Superbug genome sequenced

Steno can stick to the catheter and grow into a ‘biofilm’. When the catheter is next flushed, the Steno biofilm can enter the patient’s bloodstream. If their immune system is impaired (which is often the case in the seriously ill and those undergoing chemotherapy) the organism can multiply and cause septicaemia. The gravity of this situation has been underlined by the new research, since these patients will be treated with antibiotics against which Steno is largely resistant.

There are approximately 1,000 reports of Stenotrophomonas maltophilia (Steno) blood poisoning in the UK each year, with a mortality rate of about 30%. The organism is also found in the lungs of many adults with cystic fibrosis, and causes ventilator-associated pneumonias, particularly in elderly intensive-care patients.

The key questions that need to be addressed are: How does Steno stick to surfaces like catheters and ventilator tubes" How does it form biofilms and so survive attempts to decontaminate and clean" Why is it resistant to antibiotics"

Dr Lisa Crossman from the Sanger Institute and first author on the paper explained how the research might address these questions: “The genome sequence should help us to combat these properties. For example, if we know which proteins cause it to stick to surfaces, we could try to develop biochemical compounds that interfere with this interaction. If we understand its antibiotic resistance mechanisms, we might be able to design inhibitors that block them.”

While Steno infections are still relatively uncommon, they are on the increase. Furthermore, there are two other organisms that cause similar types of infections, but are more common.

Dr Avison added: “Genome sequences for these two also exist, and so now we can look at what they all have in common genetically that might explain why they are so resistant to antibioitics.”