From WikEM
Jump to: navigation, search


Differential Diagnosis

Acute diarrhea



Watery Diarrhea

  • Enterotoxigenic E. coli (most common cause of watery diarrhea)[1]
  • Norovirus (often has prominent vomiting)
  • Campylobacter
  • Non-typhoidal Salmonella
  • Enteroaggregative E. coli (EAEC)
  • Enterotoxigenic Bacteroides fragilis

Traveler's Diarrhea



  • Antibiotics
    • Not essential, since infection clears spontaneously in most individuals
    • However, most favor antibiotic therapy for patients with positive stool culture[2]
    • First line is fluroquinolone (e.g. Cipro 500mg PO BID x 7 days)

Antibiotic Sensitivities[3]

Category Antibiotic Sensitivity
Penicillins Penicillin G R
Penicillin V R
Anti-Staphylocccal Penicillins Methicillin R
Nafcillin/Oxacillin R
Cloxacillin/Diclox. R
Amino-Penicillins AMP/Amox I
Amox-Clav S
AMP-Sulb S
Anti-Pseudomonal Penicillins Ticarcillin S
Ticar-Clav S
Pip-Tazo S
Piperacillin S
Carbapenems Doripenem S
Ertapenem S
Imipenem S
Meropenem S
Aztreonam S
Fluroquinolones Ciprofloxacin S
Ofloxacin S
Pefloxacin S
Levofloxacin S
Moxifloxacin S
Gemifloxacin X1
Gatifloxacin S
1st G Cephalo Cefazolin X1
2nd G. Cephalo Cefotetan X1
Cefoxitin X1
Cefuroxime X1
3rd/4th G. Cephalo Cefotaxime S
Cefizoxime S
Ceftaroline S
CefTAZidime S
Cefepime S
Oral 1st G. Cephalo Cefadroxil R
Cephalexin R
Oral 2nd G. Cephalo Cefaclor/Loracarbef X1
Cefproxil X1
Cefuroxime axetil X1
Oral 3rd G. Cephalo Cefixime S
Ceftibuten S
Cefpodox/Cefdinir/Cefditoren S
Aminoglycosides Gentamicin S
Tobramycin S
Amikacin S
Chloramphenicol S
Clindamycin R
Macrolides Erythromycin R
Azithromycin I
Clarithromycin R
Ketolide Telithromycin R
Tetracyclines Doxycycline I
Minocycline I
Glycylcycline Tigecycline S
Daptomycin X1
Glyco/Lipoclycopeptides Vancomycin R
Teicoplanin R
Telavancin R
Fusidic Acid R
Trimethoprim I
Urinary Agents Nitrofurantoin S
Fosfomycin X1
Other Rifampin R
Metronidazole R
Quinupristin dalfoppristin R
Linezolid R
Colistimethate X1


  • S susceptible/sensitive (usually)
  • I intermediate (variably susceptible/resistant)
  • R resistant (or not effective clinically)
  • S+ synergistic with cell wall antibiotics
  • U sensitive for UTI only (non systemic infection)
  • X1 no data
  • X2 active in vitro, but not used clinically
  • X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
  • X4 active in vitro, but not clinically effective for strep pneumonia

Table Overview

See Also


  1. Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.
  2. Dupont HL. Shigella species (bacillary dysentery). In: Principles and Practice of Infectious Diseases, 6th Ed, Mandell GL, Bennett JE, Dolin R (Eds), Churchill Livingstone, Philadelphia 2005. p.2655.
  3. Sanford Guide to Antimicrobial Therapy 2014