Week 10 Antibiotics Flashcards
(62 cards)
First-generation cephalosporins are active against which organisms?
First-generation cephalosporins are active against gram-positive cocci, including
S. aureus and S. epidermidis (excluding methicillin-resistant strains), and most
streptococci.
Why is there often cross-sensitivity and cross-resistance between penicillins and cephalosporins?
Due to the fact that both drug classes contain structurally similar side chains and beta lactam ring.
Doxycycline is not used during pregnancy because it may cause which effect in neonates?
Doxycycline, a tetracycline, is not used during pregnancy because it may cause discoloration of deciduous teeth in neonates.
A 33-year-old pregnant female patient has developed community-acquired pneumonia (CAP). Which antibiotic is most appropriate for this patient?
erythromycin or azithromycin is the first choice because each is Pregnancy Category B
A 42-year-old pregnant female patient comes to the clinic with an outbreak of herpes simplex to the lips. Which medication would be most appropriate for the patient?
Acyclovir is Pregnancy Category B and safe to use in pregnancy.
A 46-year-old patient is newly diagnosed with hepatitis C. The APN understands that hepatitis B serum will need to be drawn prior to starting any hepatitis C virus (HCV) medications for which reason?
There is a risk of reactivation of hepatitis B, and this would need to be covered.
Which of these is first-line therapy for a mild case of impetigo, with fewer than five 2-cm lesions on the left leg of a 10-year-old patient?
First-line therapy for impetigo is mupirocin unless it is a moderate to severe case.
Mupirocin is bactericidal and has a wide range of coverage against gram-positive bacteria, including methicillin-resistant S. aureus, and a limited coverage against some gram-negative organisms. Mupirocin acts by which mechanism?
Mupirocin is bactericidal at concentrations achieved by topical administration of the 2% ointment. Mupirocin acts by binding to bacterial isoleucyl-tRNA synthetase.
What is the difference between facultative & obligate?
Obligate truest sense of the term
Obligate aerobe has to have oxygen, If the oxygen drops a little bit the bacteria start to die
Obligate anaerobe: poisoned by oxygen
Facultative: in-between “gray scale”
Facultative anaerobic “prefers no o2” but can still survive
What 2 bugs should come to mind when you think of gram +?
Strep & Staph
What bug comes to mind when you think of gram negative?
e. coli
Bacterio-static:
slows cell from growing a multiplying…drug keeps growth slow so immune system can clean up mess
Bacteri-cidal:
KILLS the cells think for immunocompromised patients
What are the bacteriocidal mechanisms of action?
Cell wall synthesis inhibitors “open up cell wall guts spill out*
DNA synthesis inhibitors *stop dna from replicating = death”
Metabolic synthesis inhibitors “need metabolism for energy = death”
What are the bacteriostatic MOA?
Protein synthesis = usually static, at high doses»_space; cidal
What are the 4 ways bacteria become resistant to abx?
Change target: Abx targets bacteria, bacteria can change self so it doesn’t get detected
Influx Pumps: for bacteria to survive it can reduce influx pump (less abx gets into it)
Efflux Pumps: Increase efflux pump to pump abx out faster (less time for abx to work)
Enzymatic inactivation: Enzymes breakdown abx so bacteria survive attack and become resistant. Trait passed down to next generation of bacteria
Pt has positive strep and medical hx of PCN allergy…what do you give?
- What’s first line and can they take? If yes, stop thinking
- If not, 1st gen cephalosporin, Kephlex
What are the cell wall synthesis inhibitors?
PCN, cephalosporin (lactam abx) Vanco
Folic acid synthesis inhibitors (Metabolism Synthesis):
Sulfonamides & Trimethoprim (put together to form Bactrim)
Macrobid (Nitrofranitoin)
DNA Synthesis inhibitors:
Quinolones & Rifampin
Protein Synthesis inhibitors:
50S subunit: Macrolides & Clindamycin
30S subunit: Tetracycline
What inhibits the 50S subunit?
Macrolides & Clindamycin
Penicillin, Cephalosporins, & Glycopeptides (Vanco)
MOA
cidal or static?
Inhibit cell wall synthesis
Bacteriocidal
Penicillin
MOA 1st line 2nd line How to take ADR #3 Drug interaction #4 Pregnancy
MOA:
- inhibit cell wall synthesis; bactericidal
1st line: Syphilis and strep throat/pharyngitis
2nd line: lyme disease
How to take: empty stomach
Adverse Reactions:
Maculopapular rash w/MONO,
C. Diff,
Seizures,
Drug Interactions:
- Warfarin,
- diuretic,
- tetracycline,
- probenecid *
VERY SAFE IN PREGNANCY
