Antibiotics Flashcards
Colour of staining of bacteria:
- gram positive
- gram negative
- gram positive -> purple
- gram - negative -> pink
Important gram positive cocci
- general names (x2)
- examples (x2 each group)
- Staphylococcus
- S aureus*
- S* epidermidis
- Steptococcus
- S* pyogenes
- S* pneumoniae
Important gram positive rods
- general name (1)
- example (1)
Gram +ive rods
Clostridia
- C difficile
Important gram negative cocci
- general names (1)
- examples (2)
Gram negative cocci
- Neisseria*
- N meningitidis
- N gonnorhoea*
Important gram negative rods
- general names (6)
Gram negative rods
- E coli
- Proteus*
- Klebsiella*
- Pseudomonas*
- Salmonella*
- Haemophilus (e.g.H influenza B)*
Forms of Haemophilus (2)
example of conditions they cause
- capsulated (much more pathogenic e.g. acute epiglottitis)
- non- capsulated (colonise lungs)
*Haemophilus B capsulated -> we can vaccinate against it -> so we can prevent epiglottitis
Example of anaerobic bacteria (1)
Location of it
Anaerobic
Strep faecalis
it survives in the gut
What bacteria is likely to cause this (picture)?
Staphylococcus Aureus
What bacteria is likely to cause this (picture)?
Streptococcus Pyogenes
*bacteria arranged in chains
What bacteria is it caused by? (picture)
Neisseria meningitidis
*polymorphic nuclei of the cells
* gram-negative intracellular diplococci = Neisseria
What bacteria is it caused by? (picture)
*this pt has a Hospital acquired infection - pt was ventilated at ITU then went to the ward
Staphylococcus Aureus
Streptococcus Pneumoniae
*it’s a mix infection
What bacteria is it caused by? (picture)
E. Coli
What organism is likely to cause this? (picture)
Candida Albicans
*fungus - branches/trees - like visible on microscopy
‘normal’/community-acquired pneumonia
- history/presentation
- likely organism
History: productive/ green cough, fever, pleuritic chest pain; lobar consolidation
Organism: Strep pneumonia (90% pneumococcus)
* 5-10 % atypical organisms
Atypical pneumonia
- features/ clinical picture
- what does it look like on chest x ray?
- likely organisms (4)
Atypical pneumonia
A. Features:
- dry, non-productive cough
- headache
- myalgia
- fever
B. CXR: lots of consolidation, sometimes on both sides, not confined to one side
C. Organisms:
- coxiella burnetii
- mycoplasma pneumonia*
- chlamydia* pneumoniae
- legionella*
Antibiotics for young and fit person with community-acquired pneumonia
Amoxicillin (penicillin) + Macrolide
*this is to cover pneumococcus and atypical organisms
Cigarette smoker with mucociliary function impaired and repeated chest infections
- what organism may colonise that person and cause chest infections?
Organisms:
- Haemophilus
- Pseudomonas (if bronchiectasis and repeated chest infections)
*these are nasty infections, multi-drug resistant
Just look at the picture
Aspiration pneumonia
- examples of patients at risk
- organisms causing it
- antibiotic used
Aspiration pneumonia
Patients at risk: patients who vomit and inhale -> epileptic/fitting, alcoholics, stroke
Organisms: anaerobes
Antibiotics: metronidazole
Patients who are at risk of pneumonia caused by TB
- HIV/ immunosuppressed
- people from Sub-Saharan Africa, South East Asia; Eastern Europe, India
Organisms causing UTI
UTI
- gram negatives
- catheter: staphs, candida
-
Abdominal infections (bowel)
- what organisms cause it
small bowel -> sterile
large bowel -> gram negatives + anaerobes
*therefore small bowel operations are separated from large bowel (on the surgeries list - small bowel operations will be first on the list)
Meningitis
What are likely organisms causing it (according to the group)?
A. normal/ adults
B. kids <5
C. neonates
Meningitis
Adults: N. meningitidis + Strep pneumoniae
Kids <5: Haemophilus
Neonates: group B Streptococcus, gram negatives, Listeria, HSV
presentation of meningitis:
A. adults
B. neonates
A. Adult: photophobia, neck stiffness, headache, fever
B. Newborn: cry, fever*
*a lot of meningitis happen in neonates presenting with cry and fever (as possible meningitis)
Just look at the picture
What’s the cause of food poisoning?
