Mechanisms of Antibiotic Resistance Flashcards
Penicillin cannot pass through the _______, so all Gram-negative bacteria are resistant to penicillins.
porin channels
Efflux pumps can be found in _______ or _______.
Gram-positive; Gram-negative
Efflux pumps can be ____________.
specific (such as the pump for tetracycline) or general
How do beta-lactams work?
They irreversibly bind to penicillin-binding proteins; PBPs are the two enzymes that are responsible for stage 3 cell-wall synthesis, transpeptidase and transglycosylase.
There are three ways that bacteria become resistant to beta-lactams: _________.
they alter their PBPs, decrease entry through porins, or degrade the drug
Genes for beta-lactamases are found ___________.
in chromosomes and plasmids; in Gram-positive and Gram-negative bacteria
Most beta-lactamases can be inhibited by _____________.
beta-lactamase inhibitors
List the characteristics of penicillinases.
They (1) only break down penicillins; (2) are not active against cephalosporins; (3) can be located in chromosomes or on transferable elements; and (4) are susceptible to beta-lactamase inhibitors.
All Staphylococcus are resistant to ___________ because of the ________ gene.
penicillin, amoxicillin, and ampicillin; bla
E. coli occasionally becomes resistant to ________ with its TEM-1 plasmid.
ampicillin
K. pneumoniae is resistant to ampicillin because of a __________ gene.
chromosomal (SHV-1)
MSSAs have bla, so they will not be killed by _________, but they can be killed by drugs that are not susceptible to beta-lactamases.
penicillin, amoxicillin, or ampicillin
ESBLs are ____________.
extended-spectrum beta-lactamases, enzymes that can degrade penicillins and cephalosporins
ESBLs are transmitted __________.
on plasmids
ESBLs are still sensitive to __________.
some beta-lactamase inhibitors
ESBL-possessing bacteria can be killed with _______.
carbapenems