2. antimicrobial therapy Flashcards
what are the classes of beta lactams
penicilin
cephalosporins
carbapenems
what is the mechanism of action of beta lactams
(enzymatic) act on bacterial cell walls by binding to penicillin binding proteins (PBP) in the cell membrane which interferes with peptidoglycan synthesis
what are macrolides used for
- penicillin allergy against gram positive staph and strep, e.g. skin and thread infections.
- atypical pneumonia
examples of macrolides
erythromycin IV&PO
clarithromycin IV&PO (newer)
azithromycin PO (newer)
what is the mechanism of action for erythromycin
bacteriostatic.
interferes with protein synthesis by ribosomal binding
what are tetracyclines used for
- broad spectrum
- resp tract and soft tissue infections
- in penicillin allergy with side effects to macrolides
- atypical respiratory pathogens
examples of tetracyclines
oxytetracycline
doxacycline
tigecycline
what is tigecyline
recent tetracycline.
potent broad spectrum
works against gram positives, negatives and anaerobes
mechanism of action of oxytetracycline + doxycycline
bacteriostatic.
inhibit tRNA binding to ribosome
doxy: PO, give once daily
what is the mechanism of action of trimethoprim + co-trimoxazole
block bacterial nucleotide synthesis in the pathway of folic acid/nucleotide synthesis
what do trimethoprim + co-trimoxazole work against
active against gram positive and negative bacteria
what is a use of trimethoprim
commonly used against UTIs
what is a use of co-trimexazole
(trimethoprim + sulfamethoxazole)
- treatment and prophylaxis of pneumocystis jirovecii pneumonia
- stenotrophomonas maltophilia infection
- nocardiosis
examples of quinolones
ciprofloxacin
levofloxacin
moxifloxacin
what is the mechanism and use of ciprofloxacin
- inhibit DNA gyrase (enzyme that supercoils bacterial DNA) = disrupt organism
- better action for gram positive
what is the function of levo and moxifloxacin
new, have better gram positive cover
‘respiratory quinilones’
what is the mechanism of aminoglycosides
interfere with ribosomal reading of mRNA
what’s the function of aminoglycosides
gram positive mainly
- synergy with penicillin against strep
- mainly used IN SERIOUS SEPSIS
- potential for nerve 8 and renal toxicity: measure levels
examples of aminoglycosides
gentamicin
amikacin
netilmicin
tobramycin
what is the mechanism for glycopeptides
act on bacterial cell walls
use of glycopeptides
against gram positive
treatment of MRSA
treatment of coagulase negative staph infection
occasionally when penicillin allergic
examples of glycopeptides
vancomycin: potentially nephrotoxic
teicoplanin
what is teicoplanin used for
outpatients with long lasting infections e.g. osteomyelitis
metronidazole
breaks DNA strands.
active against all anaerobes, amoebae and trichomonad vaginalis
linezolid
active against gram positive, including MRSA and glycopeptide-resistant enterococci
chloramphenicol
occasional therapy of meningitis and topical treatment f eye infections.
bone marrow toxicity
fosfomycin
multi-resistant gram negative bacterial infections
fidaxomycin
severe or recurrent c.difficile infections
colistin
disrupts bacterial membrane.
reserved for multi- or pan-resistant gram negative infections
daptomycin
a lipopeptide, similar activity to glycopeptide
against gram positive
fusidic acid
staphylococcal infections only
topical
if systemic: use with second anti-staph agent
rifampicin
v active against gram positive
prosthetic valve endocarditis and other prosthetic infections.
part of first line TB regimen
what is the issue in terms of resistance about staphylococcus aureus
meticillin-resistant S. aureus (MRSA)
what is the issue in terms of resistance about streptococcus pneumoniae
penicillin and multiply resistant
what is the issue in terms of resistance about enterococcus faecium
glycopeptide and linezoid resistant
what is the issue in terms of resistance about mycobactum tuberculosis
resistant to one or more anti-TB drugs: rifampicin isoniazid pyrazinamide ethambutol
what is the issue in terms of resistance about salmonella typhi
multi-resistant in some parts of the world
