A 53 year old woman with diarrhea and lower abdominal pain of 3 days duration comes to her physician after failing to relieve her symptoms with various home remedies. She denies any recent travel and states that there is blood and pus in her stool. Fecal cultures yield several flagellated, curved, oxidase positive, gram negative rods. The organism isolated is most likely ?

Campylobacter is a motile, curved, oxidase-positive, gram-negative rod with a polar flagella. The illness typically begins 1 to 7 days following ingestion of the organism. The presentation is usually lower abdominal pain and diarrhea with blood and pus. The illness is self-limited after 3 to 5 days and can last up to 2 weeks. The organisms grow optimally at 42deg C under microaerophilic conditions. Escherichia coli, although a flagellated gram-negative organism, is not the correct choice since it is not as common a cause of bloody diarrhea in this age group and is not oxidase positive. Salmonella is incorrect because it is oxidase negative. Shigella is incorrect because it is oxidase negative. Ref: Brooks G.F. (2013). Chapter 17. Vibrios, Campylobacters, Helicobacter, and Associated Bacteria. In G.F. Brooks (Ed), Jawetz, Melnick, & Adelberg's Medical Microbiology, 26e.