This is an antibiogram that I used during medical school at UCSF. I think it was created by the pharmacology department at San Francisco General Hospital. This diagram is so helpful for visual learners like me. I’ll go through as best I can based on the colors and quadrants of the diagram. 

Red – All drugs listed in the left upper quadrant (LUQ) have gram positive coverage.

The outer section of the LUQ represents MRSA coverageIn this area we see that vancomycin, daptomycin, linezolid, doxycycline, and clindamycin, and TMP/SMX (Bactrim) all cover MRSA.

On the other hand, amoxicillin, ampicillin, cephalexin cover gram-positives excluding MRSA

Yellow – this color represents atypical bacteria.

  • Drugs that cover atypicals include doxycycline, azithromycin, moxifloxacin, levofloxacin, and ciprofloxacin (weak).

Black – represents parasites and is covered by TMP/SMX (Bactrim) and Metronidazole (flagyl).


Blue – represents anaerobes.

Drugs that cover anaerobes include amox/clav (Augmentin), pip/tazo (Zosyn), metronidazole (Flagyl), ertapenem, meropenem, and moxifloxacin.

Green -represents gram negative bacteria. The outer section of the quadrant represents pseudomonas coverage.

Drugs that cover gram negatives (HNPEK: H. influenzae. Neisseria gonorrhoeae. Proteus. E. coli. Klebsiella) include TMP/SMX (Bactrim), ceftriaxone, moxifloxacin, levofloxacin, ciprofloxacin, gentamicin, aztreonam, ertapenem, meropenem, pip/tazo (Zosyn), and amox/clav (Augmentin).