Geothermal locations at the Icelandic coast as a habitat for Vibrio cholerae. Eva Benediktsdóttir and Herdís E. Hermundardóttir

Transcription

1 Geothermal locations at the Icelandic coast as a habitat for Vibrio cholerae Eva Benediktsdóttir and Herdís E. Hermundardóttir 1

2 Overview V. cholerae strains in Iceland diversity and virulence factors Environmental conditions Geothermal locations Reservoirs and dispersion Preliminary results 2

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5 V. cholerae was isolated at geothermally influenced sites only. Natural hot springs and warm water outlets. Not all such sites were positive. 5

6 Comparison using Pulse Field Gel Electrophoresis* The diversity of strains indicates that the V. cholerae is naturally occurring Identical clones were isolated at different places and occations, indicating circulation of V. cholerae strains around the coast of the island *Haley et al

7 165 Stykkishólmur, macroalgae, des Berserkseyri, water, des Ægissíða, mussel, jan Ægissíða, mussel, feb Ægissíða, water, feb 07 C31 Skarðshver, macroalgae, okt 08 C6 Ægissíða, mussel, okt 08 Comparison of strains using Biolog PM2A* shows diversity of strains *Haley et al

8 Virulence genes of 127 strains* 01/ chxa 58 VSP II 50 ctxa 0 toxr 127 ICE 114 ctxb 0 hlya 127 luxo 127 ace 0 rtxa 127 zot 0 nanh 124 tcpa 0 HA/P 127 nag ST 0 ompu 127 VSP I (TCP) 0 *Haley et al 2012 The Icelandic strains are nono1/nono139 environmental V. cholerae. Many virulence factors found, that have possible ecological function rather than pathogenic function. 8

9 Environmental conditions 9

10 Sea temperature at the coast, 2011 South west West North North Currents 10

11 The low temperature area is in the Northern and Western part of the country. Geothermally active sites at the shore, that come up in low tide and are covered at high tide, and with water temperature above 30 C. 11

12 Small isolated spots V. cholerae multiplies in isolated geothermally influenced spots in the foreshore The flow from each spring or outlet is just a few l/sec Temperatures C The niches are surrounded by sea water that is colder than the growth temperature The length of the time below the growth limits are different depending on the volume and temperature of the spring (outlet) water Cold seawater is overlayed with the warm freshwater 28 C vs 4 C at the same spot Mixing occurs at different rates depending on the tidal changes and weather conditions At high tide the warm water has small or negligible influence on the sea water temperature around 12

13 Reservoirs and dissemination Which are the reservoirs of the vegetative V. cholerae? (pelagic), bentic, shore fauna or flora Dissemination between sites How far from the springs are vegetative V. cholerae cells found? VNBC cells? Methods: Sample and cultivate from the flora and fauna Comparison of different places Four places chosen 13

14 Ægissíða, Reykjavík, SW Iceland An overflow outlet from the heating utility in Reykjavík, situated 65 m below tidemark (at high tide) 3 5 l/sec 32 C fresh water Rich in macroalgae and Enteromorpha is seen around outlet during summer 14

15 Berserkseyri, West coast A natural hot spring ca 1 m above the tidemark at high tide Fresh water runs into the intertidal zone 78 C, a few l/sec Lava with macroalgae and sand in the intertidal zone Rural area 15

16 Skarðshver, Vatnsnes, Northern Iceland A natural hot spring, C, fresh water Rocks, gravel Macroalgae, Enteromorpha and thermophilic archaea 16

17 At Reykjanes power station, SW Iceland Underground sea water, warmed to 60 C, 4000 l/sec High temperature area Pipes above sea level even at high tide Sea temperature is affected also at high tide Large rocks and lava Poor vegetation Strong heavy waves 17

18 Methods 1 L sea water, filtered through filter of 2 µm pore size Macroorganisms and sediment: Washed with sterile NaPBS solution 18

19 Methods CULTIVATION Enrichment in APW + 1% NaCl TCBS PCR PCR Biochemical tests Chromagar 19

20 Seawater, sampling days Reykjavík, SW, 10/10 positive 1 km away, 1/5 positive West coast, 3 times, 3/3 positive 2 km away, 2/2 positive North coast, 4/4 positive 4,8 km away, 1/1 positive 10 km, one sample negative Reykjanes power station, 4 times, all sampes have been negative for V. cholerae (tlh gene of V. parahaemolyticus positive) 20

21 Macroalgae Flora Postive samples at the three sites with positive water samples, negative at the Reykjanes power plant At the Reykjavík sampling station, kelp samples above the outlet were negative, but positive below the outlet 21

22 Fauna Sediment (chironomid larvae, harpecoids etc) positive at the three sites Amphipods sampled in North coast (pos) and Reykjavík Rough periwinkle sampled in Reykjanes (neg) and Reykjavík (pos) Mussels sampled in Reykjavík (pos) and North coast (pos) Burrowing lugworm sampled only in Reykjavík (January, 2.4 C) 22

23 West des.06 ág 2011 feb.12 Power plant des.10 May 2011 sep.11 april 2012 North oct 2008 Aug 2011 Nov 2011 Reykjavík, SW feb.07 sep.08 sep.10 oct 2010 jan.11 feb.11 sep.11 nov 2011 march 2012 Sampled, positive Water Water, Kelp, sediment Water, kelp, sediment Water, kelp Water, kelp, periwinkle Water, kelp, periwinkle Water Water, kelp Water, kelp, amphipods, periwincle Water, kelp, sediment Water, mussel, kelp Water, mussel, kelp Water, amphipods, barnacles, kelp Kelp Water, sediment, burrowing lugworm, kelp Water, sediment, kelp, butterfish, lugworm Water, sediment, kelp, cancer, bivalve Water, sediment, kelp Water, sediment, kelp Samples negative for V. cholerae in black Samples positive for V. cholerae in red Blue fill: samples taken in winter 23

24 Discussion Reservoir Macroalgae, sediment (harpecoids, larvae...)? Methods? Dissemination Vegetative cells: 1 <10 kilometers? VBNC cells travelling with the coast current Comparisons of more strains 24

25 Thanks 25