It looks like a cute Easter cake topping.... but it's the genius work of our colleagues in the lab.

These greetings are made purely of.... bacteria. We asked consultant microbiologist Gavin Boyd to explain the science behind their creations.

How are they made?

They are agar pictures painted using bacteria! On the chromogenic agar plate different bacteria grow in different colours, e.g. E coli is pink and Klebsiella is blue.

How do you know the bacteria will turn a different colour?

Different bacteria produce different enzymes that interact with chemicals in the agar to cause the bacteria to grow in different colours. This is to help the scientists identify what bacteria are growing from clinical samples, e.g. urine and pus.

How long does it take for the colours to form?

We incubate the cultures overnight, so 24 hours.

The team are running an Easter competition and the three most creative entries win an egg.