Bacterial diarrhea

5.2 million cases occur each year in the United States (Dupont HL).

80% of cases of bacterial diarrhea are a result of foodborne transmission.

Person to person spread can occur in situations in which only a small amount of a pathogen is required for infection and such agents include Shigella, and shiga-toxin producing Escherichia coli.

Associated with 46,000 hospitalizations and 1500 deaths per year in the United States.

The most common reported bacterial enter pathogens are: campylobacter, non-typhoid salmonella, Shiga toxin-producing E. coli, and Shigella.

Campylobacter, non-typhoid salmonella, and Shiga toxin-producing E. coli are spread to humans from animal reservoirs and threaten our food supply.

The highest incidence of campylobacter and salmonella infections occur among infants.

Cross-contamination in households and lower number of organisms required to cause infection in infants account for the high incidence of such infections among infants.

Estimated number of cases per year in the United States include the following: Clostridium difficile more than 250,000 cases, Shigella 450,000, non-typhoid salmonella 1.4 million, campylobacter 1.4 to 2 point 4 million cases, Shiga toxin-producing E. coli 100,000 cases, enterotoxigenicE. Coli 79,000 cases, Yersinia enterocolitica 96,000 cases, Staphylococcus aureus. 185,000 cases, C.perfringens 250,000 cases, Bacillus cereus 27,000 cases, typhoid and paratyphoid salmonella 800 cases, vibrio cholera 50 cases, and no choleric vibrios 8000 cases.

Aeromonas species are pathogens, particularly in tropical regions.

Plesiomonas shigelloides causes acute diarrhea associated with seafood consumption and international travel.

Enterotoxigenic E. coli is an increasingly common cause of food borne diarrhea.

Stool cultures or toxin assays can frequently help establish the diagnosis.

Laboratories routinely look for Shigella, salmonella, and campylobacter.

In the presence of bloody diarrhea, Shiga toxin-producing E. coli, should be sought.

Indications for school culture include the presence of severe diarrhea, diarrhea of any severity that persists for longer than a week, the presence of fever, dysentery, and multiple cases of similar illness, suggesting the presence of an outbreak.

Stool cultures not usually required in the presence of watery diarrhea, or traveler’s diarrhea because there is a low yield of bacterial pathogens.

In most cases of such diarrhea a single stool sample is satisfactory for work-up.

Multiple stool samples increase the findings of bacterial pathogens by approximately 20%.

Bacterial and non-bacterial enteral pathogens produce acute watery diarrhea, and therefore this type of diarrhea is clinically nonspecific.

Fewer than 3% of cases of watery diarrhea are identified as far as a pathogen is concerned.

Watery diarrhea, as noted, has a low rate of identification, and many important agents that cause this problem are not detectable by routine laboratory tests and these agents include enterotoxaemia E. coli, and non-choleric vibrios and noroviruses.

Strains of E. coli associated with diarrhea have characteristic clinical and epidemiological features that require specific typing.

Molecular studies with micro array analysis helps define the specific types of E. coli.

The passage of bloody stools, is ref2242ed to as dysentery, and suggest the possibility of bacterial colitis.

The four major causes of bloody diarrhea include Shigella, campylobacter, non-typhoid salmonella and Shiga toxin producing E. coli.

Other organisms associated with dysentery, include aeromonas species, non-choleric vibrios and Yersinia enterocolitica.

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