M A R I E E N G L I S H U N C I N S T I T U T E O F M A R I N E S C I E N C E S M E N T O R S : D R . R A C H E L T . N O B L E A N D

D R . B R E T T F R O E L I C H

VIBRIO ABUNDANCE IN TIDAL CREEKS: SEDIMENT/WATER DYNAMICS

THE GENUS VIBRIO

•  Native to estuaries (Nearly 35% of coastal bacterial pop.) •  Facultative anaerobes •  Pathogenic spp. •  Vibrio cholerae, Vibrio vulnificus, Vibrio parahaemolyticus •  V. vulnificus is most important seafood-borne pathogen in the USA

•  Can cause wound infections, septicemia, gastroenteritis •  Recent research shows climate change is leading to an

increased # of vibrio cases (Oliver, DUML seminar)

•  Ecology •  Influenced mainly by salinity and temperature •  Halophilic •  Predictive models for vibrio sp. concentrations based on salinity and

temp are 70-75% accurate (Hsieh et al., 2007)

SALINITY/TEMP RANGE FOR PATHOGENIC VIBRIO SP.

•  Optimal salinity range •  5-25 ppt •  Very low and very high salinities appear to be detrimental to

growth and persistence (Noble, 2008)

•  Optimal water temp. range •  20-30 ⁰C is where the highest concentrations are seen •  Below 20  ⁰C = low density of vibrio •  Below 10  ⁰C = no vibrio in water column

Parameter Range Mean and S.D.

Salinity (ppt) 15.00 - 32.00 26.05 ± 5.875

Temperature (⁰C) 15.41 - 30.32 22.67 ± 4.316

“The Biology of Vibrios”

STUDY SITES

INDIVIDUAL SITES

9/27

Site 1 Site 2

Site 4 Site 3

PART OF THE LOCAL COMMUNITY

Locals fish for shrimp, flounder, and mullet

CALICO CREEK SAMPLING

CALICO CREEK SAMPLING

PROCESSING

TOTAL VIBRIO ENUMERATION

10/5

CFU= colony forming units

CHROM AGAR

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10/5

Purple colonies= V. parahaemolyticus Blue colonies= V. vulnificus

WHAT CAUSES THE DECLINE IN VIBRIO ABUNDANCE IN THE WATER COLUMN?

WHAT CAUSES THE DECLINE IN VIBRIO ABUNDANCE IN THE WATER COLUMN?

BACTERIA IN THE WATER COLUMN DECREASE WHEN CONDITIONS ARE STRESSFUL

Low temperatures = Stressful for bacteria

POST-HURRICANE SANDY = COOLER WATER TEMPS

11/1

1 2 3 4 Sed. (1:10) Water (1:10) Water (1:1)

BACTERIA IN THE WATER COLUMN DECREASE WHEN CONDITIONS ARE STRESSFUL

High salinities = stressful for bacteria

VIBRIO SP. ABUNDANCE IS HIGHER IN SEDIMENTS

SEDIMENT > WATER

9/27

2S 1S 2W 1W

4S 3S 4W 3W

ARE SEDIMENT ABUNDANCES AFFECTED BY STRESSFUL CONDITIONS?

SEDIMENT PROTECTION

SEDIMENT PROTECTION

ARE SEDIMENT ABUNDANCES AFFECTED BY STRESSFUL CONDITIONS?

IS THIS UNIQUE TO VIBRIO, AN AUTOCHTHONOUS BACTERIA?

IS THIS UNIQUE TO VIBRIO, AN AUTOCHTHONOUS BACTERIA?

FUTURE STUDIES •  Continue study in colder months using qPCR to

compare with cultured methods for signs of overwintering (VBNC cells) •  Must use molecular methods below 15  ⁰C because the cells

enter a state where they are no longer culturable

•  Organic matter content of sediments and correlation with pathogenic Vibrio •  Grain size analysis of sediments and correlation with

pathogenic Vibrio

CONCLUSIONS

1.  In harsh conditions, Vibrio decrease in the water column. 2.  Bacteria are found in higher concentrations in the sediments 3.  Vibrio in the sediments are somewhat protected from salinity

and temperature changes in water column 4.  The sediments provide protection for endogenous bacteria,

but the same pattern was not seen for exogenous (the control).

ACKNOWLEDGEMENTS

Rachel Noble Brett Froelich Sarah Rhodes

Sydney Brothers Denene Blackwood

Monica Greene Raul Gonzalez

Mark Vergougstraete Rodney Guajardo

Sara Posey

BIBLIOGRAPHY

•  DUML Seminar with Dr. Jim Oliver: "Vibrio vulnificus: Death on the Half-Shell” Wednesday, August 29, 201212:30pm, LSRC A328 & Marine Lab: Repass Center

•  Thompson, Fabiano Lopes, Brian Austin, and J. G. Swings. "12: Aquatic Environment." The Biology of Vibrios. Washington, D.C.: ASM, 2006. 176. Print.

•  Hsieh, Jennifer L., J. Stephen Fries, and Rachel T. Noble. "Dynamics and Predictive Modelling of Vibrio Spp. in the Neuse River Estuary, North Carolina, USA." Environmental Microbiology 0.0 (2007): 070907020408001-??? Print.