Bacterial Diarrhea

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Bacterial Diarrhea
N Engl J Med 2009;361:1560-9.

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Bacterial Diarrhea

  1. 1. CLINICAL PRACTICE<br />Bacterial Diarrhea<br />N Engl J Med2009;361:1560-9.<br />
  2. 2. Clinical Problem<br />More than 5.2 million cases of bacterial diarrhea that occur each year in the US, estimated 46,000 hospitalizations and 1,500 deaths each year in US. <br />The 4 most commonly reported bacterial enteropathogens in the US:<br />Campylobacter<br />Salmonella<br />Shiga toxin-producing E. Coli<br />Shigell<br />
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  5. 5. Evaluation<br />Stool culture should be obtained from all patients with <br />severe diarrhea (passage > 6 unformed stools per day)<br />diarrhea of any severity that persists for longer than a week <br />fever<br />dysentery<br />multiple cases of illness that suggest an outbreak<br />Stool cultures are not routine in most cases of watery diarrhea or traveler’s diarrhea because of the low yield of bacterial pathogens.<br />
  6. 6. Conditions Associated with Bacterial Diarrhea<br />Acute Watery Diarrhea<br />Dysentery<br />Food Poisoning<br />Traveler’s Diarrhea<br />Nosocomial Diarrhea<br />
  7. 7. Acute Watery Diarrhea<br />Clinically nonspecific!<br />Most bacterial and nonbacterial enteropathogens produce acute watery diarrhea<br />Detectable enteric pathogens is identified in fewer than 3% of cases in the US.<br />Most laboratories stool culture are set up to routinely look for shigella, salmonella, and campylobacter.<br />Many of the potentially important agents that cause watery diarrhea are not detectable by routine laboratory tests; <br />these agents include entero-toxigenicE. coli, entero-aggregative E. coli, entero-invasive E. coli, non-choleraicvibrios, and noroviruses.<br />
  8. 8. Dysentery<br />Passage of bloody stools suggests possible bacterial colitis. <br />Major causes of bloody diarrhea in the US:<br />Shigella<br />Campylobacter<br />Salmonella<br />Shiga toxin-producing E. coli<br />Severe abdominal pain and cramps and passage > 5 unformed stools per 24 hours in the absence of fever<br />Watery diarrhea becomes bloody in 1 to 5 days in 80% of patients<br />Shiga toxin-producing E. coli is the main cause of renal failure in childhood<br />2/3 of children with the hemolytic-uremic syndrome require dialysis; mortality rate: 3 to 5%<br />
  9. 9. Food Poisoning<br />Food poisoning is the term used when a preformed toxin in food is ingested, resulting in an intoxication rather than an enteric infection.<br />Staphylococcus aureus causes vomiting within 2 to 7 hours after the ingestion of improperly cooked or stored food containing a heat-stable preformed toxin.<br />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.<br />
  10. 10. Traveler’s Diarrhea<br />Traveler’s diarrhea occurs when persons from industrialized regions venture into developing tropical and semitropical areas with reduced levels of personal and food hygiene. <br />Bacterial enteropathogens cause up to 80% of cases.<br />E. coli account for more than half of cases occurring in Latin America, Africa, and South Asia.<br />Campylobacter, shigella, and salmonella are relatively more important causes of traveler’s diarrhea in Asia than in the other high-risk regions.<br />
  11. 11. Traveler’s Diarrhea<br />Patients with traveler’s diarrhea should be treated empirically with antibiotics without stool examination.<br />Most authorities recommend rifaximin 200 mg once or twice a day (with major meals) while the person is in an area of risk.<br />Alternative regimen is two tablets of bismuth subsalicylate with each meal and at bedtime.<br />Indications for the use of chemoprophylaxis<br />important trip <br />(the purpose of which might be ruined by a short-term illness)<br />underlying illness that might be worsened by diarrhea (e.g., CHF) <br />persons more susceptible to diarrhea (e.g., use of daily PPI therapy)<br />previous bouts of traveler’s diarrhea<br />
  12. 12. Nosocomial Diarrhea<br />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, or both.<br />Risk factors for C. difficile diarrhea:<br />Advanced age and coexisting conditions<br />alteration of intestinal flora by antimicrobial agents<br />probably host genetics<br />
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  14. 14. Treatment<br />Fluid and electrolyte replacement<br />Easily digestible food<br />Antimotility drugs such as loperamide and diphenoxylate hydrochloride<br />Antimicrobial agents<br />
  15. 15. Salmonellosis<br />Bacteremia complicates the infection in approximately 8% of normal healthy persons.<br />Risk factors:<br />Extremes of age (younger than 3 months and 65 years or older)<br />corticosteroid use<br />Inflammatory bowel disease<br />immunosuppression<br />Hemoglobinopathy including sickle cell disease<br />hemodialysis<br />
  16. 16. Shiga toxin-roducingE. coli<br />Some antibacterial drugs, including fluoroquinolones and trimethoprim-sulfamethoxazole, may increase the risk of hemolytic–uremic syndrome.<br />Most authorities recommend supportive treatment only in patients with Shiga toxin-producing E. coli infection.<br />

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