Vibrio vulnificus is a human pathogen commonly found in coastal and estuarine
waters in temperate and subtropical regions across the world. The ecology of V.
vulnificus has been studied in these regions primarily using cultured-based methods for
enumeration of V. vulnificus from the environment. Optimal temperature and salinity
ranges have been established, but relationships with other environmental parameters
have not been studied as extensively. The primary objective of this study was to better
understand the ecology of V. vulnificus and how environmental parameters found in
south Texas bays and estuaries regulate its distribution.
A recently developed molecular biological technique for the direct enumeration
of V. vulnificus from estuarine water column samples was used to test three hypotheses:
1) V. vulnificus makes up a greater percentage of the total bacterial population in the
water column under low oxygen conditions; 2) Powderhorn Lake serves as a pointsource
for V. vulnificus in Matagorda Bay; 3) Higher V. vulnificus concentrations are
found in the water column when oyster reefs are present. These hypotheses were formed
to improve predictive models, identify potential hot-spots for V. vulnificus in the water
column, and to better inform stakeholders as to when and where risk of infection might
be greatest.
Dissolved oxygen was rarely low enough in the environment to stress aerobic
bacteria in the water column, so the first hypothesis could not be appropriately tested.
Neither higher concentrations nor detection frequencies of V. vulnificus were found in
Powderhorn Lake compared to the rest of the bay, so Powderhorn Lake was not
identified as a point-source for V. vulnificus. Higher concentrations and detection
frequencies of V. vulnificus were not found at sites with oyster beds, so oyster beds cannot be used as indicators of higher concentrations of V. vulnificus in the water
column.
Interestingly, patchiness of V. vulnificus was observed temporally and spatially
throughout the sampling region of Matagorda Bay, on a scale that has not been
frequently examined. Variation occurred between samples in close proximity to one
another, as well as between sampling dates. This distribution exhibited a small scale
patchiness not frequently reported in past studies.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1587 |
| Date | 15 May 2009 |
| Creators | Meyer, Shelli Lee |
| Contributors | Long, Richard A., Thornton, Dan C.O. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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