Bad Bug Book:
Foodborne Pathogenic Microorganisms and Natural Toxins Handbook
Vibrio cholerae Serogroup Non-O1
Vibrio cholerae Serogroup Non-O1
This bacterium infects only humans and other primates. It is related to V. cholerae Serogroup O1, the organism that causes Asiatic or epidemic cholera, but causes a disease reported to be less severe than cholera. Both pathogenic and nonpathogenic strains of the organism are normal inhabitants of marine and estuarine environments of the United States. This organism has been referred to as non-cholera vibrio (NCV) and nonagglutinable vibrio (NAG) in the past, although at least 139 "O" serogroups have been identified. (Note: for V. cholerae O139, see Chapter 7).
Non-Ol V. cholerae gastroenteritis is the name associated with this illness. Although rare, septicemic infections have been reported and deaths have resulted. Some cases are similar to the primary septicemia caused by V. vulnficus.
Diarrhea, abdominal cramps, and fever are the predominant symptoms associated with this illness, with vomiting and nausea occurring in approximately 25% of infected individuals. Approximately 25% of infected individuals will have blood and mucus in their stools. Diarrhea may, in some cases, be quite severe, lasting 6-7 days. Diarrhea will usually occur within 48 hours following ingestion of the organism. It is unknown how the organism causes the illness, although an enterotoxin is suspected as well as an invasive mechanism. Disease is caused when the organism attaches itself to the small intestine of infected individuals and perhaps subsequently invades.
Disease caused by V. cholerae O139 is indistinguishable from cholera caused by V. cholerae O1. See chapter 7.
Infective dose - It is suspected that large numbers (more than one million) of the organism must be ingested to cause illness.
Diagnosis of a V. cholerae non-Ol infection is made by culturing the organism from an individual's diarrheic stool or from the blood of patients with septicemia.
Shellfish harvested from U.S. coastal waters frequently contain V. cholerae serogroup non-Ol. Consumption of raw, improperly cooked or cooked, re-contaminated shellfish may lead to infection.
No major outbreaks of diarrhea have been attributed to this organism. Sporadic cases occur frequently mainly along the coasts of the U.S., and are usually associated with the consumption of raw oysters during the warmer months.
Diarrhea resulting from ingestion of the organism usually lasts 7 days and is self-limiting. Antibiotics such as tetracycline shorten the severity and duration of the illness. Septicemia (bacteria gaining entry into the blood stream and multiplying therein) can occur. This complication is associated with individuals with cirrhosis of the liver, or who are immunosuppressed, but this is relatively rare. FDA has warned individuals with liver disease to refrain from consuming raw or improperly cooked shellfish.
All individuals who consume raw shellfish are susceptible to diarrhea caused by this organism. Cirrhotic or immunosuppressed individuals may develop severe complications such as septicemia.
Methods used to isolate this organism from foods are similar to those used with diarrheic stools. Because many food isolates are nonpathogenic, pathogenicity of all food isolates must be demonstrated. All virulence mechanisms of this group have not been elucidated; therefore, pathogenicity testing must be performed in suitable animal models.
For more information on recent outbreaks see the Morbidity and Mortality Weekly Reports from CDC.
Literature references can be found at the links below.
Loci index for genome Vibrio cholerae
Available from the GenBank Taxonomy database, which contains the names of all organisms that are represented in the genetic databases with at least one nucleotide or protein sequence.