Abx Flashcards
What abx target the cell wall
Beta-lactate abx • Penicillins • Cephalosporins • Carbapenems • Glycopeptides and Lipoglycopeptides
What abx work by inhibiting protein production
Rifamycins Aminoglycosides Macrolides Tetracyclines Clindamycin Nitrofurantoin
Abx that inhibit replication
Bactrim
Quinolones
Metronidazole
What are the four categories that bacteria are grouped into?
Gram-positive
Gram-negative
Anaerobic
Atypical
Examples of gram positive bacteria
Staph aureus
Strep pneumo
Enterococcus
Listeria
Examples of gram-negative bacteria
H. flu
Neisseria spp
Enterobacteriaceae
Pseudomonas
Examples of anaerobic bacteria
Bacteroides fragilis
Clostridium spp
Examples of atypical bacteria
Chlamydia spp
Mycoplasma spp
Legionella pneumophilia
What are some common pathogens causing CAP?
Strep pneumo H flu Legionella Mycoplasma pneumo Chlamydia pneumo
What is the primary treatment for uncomplicated CAP?
Oral macrolide
Or
Doxycycline
If a patient’s CAP is severe enough to require hospitalization, how should you adjust their treatment regimen?
Add a ß-lactam (cefotaxime, ceftriaxone, high dose ampicillin)
Could use ß-lactam w/ a quinolone (ie moxifloxacin or levofloxacin)
If your patient’s CAP blood culture comes back positive for Strep pneumo, how would you adjust treatment?
High-dose pen G (narrow the spectrum) or 2nd/3rd gen cephalosporin
What is the first line treatment for uncomplicated acute cystitis?
Nitrofurantoin (Macrobid)
Bactrim if area is not high for resistant E. coli
How would your treatment for acute cystitis change if patient is diabetic?
Consider them complicated
Switch to Cipro (broader coverage)
How do you treat acute pyelonephritis if patient unable to maintain oral intake (2˚ to N/V)?
Inpatient treatment with IVF
Carbapenem if concern for resistant organism
Extended spectrum penicillin or beta lactam combo
Cipro or levofloxacin
What is the spectrum for quinolones?
Broad spectrum, but resistance is becoming common
What are the adverse reactions possible with quinolones (ie Cipro)?
Cartilage anormalities, including tendon rupture (avoid use in under 18 and pregnancy)
Can prolong QT interval —> TdP
Recent concern for increasing risk of aortic aneurism and dissection
What pathogens usually cause PID?
N. gonorrhoeae
C. trachomatis
How do you treat PID empirically?
Single IM dose of ceftriaxone or cefotaxime
PLUS
Oral doxycycline
How would your PID treatment regimen change if she is found to have C. trachomatis?
Doxy or Azithromycin
How would your PID treatment regimen change if she is found to have N. gonorrhoeae?
Ceftriaxone
Plus
Azithromycin
How would your PID treatment regimen change if she is pregnant?
Just use the Azithromycin
Which abx are your drug of choice during pregnancy?
Penicillins and cephalosporins
What pregnancy Category are macrolides?
Erythromycin and Azithromycin are Category B
Clarithromycin is Category C
Which abx should be avoided in pregnancy unless severe or life threatening infection
Quinolones
Tetracyclines
Metronidazole
Aminoglycosides
Exception example - doxy for Rocky Mountain Spotted Fever
Avoid trimethroprim in _____ trimester because ______
First
It’s a folate agonist (—> NTD)
Avoid sulfas and nitrofurantoin at what point in pregnancy and why?
At Term
Sulfas interfere with bile conjugation
Nitrofurantoin increases risk of neonatal hemolysis
In general, avoid abx in _______ of pregnancy if possible and use shortest effective duration
First trimester
What are the most common causative organisms for acute bacterial meningitis?
Strep pneumo
N. meningitides
How do you treat acute bacterial meningitis?
Empiric 3rd gen cephalosporin with vancomycin to cover resistant strep strains
Tailor according to CSF analysis
5-10% of those allergic to PCN will also react to …
Cephalosporins
Most common pathogens for cellulitis?
Staph aureus
Strep spp
How do you treat cellulitis empirically?
Clindamycin
Bactrim
Tetracyclines if purulent drainage
Clindamycin less frequently chosen b/c of risk of C. diff
Pros and cons of clindamycin
Effective against toxin-mediated disease from staph and strep
Active against many MRSA strains
BUT kills healthy intestinal flora —> C. diff
Why are tetracyclines contraindicated in pregnancy?
Hepatotoxic for mother and fetal bone/teeth development
Also contraindicated in children under 8
SE specific to minocycline
Can cause blue-black hyperpigmentation (3-20%)
Which abx is most commonly used against MRSA cellulitis?
Vancomycin
One of the few abx used against C. diff
Adverse effects of vancomycin and friends
Nephrotoxicity and hearing loss (esp with aminoglycoside use)
Red man syndrome with rapid infusion
