Sections

Workup

Approach Considerations

A stool pH of 5.5 or below or the presence of reducing substances indicates carbohydrate intolerance. This is usually transient in nature.

Enteroinvasive infections of the large bowel cause leukocytes, predominantly neutrophils, to accumulate in the lumen which are then shed into stool. The absence of fecal leukocytes does not eliminate the possibility of enteroinvasive organisms; however, the presence of fecal leukocytes eliminates consideration of enterotoxigenic E coli, Vibrio species, and viruses. Shigella characteristically causes marked bandemia with variable total white blood cell (WBC) count.

Examine any exudate found in the stool for leukocytes. Such exudates are highly suggestive of inflammatory bowel disease, which could be infectious or of another origin.

Antilisteriolysin O (ALLO) is positive during the convalescent phase of bacterial gastroenteritis and when invasive disease has occurred.

Commercially available multiplex molecular panels may be more sensitive and provide more rapid results (< 3 hours) than stool cultures, which are labor intensive and whose results may take longer than 1 day (66.5 hours).^{[21, 44]}

Procedures

Identification of pseudomembranes in the colon by direct visualization is diagnostic for C difficile; however, the yield may be low.

Bacterial Cultures

Identifying the causative agent underlying the gastroenteritis is important in the management of patients with severe or prolonged diarrhea, symptoms consistent with invasive disease, or a history that may predict a complicated disease course.^[22]Moreover, stool culture findings are a means for public health officials to identify and track outbreaks of bacterial gastroenteritis.

Table 3, below, lists common bacteria and the optimal culture media for their growth.

Table 3. Common Bacteria and Optimum Culture Media (Open Table in a new window)

Organism	Detection Method	Microbiologic Characteristics
Aeromonas species	Blood agar	Oxidase-positive, flagellated GNB
Bacillus species	Blood agar	Facultatively aerobic, spore-forming GPR; beta hemolytic; reduces nitrates; ferments carbohydrates
Campylobacter species	Skirrow agar	Rapidly motile, curved GNR; Campylobacter jejuni 90% of infections, Campylobacter coli 5% of infections
C difficile	CCFE agar, EIA for toxin, LA for protein	Anaerobic, spore-forming GPR; toxin-mediated diarrhea; produces pseudomembranous colitis
C perfringens	None available	Anaerobic, spore-forming GPR; toxin-mediated diarrhea
E coli	MacConkey, EMB, or SM agar	Lactose-producing GNR
Listeria species	Blood agar	Flagellated GPB
Plesiomonas species	Blood agar	Oxidase-positive GNR
Salmonella species	Blood, MacConkey, EMB, XLD, or HE agar	Nonlactose, non–H2S-producing GNR
Shigella species	Blood, MacConkey, EMB, XLD, or HE agar	Nonlactose and H2S-producing GNR; verotoxin (neurotoxin)
Staphylococcus species	Blood agar	Heat-stable, preformed toxin-mediated GPC
Vibrio species	Blood or TCBS agar	Oxidase-positive, motile, curved GNB
Y enterocolitica	CIN agar	Nonlactose-producing, oval GNR
CCFE = cycloserine-cefoxitin-fructose-egg; CIN = cefsulodin-irgasan-novobiocin; EIA= enzyme immunoassay; EMB = e-methylene blue; GNB = gram-negative bacillus; GNR = gram-negative rod; GPB = gram-positive bacillus; GPC = gram-positive cocci; GPR = gram-positive rod; H2S = hydrogen sulfide; HE = Hektoen enteric; LA = latex agglutination; SM = Sorbitol-MacConkey; TCBS = thiosulfate-citrate-bile-sucrose; XLD = xylose-lysine-deoxycholate.

The following is a list of the different culture media used to isolate bacteria. A high index of suspicion is needed to choose the appropriate medium.

