876. Analysis of the Transplant Lung Microbiome
Session: Oral Abstract Session: Microbiome and Susceptibility to Infection
Saturday, October 22, 2011: 10:15 AM
Room: 156ABC
Background: 

Lung transplant patients have decreased long-term survival compared with other solid organ transplant recipients mainly due to the development of chronic rejection, manifested clinically by bronchiolitis obliterans syndrome (BOS). While infections have been implicated in BOS and treatment with the antibiotic azithromycin stabilizes or improves BOS, no systematic approach to characterize the microbiome in lung transplantation has been performed.  We hypothesize that the lung microbiome becomes more diversified as the patient approaches BOS. To address this we sought to characterize and compare the normal lung microbiome to the transplant lung microbiome, both before and after the development of BOS.  

Methods: 

We characterized the microbiome in BALF from 4 transplant patients obtained at 3 time points (both before and after BOS diagnosis) and compared it to the microbiome in BALF obtained from 3 healthy volunteers.  The microbiome of each sample was determined using massively parallel pyrosequencing of the variable 3 region of the bacterial 16S rRNA gene.  The data analyzed using the Ribosomal Database Project Pipeline, mothur, and Fast UniFrac.

Results: 

The transplant patient samples yielded 541-2910 sequences, representing 81-241 operational taxonomic units (OTUs).  Shannon diversity indices ranged from 2.94-3.94, while Simpson diversity indices ranged from 0.77-0.90.  The control samples yielded 375-449 sequences and 16-26 OTUs.  Shannon diversity indices ranged from 1.11-2.22, while Simpson diversity indices ranged from 0.51-0.86.  Hierarchical clustering and principal component analysis demonstrated that the control and lung transplant samples clustered separately.  Lung transplant samples were dominated by Betaproteobacteria, while control samples were dominated by Firmicutes and Gammaproteobacteria.  Approximately 10% of OTUs were seen in all transplant patients at all time points.  This “core” lung transplant microbiome included bacteria in the genera Ralstonia, Ochrobactrum, Microbacterium, Cupriavidus and Ensifer.

Conclusion: 

The lung transplant microbiome is more diverse than normal lung microbiome.  Further work may help elucidate a microbiome pattern that corresponds with development of BOS.


Subject Category: O. Transplant infectious diseases

Alexa A. Pragman, MD, PhD1, Klaudyna Borewicz, MSc2, Hyeun Bum Kim, DVM, MS2, Marshall Hertz, MD3, Christine Wendt, MD4 and Richard E. Isaacson, PhD2, (1)Infectious Diseases and International Medicine, University Of Minnesota Medical School, Minneapolis, MN, (2)University of Minnesota, St. Paul, MN, (3)University of Minnesota, Minneapolis, MN, (4)Minneapolis Veterans Affairs Medical Center, Minneapolis, MN

Disclosures:

A. A. Pragman, None

K. Borewicz, None

H. B. Kim, None

M. Hertz, None

C. Wendt, None

R. E. Isaacson, None

Previous Abstract | Next Abstract >>

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.