I am poured out like water, and all my bones are out of joint: my heart is like wax; it is melted in the midst of my bowels.
—The Bible: Psalms 22:14
Vibrio cholerae is a motile (flagellated), comma-shaped oxidase-positive Gram-negative rod that grows best on specialized media. Although many infections are asymptomatic, epidemic cholera produces the most dramatic watery diarrhea known. Intestinal fluids pour out in voluminous bowel movements, which untreated rapidly leads to dehydration and electrolyte imbalance. The pathogenesis is solely due to the action of cholera enterotoxin secreted by V cholerae in the bowel lumen. Despite the profound physiologic effects, there is no fever, inflammation, or direct injury to the bowel mucosa.
Campylobacter jejuni is the most common of the pathogenic Campylobacter species all of which are curved, motile Gram-negative rods. Clinical disease with C jejuni typically begins with lower abdominal pain, which evolves into diarrhea over a matter of hours. The diarrhea may be watery or dysenteric, with blood and pus in the stool. Most patients are febrile. The illness resolves spontaneously after a few days to 1 week.
Helicobacter pylori is also a curved, flagellated, small Gram-negative rod that is distinguished by being catalase, oxidase, and urease positive. Infections are limited to the mucosa of the stomach in which urease production enables survival in the acid milieu. Most are asymptomatic even after many years. Burning pain in the upper abdomen, accompanied by nausea and sometimes vomiting, is a symptom of gastritis, but peptic gastric or duodenal ulcers may ensue with additional symptoms and complications including bleeding and perforation.
This group of curved Gram-negative rods includes Vibrio cholerae, the cause of cholera and one of the first proven infectious diseases, along with Campylobacter jejuni and Helicobacter pylori, which were incriminated as pathogens late in the 20th century (Table 32–1). Cholera has undergone resurgence in recent decades and has now spread from its historic roots in South Asia to Africa and the Americas, including the coastline of the United States. C jejuni is one of the most common causes of diarrhea in virtually every country of the world. The peptic ulcer disease now known to be caused by H pylori had been long accepted to be due to stress and disturbed gastric acid secretion.
Table Graphic Jump Location TABLE 32–1Features of Vibrio, Campylobacter, and Helicobactera ||Download (.pdf) TABLE 32–1 Features of Vibrio, Campylobacter, and Helicobactera
|BACTERIOLOGY ||PATHOGENESIS || |
|ORGANISM ||GROWTH ||UREASE ||EPIDEMIOLOGY ||ADHERENCE ||TOXINS ||DISEASE |
|Vibrio cholerae ||Facultative ||– ||Fecal–oral, waterborne, pandemics ||Surface proteinb, pili ||CTc ||Watery diarrhea (cholera) |
|Campylobacter jejuni ||Microaerophilic ||– ||Animals, unpasteurized milk ||Unknown ||Unknown ||Dysentery, watery diarrhea |
|Helicobacter pylori ||Microaerophilic ||+ ||Human, gastric secretions ||OMPsd ||Urease,e VacA,f Cagg ||Chronic gastritis, ulcers, adenocarcinoma, lymphoma |