Shigella

Background

  • Anaerobic, gram-negative rod
  • Requires a very small inoculum to cause disease
  • Symptoms usually start within 1-3 days of exposure[1]
    • Variation depends on serotype
    • Can be anywhere from 12 hours to 7 days for incubation period

Differential Diagnosis

Acute diarrhea

Infectious

Noninfectious

Watery Diarrhea

  • Enterotoxigenic E. coli (most common cause of watery diarrhea)[2]
  • Norovirus (often has prominent vomiting)
  • Campylobacter
  • Non-typhoidal Salmonella
  • Enteroaggregative E. coli (EAEC)
  • Enterotoxigenic Bacteroides fragilis

Traveler's Diarrhea

Management

Adult

  • Antibiotics
    • Not essential, since infection clears spontaneously in most individuals
    • However, most favor antibiotic therapy for patients with positive stool culture[3]
    • First line is fluroquinolone (e.g. Cipro 500mg PO BID x 7 days)

Antibiotic Sensitivities[4]

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
CefTRIAXone 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
TMP-SMX I
Urinary Agents Nitrofurantoin S
Fosfomycin X1
Other Rifampin R
Metronidazole R
Quinupristin dalfoppristin R
Linezolid R
Colistimethate X1

Key

  • 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

References

  1. Missouri Department of Health and Senior Services. Shigellosis. Last revised June 2017. https://health.mo.gov/living/healthcondiseases/communicable/communicabledisease/cdmanual/pdf/Shigella.pdf
  2. Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.
  3. 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.
  4. Sanford Guide to Antimicrobial Therapy 2014