A 6-year-old, previously healthy girl is brought to the emergency department due to fever, abdominal pain, and diarrhea for the past day. The symptoms began abruptly with high fever, as well as cramping periumbilical pain, and were quickly followed by low-volume diarrhea mixed with blood and mucus. The patient has had no sick contacts and has not traveled recently; the family had dinner at a buffet restaurant 3 days ago. Temperature is 38.9 C (102 F). Physical examination reveals mild, diffuse abdominal tenderness with no guarding or rebound tenderness. Bowel sounds are hyperactive. Stool occult blood testing is positive, with numerous leukocytes in the stool. Culture of stool yields gram-negative, oxidase-positive, curved rods. Which of the following is the most likely pathogen responsible for this patient's symptoms?
Campylobacter jejuni | |
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Campylobacter jejuni is a motile, oxidase-positive, gram-negative, curved rod that is a leading cause of bacterial gastroenteritis. This pathogen resides in the gastrointestinal tract of a wide range of mammals and is transmitted via the fecal-oral route. Most cases arise when humans ingest contaminated food, particularly undercooked poultry or unpasteurized milk, but a minority are caused by close contact with domesticated animals (eg, dogs, farm animals).
C jejuni is enteroinvasive and typically causes fever, abdominal pain, and diarrhea that may be bloody. Stool studies usually reveal inflammation (ie, blood, leukocytes); culture of stool (enriched media at 42 C [107.6 F] and microaerophilic conditions) is diagnostic. Most cases are self-limited and resolve within a week with supportive treatment.
(Choice B) Escherichia coli causes many forms of gastroenteritis, including enterotoxin-mediated watery diarrhea (enterotoxigenic), Shiga toxin–mediated hemorrhagic colitis (enterohemorrhagic), and invasive colitis (enteroinvasive). Although this pathogen is a gram-negative enteric rod, it is oxidase negative and not described as curved.
(Choice C) Nontyphoidal Salmonella (eg, S serovar Enteritidis) is a common cause of bacterial gastroenteritis. This enteroinvasive pathogen frequently causes self-limited abdominal pain, fever, and watery diarrhea; bloody diarrhea is less common but can occur. However, Salmonella is oxidase negative and not described as curved.
(Choice D) Shigella is a highly virulent bacterium that is often transmitted via the fecal-oral route in day care centers or other areas of communal habituation. It causes inflammatory colitis with fever, abdominal pain, and mucoid, bloody, and/or watery diarrhea. However, Shigella is oxidase negative and is not described as curved.
(Choice E) Vibrio cholerae is a curved, oxidase-positive, gram-negative enteric rod and can therefore occasionally be misidentified as a Campylobacter species. However, V cholerae causes massive watery diarrhea (due to cholera toxin) that is noninflammatory (ie, no fecal leukocytes or erythrocytes).
Educational objective:
Campylobacter jejuni is an oxidase-positive, gram-negative, curved rod that is a leading cause of gastroenteritis. The pathogen is a zoonotic organism most commonly contracted by consuming contaminated, undercooked poultry. The infection is marked by fever, abdominal pain, and diarrhea that may be bloody.