Always refer to the Stanford Guide &/or the Green Book put out by the FAHC Infectious Disease Department (written by Dr. Grace) and available to you for free from any of the hospital pharmacies.
You'll find important, basic information on bacterial classification on the Gram Stain Compendium page. Knowing into what category your pathogens fall is crucial to choosing appropriate antibiotics, and is highly fertile ground for pimping.
The general recommendations listed on this page are just intended to get you started, particularly the antibiotic regimens we've included. Opinions vary greatly on which antibiotics are best for which infections.
This is a tricky area, and it seems everyone has their favorite pet antibiotics. You should be able to suggest something reasonable - that seems to be the basic expectation. This list should help, although it obviously won't agree with everyone. It assumes that the patient's presentation is uncomplicated. If the presentation is not a straightforward one, consult Sanford!!
| Empiric coverage includes azithro ("Z-pack"), e-mycin. Doxycycline is an underused drug with excellent coverage for CAP's. |
| TYPICALS |
|---|
| Strep pneumo | GPC | pen (if sensitive), doxy, any ceph (if sensitive), azithro, quinolones (except Cipro) |
| H. flu | GNR | doxy, azithro, any ceph, others |
| Moraxella | GNC | doxy, azithro, any ceph, others |
| Klebsiella (uncommon, occurs in alcoholics) | GNR | doxy, azithro, any ceph, others |
| ATYPICALS (slow, indolent course - "walking penumonia" - except Legionella, which packs a punch. Atypicals tend not to show up on gram stain) |
|---|
| Mycoplasma | GNR | macrolides, doxycycline, quinolones |
| Chlamydia | GNR | macrolides, doxycycline, quinolones |
| Legionella | GNR | macrolides, doxycycline, quinolones |
| Viruses | | supportive therapy |
| See Green Book (page 30). Don't treat unless symptomatic (or if pregnant, prior to urologic procedure, or if renal transplant patient) - then empiric therapy is co-trimoxazole (Bactrim, Septra). Note that E. coli resistance to bactrim is increasing - get sensitivities (from culture taken before Tx starts). |
| Uncomplicated cystitis in females | 3 days | co-trimox, cephalexin, nitrofurantoin |
| Complicated cystitis | 7 days | co-trimox IV, norfloxacin, cefpodox |
| Pyelo with inpatient Tx | 14 days | co-trimox, cefpodox, cipro |
| Pyelo with outpatient Tx | 14 days | co-trimox, gent +/- amp, cipro |
| Pneumonia: |
| Community acquired (CAP): | think "pneumonia on the klam shell: KLMSH": Klebsiella, Legionella, Mycoplasma, Strep pneumo (pneumococcus), H flu. Cover with 3rd gen ceph, zithromax, bactrim. |
| Institutionally acquired: | Staph, GHR's, Pseudomonas, TB. Need Dx. | |
| UTI: | Uncomplicated: E coli, cover with bactrim, keflex, quinolone. Proteus?
Pyelo: IV Bactrim |
| Cellulitis: | Gram+ cocci. Cover with kefzol, penicillins. |
| Diarrhea: | if on ABX, consider c.diff (send sample to lab) - cover with flagyl PO, d/c other ABX if possible. |
| Ulcers: | H. pylori. Cover with flagyl, bizmuth (peptol-bizmol), several alternative regimens |
| TB: | cover with rifampin, isoniazid |
| Abscesses: |  surgery. Anaerobes. |
| URI's: | Usually viral, so  ABX. If bacterial, think Amoxicillin, Erythromycin |
| Neutropenic Fever: | Piper & gent, ceftaz & gent |
| CNS Penetrating: |
| Good: | flagyl, sulfa, chloramphenicol, ciproflaxacin |
| OK: | Amp, cefotaxime, ceftriaxone |
| Poor: | erythro, clinda, cefazolin | |
| PCN: | strep, mouth anaerobes, treponemes. staph only with nafcillin or oxacillin. GNR |
| Amino pen: | GNR except pseudomonas |
| Piperacillin: | Primarily used for pseudomonas. Also covers bizarre GNR & serrata |
| Nafcillin: | staph aureus |
| Cephalosporins: |
| 1st gen (keflex): | aerobic gram+ cocci & simple GNR. h flu, neisseria |
| 2nd gen (cefoxitin): | staph, strep, h flu, neisseria |
| 3rd gen (ceftriaxone = IV, cefpodox = PO): | staph, strep, good GNR, enterobacter, serratia | |
| Macrolides (erythro, azithro, clarithro, biaxin): | gram+ cocci, atypical pneumonia bugs, h. flu, chlamydia. Bacteriostatic |
| Aminoglycosides (gentamycin, tobra, amikacin): | Active against aerobic GNR's. Also used for synergy with ceph's or amp against pseudomonas, staph aureus, and enterococcus |
| Tetracycline: | tick-borne & others |
| Clindamycin: | anaerobes & gram+ cocci |
| Bactrim/Septa: | GNR, UTI |
| Flagyl/metronidazole: | anaerobes, c. diff, parasites such as giardia, entamoeba histolytica |
| Quinolones (cipro, levoquin, trovan): | everything except MRSA. Adults only. Trovan is hepatotoxic. |
| Sulfonamides (bactrim, sulf..., trimethoprim): | staph, strep (including strep pneumo), moraxella, aerobic gram-, pneumocystis, legionella, listeria. |
| Chloramphenicol: | Broad spectrum |
