Module 10: Antimicrobials Flashcards
Give two examples of earlier ways of dealing with infection.
Amputation, cauterization
What are two earlier ways that syphilis was treated?
Mercurial compounds, arsenicals
Describe the process of the creation of penicillin (3 years in particular).
1928: Accidental discovery of penicillin by A. Fleming
1935: Accidental discovery of sulfa drugs.
1942: Purification & production of penicillin
Differentiate between antibiotics, antibacterials, antivirals, and antimicrobials.
Antibiotics = natural source
Antibacterials = kill bacteria
Antivirals = kill viruses
Antimicrobials = kill microbes
Disinfectants are _______
compounds that may be able to
eliminate ____________ but are
usually too ________ for human use
(other than topical)
Chemical, microorganisms, toxic
What are the most antibiotic-resistant infections?
MSK infection, skin
and soft tissue infections, UTIs, Pneumonia/Intra-abdominal
infection
A single mutation causes what? A series of mutations?
Single: lowers affinity to antibiotic
Series: resistance
How do bacteria share resistance?
They acquire resistance genes through transfer of DNA (plasmids)
What are the three mechanisms of resistance?
- altered target site for drug
- altered uptake/increased efflux
- drug inactivation
What are the 3 ways to classify an antibacterial?
- bactericidal vs. bacteriostatic
- mechanism of action
- chemical structure
What is the difference between bactericidal and bacteriostatic antibacterials?
Bactericidal kill, immune system cleans up cellular fragments.
Bacteriostatic inhibits, immune system must still be actively fighting disease.
What are the three target sites for mechanism of action?
- cell wall synthesis
- protein synthesis
- nucleic acid synthesis
A peptidoglycan layer is specific to _______ and is the optimum target for ________ _________.
Bacteria, selective toxicity
Name 3 examples of beta-lactams. What makes them beta-lactams?
Penicillin, amoxicillin, ampicillin. Intact ring structure, which is essential for antibacterial activity.
What enzymes break down beta-lactams?
Beta-lactamases
Penicillin binds, utilizing what? What do these inhibit?
Pencillin-binding proteins (PBPs). Inhibit transpeptidases (TBPs) which normally catalyze the formation of peptidoglycan.
free card i wrote an incorrect statement LOL
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Penicillin only kills cells when bacteria are..?
Growing. Only impacts during log phase
Name two bacteria that penicillin affect.
Neisseria, treponema pallidum
Name two bacteria that ampicillin/amoxicillin impact.
Salmonella, E-coli.
Name the bacteria that nafcillin or dicloxacillin impact.
Staphylcoccus aureus.
___________, ____________, and __________ decrease the effectiveness of birth control pills.
Ampicillin, amoxicillin, rifamycin
Name three disadvantages of penicillin.
- limited effectiveness for gram-negative bacteria.
- need frequent doses
- can be inactivated by beta-lactamases
Cephalosporins have a 6-sided _____ attached to a _________ group. What is the difference between first and later generation cephalosporins?
Ring, beta-lactam. First = only effective against gram-positives. Later = gram-positive and gram-negative
When are cephalosporins used? What is it commonly used to treat (2)?
Prophylactically before/after surgery. Gonorrhea, GBS (if penicillin not possible).
Glycopeptides are _________ agents only active against ____- _____ bacteria.
Bactericidal, gram postive
Glycopeptides inhibit the addition of _________ to the ___________ ___________. What is helpful about glycopeptides?
Subunits, peptidoglycan backbone. They act at an earlier stage than beta-lactams.
Glycopeptides treat ________ _______, the main nosocomial disease. Why are gram-negatives naturally resistant?
Clostridium difficile. Gram negs are resistant because glycopeptides are too large to move through the outer memes.
Name 2 antibacterial units that are grouped in the 30S subunit of the ribosome.
Aminoglycosides, tetracyclines.
Name 2 antibacterial agents that are grouped in the 50S subunit of the ribosome.
Erythromycin, clindamycin.
What are two mechanisms of action for aminoglycosides?
- binds to proteins in 30S subunit.
- misread mRNA, bacterium dies.
What are 2 types of bacteria that aminoglycosides commonly affect? When is it given to pregnant people?
Aerobic gram-negative, facultative anaerobe. Given to those with prolonged rupture of membranes or infants with sepsis.
Are aminoglycosides recommended during pregnancy?
No, category D because it is ototoxic and nephrotoxic.
How do tetracyclines act on bacteria?
Inhibit the binding of tRNA to the ribosome to prevent protein syntheiss.
When are two infections that tetracyclines treat? How are they resistant?
Chlamydia, mycoplasma. Bacteria make new cytoplasmic membrane proteins, pump out tetracycline.
What are two side effects in children when given tetracyclines? What about adults?
- permanent tooth/bone issues
- photosensitive allergic reaction
Adults: GI issues
How do macrolides act? Are they bactericidal or bacteriostatic? When are they sued?
Prevents release of tRNA after peptide formation. Bacteriostatic. Used for STIs, especially during pregnancy (less harmful).
Erythromycin is a great alternative treatment for what? What are they typically active against?
Streptococcus. Chlamydia, mycoplasma.
A single 1g dose of _________ is as effective as a 7-day course of ______________ for what?
azithromycin, doxycycline. Chlamydial cervicitis, urethritis.
What does clindamycin do? What does it treat?
Lincosamide that inhibits peptide formation. Active against chlamydia, gonorrhea, GBS, BV.
What are the two categories of antibacterial agents?
- inhibitors of DNA replications
- folic acid synthesis inhibiton
What do quinolones inhibit? What is the MAIN quinolone, is it bactericidal or bacteriostatic?
Inhibit DNA gyrase. Ciprofloxacin, bactericidal.
Quinolones are administered _________ and are used to treat _______. It can also treat which 2 conditions?
Orally, UTIs. Chlamydia, gonorrhea.
Why can’t quinolones be given to pregnant women/children?
Effect on cartilage development, especially 1st semester.
Sulfonamides inhibit _______ _______ _______, are administered _____, and typically treat _________.
Folic acid synthesis, orally, UTIs.
Are sulfonamides bactericidal or bacteriostatic? Why don’t we prescribe to pregnant women?
Bacteriostatic. Possible effect on folic acid, affects bilirubin in fetus.
_________ and ___________ are also effective sulfonamides that treat UTIs.
Trimethoprim, sufamethoxazole.
Metronidazole is only effective against ____________ organisms. It is also active against a wide range of ______, which can help treat ____.
Anaerobic, protozoa, BV.
What are the best three treatments for GBS?
- penicillin
- cefazolin (cephalosporin)
- clindamycin/erythromycin
