Steno 'Superbug' Genome Shows Extreme Drug Resistance

ByABC News
May 9, 2008, 9:22 AM

May 12 -- FRIDAY, May 9 (HealthDay News) British research into Steno, one the most recent "superbugs" to claim lives, reveals that the bacterium has an incredible ability to resist antibiotics and other drugs, according to soon-to-be-published findings.

Steno, short for Stenotrophomonas maltophilia, thrives in moist environments, such as around taps and shower heads, and can be transmitted to people. It is responsible for roughly 1,000 cases of Steno blood poisoning in the U.K. annually. About 30 percent of these infections prove fatal.

"This is the latest in an ever-increasing list of antibiotic-resistant hospital superbugs. The degree of resistance it shows is very worrying," study senior author Dr. Matthew Avison, of the University of Bristol, said in a prepared statement. "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."

Pan-resistant Steno infections are extremely hard to treat but are rarer than similarly difficult MRSA and Clostridium difficile infections and are exclusively hospital-acquired.

The paper, to be published in Genome Biology, discusses the findings when researchers recently sequenced the Steno genome. This process, they hope, will help them learn how this bacterium works, so they can discover how to best combat it.

The organism, which is also found in the lungs of many adults with cystic fibrosis, can cause pneumonia and septicemia. Steno only enters the body through devices, such as catheters or ventilation tubes, which are left in place for long periods of time. It sticks to the catheter, grows into a 'biofilm,' and enters the patient's bloodstream when the catheter is next flushed.

Steno often affects the seriously ill, whose immune systems are already weakened. Since the new research shows Steno to be largely resistant to antibiotics, these patients face an extremely difficult situation.

"The genome sequence should help us to combat these properties," lead author Dr. Lisa Crossman, of the Wellcome Trust Sanger Institute near Cambridge, said in a prepared statement. "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."