Treatment Guideline Chart
Diarrhea is a change in normal bowel movements characterized by increase in frequency, water content or volume of stools. The usual stool output is 10 g/kg/day.
Acute diarrhea lasts ≤14 days while chronic diarrhea lasts >14 days.
Infectious diarrhea is usually associated with symptoms of nausea and vomiting and abdominal cramps.

Gastroenteritis%20-%20bacterial Treatment

Principles of Therapy

Traveler's Diarrhea

  • The objectives of antimicrobial treatment of traveler’s diarrhea are shortening illness and returning travelers to normal activities; routine use is not recommended
  • Eradication of enteropathogens from stool does not predict the clinical benefits of antimicrobial therapy
  • Traveler’s diarrhea is typically short-lived and self-limited, but many organisms that cause the infection can be treated with antibiotics
  • Choice of therapy should depend on epidemiologic data


  • Any case of watery diarrhea in endemic areas during outbreaks or seasonal epidemics should be treated as cholera and stool cultures should be done in all cases to confirm
  • Rehydration is the mainstay of therapy
  • When antibiotics are administered to cholera patients, there is reduction of stool volume loss and a shorter clinical course
  • Antibiotics administered should follow recent sensitivity data for V cholera, if available

Bloody Diarrhea

  • Antipropulsives should be avoided as these drugs may increase the severity by delaying excretion of organisms and facilitating invasion of the mucosa
  • Usage of antibiotics should be judicious and not for all cases

Empiric Antibiotic Therapy

Traveler's Diarrhea

Empiric treatment of traveler’s diarrhea has been the best approach, but its usefulness is being undermined by growing antibiotic resistance in many parts of the world


  • May be the treatment of choice for C jejuni infection for patients 2-8 years of age
  • May be considered for severe traveler’s diarrhea associated with pathogenic E coli
  • Reported effective against traveler’s diarrhea in Southeast Asia
Co-trimoxazole [Sulfamethoxazole (SMZ) and Trimethoprim (TM)]
  • Historically the drug of choice for treatment of traveler’s diarrhea
  • Resistance of enterotoxigenic E coli (ETEC) and Salmonella sp to this drug limits its usefulness
  • Eg Ciprofloxacin, Levofloxacin
  • May be considered for severe traveler’s diarrhea associated with pathogenic E coli or multi-resistant strains of Shigella sp, Salmonella sp, V cholerae or C jejuni
  • Doxycycline and Tetracycline are preferred agents against V cholera
    • Not recommended in patients <8 years of age
  • Co-trimoxazole, macrolides (ie Azithromycin, Erythromycin) and Ciprofloxacin are alternative drugs
Bloody Diarrhea
  • Antibiotics may reduce the duration of illness and shorten the carrier stage
  • Initiation of empiric antibiotics may be considered in special situations:
    • Infants <3 months old with manifestations of bacterial infection
    • Immunocompetent patients exhibiting signs and symptoms of Shigella infection (fever, abdominal pain, hematochezia)
    • Recently traveled and with fever of ≥38.5°C and other signs of septicemia
  • Once enterohemorrhagic Escherichia coli (EHEC) or Shiga toxin-producing E coli (STEC) has been excluded by stool exam, empiric therapy with antibiotics can be started
  • Broad-spectrum antimicrobials should be started in patients with signs and symptoms pointing to sepsis as soon as specimens have been collected
    • Antibiotic therapy should be tailored once results become available 
  • Antibiotics following the local sensitivities for Shigella sp may be used as empiric therapy before waiting for culture and sensitivity results
  • Ciprofloxacin or any 3rd generation cephalosporin (eg Ceftriaxone, Cefotaxime) may be used as empiric therapy for infants <3 months of age, and patients with central nervous system manifestations, or Azithromycin and Pivmecillinam in pediatric patients, depending on location and antimicrobial susceptibility data, and travel history
    • There are reports on resistance to Ciprofloxacin in some countries (please refer to local guidelines for recommended antibiotics)
    • Alternative agents to be considered depending on location and antimicrobial susceptibility data include fluoroquinolones, Nalidixic acid, Ampicillin and Trimethoprim/sulfamethoxazole
  • There is widespread resistance to the following drugs: Ampicillin, Azithromycin, Co-trimoxazole, Chloramphenicol, Nalidixic acid, Tetracycline, Ciprofloxacin, Gentamicin and 1st- and 2nd-generation cephalosporins
  • There is also reported resistance to Ciprofloxacin in some countries
Adjunctive Therapy
  •  Eg Bacillus clausii, Bifidobacterium spp, Lactobacillus spp, Saccharomyces boulardii
  • Have been shown to reduce the intensity and duration of diarrhea of acute infectious diarrhea in children
  • Bacillus clausii contributes to the recovery of the intestinal microbial flora altered during the course of microbial disorders of diverse origin
    • It is capable of producing various vitamins, in particular group B vitamins, hence it contributes to correcting the consequent vitamin disorders caused by antibiotics and chemotherapeutic agents in general
  • Bifidobacterium spp is the most commonly used probiotic that is used to improve the health of the host when given in adequate amounts
  • Lactobacillus spp is a lactic acid bacteria used as an adjunct to rehydration therapy in children with acute gastroenteritis
  • Saccharomyces boulardii is a yeast that is used as an adjunct to rehydration therapy in children with acute gastroenteritis
    • It is an intestinal replacement flora which acts as an antidiarrheal microorganism in the digestive tract
    • It transits in the digestive tract without colonizing it, rapidly attaining significant intestinal concentrations which are maintained at a constant level throughout the administration period
  • Zinc supplementation given during an episode of diarrhea may decrease the duration and severity of diarrheal illness
Antiemetic Agents
  • Eg Ondansetron
  • May be used in patients >4 years of age to decrease vomiting or help avoid the need for intravenous fluid, but may increase episodes of diarrhea
Antisecretory Agent
  • Eg Racecadotril
  • May be used as an adjunctive therapy in acute diarrhea
    • Studies showed decreased diarrhea duration and reduced stool output following administration of Racecadotril in children with acute diarrhea
Bovine Colostrum
  • Contains antimicrobial peptides (lactoferrin, lactoperoxidase), immune-regulating and inflammatory cytokines, and growth factors that may help provide passive immunity by enhancing different immune functions (eg phagocytosis, antigen presentation, antimicrobial activity via antigen chelation, inflammation control) in the gastrointestinal tract
    • Studies showed that bovine colostrum improved clinical symptoms (eg reduced stool frequency, reduced occurrence and duration of diarrhea) in children with infectious diarrhea
    • Clinical benefit in the prevention and management of infectious diarrhea is currently undergoing clinical trials
Investigational Agents
  • Human milk, gelatin tannate and other probiotics are being studied to conclude their use in the management of gastroenteritis
Other Agents
  • Antimotility agents should be avoided in patients with bloody diarrhea caused by Shigella sp

