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The authors acknowledge the contributions of L. K. Pickering to previous editions.
Most infections of the gastrointestinal tract manifest as diarrhea , a clinical syndrome of diverse origin associated with frequent loose or watery stools often accompanied by emesis, fever, abdominal bloating or pain, and occasional extraintestinal manifestations. Infectious diarrhea can have a bacterial, viral, or parasitic origin ( Table 55.1 ), and most cases are associated with specific epidemiologic factors or clinical manifestations. Establishing an etiologic diagnosis for a specific episode may be complicated by the wide array and complexity of potential agents. Therapy is directed at fluid and electrolyte replacement and maintenance, nutrition, and specific antimicrobial therapy. The mainstay of prevention is hand hygiene; licensed vaccines are available in the US for the prevention of rotavirus, typhoid, and cholera infections.
Bacteria | Parasites | Viruses |
---|---|---|
Aeromonas species Bacillus cereus Campylobacter jejuni Clostridioides difficile Clostridium perfringens Escherichia coli Listeria monocytogenes Plesiomonas shigelloides Salmonella species Shigella species Staphylococcus aureus Vibrio cholerae Vibrio parahaemolyticus Vibrio vulnificus Yersinia enterocolitica |
Cryptosporidium parvum Cyclospora cayetanensis Entamoeba histolytica Giardia intestinalis Cystoisospora belli Microsporidia (including Enterocytozoon bieneusi and Encephalitozoon intestinalis ) |
Astrovirus Enteric adenovirus Norovirus Rotavirus Sapovirus |
Enteropathogens are acquired through the fecal-oral route from person-to-person contact or via contaminated food or water. People with certain host defects may be more susceptible to infection with various enteric pathogens and may experience greater mortality or morbidity.
Approximately 179 million cases of acute gastroenteritis, defined as acute vomiting or diarrhea, result in 475,000 hospitalizations and 5000 deaths annually in the US. Children who are at higher risk of death from diarrhea include premature infants, children residing in crowded settings where dehydration may not be recognized, and children with underlying immunodeficiencies. In the US, the incidence of diarrhea in children <3 years of age is estimated to be 1–3 episodes per child per year, with higher rates in children attending group childcare. , Worldwide, diarrheal diseases are a leading cause of morbidity with 1.7 billion pediatric infections per year, resulting in about 525,000 deaths in children <5 years of age annually. Repeated early-childhood enteric infections can result in long-term disability, including stunted growth.
Most episodes of severe diarrhea worldwide in children <5 years of age have been attributed to rotavirus infections; however, hospitalizations attributed to rotavirus infections have decreased between 60% and 94% in the US since licensure of 2 rotavirus vaccines (RotaTeq [RV5; Merck & Co., Kenilworth, NJ] in 2006 and Rotarix [RV1; GlaxoSmithKline, Research Triangle Park, NC] in 2010). In 2009, the World Health Organization (WHO) recommended inclusion of a rotavirus vaccine series in all national immunization programs to lower the global disease burden of rotavirus. , An estimated 28,000 deaths worldwide in children <5 years of age were averted in 2016 as a result of rotavirus vaccine uptake of 28%. Norovirus is now considered to be the leading cause of gastroenteritis in US children, resulting in an estimated 14,000 hospitalizations, 218,000 emergency department visits, and 627,000 outpatient visits annually. Worldwide, norovirus is estimated to be associated with approximately 200,000 deaths annually, with 70,000 or more deaths annually among children in resource-disadvantaged settings. Efforts to develop an effective norovirus vaccine are ongoing.
The gastrointestinal tract is barraged constantly by foreign material, including bacteria, viruses, parasites, and toxins. Numerous protective host factors include gastric acidity, intestinal motility, enteric microflora, glycoconjugates, and specific immune components (cells and humoral compounds). Host age, personal hygiene, intestinal receptors, past exposures, and food intake influence these protective factors and are major determinants of colonization and disease.
The effects of these microbial factors are influenced by the size of the inoculum and specific virulence traits of the enteropathogen. For example, Escherichia coli can cause gastrointestinal tract disease by transmitting plasmids or phages that encode for virulence traits, producing secretory heat-stable or heat-labile enterotoxins and cytotoxins, promoting invasiveness, or increasing aggregability. In addition, some bacteria (e.g., Clostridium botulinum, Staphylococcus aureus, and Bacillus cereus ) produce enterotoxins, whereas other bacteria have variations in toxin genes that enhance virulence. Generally, all bacteria that cause gastrointestinal tract disease possess one or more of these virulence traits.