Blood agar - All aerobic bacteria and yeast; detects cytochrome oxidase production
MacConkey EMB agar - Inhibits gram-positive organisms; permits lactose fermentation
XLD agar and HE agar - Inhibit gram-positive organisms and nonpathogenic gram-negative bacilli; permit lactose fermentation and H2S production
Skirrow agar - Selective for Campylobacter species
SM agar - Selective for enterohemorrhagic E coli
CIN agar - Selective for Y enterocolitica
Thiosulfate-citrate-bile-sucrose agar - Selective for Vibrio species
CCFE agar - Selective for C difficile

Stool cultures are useful when positive, but the yield is usually low. Refrigerate stool that is not cultured at 4°C within 2 hours of collection, or place it in a transport medium. Always culture stool for Campylobacter, Salmonella, and Shigella species, especially if stool leukocytes or gross blood is found in the stool.

Serotype Salmonella for S typhimurium DT104, particularly if the gastroenteritis is associated with raw milk or cheese ingestion. S typhimurium DT104 is a multidrug-resistant organism, and antibiotic sensitivities are crucial to guide therapy.^{[23, 24]}

Preformed toxin from Bacillus or Staphylococcus species may cause rapid-onset gastroenteritis. In such cases, the bacteria may not exist in the gastrointestinal tract; therefore, culture the food ingested by the person.

Bloody diarrhea with a history of ground beef ingestion should raise the suspicion for enterohemorrhagic E coli. If E coli is found in the stool, type it to determine if it is O157:H7. Report cases of E coli O157:E7 gastroenteritis (and other infectious problems) to the state health department. Shiga toxin-producing Escherichia coli (STEC) O103:H2 has also been detected in raw cow milk and dairy farm cattle.^[43]

History of raw seafood ingestion or foreign travel should prompt additional screening for Vibrio and Plesiomonas species.