Do antibiotics help?
Food poisoning -> ingestion of pre-formed toxin
Antibiotics would not help
*if dehydrated, may need IV drip
What’s gastroenteritis?
- what location is infected?
- how does the diarrhoea look like?
- likely organisms
- management
Gastroenteritis -> ingestion of the bug -> it colonises the gut and multiplies (may or not produce toxins)
- location: small bowel is infected
- diarrhoea: green and watery
- likely organisms: viral, salmonella, E coli
Management:
- -* usually no antibiotics
- usually self-limiting
Colitis
- location of infection
- appearance of diarrhoea/ features of infection
- likely organisms
- management
Colitis
- Location: large bowel
- Diarrhoea: less watery/more formed (than gastroenteritis), but more sick (abdominal pain, feverr, high WBCs, fresh/red blood in the stool)
- Organisms: Campylobacter, E coli 0157, Ameobic dysentery
- Management: needs antibiotics
Bacteria (2) causing skin/ soft tissue/ bone infections
Staphylococcus, Streptococcus
Organisms causing endocarditis associated with:
A. native valve
B. IVDU
C. Artificial valve
A. native valve -> Strep viridans
B. IVDU -> Staph aureus, fungal
C. Artificial vale -> staphs (they love plastics/metals)
What are the key questions to be asked before we prescribe antibiotics?
- is there an infection
- what’s the location
- what’s the likely organism
- what antibiotics are likely to be effective
- is there likely resistance
- will antibiotic penetrate the site of infection
- route of administration
- what’s the toxicity and cost
Look at the pic
MoA and examples of:
B- lactams
Aminoglycosides
Look at the pic
MoA and examples of:
- Macrolides
- quinolones
Look at the pic
MoA of:
- metronidazole
- glycopeptides
- tetracycline
Flucloxacillin
- against which organism?
- what type of spectrum is it?
Flucloxacillin
- against Staphs
it is narrow spectrum
What spectrum activity amoxicillin has?
Amoxicillin
- brad spectrum (covers some gram-negative and positives)
What’s in the Co-Amoxiclav (2 substances)
- spectrum
- side effect
Amoxicillin + clavulanic acid (Co-Amoxiclav)
clavulanic acid -> it is an inhibitor of Beta-lactamase (so bacteria cannot incorporate B-lactams into their cell wall)
S__pectrum: broad -> positives (Penicillins), anaerobes and negatives
Side effect: more of own bacteria killed -> risk of C Diff diarrhoea
What’s the most commonly Cephalosporin used?
- spectrum
Ceftriaxone -> broad spectrum
What’s the name of antibiotic from carbapenam class that is reserved for difficult infections?
- what’s its spectrum?
Imipenem
(very broad spectrum)
Aminoglycosides
- MoA
- examples
- spectrum
look at the picture
Macrolides
- MoA
- examples
- spectrum
Look at the picture
Quinolones
- MoA
- example
- spectrum
Look at the picture
Tetracyclines
- MoA (simple)
- example
- spectrum
Look at the picture
Anti-folate
- MoA (simple)
- example
- spectrum
Look at the pic
Glycopeptides
- MoA (simple)
- example
- spectrum
look at the pic
Metronidazole
- MoA (simple)
- example
- spectrum
look at the pic
What questions (3) and why do we need to ask in terms of antibiotics (related to resistance)?
- community-acquired or hospital-acquired? -> hospital-acquired are usually resistant
- previous antibiotic? -> if one antibiotic does not work -> prescribe different one
- travel history? -> e.g. penicillin-resistant pneumococcus is rare in the UK, but may be even 20% in Spain/ Southern Europe; depends on the country
What factors (in term of the patient’s condition ) would prompt us to use IV antibiotics?
- very sick patient
- serious infection
- the barrier to drug absorption
- malabsorption
- vomiting/swallowing problems
- poor bioavailability
- poor tissue penetration
