Is Clostridium difficile a threat to Australia's biosecurity?

t is 30 years since Clostridium difficile was shown to be the cause of pseudomembranous colitis and many cases of antibiotic-associated diarrhoea in humans. In the interim, C. difficile has risen from relative obscurity to become a major hospital pathogen. Two factors were particularly important in its emergence during the 1980s. First, increased and inappropriate use of some broad-spectrum antibiotics, particularly cephalosporins, predisposed more patients to infection with C. difficile. Second, contamination of the hospital environment with C. difficile spores was, and remains, a significant problem, as the spore is likely to be the infective particle. The epidemiology of C. difficile infection continues to evolve, and developments overseas in the past decade threaten not only parts of Australia' s vast agricultural sector but also the country' s health care system. Since 2002, rates of C. difficile infection have escalated, with outbreaks of severe infection in North America and Europe caused by an epidemic strain — polymerase chain reaction (PCR) ribotype 027 (also known as North American pulsed-field type 1 [NAP1]). This strain is characterised by the production of greater amounts of toxins A and B and an additional, binary toxin, as well as resistance to fluoroquinolone antimicrobials. 1 When this editorial was submitted for publication in January 2009, there was no evidence that this epidemic strain was present in Australia. However, C. difficile PCR ribotype 027 has now been isolated for the first time in Australia, as reported in this issue of the Journal 2 (page 706). Although the patient most probably acquired the organism while travelling in North America, this case illustrates the ease with which it could be introduced into Australia. Thought to be driving the epidemic in humans in North America and Europe are the overuse of fluoroquinolones and fluoroquinolone resistance, but the ageing population and improved case ascertainment may also be contributing to the dramatic increase in cases. Other factors may also be important, such as the increase in prescription of proton-pump inhibitors, which coincided with the emergence of epidemic C. difficile. 3 Several recent observations from overseas have broad relevance for Australia. First, there has been an apparent increase in community-acquired C. difficile infection in the absence of classic risk factors such as antibiotic exposure, leading to suggestions that all patients with community-acquired diarrhoea should be tested for C. difficile. 4 Assertions that community-acquired C. difficile infection is a new disease 4 are not correct …