Dynamics of Vibrio spp. in rela1on to phytoplankton community composi1on and environmental condi1ons

Transkript

1 Dynamics of Vibrio spp. in rela1on to phytoplankton community composi1on and environmental condi1ons Rehnstam- Holm Ann- Sofi, Collin BeAy and Godhe Anna

2 The Vibrio situa1on in Sweden Few human infec1ons, but some severe. Warm summers means more Vibrio cases. A trend towards more domes1c cases. Infec1ons due to V. cholerae non O1/O139 and V. vulnificus are more common in the south east of the Bal1c Sea and infec1ons due to V. alginoly4cus and V. parahaemoly4cus are more common at the west coast.

3 Vibrio cholerae in Blekinge Three cases of V. cholerae infections during July 2006, one fatal. Eight domestic cases in summer 2010, one fatal. V. cholerae (red) positive water samples during the summer 2006 (Skåne Smittskydd nr ). Figur 2.

4 Vibrio in mussels collected in the Sound 2006, determined by direct PCR V. cholerae V. vulnificus V. parahaemolyticus ctx toxr negativ vvh/viub negativ tlh/tdh/ trh tlh negativ RESEARCH ARTICLE Occurrence and potential pathogenesis of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulni cus on the South Coast of Sweden Betty Collin 1,2 & Ann-Sofi Rehnstam-Holm 1,2 1 Department of Clinical Microbiology, Institute of Biomedicin, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden and 2 Department of Biomedicine, Kristianstad University, Kristianstad, Sweden

5 The Sea is blooming!

6 The Vibrio phytoplankton connec1on

7 74 46 M angalor e p ort INDIA S am pling area Mangalore 1km Fig. 1 Mesocosm and field experiments in India Asplund ME, Rehnstam- Holm A- S., Vidjay, A., Raghunath PR, Saravanan V, Härnström K, Collin B, Karunasagar I, Godhe A. (2011). Water column dynamics of Vibrio in rela1on to phytoplankton community composi1on and environmental condi1ons in a tropical coastal area. Environ. Microbiol. 13(10):

8 We measured abio1c and bio1c factors in a mesocosm study and in the coastal water and compared them with total Vibrio and algal species

9 CCA biplot Chaetoseros simplex Coscinodiscus consinnus Mesocosm data

10 Field data

11 The most important factors contributing to Vibrio genus abundance were diatom abundance and chlorofyll a

12 In the next study we measured abio1c and bio1c factors in the coastal water and compared them with total Vibrio and V. parahaemoly4cus (analyzed by Real1me- qpcr) just before and ader the monsun (December and February- March).

13 Vibrio abundances before and ader the monsun Vibrio spp. V. paraheamolyticus cells L ND NQ NQ December February-March

14 V. parahaemolyticus correlates with phosphate and zooplankton abundance (A) Defining the niche of Vibrio parahaemoly.cus in coastal Arabian Sea, Rehnstam- Holm, A.- S., Atnur, V., Godhe, A. Model coefficient (V. paraheamolyticus) Model coefficient (Vibrio spp.) PO 4 Copepods Total bacteria Diatom biovolume Phaeopigments Vibrio spp. DOC Temperature NH 4 Secchi depth Chlorophyll a Tide SiO 2 NO 3 Salinity Dinoflag:Diatoms HNF ph Temperature Chlorophyll a Total bacteria Diatom biovolume Phaeopigments Copepods O 2 A O 2 B Tide Dinoflag:Diatoms DOC Salinity SiO 2 DN PO 4 ph HNF NO 3 NH4 Secchi depth Fig. 3 A-B

15 Water temperature and salinity was constant both within and between the measured periods. V. parahaemoly4cus on average six 1mes higher in December. V. parahaemoly4cus abundance correlated strongly to PO 4 and copepods

16 Effect of phytoplankton taxa, biomass, diversity, and temperature on the growth of Vibrio parahaemoly.cus

17 Phytoplankton excrete/leak dissolved organic carbon compounds (DOC). DOC is important for heterotrophic bacteria, including poten1al pathogens as Vibrio spp.

18 V. parahaemoly4cus was added to single algal cultures, or mixtures of two or three algal species cultures. The dinoflagellate Prorocentrum micans and the diatoms Skeletonema tropicum, Ditylium brightwelli och Thalassiosira pseudonana were used.

19 A 15 C 21 C D.brightwelli Low biomass High Biomass P. micans Low biomass High Biomass A B C A B C A B C A B C A B C A B C A B C A B C B Species richness 1 D D D S S S T T T 2 Experimentuppställning S S S T D D D D T D T D S T S T S T 3 S DT S DT S DT

20 Results The bacterial growth rate was significantly higher in the D. brightwelli culture The growth rate of V. parahaemoly4cus was nega1vely affected by higher algal biomass No temperature effect. Effect of phytoplankton taxa, biomass, diversity, and temperature on the growth of Vibrio parahaemoly.cus, Ann- Sofi Rehnstam- Holm, Olof Petersson, Anna Godhe.

21 2.0 A 1.0 Maximum growth rate (µ) per day B D. brightwelii P. micans LOW HIGH

22 Higher species richness promote Vibrio growth A CFU ml -1 A A A CFU ml S. tropicum T. pseudonana D. brightwelii A A A B S+T S+D D+T Species Combination B B C CFU ml -1 A Species Richness Level Fig. 3 A-C

23 Conclusions Phytoplankton are the most important factor that promote Vibrio growth in a tropical area with stable salinity and temperatures. However, specific Vibrio species might show a different paaern. Specific phytoplankton species might influnece the Vibrio abundances (nega1ve or posi1ve) The phytoplankton species richness will effect Vibrio abundances.