Hospital acquired infection and antibiotic resistance Flashcards
What is the breakpoint?
The concentration of antibiotic that can be achieved in a clinical setting If the bacteria can divide at a concentration at or higher than the breakpoint, it is deemed resistant
Name some major antibiotic resistant Gram-negative bacterial pathogens.
- Pseudomonas aeruginosa
- E.coli
- Klebsiella
- Salmonella
- Acinetobacter baumanii
- Neisseria gonorrheae
Name some major antibiotic resistant Gram-positive bacterial pathogens.
-Staphylococcus aureus (MRSA) -Streptococcus pneumoniae -Clostridium dificile -Enterococcus spp. -Mycobacterium tuberculosis
Name 7 types of antibiotic.
Beta-lactams Aminoglycosides Chloramphenicol Tetracycline Quinolones Sulphonamides Macrolides
How do beta-lactams work?
Give some examples
Penicillin and Methicillin
-Interferes with synthesis of the peptidoglycan componenet of the bacterial cell wall, by binding to penicillin binding proteins- which catalyses a number of steps in peptidoglycan synthesis.
They have a beta-lactam ring that is a similar shape to a precursor of peptidoglycan in the bacterial cell wall and hence interferes with the synthesis of the cell wall
CELL WALL
How do aminoglycosides work? Give some examples.
Gentamicin and streptomycin.
- Bactericidal: kills bacteria
- Affects protein synthesis.
- affects RNA proofreading which leasd to misfolded protein Some of these proteins get incorporated into the membrane and cause leakage so cells rupture
How does Rifampicin work?
- bactericidal
- targets subunit of RNA polymerase
- makes secretions go orange/red: affects compliance
How does vancomycin work?
bactericidal
-targets Lipid II component of cell wall biosynthesis, and wall crosslinking via D-ala residues
CELL WALL
How does Linezolid work?
- bacteriostatic
- inhibits the initiation of protein synthesis by binding to 50S rRNA subunit.
- gram-positive spectrum of activity
How does daptomycin work?
- bactericidal
- targets bacterial cell membrane
- gram positive specturm
- toxicity limits dose
How does tetracycline work?
- bacteriostatic ( stops bacteria growing)
- Prevents charged amino-acyl tRNAs from binding to the mRNA/ribosome complex, so prevents elongation
- binds to 30S subunit
PROTEIN SYNTHESIS
How does chloramphenicol work?
Inhibits the peptidyl transfer step Binds to the 50S subunit
PROTEIN SYNTHESIS
How do quinolones work?
Quinolones inhibit the functioning of DNA gyrase (Gram-negative) and topoisomerase (Gram-positive) hence hampering the unravelling of DNA during replication
DNA REPLICATION
How do macrolides work? Give an example.
Erythromycin.
Only Gram-positive infections and some gram-negative Targets the 50S ribosomal subunit and prevents the aminoacyl transfer, causes truncation
PROTEIN SYNTHESIS
How do sulphonamides work?
Bacteriostatic
Inhibits the folate pathway
