Oral Presentation 64th International Conference of the Wildlife Disease Association 2015

Genomic analysis demonstrates continuing evolution, recombination and environmental sources of enteric bacteria in isolated wildlife populations (#46)

Zoe L Grange 1 2 3 , Brett D Gartrell 1 , Patrick J Biggs 2 3 , Nicola J Nelson 4 , Nigel P French 2 3
  1. Wildbase, Massey University, Palmerston North, Manawatu, New Zealand
  2. Allan Wilson Centre, Massey University, Palmerston North, Manawatu, New Zealand
  3. mEpiLab, Hopkirk Research Institute, Massey University, Palmerston North, Manawatu, New Zealand
  4. School of Biological Sciences, Allan Wilson Centre, Victoria University of Wellington, Wellington, New Zealand
The process of translocation of threatened wildlife may have unforeseen consequences on pathogen transmission and evolution in host populations. Our understanding of some of the epidemiological features of infectious disease in vulnerable populations can be enhanced by the use of genomic sequencing of microbes in natural ecosystems. The genomic epidemiology of a prevalent rail-associated endemic bacterium, Campylobacter sp. nova 1, and a host-generalist bacterium, Salmonella spp., was explored in a well-described population of a New Zealand endangered flightless bird, the takahe (Porphyrio hochstetteri). The distinctive population structure of translocated takahe provides a unique opportunity to investigate the influence of host isolation on enteric microbial diversity. Whole genome sequencing, ribosomal multi-locus sequence typing (rMLST) and CRISPR analysis was performed on 70 C. sp. nova 1 isolated from multiple takahe populations. C. sp. nova 1 was genomically diverse and multivariate analysis of 52 rMLST alleles revealed location-associated differentiation of C. sp. nova 1 sequence types. Possible explanations for the observed pattern include; the spatial expansion and isolation of hosts resulting in reduced gene flow of Campylobacter spp. and allopatric speciation, the presence of heterogeneous environmental attributes influencing sequence type carriage or cross-species transmission of Campylobacter spp. from sympatric reservoir hosts. The same methods were used to analyse Salmonella spp. isolated from a single island population of takahe and their environment. Salmonella spp. isolated from takahe, their environment and a reptile showed identical rMLST profiles suggesting a shared source or transmission within the location not present in other populations. This study suggests subtle but important differences in host-microbe relationships may occur as a consequence of conservation management which has important implications when relocating wildlife populations.