Genome sequence of emerging superbug reveals high degree of drug resistance
8 May 2008
Scientists at the Wellcome Trust Sanger Institute and the University of Bristol have sequenced the genome of a newly emerging superbug. The results, published in the journal Genome Biology, have revealed that the bacterium has a high capacity for drug resistance. Described as “worrying” by the senior author of the paper, the high level of resistance could mean that infection with the bug is extremely difficult to treat with existing antibiotics.
The bacterium in question - Stenotrophomonas maltophilia, or Steno for short - is common in the environment, although infections are rarer than with some other superbugs, namely Clostridium difficile (Cdiff) and methicillin-resistant Staphylococcus aureus (MRSA).
Steno is exclusively acquired in hospitals. The bacterium thrives in moist environments and typically infects patients through catheters that are left in place for a long time. Bacteria stick to the catheter and grow into a biofilm, a process that makes decontaminating equipment extremely hard. When the catheters are flushed, the bacterial biofilm can enter a patient’s bloodstream and - in patients with an impaired immune system - might lead to the potentially fatal condition septicaemia.
“The genome sequence should help us to combat Steno,” says Dr Lisa Crossman of the Wellcome Trust Sanger Institute. “For example, if we know which proteins allow 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.”
Around 1000 cases of blood poisoning caused by Steno are reported in the UK each year, of which approximately 300 are fatal.
Image: The Steno genome. The multicoloured boxes in the outer ring are genes; the red boxes are regions transferred from other organisms.
References
Crossman L et al. The complete genome, comparative and functional analysis of Stenotrophomonas maltophilia reveals an organism heavily shielded by drug resistance determinants. Genome Biol 2008;17;9(4):R74.