Superbug Genome Sequenced

The genome of the deadly superbug that claims one in three of its victims has been sequenced by scientists at the Wellcome Trust Sanger Institute near Cambridge and University of Bristol.

The scientists said that the newly emerging superbug, commonly known as Steno, reveals a remarkable capacity for drug resistance.

They said that understanding the genome of this bacterium would help researchers discover how to deal with this particularly resistant organism.

"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 no new drugs capable of combating these 'pan-resistant' strains are currently in development," said Dr Matthew Avison from the University of Bristol, and senior author on the paper.

Pan-resistant Steno infections are equally hard to treat as MRSA and C.diff infections. Despite being common in the environment, Steno infections are rarer than MRSA and C.diff infections and are exclusively hospital-acquired.

Steno flourishes in moist environments, such as around taps and shower heads, and can be transferred to patients, causing infection. They can distinctly be transferred into the body via devices such as catheters or ventilation tubes that are left in place for long periods of time, which are used for seriously ill patients and those undergoing chemotherapy.

Steno can stick to the catheter and grow into a 'biofilm', which can enter the patient's bloodstream when it is next washed. And in patients with a weak immune system, the organism can multiply and cause septicaemia.

The condition is severe as the new research has highlighted that these patients will be treated with antibiotics against which Steno is largely resistant.

There are almost 1,000 reports of Stenotrophomonas maltophilia (Steno) blood poisoning in the UK each year, with a mortality rate of about 30 percent. 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 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," said Dr Lisa Crossman from the Sanger Institute and first author on the paper.

Though relatively uncommon, Steno infections are on the increase. Also, there are two other organisms that cause similar types of infections, but are more common.

"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," added Dr Avison.

The paper will be published in Genome Biology.

Source-ANI
RAS/L