Antibiotic Resistance Flashcards
Metronidazole inhibited under
aerobic conditions
failure to activate drug
aminoglycosides inneffective against
anaerobes
target inaccessibility
6 mechanism for how bacteria cope with antibiotics
- Chemical destruction of the antibiotic
- Chemical modification of the antibiotic
- Elimination of antibiotic from site of action
- Changes in antibiotic permeability
- Mutation of antibiotic target
- Bypass mechanism
- Chemical destruction of antibiotic
Beta-Lactamse, carbapenemase, cefalosporinase, oxacillinase, ESBL
- Chemical modification of antibiotic
phosphorylation, acetylation, glycosylation
chloramphenicol resistance
- Elimination of antibiotic from site of action
efflux pumps, multi drug resistance transporter, particularly among gram neg
kanamycin, tetracycline, fluorquinolone (cipro)
fluoroquinolone resistance also does
target alteration- mutation of DNA gyrase
- Changes in antibiotic permeability
VISA vancomycin intermediate staph aureus
WalRK decreases meaning thicker cell wall
MprF decreases meaning less membrane charge
- Mutation of antibiotic target
Rifampin- RNA polymerase beta subunit mutation
VRE and VRSA- VanHAXY, D ALA D ALA to D ALA D LAC
Colistin and polymyxins- MCR-I- modifies lipid A of LPS
- Bypass resistance
acquire new enzyme to renders the inhibited target absolute
MRSA- MecA is an alternative PBP that does not bind penicillin or cephalosporins
persistence examples
L-forms (cell wall less mutants)
Toxin-antitoxin
ESKAPE
Entercoccus facieum
Staph Aureus
Klebsiella pneumonae
Acinetobacter baumannii
Pseudomonas aeurginosa
Enterbacter
antiseptic vs disinfectant
antiseptic is on tissues or skin- stops growth
disinfectant- applied to surfaces and equipment acts as germicide
things that kills spores (sterelizers)
H2O2
Chlorine products (bleach)
High concentration of aldehydes (OPA)
Etheylen oxide gas
Heat
Iodizing radiating in high doses
Filtration
