Clostridia difficile genome deciphered
Researchers deciphered the genome of a virulent strain of Clostridium difficile. The bacterium has acquired foreign genetic material and has thus become particularly pathogenic for humans.
Mohammed Sebaihia from the Welcome Trust Sanger Institute in Cambridge examined Clostridium germs in a patient suffering from a chronic intestinal disease, pseudomembranous colitis. Doctors can only fight the multi-resistant bacteria with the antibiotics vancomycin and metronidazole.
More than ten percent of the bacterial genome is made up of mobile genetic elements, observed Sebaihia's research team. It is possible that many of these so-called transposons originate from other bacteria and provided Clostridium difficile with the genes that optimize its survival in the ecological niche, the human intestine, and thus increase its virulence. Apparently imported genes encode, for example, certain surface structures or mediate antibiotic resistance. The pathogen also produces the chemical paracresol, killing competing gut bacteria.
Clostridium difficile is the most common causative agent of hospital-acquired diarrhea and pseudomembranous colitis worldwide. In 2004, the pathogen infected more than 44,000 people in English hospitals. As the bacterium's name suggests, its cultivation in the laboratory is difficult because the bacterium is very sensitive to oxygen.
