Vagococcus fluvialis
Classification
Bacteria; Bacillota; Bacilli; Lactobacillales; Enterococcacae
Species
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NCBI: [1] |
Vagococcus fluvialis
Description and Significance
Vagococcus fluvialis is a species of lactic acid bacteria that is a gram-positive, catalase-negative cocci that is closely related to the genera Enterococcus and Carnobacterium (1). V. fluvialis is commonly found in aquatic environments like rivers and seawater (2). It is believed to be probiotic in fish, however in mammals it is frequently related to infectious tissue (4).
Genome Structure
The genome size ranges from 2.65 to 3.16 Mb, with roughly 2801 protein-coding genes and 104 RNA genes (4). V. fluvialis has one single circular chromosome that contains several plasmids and insertion sequences. The genome is dynamic and adaptable to allow for various environments (5). Some strains that were isolated from marine sponges had a high number of mobile genetic elements, which is believed to play part in their adaptability and symbiotic relationships (4).
Cell Structure, Metabolism and Life Cycle
V. fluvialis is a gram-positive, catalase-negative bacterium typically arranged in pairs or chains and some strains have flagella (6). This microorganism is a facultative anaerobe that obtains energy by oxidizing organic compounds. It also ferments various sugars, producing lactic acid as a major end product. One interesting fact about this microbe is that it has a unique lipid pattern with a high concentration of d-alanylcardiolipin, which is unusual for bacteria (4). V. fluvialis strains produce two major molecules: lactic acid and exopolysaccharides, some even produce probiotic properties.
V. fluvialis can be found in various sources, this includes river water, chicken feces, and urine of healthy cattle. It is usually cultured on blood agar plates and form white/gray colonies with partial a-hemolysis. Optimal growth is between 10C and 40C. Like other bacteria, V. fluvialis reproduces asexually through binary fission.
Ecology and Pathogenesis
Vagococcus fluvialis can be found primarily in rivers and seawater, either free-living or within an aquatic organism host. Specific water sources containing this bacteria have not been described in detail. Although V. fluvialis can cause infection within marine life, it is also believed that it may serve as a probiotic agent against infection from other pathogens such as Vibrio anguillarum in fish (4). 20 years after it was first discovered in aquatic environments, it began to be isolated from lesions in mammals such as pigs, horses, cats, and cattle (2). It was later isolated from human hosts, most commonly in blood, peritoneal fluid, wounds, and occasionally urine (7).
V. fluvialis is typically isolated from environmental samples such as river water, but has also been isolated from human and animal infectious tissues on occasion. This microbe is often found in the urine of healthy cattle, so it is not pathogenic in all cases. The genome does not encode for any virulence genes, which may indicate its potential as a commensal organism rather than a pathogenic organism (1). One particular case in 2024 described the first instance of V. fluvialis found in the urine of a patient in Japan, who worked as a zoo keeper. This case study demonstrated the potential of V. fluvialis to be a zoonotic organism (7). V. fluvialis and other Vagococcus species have been found to be most susceptible to antibiotics such as ampicillin, trimethoprim/sulfamethoxazole, vancomycin, teicoplanin and linezolid (8).
References
Author
Page authored by Haleigh Elkins, Bri Collins, and Abby Ziegler, students of Prof. Bradley Tolar at UNC Wilmington.
