Gastrointestinal Infections(GI) Diagnosis

> 200 million episodes/year of infectious gastroenteritis in US
Worldwide 3-6 million children die each year from infectious gastroenteritis
Outbreaks of gastrointestinal infections are a serious concern in the hospital environment

Definition

Gastrointestinal infections are viral, bacterial or parasitic infections that cause gastroenteritis, an inflammation of the gastrointestinal tract involving both the stomach and the small intestine. Symptoms include diarrhea, vomiting, and abdominal pain. Dehydration is the main danger of gastrointestinal infections, so rehydration is important, but most gastrointestinal infections are self-limited and resolve within a few days. However, in a healthcare setting and in specific populations (newborns/infants, immunocompromized patients or elderly populations), they are potentially serious. Rapid diagnosis, appropriate treatment and infection control measures are therefore particularly important in these contexts.

Diagnosis

When symptoms point to a possible gastrointestinal infection, diagnosis can be confirmed through laboratory tests used for culture or antigen detection from stool specimens. In certain cases (e.g. for E. coli, Salmonella, C. difficile …), antibiotic susceptibility testing is used to determine microbial resistance to antibiotic therapy, if appropriate. Particularly in hospital settings, rapid diagnosis provides important information for implementing infection control measures.

To diagnose the cause of a diarrhea, it is helpful to consider where the context is a food-borne outbreak or “travelers’ diarrhea”.

Food-borne outbreaks:

Often local – a group of people eating together suffer the same illness.
A public health concern when widespread, affecting people in different places and over a longer period of time.
Important to recognize and track epidemiologically, to prevent more people from being infected.
E. coli, Salmonella, Campylobacter and Staphylococcus are among the most common pathogens causing food-borne outbreaks.
Travelers’ diarrhea:

Most common travel-related illness.
Contracted by people travelling in places where there are different pathogens from what they are used to, especially in regions where food/water contamination is more prevalent.
Most commonly transmitted through ingestion of food or water contaminated with feces.
Most cases caused by bacteria including E. coli, Salmonella and Shigella.