2026, Number 2
Recommendations for the diagnosis and management of gastrointestinal infections
Full text
10.35366/122615
Language: English/Spanish [Versión en español]
References: 26
Page: 125-132
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ABSTRACT
Acute gastroenteritis is defined as a decrease in stool consistency and/or increased frequency of evacuations (≥ 3 in 24 hours), with or without fever or vomiting. Diarrhea is a symptom of infection, caused by various viral, bacterial, and parasitic organisms, most of which are transmitted by contaminated water. The etiology varies depending on the type of diarrhea, age group, and geographical area. Throughout history, acute diarrhea has been recognized as one of the leading causes of morbidity and mortality in childhood. Worldwide, it is considered the second leading cause of death in children under five years of age, with a higher incidence in developing countries, where one in eight children dies each year from this condition. Two interventions in the management of acute gastroenteritis that can significantly reduce child mortality are the newly formulated oral rehydration solution and zinc supplementation. This review aims to contribute to the body of knowledge focused on reducing the morbidity and mortality associated with acute gastroenteritis by presenting the latest updates in the state of the art of diagnosis and treatment of gastrointestinal infections in both children and adults.ABBREVIATIONS:
- ECTS/STEC = Shiga toxin-producing Escherichia coli
- ETEC = Enterotoxigenic Escherichia coli
- FDA = Food and Drug Administration
- IDSA = Infectious Diseases Society of America
- MDR = Multidrug-Resistant
- XDR = Extensively Drug-Resistant
INTRODUCTION
Acute gastroenteritis is defined as a decrease in the consistency of stools (liquid or semi-liquid) and/or an increase in the frequency of evacuations (≥ 3 in 24 hours), with or without fever or vomiting. A change in stool consistency is more indicative of diarrhea than the number of evacuations, particularly during the first months of life.1
The Infectious Diseases Society of America (IDSA) describes four clinical presentations of infectious diarrhea: acute watery diarrhea (including cholera) and acute bloody diarrhea (including dysentery), which last less than seven days; prolonged diarrhea, when it lasts 7 to 13 days; persistent diarrhea, when it lasts 14–29 days; and chronic diarrhea, when it exceeds 30 days.2
Diarrhea is a symptom of infection caused by viruses, bacteria, and parasites, which are generally transmitted through contaminated water via a fecal-oral mechanism.3
In order to contribute to the body of knowledge aimed at reducing morbidity and mortality from acute gastroenteritis, this review lists the main updates in the state of the art of the diagnosis and treatment of gastrointestinal infections in children and adults.
ACUTE GASTROENTERITIS
Since dehydration is the main complication of any gastroenteritis episode, especially in pediatric patients, it is important to perform an intentional search for signs and symptoms that evidence the amount of fluid lost. To this end, the World Health Organization recommends identifying the degree of dehydration using the Dhaka method (Table 1).3 When the patient's weight prior to the diarrheal episode is known, the percentage of body weight loss should be calculated to determine the degree of dehydration.3
Patients with diarrhea lasting ≥ 14 days should be evaluated for a parasitic infection.2 Complementary tests will only be requested for patients with suspected fluid and electrolyte or metabolic alterations, or those with hydration failure.3
Based on the history, it is possible to obtain orientation regarding the etiological agent: if the patient reports vomiting, this points toward a viral infection or intoxication; fever, bloody stools, and rectal tenesmus point toward invasive bacterial diarrhea; and chronic diarrhea points toward a parasitosis.4
Microbiological stool examinations should be performed in patients with dysentery, severe abdominal pain, fever > 39 °C, symptoms lasting > 7 days, infants < 3 months of age, as well as in patients with immunosuppression, moderate or severe malnutrition, concomitant chronic diseases, a recent history of international travel, or in the presence of epidemiological outbreaks of diarrhea.3,5 In the event that nucleic acid amplification testing for multiple microorganisms is performed, the clinical history is vital to interpret the results, given that these types of tests detect DNA and not necessarily the viable microorganism.2 The detection of fecal leukocytes and stool lactoferrin should not be used to determine the cause of the acute diarrhea episode. There are insufficient data to support the utility of measuring fecal calprotectin in patients with acute diarrhea.2,5
Treatment for most cases in both adults and the pediatric population should be symptomatic, and the WHO has formulated a three-step rehydration therapy based on the presence of clinical evaluation criteria (Tables 1 and 2).6,7
The guideline of the European and North American Societies for Paediatric Gastroenterology, Hepatology, and Nutrition does not recommend the routine purchase of lactose-free formulas, although they may be considered for hospitalized patients with prolonged diarrhea (> 7 days) and for all patients with chronic diarrhea (> 14 days).8 Zinc supplementation is recommended for patients > 6 months of age in developing countries or in contexts with a high risk of zinc deficiency; it is considered ineffective in patients < 6 months of age, regardless of nutritional status.8
The IDSA, in its 2017 guidelines, recommends against administering empirical antibiotic therapy in immunocompetent patients of any age, even if the watery diarrhea persists for more than 14 days, with the exception of:
- 1. Infants < 3 months of age with a clear suspicion of bacterial etiology.
