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Impact of infection with transmissible strains of Pseudomonas aeruginosa on lung transplantation outcomes in patients with cystic fibrosis

  • Researchers

    Nadim Srour, Cecilia Chaparro, Katherine Vandemheen, Lianne G. Singer, Shaf Keshavjee, Shawn D. Aaron.

  • Place of research

    Université de Sherbrooke, Faculté de Médecine et des Sciences de la Santé; McGill University, Faculty of Medicine; Hôpital Charles-LeMoyne, Department of Medicine, Division of Pulmonology; The Ottawa Hospital Research Institute, Clinical Epidemiology Program; Toronto Lung Transplant Program, University of Toronto; University Health Network, Toronto, Ontario; Adult Cystic Fibrosis Clinic St. Michael’s Hospital, Toronto; The University of Ottawa

  • Publication

    The Journal of Heart and Lung Transplantation, October 2014

  • Subjects

    , , ,

  • We wished to determine if those patients infected with transmissible strains of P. aeruginosa do worse after lung transplant than those infected with unique strains of P. aeruginosa.

  • Why is this important?

    Infection with P. aeruginosa is frequent among cystic fibrosis (CF) patients and is associated with poor outcomes. A significant proportion of CF patients are infected with transmissible strains of P. aeruginosa (strains that are even more easily transmitted between patients). We had already shown that infection with transmissible strains of P. aeruginosa in patients with CF is associated with poorer outcomes than infection with unique strains, such as a greater risk of requiring a lung transplant. It is not known whether infection with transmissible strains of P. aeruginosa continues to be associated poorer outcomes after lung transplant. This is important as such patients may need to be treated with more antibiotics following lung transplant than they would otherwise.

  • What did you do?

    We had previously identified 446 patients with CF from Ontario, Canada, 320 of which were infected with P. aeruginosa. 102 of these were infected with transmissible strains. We identified which of these patients had undergone a lung transplant and collected information about long term outcomes, particularly survival.

  • What did you find?

    We identified 56 lung transplant recipients from the group of 446 patients. 18 of these had infection with transmissible strains of P. aeruginosa, and 26 with unique P. aeruginosa strains. Post-transplant survival 3 years after transplant was not significantly different between the transmissible group (86%) and the unique group (84%). No significant differences between groups were found in other outcomes including developing bronchiolitis obliterans (a form of chronic lung rejection, a complication of lung transplant), the frequency of acute rejection episodes, the frequency of respiratory tract infections after lung transplant, or the rate of change of lung function after lung transplant.

  • What does this mean and reasons for caution?

    Pre-operative infection with transmissible strains of P. aeruginosa is not associated with poorer post-transplant outcomes compared to patients infected with unique strains of P. aeruginosa. However, our study could only determine if there was a large difference in survival. Smaller differences are not completely excluded. We also determined if patients were infected with transmissible strains of P. aeruginosa about 1 year before transplant. It is unlikely, but possible, that this would have changed by the time of transplant, which could have changed our conclusions.

  • What's next?

    To confirm our results, a larger study involving several centres would be needed. In this study, it should be determined systematically whether patients are infected with transmissible strains of P. aeruginosa, immediately before transplant, and throughout the post-transplant period.