Pathogen-Specific Treatment of Bacterial Diarrhea

Pathogen Preferred Agent(s) Alternative Agent(s) Remarks
Aeromonas/ Plesiomonas spp Antibiotics not usually required 
Aeromonas sp: Antibiotics may be indicated in patients prone to septicemia (eg cirrhosis, immunocompromised patients)
Plesiomonas sp: Antibiotics may be required in severely ill or immunocompromised patients
Co-trimoxazole  Ciprofloxacin1

 Campylobacter spp Antibiotics not usually required; may be used in severely ill patients or traveler’s diarrhea
  • A self-limiting condition
  • Early treatment can shorten the duration of the illness and prevent any relapse
Tetracycline or Doxycycline2
EHEC 0157:H7 Antibiotics and antipropulsives are contraindicated; may increase the chance of developing hemolytic uremic syndrome
Salmonella spp Cefotaxime
  • Ceftriaxone may be considered in suspected septicemic cases
  • Follow available local epidemiologic data
Shigella spp Cefotaxime
  • A self-limiting condition
Yersinia spp Co-trimoxazole
Tetracycline or Doxycycline2
Antipseudomonal aminoglycosides
3rd generation cephalosporins (eg Cefotaxime)
1Ciprofloxacin is not recommended in patients <18 years of age, except in cases when potential benefits outweigh the risks.
2Tetracycline and Doxycycline are contraindicated in patients <8 years of age.

Non-Pharmacological Therapy

Dietary Therapy

  • Depends on age and diet history
  • Breastfed patients should continue nursing on demand while formula-fed patients must continue their usual full-strength milk
    • Based on several trials, feedings with diluted formula is associated with protracted symptoms and delayed nutritional recovery
  • Lactose-free formulas are recommended in patients with documented and persistent lactose intolerance
  • Intake of patient’s usual diet is recommended
  • Foods high in simple sugars should be avoided
Editor's Recommendations
Special Reports