Prevalence of urease in Vibrio parahaemolyticus from the Mississippi Sound.
Vibrio parahaemolyticus is a pathogenic marine bacterium that causes food-borne gastroenteritis and, less commonly, wound infections. As is the case for many pathogens, all V. parahaemolyticus strains possess at least one erythrocyte-lysing haemolysin. In addition, many V. parahaemolyticus also possess the enzyme urease. We tested 206 environmental V. parahaemolyticus isolates from Mississippi coastal waters for urease and haemolytic activity using urea agar with added salt and Wagatsuma agar, respectively. The relative abundance of haemolysin-producing V. parahaemolyticus was consistently high throughout the sampling period. In contrast, the number of urease-positive organisms increased from 36% in 2006 to 80% in 2007 and 97% in 2009. We then tested the ability of four strains representing each of the three sample years along with seven other bacterial strains for their ability to grow in seawater urea and raise the pH of this seawater broth. Finally, one of the 4 strains was tested for its ability to form an alkaline microhabitat immediately above its biofilm.


CONCLUSIONS
The results of this study illustrate that V. parahaemolyticus has the ability to create alkaline microhabitats that could enhance virulence, including virulence from haemolysins. This finding could have both clinical and ecological impact as to how V. parahaemolyticus can modify its habitat.
Gulf Coast Research Laboratory, The University of Southern Mississippi, Ocean Springs, MS, USA.
T R
TR
Berutti
R E
RE
Williams
S
S
Shen
M M
MM
Taylor
D J
DJ
Grimes
D001426:Bacterial Proteins / Q000096:biosynthesis*; D017753:Ecosystem; D006461:Hemolysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008922:Mississippi; D012623:Seawater / Q000737:chemistry / Q000382:microbiology; D014510:Urease / Q000096:biosynthesis*; D014736:Vibrio parahaemolyticus / Q000201:enzymology*; D014871:Water Microbiology
D001426:Bacterial Proteins; D014510:Urease
Kanagawa; Vibrio; biofilms; microhabitats; pH; urease; virulence; vulnificus