Definition
Vibrio fluvialis is a Gram‑negative, facultatively anaerobic, curved rod‑shaped bacterium belonging to the family Vibrionaceae. It is recognized as a potential human pathogen that can cause gastrointestinal illness, particularly watery diarrhea.
Overview
Vibrio fluvialis is commonly isolated from brackish water, marine environments, and seafood such as raw fish and shellfish. The organism is halophilic, requiring moderate concentrations of sodium chloride for optimal growth, and it thrives at alkaline pH (typically pH 7.5–9.0) and temperatures ranging from 20 °C to 37 °C. Clinical reports associate the bacterium with sporadic cases of acute gastroenteritis, often following the consumption of contaminated water or food. In addition to diarrheal disease, V. fluvialis has been implicated, though less frequently, in extra‑intestinal infections such as wound infections and septicemia, particularly in immunocompromised individuals.
Etymology/Origin
The genus name Vibrio derives from the Latin vibrare, meaning “to vibrate,” referencing the organism’s characteristic motility. The species epithet fluvialis is Latin for “of a river,” reflecting the bacterium’s frequent isolation from riverine and estuarine waters. The species was first described in the late 1970s, initially classified within the genus Aeromonas as Aeromonas fluvialis and later reclassified into the genus Vibrio based on phenotypic and genetic analyses.
Characteristics
| Feature | Description |
|---|---|
| Morphology | Curved, comma‑shaped rods; typically 0.5–0.8 µm wide and 1.5–3.0 µm long; possesses a single polar flagellum providing motility. |
| Gram stain | Negative. |
| Oxygen requirement | Facultatively anaerobic; grows under both aerobic and anaerobic conditions. |
| Oxidase | Positive. |
| Catalase | Positive. |
| Growth conditions | Requires NaCl (0.5–3 %); optimal growth at 30–37 °C; alkaline pH (7.5–9.0). |
| Metabolism | Ferments glucose without gas production; can utilize a range of carbohydrates. |
| Virulence factors | Produces hemolysin, cytotoxin, and enterotoxin-like proteins; possesses genes associated with adhesion and biofilm formation. |
| Antibiotic susceptibility | Generally susceptible to tetracyclines, fluoroquinolones, and third‑generation cephalosporins; resistance to ampicillin and some sulfonamides has been reported. |
| Genomic features | Genome size ~4.3 Mb; contains plasmids encoding additional toxin and resistance determinants in some strains. |
Related Topics
- Vibrio cholerae – The etiologic agent of cholera; shares ecological niches and some pathogenic mechanisms with V. fluvialis.
- Vibrio parahaemolyticus – Another marine Vibrio species causing seafood‑borne gastroenteritis.
- Water‑borne diseases – Infections transmitted via contaminated water, encompassing a range of bacterial, viral, and parasitic pathogens.
- Food safety (seafood) – Practices aimed at preventing contamination of fish, shellfish, and other marine products by pathogenic microbes.
- Enteric bacterial pathogens – Group of bacteria that colonize the gastrointestinal tract and cause diarrheal disease, including Escherichia coli, Shigella, and Salmonella species.