Treatment & Management

Guandalini S, Pensabene L, Zikri MA, et al. Lactobacillus GG administered in oral rehydration solution to children with acute diarrhea: a multicenter European trial. J Pediatr Gastroenterol Nutr. 2000 Jan. 30(1):54-60. [QxMD MEDLINE Link].
Simakachorn N, Pichaipat V, Rithipornpaisarn P, et al. Clinical evaluation of the addition of lyophilized, heat-killed Lactobacillus acidophilus LB to oral rehydration therapy in the treatment of acute diarrhea in children. J Pediatr Gastroenterol Nutr. 2000 Jan. 30(1):68-72. [QxMD MEDLINE Link].
Duggan C, Nurko S. "Feeding the gut": the scientific basis for continued enteral nutrition during acute diarrhea. J Pediatr. 1997 Dec. 131(6):801-8. [QxMD MEDLINE Link].
Salminen S, Isolauri E, Onnela T. Gut flora in normal and disordered states. Chemotherapy. 1995. 41 suppl 1:5-15. [QxMD MEDLINE Link].
Marks MI. Infectious diarrhea: introduction and commentary. Pediatr Ann. 1994 Oct. 23(10):526-7. [QxMD MEDLINE Link].
Liebelt EL. Clinical and laboratory evaluation and management of children with vomiting, diarrhea, and dehydration. Curr Opin Pediatr. 1998 Oct. 10(5):461-9. [QxMD MEDLINE Link].
Hamer DH, Gorbach SL. Infectious diarrhea and bacterial food poisoning. Feldman M, Scharschmidt BF, Sleisenger MH, eds. Sleisinger and Fordtran’s Gastrointestinaland Liver Disease. 6th ed. Philadelphia, Pa: WB Saunders; 1998. 1594-1632.
Xu F, Gonzalez-Escalona N, Haendiges J, et al. Vibrio parahaemolyticus sequence type 631, an emerging foodborne pathogen in North America. J Clin Microbiol. 2016 Dec 14. [QxMD MEDLINE Link].
Cadle RM, Mansouri MD, Logan N, Kudva DR, Musher DM. Association of proton-pump inhibitors with outcomes in Clostridium difficile colitis. Am J Health Syst Pharm. 2007 Nov 15. 64(22):2359-63. [QxMD MEDLINE Link].
Wei L, Ratnayake L, Phillips G, et al. Acid suppression medications and bacterial gastroenteritis: a population-based cohort study. Br J Clin Pharmacol. 2017 Jan 5. 27 (1):40-51. [QxMD MEDLINE Link].
Steffen R, Collard F, Tornieporth N, et al. Epidemiology, etiology, and impact of traveler's diarrhea in Jamaica. JAMA. 1999 Mar 3. 281(9):811-7. [QxMD MEDLINE Link]. [Full Text].
Streit JM, Jones RN, Toleman MA, Stratchounski LS, Fritsche TR. Prevalence and antimicrobial susceptibility patterns among gastroenteritis-causing pathogens recovered in Europe and Latin America and Salmonella isolates recovered from bloodstream infections in North America and Latin America: report from the SENTRY Antimicrobial Surveillance Program (2003). Int J Antimicrob Agents. 2006 May. 27(5):367-75. [QxMD MEDLINE Link].
Vital Signs: Preventing Clostridium difficile Infections. MMWR Morb Mortal Wkly Rep. 2012 Mar 9. 61:157-62. [QxMD MEDLINE Link].
World Health Organization. Cholera: fact sheet no. 107. November 2008. Available at http://www.who.int/mediacentre/factsheets/fs107/en/. Accessed: February 19, 2009.
May FJ, Polkinghorne BG, Fearnley EJ. Epidemiology of bacterial toxin-mediated foodborne gastroenteritis outbreaks in Australia, 2001 to 2013. Commun Dis Intell Q Rep. 2016 Dec 24. 40 (4):E460-E469. [QxMD MEDLINE Link].
Lee LA, Gerber AR, Lonsway DR, et al. Yersinia enterocolitica O:3 infections in infants and children, associated with the household preparation of chitterlings. N Engl J Med. 1990 Apr 5. 322(14):984-7. [QxMD MEDLINE Link].
Centers for Disease Control and Prevention. Yersinia enterocolitica. October 25, 2005. Available at http://www.cdc.gov/ncidod/dbmd/diseaseinfo/yersinia_g.htm. Accessed: February 18, 2009.
Centers for Disease Control and Prevention (CDC). Deaths from gastroenteritis double. Available at http://www.cdc.gov/media/releases/2012/p0314_gastroenteritis.html.
Garcia Rodriguez LA, Ruigomez A, Panes J. Acute gastroenteritis is followed by an increased risk of inflammatory bowel disease. Gastroenterology. 2006 May. 130(6):1588-94. [QxMD MEDLINE Link].
Calbo E, Freixas N, Xercavins M, et al. Foodborne nosocomial outbreak of SHV1 and CTX-M-15-producing Klebsiella pneumoniae: epidemiology and control. Clin Infect Dis. 2011 Mar. 52(6):743-9. [QxMD MEDLINE Link].
Biswas JS, Al-Ali A, Rajput P, Smith D, Goldenberg SD. A parallel diagnostic accuracy study of three molecular panels for the detection of bacterial gastroenteritis. Eur J Clin Microbiol Infect Dis. 2014 Nov. 33 (11):2075-81. [QxMD MEDLINE Link].
Humphries RM, Linscott AJ. Laboratory diagnosis of bacterial gastroenteritis. Clin Microbiol Rev. 2015 Jan. 28 (1):3-31. [QxMD MEDLINE Link].
Cody SH, Abbott SL, Marfin AA, et al. Two outbreaks of multidrug-resistant Salmonella serotype typhimurium DT104 infections linked to raw-milk cheese in Northern California. JAMA. 1999 May 19. 281(19):1805-10. [QxMD MEDLINE Link]. [Full Text].
World Health Organization. Drug-resistant Salmonella: fact sheet no. 139. Revised April 2005. Available at http://www.who.int/mediacentre/factsheets/fs139/en/. Accessed: February 19, 2009.
