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== Beta-lactams ==

* Our gold-standard class of antibiotics that are extremely effective and very well tolerated

=== Penicillins +/- Beta-lactamase Inhibitors ===

* '''Amoxicillin''' (PO) and '''ampicillin''' (IV) are great against most streptococci, and a few Gram-negatives
* '''Cloxacillin''' (and oxacillin and others) is great against methicillin-sensitive ''Staphylococcus aureus'' (MSSA)
* '''Amoxicillin/clavulanic acid''' (PO) is broad-spectrum, and works against most Gram-positives and Gram-negatives, as well as some anaerobes
* '''Piperacillin'''-tazobactam (IV) adds even better anaerobic coverage, as well as anti-pseudomonal activity

=== Cephalosporins ===

* '''Cephalexin''' (PO) and '''cefazolin''' (IV) are first-generation cephalosporins that are fantastic against most Gram-positives, including streptococci and MSSA, as well as many non-resistant Gram-negatives
* '''Ceftriaxone''' (IV) is worse for ''Staph. aureus'', but maintains excellent streptococcal coverage and improves the Gram-negative coverage significantly
* '''Ceftazidime''' (IV) is like ceftriaxone but adds anti-pseudomonal activity

=== Carbapenems ===

* '''Ertapenem''' (IV) covers essentially everything except MRSA and some very resistant Gram-negatives
* '''Meropenem''' (IV) adds anti-pseudomonal activity

== Fluoroquinolones ==

* Broad-spectrum and great oral bioavailability (PO ~= IV), but low barrier to resistance and many side effects
* '''Levofloxacin''' (PO/IV) and '''moxifloxacin''' (PO/IV) cover Gram-positives that includes ''staph. aureus'' and Gram-negatives
* '''Ciprofloxacin''' (PO/IV) has less good Gram-positive coverage but better Gram-negative coverage, including anti-pseudomonal activity

== Vancomycin/Daptomycin/Linezolid ==

* '''Vancomycin''' (IV) and '''daptomycin''' (IV) work ''only'' against Gram-positives, and are reserved for resistant infections such as methicillin-resistant ''Staphylococcus aureus'' (MRSA) and vancomycin-resistant ''Enterococcus'' (VRE)
** Vancomycin has renal toxicity and possibly ototoxicity
** Daptomycin doesn't work for pneumonia (inactivated by surfactant)
* '''Vancomycin''' (PO) is not absorbed, and is used ''only'' for ''Clostridium difficile''-associated diarrhea
* '''Linezolid''' (PO/IV) is another antibiotic that treats only Gram-positives, including MRSA

== Aminoglycosides ==

* '''Tobramycin''' (IV) and '''gentamicin''' (IV) are reserved for very resistant Gram-negative infections, and have side effects of renal toxicity and ototoxicity

== Miscellaneous ==

* '''Septra (TMP-SMX)''' (PO/IV) has good Gram-negative coverage, including many resistant Gram-negatives, as well as MRSA coverage
* '''Azithromycin''' (PO) is used for community-acquired pneumonia, covering ''Strep. pneumoniae'' and atypicals like ''Chlamydia'', ''Mycoplasma'', and ''Legionella''
* '''Clindamycin''' (PO/IV) is used for Gram-positives (including MRSA) and oral anaerobes, as well as streptococcal toxic shock syndrome
* '''Doxycycline''' (PO) is used for weird infections, but also includes MRSA coverage
* '''Metronidazole''' (PO/IV) treats gut anaerobes and ''C. difficile''

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