- 2. Documented fever, abdominal pain, bloody diarrhea, and bacillary dysentery presumably due to Shigella spp.
- 3. Temperature ≥ 38.5 °C and/or signs of sepsis with a recent history of international travel.
- 4. Immunocompromised individuals with severe disease and bloody diarrhea.2
In these cases, local antimicrobial susceptibility patterns and travel history should be considered. It is also recommended to avoid antimicrobial therapy in patients with infections attributed to E. coli O157:H7 and other Shiga toxin-producing E. coli (STEC) type 2; evidence regarding its benefit against other types of non-Shiga toxin 2-producing EC is insufficient.2
For their part, Mexican guidelines suggest the following hospitalization criteria:
- 1. Severe dehydration or signs of hypovolemic shock.
- 2. Neurological alterations.
- 3. Persistent and uncontrollable vomiting.
- 4. Recurrence of dehydration during the same diarrheal episode.
- 5. Suspicion of hypernatremic dehydration.3
For symptomatic treatment, the guideline of the European and North American Societies for Paediatric Gastroenterology, Hepatology, and Nutrition does not recommend the use of loperamide and intestinal motility inhibitor drugs in the treatment of acute watery diarrhea in pediatric patients due to their association with paralytic ileus, lethargy, and the risk of respiratory depression. Metoclopramide, although effective, has significant adverse effects and should not be recommended in pediatric patients. Domperidone also lacks sufficient evidence from randomized controlled trials. Ondansetron has shown effectiveness in reducing vomiting and the need for hospitalization; however, it has been associated with QT interval prolongation and severe cardiac arrhythmias.8
Chinese clinical practice guidelines recommend adsorbents to shorten the duration, frequency, and volume of stools, such as montmorillonite in children with acute watery diarrhea and racecadotril in patients > 3 months of age.9
In the case of diosmectite, a review found that it reduced the duration of diarrhea episodes within 24 hours and increased the clinical resolution rate by the third day of intervention.10
The study by Abdulrazzaq and his team indicates that dietary lactose restriction significantly improves diarrhea symptoms compared to control groups (p < 0.01).11
In adults, travelers' diarrhea is particularly relevant, which, although usually self-limiting, can have severe outcomes. It is generally caused by enterotoxigenic E. coli (ETEC), Campylobacter jejuni, Salmonella spp., and Shigella spp. A systematic review found that bismuth subsalicylate was the most effective agent for the treatment of this disease, followed by the use of rifaximin and probiotics.12
Bismuth subsalicylate has demonstrated antimicrobial activity by inhibiting the growth of E. coli, Salmonella spp., Shigella spp., and Vibrio spp. both in vitro and in vivo, in addition to binding and inactivating bacterial toxins and the diarrheal effects of bile acids, without altering the composition of the normal intestinal microbiota.13
Probiotics have a moderate effect in the treatment of acute infectious diarrhea in pediatric patients, which is strain- and dose-dependent. Doses greater than 1010-1011 colony-forming units (CFU) are recommended, especially for watery diarrhea caused by viruses. They are not recommended for inflammatory diarrhea caused by bacteria. Particularly, specimens of the genus Bifidobacterium combined with Lactobacillus and Streptococcus thermophilus have been shown to reduce the duration of the disease in pediatric patients with acute diarrhea of infectious origin.9 A study demonstrated that both Lacticaseibacillus rhamnosus GG and Saccharomyces cerevisiae var. boulardii improve the production of short-chain fatty acids and consequently increase the abundance of organisms of the Bifidobacteriaceae family,14 whereas Lactobacillus rhamnosus R0011, Bacillus clausii, and L. helveticus R0052 did not show significant effects in reducing the duration of the diarrheal episode.15
The combination of prebiotics with probiotics forms synbiotics, which, in animal models, have shown beneficial effects in reducing the adherence of pathogenic bacteria to the jejunum and colonic mucosa. According to the guidelines of the American College of Gastroenterology, information regarding their use presents wide heterogeneity; therefore, more research is needed to recommend them.5
Vitamin A supplementation did not show a statistically significant difference in preventing morbidity and mortality from diarrhea in pediatric patients from six months to five years of age; therefore, its administration is not recommended.16
DYSENTERY
The IDSA recommends that patients with a clinical presentation of diarrhea accompanied by fever, dysentery, cramps, or severe abdominal pain be evaluated to identify enteropathogens such as Salmonella enterica, Shigella, Campylobacter, Yersinia, and C. difficile.