Guandalini S, Dincer AP. Nutritional management in diarrhoeal disease. Baillieres Clin Gastroenterol. 1998 Dec. 12(4):697-717. [QxMD MEDLINE Link].
Sullivan PB. Nutritional management of acute diarrhea. Nutrition. 1998 Oct. 14(10):758-62. [QxMD MEDLINE Link].
Ruiz-Palacios GM, Perez-Schael I, Velazquez FR, et al, for the Human Rotavirus Vaccine Study Group. Safety and efficacy of an attenuated vaccine against severe rotavirus gastroenteritis. N Engl J Med. 2006 Jan 5. 354(1):11-22. [QxMD MEDLINE Link]. [Full Text].
Brooks M. FDA clears novel test for infectious gastroenteritis. Medscape Medical News. January 15, 2013. Available at http://www.medscape.com/viewarticle/777671. Accessed: February 9, 2013.
DuPont HL, The Practice Parameters Committee of the American College of Gastroenterology. Guidelines on acute infectious diarrhea in adults. Am J Gastroenterol. 1997 Nov. 92(11):1962-75. [QxMD MEDLINE Link].
Garcia Rodriguez LA, Ruigomez A, Panes J. Use of acid-suppressing drugs and the risk of bacterial gastroenteritis. Clin Gastroenterol Hepatol. 2007 Dec. 5(12):1418-23. [QxMD MEDLINE Link].
Gibreel A, Taylor DE. Macrolide resistance in Campylobacter jejuni and Campylobacter coli. J Antimicrob Chemother. 2006 Aug. 58(2):243-55. [QxMD MEDLINE Link]. [Full Text].
Kaur S, Vaishnavi C, Prasad KK, Ray P, Kochhar R. Comparative role of antibiotic and proton pump inhibitor in experimental Clostridium difficile infection in mice. Microbiol Immunol. 2007. 51(12):1209-14. [QxMD MEDLINE Link]. [Full Text].
Mines D, Stahmer S, Shepherd SM. Poisonings: food, fish, shellfish. Emerg Med Clin North Am. 1997 Feb. 15(1):157-77. [QxMD MEDLINE Link].
Nataro JP, Steiner T, Guerrant RL. Enteroaggregative Escherichia coli. Emerg Infect Dis. 1998 Apr-Jun. 4(2):251-61. [QxMD MEDLINE Link].
Paterson DL. Resistance in gram-negative bacteria: Enterobacteriaceae. Am J Med. 2006 Jun. 119(6 suppl 1):S20-8; discussion S62-70. [QxMD MEDLINE Link].
Rodriguez LA, Ruigomez A. Increased risk of irritable bowel syndrome after bacterial gastroenteritis: cohort study. BMJ. 1999 Feb 27. 318(7183):565-6. [QxMD MEDLINE Link]. [Full Text].
Trachtman H, Christen E. Pathogenesis, treatment, and therapeutic trials in hemolytic uremic syndrome. Curr Opin Pediatr. 1999 Apr. 11(2):162-8. [QxMD MEDLINE Link].
Wong CS, Jelacic S, Habeeb RL, Watkins SL, Tarr PI. The risk of the hemolytic-uremic syndrome after antibiotic treatment of Escherichia coli O157:H7 infections. N Engl J Med. 2000 Jun 29. 342(26):1930-6. [QxMD MEDLINE Link]. [Full Text].
Campylobacter (Campylobacteriosis). Centers for Disease Control and Prevention (CDC). Available at https://www.cdc.gov/campylobacter/technical.html. Accessed: February 15, 2018.
Cuypers WL, Jacobs J, Wong V, Klemm EJ, Deborggraeve S, Van Puyvelde S. Fluoroquinolone resistance in Salmonella: insights by whole-genome sequencing. Microb Genom. 2018 Jul 5. [QxMD MEDLINE Link].
US Food and Drug Administration. FDA updates warnings for fluoroquinolone antibiotics on risks of mental health and low blood sugar adverse reactions. Available at https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm612995.htm. July 10, 2018; Accessed: July 18, 2018.
Frellick M. FDA: Stronger fluoroquinolone warnings for mental health, hypoglycemia. Available at https://www.medscape.com/viewarticle/899142. July 10, 2018; Accessed: July 18, 2018.
Mylius M, Dreesman J, Pulz M, et al. Shiga toxin-producing Escherichia coli O103:H2 outbreak in Germany after school trip to Austria due to raw cow milk, 2017 - The important role of international collaboration for outbreak investigations. Int J Med Microbiol. 2018 Jul. 308 (5):539-44. [QxMD MEDLINE Link].
Calderaro A, Martinelli M, Buttrini M, et al. Contribution of the FilmArray(R) Gastrointestinal Panel in the laboratory diagnosis of gastroenteritis in a cohort of children: a two-year prospective study. Int J Med Microbiol. 2018 Jul. 308 (5):514-21. [QxMD MEDLINE Link].
Goldenberg JZ, Yap C, Lytvyn L, et al. Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children. Cochrane Database Syst Rev. 2017 Dec 19. 12:CD006095. [QxMD MEDLINE Link].
Surana NK, Kasper DL. Moving beyond microbiome-wide associations to causal microbe identification. Nature. 2017 Dec 14. 552 (7684):244-7. [QxMD MEDLINE Link].
[Guideline] Berenger B, Chui L, Reimer AR, et al, for the Canadian Public Health Laboratory Network. Canadian Public Health Laboratory Network position statement: Non-culture based diagnostics for gastroenteritis and implications for public health investigations. Can Commun Dis Rep. 2017 Dec 7. 43 (12):279-81. [QxMD MEDLINE Link].
Lee H, Ku HJ, Lee DH, et al. Characterization and genomic study of the novel bacteriophage HY01 infecting both Escherichia coli O157:H7 and Shigella flexneri: potential as a biocontrol agent in food. PLoS One. 2016. 11 (12):e0168985. [QxMD MEDLINE Link].
Chen Y, Liu B, Glass K, Du W, Banks E, Kirk M. Use of proton pump inhibitors and the risk of hospitalization for infectious gastroenteritis. PLoS One. 2016. 11 (12):e0168618. [QxMD MEDLINE Link].

