Approach to the Diagnosis and Management of Gastrointestinal Tract Infections

Foodborne and Waterborne Disease

Foodborne and waterborne diseases, including infections and intoxications, are acquired by consumption of contaminated food at a variety of locations, including at home and in restaurants. ^{, ,} Major causes of foodborne disease are listed in Table 55.5 (see also Chapter 59 ). Viruses are the most common etiologies of foodborne illness, of which 42%–60% of episodes are attributed to norovirus. ^, The Foodborne Diseases Active Surveillance Network (FoodNet), an active surveillance system of the Centers for Disease Control and Prevention (CDC), monitors the incidence of laboratory-confirmed cases of infection caused by nine pathogens ( Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella, Shiga toxin-producing E. coli [STEC], Shigella, Vibrio, and Yersinia ) commonly transmitted through food at 10 US sites. Data collected from this system identifies Campylobacter and Salmonella as the most common bacterial etiologies of foodborne infections. ^, From 2006 to 2014, STEC O157 was implicated in the most foodborne outbreaks (16%) in which a pathogen was identified.

An outbreak of foodborne disease is defined as an occurrence in ≥2 people of a similar illness, usually involving the gastrointestinal tract, following consumption of a common food. ^, Prompt and thorough laboratory evaluation of involved people and implicated food or water is critical for a definitive diagnosis. Individual cases may be difficult to identify unless a distinct clinical syndrome exists, such as with foodborne botulism.

Most foodborne infections are self-limited and require only supportive care. Exceptions include foodborne and infant botulism (which result in constipation rather than diarrhea), paralytic shellfish poisoning, long-acting mushroom poisoning, and typhoid fever, all of which can result in significant morbidity and mortality in previously healthy hosts. Antitoxins or antibiotics may be indicated in the management of these infections, and prevention and control of these diseases are based on avoidance of food contamination or on destruction or denaturation to prevent further spread or multiplication of contaminants. A suspected case of foodborne illness should be reported to public health officials because it could represent the sentinel case of a widespread outbreak. Detailed information on food safety issues and practices, including steps consumers can take to protect themselves, can be obtained online at the following sites: www.foodsafety.gov , www.fightbac.org , and www.cdc.gov/foodsafety/outbreaks/index.html . A list of nationally notifiable enteric diseases can be found at www.cdc.gov/foodborneburden/surveillance-systems.html .

Waterborne outbreaks occur in the US despite improvements in water management and sanitation. From 1971 to 2014, cryptosporidiosis was the most common gastrointestinal tract illness reported to the CDC’s US Waterborne Disease and Outbreak Surveillance System (WBDOSS, www.cdc.gov/healthywater/surveillance/ ). From 2013 to 2014, 42 outbreaks associated with drinking water were reported to WBDOSS. Cryptosporidium was implicated in 97% and Giardia duodenalis was implicated in 3% of outbreaks. Recreational water-associated outbreaks may occur through fecal or soil contamination of treated water (e.g., pools, hot tubs, interactive water play venues) or untreated water (e.g., oceans and lakes) and most commonly manifests as diarrhea. From 2000–2014, 493 outbreaks associated with treated recreational water were reported. Of those with an infectious etiology, 58% (212) were due to Cryptosporidium, 16% (57) to Legionella , and 13% (47) to Pseudomonas . From 2011–2010, 21 outbreaks were associated with untreated recreational water. Most of these episodes (95%) were associated with fresh water, and of these, 33% were associated with E. coli O157:H7 or O111. In addition to maintaining appropriate chlorine and disinfectant levels in pools and hot tubs, the CDC recommends showering before swimming, checking children with diapers every hour, and taking regular bathroom breaks to prevent contamination of water. Resources for prevention of recreational water illnesses can be found at www.cdc.gov/healthywater/swimming/index.html . Recommendations for responding to fecal accidents in swimming venues can be found at www.cdc.gov/healthywater/swimming/aquatics-professionals/fecalresponse.html .

Antimicrobial-Associated Diarrhea

Antimicrobial-associated diarrhea occurs commonly in children and can result from changes in small bowel peristalsis or from alterations in the intestinal microflora . A subset of antimicrobial-associated diarrhea has been associated with Clostridioides difficile (formerly Clostridium difficile ) overgrowth and toxin production. ^, Risk factors for pediatric C. difficile infection include antibiotic exposure within the past 4–12 weeks, a previous or prolonged (>3 days) hospitalization, and an underlying diagnosis of cancer or inflammatory bowel disease. There is an increasing trend toward C. difficile detection in hospitalized children, but interpretation of the role of C. difficile toxin detection by molecular methods in young children is difficult. Studies have shown that C. difficile toxin detection rates are similar in children with and without diarrhea in both the inpatient and outpatient settings. Furthermore, C. difficile toxin has been isolated in one-fourth to two-thirds of asymptomatic infants <1 year of age, ^, as well as in pediatric gastrointestinal pathology specimens that did not show evidence of the organism on tissue immunohistochemistry or polymerase chain reaction (PCR). Concomitant infection, dysbiosis resulting from antibiotics or chemotherapy, and alteration in gastrointestinal flora as a consequence of enteral nutrition should be considered as contributing factors when C. difficile toxin production is detected.

The Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA) have published clinical practice guidelines for the management of C. difficile infections in adults and children. In children <2 years of age, routine C. difficile testing is not advised unless other etiologies have been excluded, and for children ≥2 years of age, testing is recommended only for those with worsening or prolonged diarrhea and risk factors or relevant exposures (e.g., inflammatory bowel disorder, immunocompromising condition, healthcare, or receipt of antibiotics). Hirschsprung disease may also increase the risk of C. difficile infection, and testing should be considered in children with this disorder. ^,

Complications of pediatric C. difficile infection are rare, and rates of colectomy and morbidity are low among affected children compared with those among adults. ^,

Healthcare-Associated Diarrhea

Diarrhea can develop in children as a result of infections acquired before or during healthcare encounters. Episodes that meet the CDC National Healthcare Safety Network (NHSN) definition of a gastrointestinal infection with respect to laboratory identification, clinical presentation, and timing of symptom onset are considered to be healthcare-associated infections.

Several important factors affect transmission of enteric organisms in hospitals: (1) patient-to-patient transmission through the hands of hospital personnel, generally after contact with a child who has diarrhea; (2) asymptomatic carriers, either children or hospital personnel; (3) hospital personnel with gastroenteritis; (4) contaminated food, medications, or medical instruments; (5) hospital crowding; and (6) improper cleaning procedures. Host risk factors include immunocompromised states, prolonged hospitalization, young age, and antibiotic use. Reducing the risk for healthcare-associated gastrointestinal tract infections is accomplished by prevention and control. Contact isolation is recommended for children with diarrhea or vomiting to prevent the potential transmission of infectious organisms among staff members and children. Guidelines for isolation precautions in healthcare settings are available at www.cdc.gov/infectioncontrol/guidelines/isolation/index.html .