Enteric viruses can cause diarrhea through selective destruction of absorptive cells (villus tip cells) in the mucosa, thus leaving secretory cells (crypt cells) intact, affecting absorptive fluid balance, and reducing brush-border digestive enzymes. , E. coli pathotypes and many parasitic infections induce similar changes.
Clinical manifestations usually consist of gastrointestinal tract manifestations, including diarrhea and vomiting, with resulting extraintestinal complications as sequalae. The WHO defines diarrhea as ≥3 loose or liquid stools per 24 hours, or more frequently than is normal for an individual person. Stools that are formed, regardless of the frequency, or loose, “pasty” stools in infants, are not considered diarrheal. Diarrhea can be classified by exposure and by the duration of symptoms, which may provide clues to the implicated pathogen ( Fig. 55.1 ). Clinical manifestations localized to the gastrointestinal tract can be categorized by likely organisms and their pathogenesis for diagnostic and therapeutic considerations ( Fig. 55.2 and Table 55.2 ).
Clinical Manifestations | Corresponding Pathogens |
---|---|
Watery diarrhea | Enteric viruses, enterotoxin-producing bacteria, and protozoa that infect the small intestine |
Dysentery with scant stools that contain blood and mucus | Pathogens that invade the large intestine such as Shigella and Campylobacter |
Prolonged diarrhea that lasts for ≥14 days | Select viruses and bacteria, Cryptosporidium spp. , Giardia intestinalis, Cyclospora spp. , Cystoisospora belli |
Vomiting with minimal or no diarrhea | Chemical contaminants and toxins associated with foodborne and waterborne outbreaks, viral enteropathogens |
Bloody stool | STEC, Shigella spp. , Salmonella spp. , Campylobacter spp. , Entamoeba histolytica, noncholera Vibrio species, Clostridioides difficile |
Abdominal pain | STEC, Salmonella spp. , Shigella spp. , Campylobacter spp. , Yersinia spp. , noncholera Vibrio species, Clostridioides difficile |
Persistent abdominal pain and fever | Yersinia enterocolitica (can mimic appendicitis) |
Severe abdominal pain, grossly bloody stool (occasionally non-bloody), minimal or no fever | STEC |
Nausea and vomiting lasting ≤24 hr | Food poisoning from Staphylococcus aureus enterotoxin or Bacillus cereus |
Diarrhea and abdominal cramping lasting 1–2 days | Food poisoning from Clostridium perfringens or Bacillus cereus |
Vomiting and diarrhea lasting 2–3 days | Norovirus |
Chronic, watery diarrhea, often lasting ≤1 year | Diarrhea of unidentified origin (Brainerd diarrhea), postinfectious irritable bowel syndrome |
Extraintestinal manifestations result from the spread of the enteropathogen and immune-mediated mechanisms ( Table 55.3 ) and usually occur after diarrhea has resolved. In a population-based cohort study, an increased risk of inflammatory bowel disease was demonstrated in people with a preceding episode of gastroenteritis attributed to Salmonella or Campylobacter spp. Functional gastrointestinal disorder, which is defined as the presence of chronic or recurrent gastrointestinal symptoms without a clear cause, may occur in 50% of children following acute gastroenteritis, lasting for up to 6 months after the initial infection. This disorder is not well-understood, but may be explained by multiple etiologic factors including ongoing intestinal inflammation, altered motility, increased intestinal permeability, smooth muscle hyperreactivity, genetic disposition, continuous antigenic exposure, and molecular mimicry.