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Table 1. Stool Characteristics and Sources

Stool Characteristics	Small Bowel	Large Bowel
Appearance	Watery	Mucus and/or blood
Volume	Large	Small
Frequency	Increased	Increased
Blood	Possibly heme-positive but never gross blood	Possibly grossly bloody
pH	Possibly < 5.5	>5.5
Reducing substances	Possibly positive	Negative
White blood cell (WBC) count	< 5/high-power field (HPF)	Possibly >10/HPF
Serum WBC count	Normal	Possible leukocytosis, bandemia
Organisms	Preformed toxins: Bacillus species, Staphylococcus aureus	Invasive bacteria: E coli and Shigella, Salmonella, Campylobacter, Yersinia, Aeromonas, and Plesiomonas species
	Toxic bacteria: E coli, cholera, C perfringens, Vibrio species, Listeria monocytogenes	Toxic bacteria: C difficile
	Other causes: rotavirus, adenovirus, calicivirus, astrovirus, Norwalk virus, and Giardia and Cryptosporidium species	Other causes: Entamoeba species

Table 2. Symptoms and Their Characteristics

Organism	Incubation	Duration	Vomiting	Fever	Abdominal Pain
Aeromonas species	None	0-2 weeks	+/-	+/-	No
Bacillus species	1-16 hours	1-2 days	Yes	No	Yes
Campylobacter species	2-4 days	5-7 days	No	Yes	Yes
C difficile	Variable	Variable	No	Few	Few
C perfringens	0-1	1 day	Mild	No	Yes
Enterohemorrhagic E coli	1-8 days	3-6 days	No	+/-	Yes
Enterotoxigenic E coli	1-3 days	3-5 days	Yes	Low	Yes
Listeria species	20 hours	2 days	Few	Yes	+/-
Plesiomonas species	None	0-2 weeks	+/-	+/-	+/-
Salmonella species	0-3 days	2-7 days	Yes	Yes	Yes
Shigella species	0-2 days	2-7 days	No	High	Yes
S aureus	2-6 hours	1 day	Yes	No	Yes
Vibrio species	0-1 days	5-7 days	Yes	No	Yes
Y enterocolitica	0-6	1-46 days	Yes	Yes	Yes

