New superbug threat to hospitals

Doctors studying the genetic code of the bug, commonly known as Steno, are worried about its ability to shrug off antibiotics.

Around 1,000 cases of blood poisoning caused by Stenotrophomonas maltophilia are reported in the UK each year. Of these, almost a third are fatal.

Although Steno infections are still relatively uncommon, they are on the increase, say experts. Highly resistant strains of the bug are at least as hard to treat as MRSA and Clostridium difficile (C.diff). The bacterium flourishes in moist environments such as around taps and shower heads.

It has a distinct method of infecting patients, via devices such as catheters or ventilation tubes that have been left in place for long periods of time. Steno can stick to a catheter or ventilator tube and grow into a "biofilm" coating which is difficult to remove by normal cleaning.

From this vantage point it is able to enter a patient's bloodstream or lungs. In weakened patients, the result may be septicaemia - blood poisoning - or pneumonia.

A complete blueprint of the genetic code sequence, or genome, of Steno appears in the journal Genome Biology.

Dr Matthew Avison, from the University of Bristol, who co-led the research team, said: "This is the latest in an ever-increasing list of antibiotic-resistant hospital superbugs. The degree of resistance it shows is very worrying. Strains are now emerging that are resistant to all available antibiotics, and so new drugs capable of combating these pan-resistant strains are currently in development."

Doctors are keen to know how Steno sticks to surfaces like catheters and ventilators, how it forms biofilms, and why it is so resistant.

Dr Lisa Crossman, from the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, who also took part in the research, said: "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."