Manifestation | Related Enteric Pathogens |
---|---|
Erythema nodosum a | Yersinia spp. , Campylobacter spp., Salmonella spp. |
Glomerulonephritis a | Shigella spp. , Campylobacter spp. , Yersinia spp. |
Guillain-Barré syndrome a | Campylobacter spp. |
Hemolytic anemia a | Campylobacter spp. , Yersinia spp. |
Hemolytic uremic syndrome a | STEC |
Immunoglobulin A nephropathy a | Campylobacter spp. |
Reactive arthritis a | Salmonella spp. , Shigella spp. , Yersinia spp. , Campylobacter spp. , Cryptosporidium spp. |
Reiter syndrome a | Shigella spp. , Salmonella spp. , Campylobacter spp. , Yersinia spp. |
Postinfectious irritable bowel syndrome | Campylobacter spp. , Salmonella spp. , Shigella spp. , STEC, Giardia intestinalis |
Meningitis | Listeria monocytogenes, Salmonella spp. (infants ≤3 months at high risk) |
Intestinal perforation | Salmonella spp. (including Typhi) , Shigella spp. , Campylobacter spp. , Yersinia spp. |
Encephalopathy, seizure | Shigella spp. |
Toxic megacolon | Shigella spp. , Clostridioides difficile |
Aortitis, osteomyelitis | Salmonella spp. |
Consideration of possible exposures assists in evaluation of the cause of diarrhea. Etiologic factors may overlap, but a single agent may be deemed responsible for most episodes of gastroenteritis following an exposure. Evidence-based recommendations, reviews, and meta-analyses that provide guidance for management of people with diarrhea are available ( Table 55.4 ) and include information about the following: (1) administration of fluid and electrolyte solutions, (2) clinical and epidemiologic evaluation in immunocompetent and immunocompromised hosts, (3) selection of diagnostic tests, (4) use and avoidance of antimotility agents, (5) institution of selective antimicrobial therapy, (6) immunization recommendations, and (7) prevention of travelers diarrhea. ,
Topic | Title/Website a | Author/Issuing Agency |
---|---|---|
Infectious Diarrhea, Diagnosis and Management | 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea: www.idsociety.org/practice-guideline/infectious-diarrhea/ | IDSA |
Clostridioides difficile ( Clostridium difficile ) | Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA): www.idsociety.org/practice-guideline/clostridium-difficile/ | IDSA, SHEA |
Immunocompromised Hosts | Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Exposed and HIV-Infected Children: https://aidsinfo.nih.gov/guidelines/html/5/pediatric-opportunistic-infection/0 Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents: https://aidsinfo.nih.gov/guidelines/html/4/adult-and-adolescent-opportunistic-infection/392/whats-new |
Panel on Opportunistic Infections in HIV-Exposed and HIV-Infected Children Panel on Opportunistic Infections in Adults and Adolescents with HIV |
Diagnostic Testing | A Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2018 Update by the Infectious Diseases Society of America and the American Society for Microbiology: www.idsociety.org/practice-guideline/laboratory-diagnosis-of-infectious-diseases/ | IDSA, ASM |
Immunizations | The Yellow Book . Chapter 2 . Preparing International Travelers. Vaccination and Immunoprophylaxis: General Recommendations: wwwnc.cdc.gov/travel/yellowbook/2020/preparing-international-travelers/vaccination-and-immunoprophylaxis-general-recommendations Traveler’s Health (Destination-based traveler advice for clinicians): wwwnc.cdc.gov/travel Advisory Committee on Immunization Practices (ACIP). Vaccine Recommendations and Guidelines: www.cdc.gov/vaccines/hcp/acip-recs/index.html |
CDC CDC CDC |
Prevention and Treatment of Traveler’s Diarrhea | The Yellow Book . Chapter 2 . Preparing International Travelers. Food and Water Precautions: wwwnc.cdc.gov/travel/yellowbook/2020/preparing-international-travelers/food-and-water-precautions Traveler’s Diarrhea: wwwnc.cdc.gov/travel/yellowbook/2020/preparing-international-travelers/travelers-diarrhea#box203 The Yellow Book . Chapter 11 . Posttravel Evaluation, Persistent Diarrhea in Returning Travelers: wwwnc.cdc.gov/travel/yellowbook/2020/posttravel-evaluation/persistent-diarrhea-in-returned-travelers Guidelines for the Prevention and Treatment of Travelers’ Diarrhea: a Graded Expert Panel Report: www.ncbi.nlm.nih.gov/pmc/articles/PMC5731448/pdf/tax026.pdf |
CDC CDC CDC CDC Riddle (Ref. 67) |
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.
Category | Cause |
---|---|
Chemical contaminants | Heavy metals, organic compounds |
Bacteria | Salmonella spp. , Shigella spp. , Escherichia coli, Brucella spp. , Yersinia spp. , Campylobacter spp. , Vibrio spp. , and Listeria monocytogenes |
Bacterial toxins | Enterotoxins of Bacillus cereus, Staphylococcus aureus, Clostridium perfringens, Clostridium botulinum, Escherichia coli |
Viruses | Norovirus, rotavirus, and hepatitis A virus |
Parasites | Giardia intestinalis, Cyclospora cayetanensis, Cryptosporidium spp. , Taenia spp. , Toxoplasma gondii, and Trichinella spp. |
Products accumulated in the food chain of fish and shellfish | Scombroid, ciguatera, mycotoxins, neurotoxic and paralytic shellfish poisoning, pufferfish tetrodotoxin, domoic acid |
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 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. ,
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 .
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