Table 3. Common Bacteria and Optimum Culture Media

Organism	Detection Method	Microbiologic Characteristics
Aeromonas species	Blood agar	Oxidase-positive, flagellated GNB
Bacillus species	Blood agar	Facultatively aerobic, spore-forming GPR; beta hemolytic; reduces nitrates; ferments carbohydrates
Campylobacter species	Skirrow agar	Rapidly motile, curved GNR; Campylobacter jejuni 90% of infections, Campylobacter coli 5% of infections
C difficile	CCFE agar, EIA for toxin, LA for protein	Anaerobic, spore-forming GPR; toxin-mediated diarrhea; produces pseudomembranous colitis
C perfringens	None available	Anaerobic, spore-forming GPR; toxin-mediated diarrhea
E coli	MacConkey, EMB, or SM agar	Lactose-producing GNR
Listeria species	Blood agar	Flagellated GPB
Plesiomonas species	Blood agar	Oxidase-positive GNR
Salmonella species	Blood, MacConkey, EMB, XLD, or HE agar	Nonlactose, non–H2S-producing GNR
Shigella species	Blood, MacConkey, EMB, XLD, or HE agar	Nonlactose and H2S-producing GNR; verotoxin (neurotoxin)
Staphylococcus species	Blood agar	Heat-stable, preformed toxin-mediated GPC
Vibrio species	Blood or TCBS agar	Oxidase-positive, motile, curved GNB
Y enterocolitica	CIN agar	Nonlactose-producing, oval GNR
CCFE = cycloserine-cefoxitin-fructose-egg; CIN = cefsulodin-irgasan-novobiocin; EIA= enzyme immunoassay; EMB = e-methylene blue; GNB = gram-negative bacillus; GNR = gram-negative rod; GPB = gram-positive bacillus; GPC = gram-positive cocci; GPR = gram-positive rod; H2S = hydrogen sulfide; HE = Hektoen enteric; LA = latex agglutination; SM = Sorbitol-MacConkey; TCBS = thiosulfate-citrate-bile-sucrose; XLD = xylose-lysine-deoxycholate.

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Author

Jennifer Lynn Bonheur, MD Attending Gastroenterologist

Jennifer Lynn Bonheur, MD is a member of the following medical societies: American Gastroenterological Association, American Society for Gastrointestinal Endoscopy, New York Academy of Sciences, New York Society for Gastrointestinal Endoscopy, Sigma Xi, The Scientific Research Honor Society

Disclosure: Nothing to disclose.

Coauthor(s)

Mukul Arya, MD Associate Professor of Internal Medicine, Weill Cornell Medical College; Assistant Director of Therapeutic Endoscopy, Department of Gastroenterology and Internal Medicine, Wyckoff Heights Medical Center

Mukul Arya, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Medical Association, American Society for Gastrointestinal Endoscopy

Disclosure: Nothing to disclose.

M Akram Tamer, MD Professor, Program Director, Department of Pediatrics, University of Miami, Leonard M Miller School of Medicine

M Akram Tamer, MD is a member of the following medical societies: American Medical Association, Florida Medical Association

Disclosure: Nothing to disclose.

Chief Editor

BS Anand, MD Professor, Department of Internal Medicine, Division of Gastroenterology, Baylor College of Medicine

BS Anand, MD is a member of the following medical societies: American Association for the Study of Liver Diseases, American College of Gastroenterology, American Gastroenterological Association, American Society for Gastrointestinal Endoscopy

Disclosure: Nothing to disclose.

Acknowledgements

Simmy Bank, MD Chair, Professor, Department of Internal Medicine, Division of Gastroenterology, Long Island Jewish Hospital, Albert Einstein College of Medicine

Disclosure: Nothing to disclose.

Richard E Frye, MD, PhD Assistant Professor, Departments of Pediatrics and Neurology, University of Texas Medical School at Houston

Richard E Frye, MD, PhD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, Child Neurology Society, and International Neuropsychological Society

Disclosure: Nothing to disclose.

John Gunn Lee, MD Director of Pancreaticobiliary Service, Associate Professor, Department of Internal Medicine, Division of Gastroenterology, University of California at Irvine School of Medicine

John Gunn Lee, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, and American Society for Gastrointestinal Endoscopy

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

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