Bacterial Diarrhea

Bacterial Diarrhea on Prezi

Bacterial Diarrhea N Engl J Med   October 15, 2009;361:1560-9 4 most commonly bacterial enteropathogens in the US:

1. Campylobacter
2. Nontyphoid salmonella
3. Shiga toxin-producing E. Coli
4. Shigell

Stool culture should be obtained from all patients with

1. severe diarrhea (passage of 6 or more unformed stools per day)
2. diarrhea of any severity that persists for longer than a week
3. fever
4. dysentery
5. multiple cases of illness that suggest an outbreak

Conditions Associated with Bacterial Diarrhea

• Acute Watery Diarrhea
• Dysentery
• Food Poisoning
• Traveler’s Diarrhea
• Nosocomial Diarrhea

Acute Watery Diarrhea

• Clinically nonspecific!
• Detectable enteric pathogens is identified in < 3% of cases in the US.
• Most laboratories stool culture are set up to routinely look for shigella, salmonella, and campylobacter.

Dysentery

• Passage of bloody stools suggests possible bacterial colitis.
• Major causes of bloody diarrhea in the US: Shigella, Campylobacter, Salmonella, Shiga toxin-producing E. coli
• Severe abdominal pain and cramps and passage > 5 unformed stools per 24 hours in the absence of fever
• Watery diarrhea becomes bloody in 1 to 5 days in 80% of patients
• Shiga toxin-producing E. coli is the main cause of renal failure in childhood
• 2/3 of children with the hemolytic-uremic syndrome require dialysis; mortality rate: 3 to 5%

Food Poisoning

• Food poisoning is the term used when a preformed toxin in food is ingested, resulting in an intoxication rather than an enteric infection.
• Staphylococcus aureus causes vomiting within 2 to 7 hours after the ingestion of improperly cooked or stored food containing a heat-stable preformed toxin.
• Most cases of food poisoning are of short duration, with recovery occurring in 1 to 2 days. The diagnosis is made in nearly all cases clinically without laboratory confirmation.

Traveler’s Diarrhea

• Bacterial enteropathogens cause up to 80% of cases.
• Patients with traveler’s diarrhea should be treated empirically with antibiotics without stool examination.
• Most authorities recommend rifaximin 200 mg once or twice a day (with major meals) while the person is in an area of risk.
• Alternative regimen is two tablets of bismuth subsalicylate with each meal and at bedtime.
• Indications for the use of chemoprophylaxis:




important trip (the purpose of which might be ruined by a short-term illness)

underlying illness that might be worsened by diarrhea (e.g., CHF)

persons more susceptible to diarrhea (e.g., use of daily PPI therapy)

previous bouts of traveler’s diarrhea

Nosocomial Diarrhea

• C. difficile accounts for a minority of antibiotic-associated and hospital-associated diarrhea, it should be considered in patients with clinically significant diarrhea (passage > 3 unformed stools per day), toxic dilatation of the colon or otherwise unexplained leukocytosis.
• Risk factors for C. difficile diarrhea:




Advanced age and coexisting conditions

alteration of intestinal flora by antimicrobial agents

probably host genetics

Treatment

• Fluid and electrolyte replacement
• Easily digestible food
• Antimotility drugs such as loperamide and diphenoxylate hydrochloride
• Antimicrobial agents

Salmonellosis

• Bacteremia complicates the infection in approximately 8% of normal healthy persons.
• Risk factors:




Extremes of age (younger than 3 months and 65 years or older)

corticosteroid use

Inflammatory bowel disease

immunosuppression

Hemoglobinopathy including sickle cell disease

hemodialysis

Shiga toxin-producing E. coli

• Some antibacterial drugs, including fluoroquinolones and trimethoprim-sulfamethoxazole, may increase the risk of hemolytic–uremic syndrome.
• Most authorities recommend supportive treatment only in patients with Shiga toxin-producing E. coli infection.