When the clinical history suggests that the presentation is caused by an infectious agent producing Shiga toxin, testing should be performed to detect Shiga toxin 1 and 2; to distinguish Escherichia coli O157:H7 from other Shiga toxin-producing E. coli (STEC), as well as Shigella dysenteriae type 1.2
Testing to detect Yersinia enterocolitica should be performed in individuals with persistent abdominal pain, especially school-aged children with right lower quadrant pain, a history of direct or indirect contact with raw or undercooked pork products, or in those with fever and epidemiological risk of yersiniosis.2
The antibiotic treatment regimen to be used depends on the suspected or isolated agent (Table 3).3
PSEUDOMEMBRANOUS COLITIS
The infection is defined as the presence of symptoms (usually diarrhea) and a positive stool test for C. difficile toxins, or findings on colonoscopy or histopathology revealing pseudomembranous colitis.17
Although a variable percentage of the population is colonized, advanced age (> 65 years), contact with the hospital environment, and antibiotic use are major risk factors for the development of an active infection.18
The 2021 IDSA guideline considers that, in an initial episode, the administration of fidaxomicin is superior to the traditional vancomycin regimen, because patients are more likely to present a sustained response at four weeks after the end of therapy, with a comparable rate of initial clinical improvement, although without a reduction in mortality or major adverse effects. The recommendation to administer vancomycin remains for fulminant infection (formerly known as severe or complicated).19
In patients with recurrent episodes, the administration of fidaxomicin is suggested as first-line treatment (conditional recommendation with low-certainty evidence).19
Bezlotoxumab is a monoclonal antibody approved in 2016 by the FDA that binds to C. difficile toxin B. It is indicated for patients at high risk of infection recurrence. It is recommended to administer it during recurrent episodes concomitantly with the standard antibiotic therapy of vancomycin, especially in those with a primary episode and relevant risk factors for recurrence (at least one recurrent episode within the last six months, age ≥ 65 years, a history of any type of immunocompromise, or an initial presentation of fulminant infection). The FDA has placed a fatal risk warning for patients with a history of congestive heart failure.19
CHOLERA
In individuals with a severe diarrheal presentation characterized by acute watery diarrhea, with a rice-water appearance, vomiting, and severe dehydration or hypovolemic shock, infection by Vibrio cholerae should be suspected; likewise in patients ≥ 5 years of age who present ≥ 5 diarrheal evacuations in 24 hours and a duration of the condition no longer than five days of evolution, which is known as "the rule of five."4
Early administration of cholera vaccines during an outbreak offers up to 79% protection; even a single dose of the vaccine significantly reduces the risk.20
Most cases are mild to moderate and can be easily managed with newly formulated oral rehydration solutions. In the event that vomiting is repeated more than three times in an hour or if rehydration with oral serum does not improve the patient's condition, the implementation of intravenous fluid treatments may be considered.20
In malnourished pediatric patients, it is necessary to complement the therapy with a high-carbohydrate diet following the correction of fluid deficiency, with the aim of preventing hypoglycemia, hyponatremia, and hypokalemia.20
Antimicrobial therapy is indispensable, regardless of age or hospitalization requirements (Table 4).20
Mass chemoprophylaxis with antibiotics is not recommended for the control of cholera outbreaks at the population level.20 Regarding probiotics, the administration of strains of Ruminococcus obeum has been positively correlated with clinical recovery.20
FOOD POISONING
