Antibiotics 2 - Inhibitors of cell wall synthesis/ B lactamases

Question 1

4 main Cell Wall Antibiotics ( B Lactam Antibiotics)

Answer 1

Penicillins, Cephalosporins, Carbapenems, Monobactams (Aztreonam)

Question 2

How the B lactams work?

Answer 2

they bind to PBPs, the penicillin binding proteins, inactivating them and ultimately inhibiting cell wall synthesis

Question 3

what are insertion sequences?

Answer 3

are mobile genetic elements that switch genes on and off by promoter sequences . have insertion and excision enzymes. Can up regulate or down regulate gene expression

Question 4

what are integrons?

Answer 4

are mobile gene capturing machines, have the ability to capture antibiotic resistance genes on gene cassettes. have promoters, can not replicate on their own, have to be contained on a plasmid.

Question 5

gene cassettes

Answer 5

typically carry one gene, and a short 59 base pair element - which protects cassette from DNAses and allows for integration into an integron. these are free circular non-replicating molecules

Question 6

transposons

Answer 6

are jumping genes, sequences of DNA that have their own recombination enzymes, do not have their own promoter. can move from chromosomes to plasmids and vice versa

Question 7

ESBL’s

Answer 7

bacterial enzymes which mediate resistance to 3rd generation cephalosporins, ESBL producers are primarily found in Klebsiella, E.Coli, and Proteus mirabilis. and may be treated with a Carbapenem

Question 8

Amp C Beta Lactamases

Answer 8

are mostly chromosomal, now plasmids are more common. mediate resistance to penicillins and narrow spectrum antibiotics.

Question 9

Carbapenemases

Answer 9

are the most antibiotic resistant of them all. Can hydrolyze carbapenems, Broad spectrum penicillins, Cephalosporins. Carbapenemases are now common in many gram negative bacteria