When should routine stool cultures be obtained? Stool cultures are overused in clinical practice and are often a source of misspent time and money. Bacteria that are commonly tested include Salmonella spp., Campylobacter spp., Shigella spp., and STEC. They are positive in only approximately 1.5% to 5% of samples submitted. Stool cultures are clinically useful in nonhospitalized patients who have had …
What tests are used to diagnose infectious diarrhea? Although routine stool cultures for common bacterial agents ( E. coli, Salmonella, Shigella, and Campylobacter ) and microscopy (for ova and parasites) can be useful in clinical practice, newer tests have emerged that are faster, more sensitive, and less labor intensive. Enzyme immunoassays (EIAs) for pathogenic antigens have become the tests …
What is the most common cause of traveler’s diarrhea? ETEC infection is the most common identified cause of traveler’s diarrhea in most of the world. ETEC strains cause a watery diarrhea syndrome of varying severity resulting from the production of one or two enterotoxins: heat-stable toxin and heat-labile toxin (LT). The LT variant is closely …
What presentation and historical features are useful in defining the etiologic factors of acute diarrhea syndromes? Host factors (age, immune status, medications, comorbid conditions), geography, and socioeconomic status heavily influence the infectious differential diagnosis of diarrheal illness. Diarrhea type, and location of presentation are useful determinants. The below table groups the common diarrheal syndromes with …
Which bacterial agent of acute diarrhea has humans as its most important reservoir and is more likely to spread and cause disease outbreaks from person-to-person contact? Shigella species (s onnei, dysenteriae, flexneri, and boydii ) are highly adapted to human hosts and humans are the most significant reservoir that may contribute to outbreaks within close contacts in family, daycare settings, …
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What are the common causes of acute diarrheal illness among solid organ transplant patients? Valganciclovir use has resulted in less CMV-related disease. Community viral pathogens, in particular Norovirus, are more common. In the setting of colitis, CMV remains the most common etiologic factor. CMV presence on biopsy polymerase chain reaction (PCR) does not always correlate to causative …
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What infectious agents are associated with acute and persistent diarrheal illness in HIV patients? The degree of immune deficiency influences the differential diagnosis. Generally, the same pathogens as seen among immunocompetent community dwellers is seen among patients with HIV infection, but persistent and chronic presentations may be more common for these same organisms. In addition, …