29 - Antibiotic Medication Flashcards
What are bacterial cell walls made up of?
What about gram positive and gram negative bacteria
Polysaccharide chains called peptidoglycan
Gram positive bacteria possess a thick cell wall with many layers of peptidoglycan
Gram negative bacteria have a relatively thin cell wall with few layer of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins surrounded by a second lipid membrane
Most bacteria have the gram negative cell wall
What does peptidoglycan structure consist of?
What is each individual strand polymerized by?
What cross links the strands?
Glycan strands made of alternating N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues cross-linked by peptides
Individual strands are polymerized by enzyme glycosyltransferase (GT) into peptidoglycan chain
transpeptidase (TP) cross link the strands. TP is targeted by many antibiotics (penicillin binding protein)
What does bactericidal and bacteriostatic antibiotics lead to?
permanent loss of replicative ability
temporary loss of growth and replication that returns following the removal of antibiotics
Because of their unusual 4 member ring, penicillin and cephalosporins are called:
They inhibit cell wall synthesis by inhibiting an enzyme (blank) which is responsible for cross-linking components of the cell wall, which is why they are (blank)
DD transpeptidase is also called:
They work better on (blank) bacteria
beta lactams
DD-transpeptidase
bactericidal
penicillin binding protein
Gram positive
Beta lactamases are bacterial enzymes made by most (blank) and may gram negative organisms that hydrolyze the beta lactam ring of certain penicillin and cephalosporins confer resistance
staphylococci
What is clavulanic acid?
beta lactamase inhibitor
What is vancomycin?
Not a beta lactam, but also inhibits peptidoglycan cross linking
produced in nature by actinobacteria species, amycolatopsis orientalis, commonly found in soil
What do bacteria use folic acid for?
to synthesize nucleic acids that make up their DNA
What is para-aminobenzoic acid? (PABA)
nutrient obtained from the environment that is the precursor for folate in bacteria
Eukaryotes can pull food from 2 places:
folic acid and environment
What resembles PABA and dihydrofolic acid respectively, and interfere with PABA metabolic pathways?
Sulfonamides and trimethoprim
usually given together to block sequential steps in synthesis of folic acid
Bacteria make protein from mRNA template within the bacterial:
70s ribosomal complex
What occurs in transpeptidation?
tRNA transfers an amino acid to the growing amino acid chain
Why are eukaryotes unaffected by protein synthesis inhibitors?
They have 80s ribosomal complex (60S and 40S subunits)
Chloramphenicol (C triangle) and macrolides (M) bind to the (blank) and block (blank)
50S subunit
Tetracyclines (T) bind to the (blank) and prevent (blank)
30S
prevent binding of incoming tRNA
Aminoglycosides are a class of antibiotics. What do they bind to and what do they do?
Bind to the 30S ribosomal subunit
block initiation of the complex
cause misreading of the code on the mRNA template
inhibit translocation
What is bacterial resistance caused by?
1) drug inactivation or modification
2) alteration of binding site
3) alteration of metabolic pathways
4) reduced drug accumulation
What are side effects of antibiotics?
Gastrointestinal distress
antibiotic therapy alters the bacterial environment of the body
Loss of normal intestinal flora produces diarrhea or GI discomfort with a number of antibiotics
Probiotic products, including active culture yogurt, may be used as adjunctive therapy to minimize GI effects
What is Stevens Johnson syndrome and toxic epidermal necrolysis?
rare conditions in which the skin becomes detached from the underlying tissue and cloughs off the body
