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 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
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
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
How do macrolides work? Give an example.
Only Gram-positive infections
Targets the 50S ribosomal subunit and prevents the peptidyl transfer step
Erythromycin
How do aminoglycosides work? Give some examples.
Aminoglycosides affect RNA proofreading leading to misfolded proteins
Some of these proteins get incorporated into the membrane and cause leakage
Gentamycin and Streptomycin
How do sulphonamides work?
Inhibits the folate pathway
How does tetracycline work?
Prevents charged amino-acyl tRNAs from binding to the mRNA/ribosome complex
How does chloramphenicol work?
Inhibits the peptidyl transfer step
Binds to the 50S subunit
What are the four main mechanisms of antibiotic resistance?
Altered target site
Inactivation of antibiotic
Altered metabolism
Decreased drug accumulation
