Antibiotic Ladder

Penicillin PCN

Gram +

Gram -

most organisms have grown resistance except syphilis.

Staph targeted drugs

MSSA

Methicillin

Clox

Ox

Nafcillin

MSSA use exclusively

MRSA

Vancomycin

  • often we start with Vanco for broad spectrum,
  • on test though try to see if it is indeed MRSA. IF MSSA give Nafcillin

Linezolid (PO/IV) $$$

Start at the bottom of the ladder: closest to the nodes.

Amoxicillin/Ampicillin

Gram - coverage

some Gram + if paired with

ß lactamase inhibitor

No MRSA coverage

No psudommonas

Pseudomonas

Piperacillin

ß lactamase i: Tazobactam

Pip/Tazo covers everything except MRSA

intolerant to pip/tazo

or ESBL activity

Carbapenems

Cephalosporins

Gram +

1st gen

2nd gen

Gram -

4th gen

Both Gram +/-

3rd gen

cellulitis/sx prophy

pseudomonas only

MRSA

5th gen

won't use, need mics

Be as targeted as poss/cheapest

but if you dont know what it is, go broad (pip/tazo)

Escalate quickly, deescalate slowly

Flouroquinolones

in baseball, have to get from first to second etc to get home.

Correlation of flouroquinolones to subsequent generations is that all subsequent generations contain aspects of the first

Gram -

1st gen

Cipro

Commonly for UTI

Gram +

3rd gen

Moxifloxacin

Respiratory (covers PNA)

2nd gen

Levofloxacin

can cover gram -, but too high on the ladder

More targeted anaerobe coverage

Metronidazole

Groin

Belly

Vagina

Abdomen

Anaerobes too

Clinda

anywhere else

Empiric coverage Abx regimens

CAP

HAP

Meningitis

UTI

Cellulitis

Moxifloxacin (PO/IV)

risk of fluoro resistance, try to avoid (abx stewardship)

Ceftriaxone + Azithromycin (IV, hospitals)

Azithromycin (PO, outpatient)

Culprits: MRSA and Pseudomonas

Vanc + Pip/tazo

Ceftriaxone 2g + Vanco +/- steroids +/- ampicillin

M3 students: every meningitis patient gets steroids, only immunocompromised patients get ampicillin

Amoxicillin

Nitrofurantoin

Bactrim: TMP/SMX

Ceftriaxone

If pregnant

If a woman

only if no renal failure

inpatient IV: septic and w/ bad pyelonephritis

Cipro

ambulatory pyelonephritis

suspect MRSA

Vancomycin (IV)

Clinda

Bactrim: TMP/SMX

OK to initially use

1st or 2nd gen Cephalosporin

for VISA, VRSA, and Enterococcus (VRE)

Ticarcillin

same coverage as pip/tazo

(+)

(-)