Toxin-mediated gastroenteritis occurs following the ingestion of a preformed toxin produced by a bacterium. The predominant symptom is vomiting, accompanied by mild watery diarrhea, with a short period between ingestion and symptomatology, as well as a rapid resolution of the condition.21 It is associated with toxins produced by Staphylococcus aureus or Bacillus cereus, especially given the paroxysmal onset of repetitive vomiting and diarrhea within the first six hours of food intake, or with toxins produced by Clostridium perfringens, given the appearance of diarrhea up to 24 hours after consumption.22
There are molecular diagnostic methods, such as polymerase chain reaction (PCR), used to detect the presence of genes encoding exotoxins during food poisoning outbreaks caused by bacteria like Staphylococcus aureus. Treatment is based on controlling the effect of the exotoxins or the transmission of the bacteria, as well as the timely administration of rehydration serums.22
In the case of poisoning by staphylococcal toxins, the use of antimicrobials is not recommended to avoid shock due to additional toxin release or alteration of the intestinal microbiota.23
ENTERIC FEVER
It is an acute generalized infection of the reticuloendothelial system, with a predilection for the intestinal lymphoid tissue and the gallbladder. Typhoid fever is caused by Salmonella typhi (80% of cases) and by Salmonella paratyphi types A and B (20% of cases).24
Following an incubation period of 6 to 30 days, the onset of symptoms is insidious, characterized by fatigue and high fever from the third and fourth day, from 38 to 40 °C, with nocturnal peaks. These symptoms are accompanied by headache, anorexia, and general malaise, as well as abdominal pain, constipation, or diarrhea. Additionally, dry cough, myalgias, pharyngodynia, a pink maculopapular rash on the trunk, and potentially life-threatening complications such as intestinal perforation, encephalopathy, and gastrointestinal hemorrhage may present.25
Antibiotic therapy depends on the sensitivity conditions of the agent (Table 5).
The most recent studies favor the combination of antibiotics against MDR (multidrug-resistant) pathogens; however, randomized clinical trials on the efficacy of combining meropenem with azithromycin for the treatment of XDR (extensively drug-resistant) organisms are not yet known.26
CONCLUSIONS
Given the constant emergence of guidelines for the management of gastrointestinal infections, it is important for healthcare personnel to remain updated. Most medical societies worldwide insist on the importance of the rational use of antibiotics and rehydration strategies. Although the results regarding the use of probiotics, prebiotics, and synbiotics are encouraging, the quality of the evidence is low. More research is required to support their use.
Randomized clinical trials with a larger number of patients are crucial for the improvement in the diagnosis and treatment of gastrointestinal infections.
REFERENCES
Guarino A, Ashkenazi S, Gendrel D, Lo Vecchio A, Shamir R, Szajewska H et al. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases evidence-based guidelines for the management of acute gastroenteritis in children in Europe: update 2014. J Pediatr Gastroenterol Nutr. 2014; 59 (1): 132-152.
CENETEC. Guía de práctica clínica: evidencias y recomendaciones. Prevención, diagnóstico y tratamiento de diarrea aguda en pacientes de 2 meses a 5 años de edad en el primer y segundo nivel de atención. 2024. [Accesado Enero 2025] Disponible en: https://www.cenetec-difusion.com/CMGPC/GPC-SS-156-24/ER.pdf
McDonald LC, Gerding DN, Johnson S, Bakken JS, Carroll KC, Coffin SE et al. 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). Clin Infect Dis. 2018; 66 (7): e1-e48. Available in: https://doi.org/10.1093/cid/cix1085
AFFILIATIONS
1 Laboratorio de Investigación en Enfermedades Infecciosas, División de Investigación, Facultad de Medicina. Universidad Nacional Autónoma de México. Ciudad de México, México.
ORCID:
2 0000-0002-9189-6732
3 0000-0002-9706-6545
4 0000-0003-1641-127X
5 0000-0002-3582-5120
If you wish to consult the supplementary data for this article, please contact editorial.actamedica@saludangeles.mx
CORRESPONDENCE
Rosa María Wong Chew. Correo electrónico: rmwong@unam.mxReceived: 2025-02-06. Accepted: 2025-02-25.