Term | Definition |
how can prokaryotes be destroyed? | by inhibiting translation (protein synthesis inhibitors) |
what type of ribosomal subunits are bacterial ribosomes made up of? | 50S, 30S |
what are the drugs that are 50s inhibitors? | chloramphenicol, erythromycin, clindamycin (CEC) |
what drugs are 30S inhibitors? | tetracyclines, aminoglycosides (TA) |
is chloramphenicol bacteriostatic or bactericidal? | bacteriostatic |
is erythromycin bacteriostatic or bacteriocidal | bacteriostatic |
what about tetracyclines? | bacteriostatic |
Aminoglycosides? | bactericidal |
what is the MOA of aminoglycosides? | they bind to the 30S subunit of the ribosome (where translation and protein synthesis occur). this blocks initial steps towards protein synthesis and cause misreading of the mRNA codon. |
do aminoglycosides work against gram positive or gram negative bacteria? | gram positive. they require oxygen dependent transport across the membranes of the bacterium, so they generally only work on aerobic organisms. furthermore, they are targeted against gram negatives |
what are some toxicities of aminoglycosides? | strongly ototoxic, nephrotoxic, neurotoxic. |
what is the MOA of tetracyclines? | enter bacterium via cell membrane proteins, bind to 30S ribosome subunit, block acceptor site for incoming aminoacyl tRNA. ribosome docking does not occur. |
are tetracyclines narrow or broad spectrum? | broad spectrum, but widespread resistance exists. |
what are some side effects of tetracyclines | photosensitivity, development of pseudotumor cerebri, yellowing of teeth in children, contraindicated in pregnant women. |
use of tetracyclines is contraindicated with concurrent use of which drug? | isotretinoin (another risk factor drug for pseudotumor cerebri). |
what things should be avoided when taking tetrachyclines and why? | antacids, iron, and calcium, including dairy products must be avoided, because they significantly impair absorption of the antibiotic. |
what is the MOA of chloramphenicol? | binds to 50S subunit of ribosome, physically blocking action of peptidyl transferase, enzyme needed to form the peptide bond between amino acids. if no peptide bond forms, AAs cannot be joined to form a protein. |
is chloramphenical toxic? | yes-very toxic, but it has good broad spectrum coverage. especially effective against aerobes. it is also bone marrow toxic, so can cause aplastic anemia, and grey baby syndrome. |
what is the MOA of erythromycin | like all other drugs in the erythromycin drug class, it inhibits the 50S subunit of the ribosome. However, by binding, they block translation, meaning amino acids cannot be shifted to their proper position in order to allow for peptide bond formatin. |
erythromycins are also known as what? | macrolides. |
erythromycin is usually the drug of choice for what population? | penicillin allergic patients. |
macrolides are the DOC for what? | mycoplasma pneumoniae. |
all macrolides have what side effect? | increase risk for QT interval prolongation, which can cause torsade de pointe; this risk is magnified by concomitant use of P450 inhibitors. |
what is the MOA of clindamycin? | same for chloramphenicol. |
what is clindamycin the DOC for? | anaerobic infections that occur above the diaphragm. |
what toxin is a protein synthesis inhibitor in eukaryotes? | diptheria toxin. eukaryotes: non bacterial cells, including our own cells, fungi, and protozoa. |