Cell Wall Synthesis Inhibitors Part 1

Cell wall synthesis inhibitors

Antimicrobials that interfere with bacterial cell wall formation.

Primary target of cell wall synthesis inhibitors

Peptidoglycan synthesis.

Effect of cell wall synthesis inhibition

Weakening of the bacterial cell wall leading to cell death.

Most cell wall synthesis inhibitors are

Bactericidal.

Why cell wall inhibitors are bactericidal

They cause osmotic instability and bacterial lysis.

Major groups of cell wall synthesis inhibitors in this module

Penicillins, Cephalosporins, Bacitracin, Glycopeptides, Fosfomycin, Monobactams, and Carbapenems.

Penicillins belong to which antimicrobial class?

Beta-lactam antibiotics.

Cephalosporins belong to which antimicrobial class?

Beta-lactam antibiotics.

Monobactams belong to which antimicrobial class?

Beta-lactam antibiotics.

Carbapenems belong to which antimicrobial class?

Beta-lactam antibiotics.

Common feature of beta-lactam antibiotics

Presence of a beta-lactam ring.

Main bacterial target of beta-lactams

Penicillin-binding proteins (PBPs).

PBPs stand for

Penicillin-binding proteins.

Function of PBPs

Enzymes involved in bacterial cell wall synthesis.

Most beta-lactams inhibit which stage of cell wall synthesis?

Third stage (transpeptidation).

Penicillins inhibit which stage of cell wall synthesis?

Third stage.

Cephalosporins inhibit which stage of cell wall synthesis?

Third stage.

Monobactams inhibit which stage of cell wall synthesis?

Third stage.

Carbapenems inhibit which stage of cell wall synthesis?

Third stage.

Bacitracin inhibits which stage of cell wall synthesis?

Second stage.

Vancomycin inhibits which stage of cell wall synthesis?

Second stage.

Fosfomycin inhibits which stage of cell wall synthesis?

First stage.

Prototype glycopeptide

Vancomycin.

Prototype monobactam

Aztreonam.

Prototype phosphonic acid antibiotic

Fosfomycin.

Most important glycopeptide in veterinary medicine

Vancomycin.

Most important monobactam in veterinary medicine

Aztreonam.

Most important phosphonic acid antibiotic

Fosfomycin.

Source of bacitracin

Bacillus subtilis.

Source of vancomycin

Streptomyces orientalis.

Source of fosfomycin

Streptomyces fradiae.

Cephalosporins are classified into

First, second, third, and fourth generations.

Proposed fifth-generation cephalosporins

Ceftobiprole and Ceftaroline.

Fifth-generation cephalosporins are active against

Methicillin-resistant staphylococci.

Fifth-generation cephalosporins are commonly used in veterinary medicine

False.

Classification of cephalosporins is based on

Gram-negative activity and beta-lactamase resistance.

Later-generation cephalosporins generally have

Greater Gram-negative activity.

Later-generation cephalosporins generally have

Greater beta-lactamase resistance.

Most cephalosporins are

Generally bactericidal.

Cephalosporins usually bind which PBPs?

PBP-2 and PBP-3.

Carbapenems bind

More PBPs than other beta-lactams.

Carbapenems have broader activity than

Most other beta-lactams.

Monobactams are mainly active against

Gram-negative aerobic bacteria.

Vancomycin is considered a

Reserve antibiotic.

Fosfomycin is considered a

Critically important antibiotic.

Carbapenems are used mainly for

Very serious infections.

Cell wall inhibitors work best against

Actively dividing bacteria.

Why bacteriostatic drugs may antagonize beta-lactams

Beta-lactams require active bacterial growth.

Most important cephalosporin generations to memorize

First through fourth generation.

Most important reserve drugs in this module

Vancomycin, Fosfomycin, Monobactams, and Carbapenems.

High-yield association

Penicillins = Beta-lactams.

High-yield association

Cephalosporins = Beta-lactams.

High-yield association

Aztreonam = Monobactam.

High-yield association

Vancomycin = Glycopeptide.

High-yield association

Fosfomycin = Phosphonic acid antibiotic.

High-yield association

Bacitracin = Decapeptide antibiotic.

High-yield association

Carbapenems = Broadest beta-lactams.

High-yield association

PBP inhibition = Beta-lactams.

High-yield association

First stage inhibition = Fosfomycin.

High-yield association

Second stage inhibition = Bacitracin and Vancomycin.

High-yield association

Third stage inhibition = Penicillins, Cephalosporins, Monobactams, and Carbapenems.

Mnemonic for cell wall synthesis stages

Fo-Ba-Van-Pen/Ceph/Mono/Carba = 1st, 2nd, 2nd, 3rd.

Most important exam fact

Cell wall inhibitors are usually bactericidal.