- Concentrated culture supernatants from strains of Vibrio
parahaemolyticus of gastroenteric origin, "suspected" V. parahaemolyticus
isolated from cases of skin infection, nonpathogenic marine
Vibrio, V. anguillarum and V. alginolyticus, were submitted to flat
gel electrophoresis, followed by the examination of the polyacrylamide
gels for total protein and enzyme patterns.
Variations related to the presence of single and multimolecular
forms of proteolytic enzymes, lipases, esterases, phosphatases,
amylases and deoxyribonucleases, permitted a differentiation among
the cultures being examined. A close similarity was observed between
the pathogenic cultures isolated from skin infections and the V.
parahaemolyticus strains of gastroenteric origin. This group was
well differentiated from the nonpathogenic Vibrio, V. anguillarum and
V. alginolyticus, but under the conditions of the experiment these last
three groups could not be easily differentiated. The tests involving
the detection of DNase, amylase, egg yolk lipase (mainly related to
time and intensity of reaction) appeared to be the most useful for the
characterization of V. parahaemolyticus and these results suggested
that the application of gel electrophoresis of culture supernatants,
might be of importance in the rapid identification of this bacterium.
No evidence was found indicating the presence of the hemolytic factor
responsible for the "Kanagawa phenomenon".
Another purpose of the present study was the determination of
the heat resistance of V. parahaemolyticus, the strain ATCC 17802
being used as a test organism. The flask method was employed and
peptone salt water, pH 7.2 was the suspending menstruum. Decimal
reduction time (D value) was the parameter used to express the heat
resistance, with values of 38.2, 2.01, and 0.51 min being observed at
the temperatures of 113°, 118.4°, and 122°F, respectively.
A study to determine the influence of the composition of the recovery
medium on the apparent heat resistance, showed that higher
counts and survival rates were observed when Vibrio Maintenance
Medium was employed for counting the heated cells, with a statistically
significant difference (at five percent level) being observed when
compared with Brain Heart Infusion Agar plus 2.5 percent NaCl and
Trypticase Soy Agar plus 2.5 percent NaCI, without a significant difference
between the last two media.