The impact of pan-resistant bacterial pathogens on survival after lung transplantation in cystic fibrosis: results from a single large referral centre

Abstract

Reported actuarial one-year survival for patients with cystic fibrosis (CF) after lung transplant is 55–91%. Infection is the most common cause of early death. Colonization with Burkholderia cepacia complex is associated with reduced survival and international lung transplant referral guidelines support individual unit assessment policies for patients colonized with other pan-resistant bacteria. We examined local data on survival after transplant for CF to determine the impact of colonization with pan-resistant bacteria.

A retrospective review of all CF patients from Royal Prince Alfred Hospital (RPAH), Sydney, who underwent lung transplantation at St Vincent's Hospital, Sydney, 1989–2002, was performed. Sixty-five patients were listed for lung transplantation with 54 (male: female=29:25) receiving transplants. Of the 11 patients (17%) who died on the waiting list, six were colonized with pan-resistant Pseudomonas aeruginosa. Thirty of the 54 transplanted patients had at least one pan-resistant organism before transplant. In 28 this included P. aeruginosa. Overall one-year survival was 92% with a median survival of 67 months. Overall survival for the pan-resistant group (N=30) was not significantly different to survival in those with sensitive organisms (N=24) (Logrank χ²=1.6, P=0.2). Three patients colonized with B. cepacia complex pre-transplant survive at 11, 40 and 60 months post-transplant. Infection contributed to 11 of the 18 post-transplant deaths, with pre-transplant-acquired bacterial pathogens responsible in two cases. Patients continued to acquire multiresistant bacteria post-transplantation. Lung transplant survival at St Vincent's Hospital for CF adults from RPAH compares favourably with international benchmarks. Importantly, colonization with pan-resistant bacteria pre-transplant did not appear to adversely affect survival post-transplant.

Introduction

Lung transplantation remains the major therapeutic intervention offering prolonged survival and improved quality of life for patients with end-stage lung disease from cystic fibrosis (CF). The first lung transplantation for CF in Australia was performed at St Vincent's Hospital in 1989 on a patient from our clinic. International survival data for CF patients post-transplantation vary widely with one-year survival ranging from 55 to 91%.1., 2., 3., 4. The 2002 data registry of The International Society for Heart and Lung Transplantation reports a one-year survival rate of 77.9% in 1809 CF patients after transplantation.⁵ Many factors influence the survival of patients after lung transplantation. This study focuses on one important aspect, namely microbiology.

Recent North American audits have highlighted the poor prognosis associated with pre-transplantation colonization with Burkholderia cepacia complex,1., 2. but have not substantiated earlier reports of increased mortality in patients colonized with pan-resistant Pseudomonas aeruginosa pre-transplant.1., 6. The applicability of these studies to the local Australian experience may be limited given the considerable international variation in some microbial pathogens in patients with CF, for example differences in the genomovars of B. cepacia complex,⁷ variation in the prevalence of mycobacteria other than tuberculosis (MOTT)⁸ and differing genotypes of reported clonal strains of P. aeruginosa.9., 10.

Currently selection of lung transplant candidates in Australia is based on the international consensus guidelines.¹¹ Risk assessment of patients colonized with resistant pathogens is performed by the individual transplant units. We believe the distinctive microbial flora of Australian CF patients warrants a review of local transplant outcomes, to assist in this risk assessment. Accordingly, we examined survival rates of adult patients attending Sydney's Royal Prince Alfred Hospital (RPAH) who were listed for or received transplants at St Vincent's Hospital, Sydney in order to determine whether colonization with pan-resistant bacteria pre-transplant was a factor affecting post-transplantation survival or survival to transplant.