antibiotics and bugs Flashcards
treat ESCAPPM organisms?
ESCHAPPM is a mnemonic for the organisms with inducible beta-lactamase activity that is chromosomally mediated
carbapenems
fourth gen cephalosporins
ciprofloxacin or aminogycosides
Enterobacter Serratia Citrobacter Hafnia Aeromonas Proteus Providencia Morganella Morganii
Mechanism of rifampicin
inhibits bacterial DNA dependent RNA polymerase preventing transcription of DNA into mRNA
Mechanism of isoniazid
mechanism of action: inhibits mycolic acid synthesis
Pyrazinamide MOA
mechanism of action: converted by pyrazinamidase into pyrazinoic acid which in turn inhibits fatty acid synthase (FAS) I
Causes gout!!
MOA of ethambutol
inhibits the enzyme arabinosyl transferase which polymerizes arabinose into arabinan
MOA beta lactam (penicillins, cephalosporins, carbapenems, monobactams)
inhibit cell wall synthesis
MOA glycopeptides eg vanc, teicoplanin
inhibit cell wall synthesis
aminoglycoside MOA
inhibit protein synthesis (30S ribosomal subunit)
tetracycline MOA
eg doxy
inhibit protein synthesis (30S ribosomal subunit)
MOA chloramphenicol
inhibit protein synthesis (50S ribosomal subunit)
MOA clindamycin
inhibit protein synthesis (50S ribosomal subunit)
MOA macrolides
eg eryth, azith, roxith
inhibit protein synthesis (50S ribosomal subunit)
MOA linezolid
inhibit protein synthesis (50S ribosomal subunit)
MOA trimethoprim and sulphonamides
block folic acid synthesis
MOA fluoroquinolones
DNA gyrase inhibition
MOA Daptomycin
inhibit cell membrane function
What is the main drawback of cephalosporins?
Do not cover enterococcus
Which antibiotics are bactericidal? (5)
Beta lactams Glycopeptides Aminoglycosides Fluoroquinolones Colistin
How are ESBLs encoded and transmitted?
Plasmids
What are three examples of altered binding sites as a mechanism of resistance?
Rifampicin binding RNA polymerase
S pneumoniae and penicillin resistance
Methicillin resistance in S aureus and coag negative staph
Fluoroquinolone resistance by alteration of DNA gyrase
Cephalosporins do not cover LAME organisms…
Listeria
Atypicals
MRSA (except ceftaroline 5th gen)
Enterococci
Four notorious for C diff?
Amox
Amp
Clinda
Linco
Indications for infection VZV in immunocompetent person?
Age over 50
severe rash
mod-sev pain
eye involvement or face
should initiate within 72 hours of the rash
Melioid treatment?
First line is either ceftazidime or meropenem followed by BACTRIM
Imipinem second line
Get actual tetnus?
IM tetanus immunoglobulin
vent support
muscle relaxants
METRO NOT BENPEN
Who gets a tetanus booster?
Uncertain history of immunisation three or more times? minor wounds- tetanus vax only
all other- vax and Immunglob
History of three or more doses of vax?
less than 5 years ago- no worries
5-10 years ago and a minor wound- no worries
5-10 and a nasty wound or more than 10- vax
Ertapenem is the carbapenem that does not cover///
pseudomonas
What do carbapenems not cover
MRSA
burkholderia cepacia
not atypicals
not stenotrophomonas maltophilia
only ok for enterococcus
causes SEIZURES
WHy is nitrofurantoin creepy?
hepatitis
haemolysis
pulmonary toxicity
polyneuropathy
side effects linezolid
lactic acidosis!! serotonin syndrome bone marrow supression peripheral neuropathy optic neuropathy
Which NNRTI avoid in suicidal history?
Efavirenz
What will cover enterobacter and bacteroides for HITH?
Ertapenem
Remember mero covers pseudo- erta does not
Erta does not cover nocardia
Why is there a rash in Dengue?
Immune complex formation
If skin prick to penicillin positive, what is the chance you are also ceph positive sens?
2%
What proportion of Pneumococcal meningitis patients have pneumonia
1/3
