Microscopic life in marine tank and the German outbreak of EHEC E. coli

I spent the evening at the microscope, studying both the PMS box ready for despatch and a sample of the debris at the bottom of the marine tank.

The tank sample was buzzing with activity with a range of organisms from different groups represented.

• Crustaceans – very small but several present in a drop of water
• Nematodes – at least one species
• ciliates – several species, the most abundant being an ovoid motile version that possibly contained photosynthetic material
• Amoebae – both monopod and multiple pseudopodia varieties seen
• Blue green algae – abundant
• Diatoms – both elongated rhomboids and chained versions
• Filamentous bacteria

I attempted to video the samples using a variety of lighting systems, darkfield being best for amoeba detail and phase contrast good for the abundant oval ciliates. The recordings need to be uploaded and checked.

News from Germany via family is, that people are very concerned about an E. coli outbreak, referred to as EHEC in German, from “enterohaemorrhagic E. coli”. It is a strain that has a high infectivity, with as few as 100 bacteria sufficing, and produces shiga like toxin which causes severe diarrhoea and can be fatal. It appears to be similar to the E.coli known as O157:H7, which has caused outbreaks in the UK, for example in 2009. The German strain is O104 according to the Hamburg Health Ministry.

The bacteria are spread via fecal contamination, usually of meat. However, the German outbreak has been attributed to contaminated organic cucumbers originating from Spain, Malaga and Almeira. Shiga and shigla like toxins are genes carried by prophages (viruses of bacteria that integrate into the host). They act like the toxin ricin by inhibiting protein synthesis.

As of 2am Tuesday 31st May, the most recent UK Food Standards Agency news item is from 27th May and states that there is currently no evidence that cucumbers have come into the UK from those companies that supplied infected cucumbers to German.

Relevant articles can be found here:

• http://www.hpa.org.uk/NewsCentre/NationalPressReleases/2011PressReleases/110527GermanEcoliupdate/
• http://www.hs.fi/english/article/Food+Safety+Authority+Spanish+cucumbers+infected+with+EHEC+have+not+been+imported+into+Finland/1135266532095
• http://www.bild.de/news/inland/ehec/identifiziert-18094752.bild.html
• http://en.wikipedia.org/wiki/Shiga_toxin