Low glucose
57
Feature of cryptococcus meningitis
High opening pressure
58
Hydrocephalus with basal meningeal enhancement
TB
59
Appearance of CSF: clear but small spidery clot on standing
Cryptococcus or TB
60
Lymphocytic meningitis
Listeria
61
Who is at risk of listeria?
Pregnant women
Older people
Alcoholics
Malignancy
62
Antibiotics contraindicated in pregnancy
Trimethoprim (antifolate. Don't give in first trimester)
Coamoxiclav (link to cerebral palsy and necrotising enterocolitis)
Quinolones (ciprofloxacin) teratogen
Gentamicin- ototoxic
63
Antibiotic that is safe to use in pregnancy
Cephalosporins
64
What is Cholecystitis and the symptoms?
Inflammation of the gall bladder
| – RUQ pain, inflamed GB
65
What is Cholangitis and the symptoms?
Inflammation of the common bile duct
| RUQ, jaundice, deranged LFT (CBD obstruction)
66
Treatment for intra abdominal infection
– Imaging
– Source Control + sampling
– Antibiotics (Aug +/- met +/- gent)
67
Commonest cause of D+V in children
Rotavirus
68
Commonest cause of D+V in adults
Norovirus
69
Bacterial causes of GI infection
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
Treatment of invasive GI bugs
Only treat extremes of age
| Azithromycin
71
Protozoa that cause GI upset. How do you distinguish them and treat them?
Amoebic (acute), Giardia (chronic)
Metronidazole
72
Risk factors for UTIs
```
Age
sex
pregnancy
diabetes
obstruction
stones
catheter
```
73
Cause of UTIs
– Community – Coliforms (E.coli, Proteus), Staph.saprophyticus
– Hospital – Coliforms (E.coli, Klebsiella), Pseudomonas, Candida
74
When to treat UTIs
– Asymptomatic bacturia – No treatment (apart from pregnancy)
– Uncomplicated cystitis – Short course (3-5 days)
– Complicated/Pyelonehritis – Longer (7-14 days)
75
What do you treat UTIs with
First line
– Nitrofurantoin
– Trimethoprim
– Cephalexin
Second line
– Coamoxiclav
– Ceftriaxone
– Ciprofloxacin
Cephadrine (preferred in pregnancy)
– Avoid Trimethoprim, gentamicin, cipro in pregnancy
76
Purulent skin and soft tissue infections
Furuncle
Carbuncle
Abcess
77
Non purulent skin and soft tissue infections
Erysipela
Cellulitis
Necrotizing fascitis
78
Management of skin and soft tissue infections
– I+D if purlent, debridement if necrotizing (source control)
– Fluclox (Vanc if concerned re MRSA), Aug/Gent + clinda if severe
79
Less common causes of skin and soft tissue infections
```
Other infections (pseudomonas, C.perfringens, Fungal
(tinea/candida)
```
Viral (HSV/VZV)
80
Osteomyelitis typically affects
the growth plate
81
Common cause of osteomyelitis
Steph aureus
82
Management of osteomyelitis
– Imaging
– Surgical sampling and debridment
– Prolonged antibiotics as dead fragments of bone with little blood supply
83
What's SIRS?
Systemic Inflammatory Response Syndrome
84
Criteria for SIRS
```
2 or more of:
Temp >38 or <36
RR > 20/min
HR > 90 bpm
WCC >12 or <4 x 10^9/L
```
85
What is sepsis?
SIRS + clinical evidence of infection
86
What is severe sepsis?
Sepsis + organ dysfunction
87
Septic shock
- sepsis with hypotension SBP <90 despite adequate fluid resuscitation
- raised lactate (>4)
88
Sepsis 6
Take
- blood cultures
- lactate
- urine output
Give
- antibiotics
- oxygen
- fluid
89
HIV infections
```
Bacterial skin infections
VZV, Kaposi's sarcoma
Oral candidiasis
PCP
Non-hodgkin lymphoma
Cryptococcal meningitis
HSV
CMV
Mycobacterium avium
```
90
Diagnosing TB
Smear (60% sensitive)
GeneXpert (90% sensitive)
Liquid culture (gold standard but slow)
91
If you have been back from travelling for more than 21 days what do you not have?
Ebola
Lassa
Marburg
Crimean congo HF
21 dy incubation period
92
People at risk of HIV
4 Hs
Haemophiliacs
Heroin users
Homosexuals
Haitians
93
HIV diagnosis
ELISA- detects anti-HIV antibodies
| PCR but problems with false positives and negatives
94
Treatment for PCP
Co-trimoxazole (septrin) 16 tablets/day!
(trimethoprim and sulfamethoxazole)
or IV pentamidine
95
When do you treat for PCP?
Prophylactic treatment whe T cell count is below 200
96
Targets for HIV therapeutics
Reverse transcriptase enzymes zidovudine
Protease enzyme ritonavir
Entry inhibitors (CCR5 and CXCR4)
Integrase inhibitors
97
Treatment of malaria
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
Infection prevention and control for C. difficile
```
Suspect
Isolate person
Gown and glove
Hand washing
Test (stool sample for toxin)
```
99
Treatment for legionella pneumo.
Clarithromycin and rifampicin
or
Ciprofloxacin
