Inhibitors Of Bacterial Cell Wall Synthesis

Front 1

What are the narrow spectrum penicillins?

Back 1

Penicillin G, Penicillin V, Dicloxacillin, Nafcilin, Methicillin

Front 2

What are the broad spectrum penicillins?

Back 2

ampicillin, amoxicillin, ticarcillin, piperacillin

Front 3

what are the 1st gen Cephalosporins?

Back 3

Cefazolin, Cephalexin

Front 4

what are the 2nd gen cephalosporins?

Back 4

Cefuroxime, Cetotetan, Cefoxitin

Front 5

what are the 3rd gen cephalosporins?

Back 5

ceftriaxone, cefoperazone, ceftazidime

Front 6

what are the 4th generation cephalosporins?

Back 6

Cefepime

Front 7

What are the Carbapenems?

Back 7

Imipenem(plus cilastatin) and meropenem

Front 8

what are the monobactams?

Back 8

aztreonam

Front 9

what are the beta lactamase inhibitors?

Back 9

Clavulanate

Front 10

what are some other cell wall synthesis inhibitors?

Back 10

vancomycin and fosfomycin

Front 11

what are the mechanisms of beta lactam antibacterial effects?

Back 11

1)B lactam antibiotics bind to specific beta lactam receptors called PBP located on cytoplasmic membrane, these proteins are enzymes endowed with various catalytic functions which are inhibited by binding with the Abx, most important enzyme inhibited are transpeptidases which catalyze the final cross link step in the synthesis of murein(aka peptidoglycan), since PG layers are constituents of bacterial cell wall, synthesis of wall is blocked 2)autolytic enzymes(autolysins or murein hydrolases) are present in the cell wall and degrade the PG, beta lactam Abx can activate these autolysins(by blocking autolysin inhibitor) promoting the lysis of bacteria

Front 12

What are the features of the antibacterial effect of b lactams?

Back 12

usually both mechanisms are operative and the ultimate effect is BACTERICIDAL, when only the first mechanism is operative the ultimate effect is bacteriostatic, bactericidal effect is TIME DEPENDENT

Front 13

what does the susceptibility of bacteria to to b lactams depend on?

Back 13

1)constitution of outer layers of cell envelope that Abx must cross 2)thickness of PG layer

Front 14

what are some natural features of bacteria that give them resistance to b lactams?

Back 14

1)lack PG cell wall(mycoplasma) 2)cell walls impermeable to drug(G neg)3)beta lactamase producing organisms 4)PBPs with low affinity for drug

Front 15

describe acquired resistance

Back 15

mainly extrachromosomal and mediated by plasmid that can be transferred to other bacterie

Front 16

describe cross resistance

Back 16

occurs among all beta lactamase sensitive penicillins

Front 17

describe partial cross resistance

Back 17

between beta lactamase resistant penicillins and cephalosporins

Front 18

what are the main mechanisms of microbial resistance to beta lactam abx?

Back 18

1)production of beta lactamase enzymes(MOST IMP)-hydrolyzes beta lactam ring producing penicilloic acids devoid of antibacterial activity 2)development of PBPs which have decreased affinity for Abx(pneumococci and MR staphlyococci) 3)decreased permeability of cell membrane to the drug(many G neg bacteria), 4)development of active efflux pump

Front 19

what are the penicillinase(B lactamase) sensitive penicillins?

Back 19

Penicillin G, Penicillin G benzathine, Pen G procaine, Pen V

Front 20

what are the penicillinase resistant penicillins?

Back 20

oxacillin, dicloxacillin, nafcillin, methicillin