A comprehensive data linkage study in Western Australia has identified risk factors for Clostridium difficile infection in patients with haematological malignancy.
It discovered that infection was rarely listed as a direct cause of death, and community-acquired infection was more common than previously thought.
Associate Professor Linda Selvey, from Curtin University, and colleagues identified 2,085 patients admitted to the state’s hospitals with a haematological malignancy between July 2011 and June 2012.
They linked hospital admission data with the Healthcare Associated Infection Surveillance WA program, which records all hospital-identified C. difficile infections, and found 65 patients had at least one infection.
Finally, they reviewed statutory death notifications checking for death within the following 60 or 90 days.
The strongest risk factor for infection was any history of neutropenia (odds ratio 12.5) followed by any history of bacterial pneumonia (OR 6.23), and acute lymphocytic leukaemia not in remission (OR 2.60).
In a novel finding, peptic ulcer disease emerged as a possible risk factor. Renal disease was also a contributor, but not diabetes.
Reassuringly, there were no cases of the virulent ribotype 027 of C. difficile, a strain now epidemic in North American and Europe.
“Notwithstanding several known introductions to Australia, this strain has not become established,” Professor Selvey and her colleague wrote in PLOS One.
“Ribotyping information was available on 33 of 65 infections,” they said. “There were 19 different ribotypes identified. The most common was 014/020 group (7 cases) followed by 002 (5 cases). There were three cases of 007 and two each of 244 and 070. All other ribotypes infected one case only.”
They estimated that 13 of the cases – 20% – either acquired their infection in the community, had an indeterminate source, or had only single day admissions within the 28 days prior to infection, suggesting that the community is an important source of infection.
Although C. difficile infection was associated with an increased risk of death, only two cases had the infection recorded as an antecedent factor.
“In many cases it might not be a direct contributor to death but may reflect patients having higher morbidity,” they said.
The cumulative incidence of infection in all haematological malignancy patients was 3.1%, which was much lower than in many studies, but increased to 11.3% in those have autologous stem cell transplantation.
“More work is needed to best understand the pathogenesis of C. difficile infection in this group of patients, and the mode of contact and spread, in order to reduce the burden of disease and mortality,” they concluded.