Identification and genotyping of Campylobacter spp. strains isolated from a captive wildlife population in New Zealand
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The Auckland Zoological Park holds 120 species and over 850 animals within a 17-hectare park in central Auckland. Species include non-primate mammals, avians, primates and reptiles, including a mixture of exotic and native species. Little is known about the epidemiology of Campylobacter in wildlife populations, as previous and current studies focus on domestic and food producing animals, as well as Campylobacter in medical settings. This study set out to determine and identify Campylobacter in a healthy captive wildlife population and present the isolated organisms virulence potential by investigating the presence of putative virulence genes (flaA, cadF, cdtA, cdtB, cdtC and gyrA). The genes investigated are commonly associated with multifactorial processes that are involved with Campylobacter infection. Based on sequencing profiles of the virulence genes investigated, phylogenetic relationships were demonstrated between the different Campylobacter strains isolated from such a wide variety of animals. Over a 9-month period (December 2013 to August 2014) 202 faecal samples were collected from a variety of animal species of the Auckland Zoo’s captive population, for evaluation of the presence of Campylobacter. From the 202 samples collected, Campylobacter was isolated from 17 (8.9%), where Campylobacter jejuni was the most frequently isolated Campylobacter species, with a recovery rate of 52.9% in the present study. Upon isolation, isolates were then investigated for the presence of specific genes that are commonly associated with pathogenesis of Campylobacter infection. The genes were selected on the basis of their involvement in motility, adhesion, invasion and toxin production, which are all associated with the multifactorial bacterial pathogenic mechanisms. The absence of one of these virulence factors can limit and reduce the organism’s pathogenicity and virulence potential. Of the 6 genes investigated, flagella A (flaA) genes were found in 100%, Campylobacter adhesion factor (cadF) was found in 58.8%, gyrase A (gyrA) in 70.6%, and cytotoxin A, B and C (cdtA, cdtB and cdtC) in 70.6%, 47.1% and 35.3% respectively. Sequencing of these genes revealed both homology and heterogeneity of gene sequences between the different Campylobacter species, demonstrating both genetic conservation and variation respectively.