Rhys White

Rhys White

PhD in Microbial Genomics | Comparative Genomics | Bioinformatics | Antibioic Resistance | Phylogenomics

The first genomic insight into Chlamydia psittaci sequence type (ST)24 from a healthy captive psittacine host in Australia demonstrates evolutionary proximity with strains from psittacine, human, and equine hosts

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In 2022, we went into a pet shop and collected a faecal sample from a healthy (asymptomatic) pet bird. We discovered that a strain of Chlamydia psittaci found in a pet bird in 2022 is very similar to the C. psittaci strains that caused foal loss in horses in 2016. This is a bit concerning because it means that there’s a possibility that people and animals could get sick from C. psittaci, so we need to keep a close eye on it to make sure everyone stays healthy. To do that, we need to figure out who is giving C. psittaci to whom so we can come up with evidence-based ways to stop C. psittaci from spreading.

Abstract

Chlamydia psittaci is a zoonotic pathogen that infects birds, humans, and other mammals. Notably, recent studies suggested the human-to-human transmission of C. psittaci, and this pathogen also causes equine reproductive loss in Australia. Molecular studies in Australia to date have focused on and described clonal sequence type (ST)24 strains infecting horses, wild psittacine, and humans. In contrast, the genetic identity of C. psittaci strains from captive psittacine hosts is scarce. In 2022, C. psittaci was detected in the faeces of a healthy captive blue-fronted parrot (Amazona aestiva). Genomic DNA was extracted and underwent whole-genome sequencing. Here we report the 1,160,701 bp circular chromosome of C. psittaci strain BF_amazon_parrot13 and the 7,553 bp circular plasmid pCpsBF_amazon_parrot13. Initial in silico multi-locus sequence typing and ompA genotyping revealed that BF_amazon_parrot13 belongs to the clonal ST24 lineage and has an ompA genotype A. Further context involved the genomes of 31 published ST24 strains, utilising a single-nucleotide variant (SNV) based clustering approach. Despite temporal, host, and biogeographical separation, a core-genome SNV-based phylogeny revealed that BF_amazon_parrot13 clustered in a distinct subcluster with seven C. psittaci strains from equines in Australia (maximum pairwise distance of 13 SNVs). BF_amazon_parrot13 represents the first complete C. psittaci ST24 genome from a captive psittacine in Australia. Furthermore, by using whole-genome sequencing to coordinate surveillance, we can also learn more about the possible health risks and routes of chlamydia transmission among people, livestock, wild animals, and domesticated animals.

Read the full publication here: https://doi.org/10.1016/j.vetmic.2023.109704

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Data availability

Sequence read data has been submitted to the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA) under BioProject PRJNA888783

Raw Illumina sequence read data have been deposited to the NCBI SRA under the accession number SRR21848900

In addition, the high-quality assembly has been deposited to the NCBI GenBank database under the accession numbers CP110211 and CP110212.

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One clone to rule them all: Culture-independent genomics of Chlamydia psittaci from equine and avian hosts in Australia

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In Australia, novel C. psittaci infections in horses raise biosecurity concerns. Here, we used limited whole-genome sequencing to figure out ’who is giving it to who’ and when these modern C. psittaci strains may have appeared in Australia. Our findings suggest that strains from parrots and horses have likely descended from a single progenitor strain.

Phase variation in the glycosyltransferase genes of Pasteurella multocida associated with outbreaks of fowl cholera on free-range layer farms

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In poultry, P. multocida causes fowl cholera which leads to acute and fatal septicaemia with significant economic loss on the poultry industry. In Australia, gene-centric molecular studies are valuable in studying the epidemiology of outbreaks and guiding autogenous vaccination programmes. But these techniques do not provide the resolution for insight into the LPS structure of strains - enter whole-genome sequencing.

Completing the genome sequence of Chlamydia pecorum strains MC/MarsBar and DBDeUG: New insights into this enigmatic koala (Phascolarctos cinereus) pathogen

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We present the first two complete C. pecorum genomes sequenced from diseased koalas. With these genomes, we expand on previous works by improving the gene annotations and by providing the genomic context of important virulence and accessory gene content. These findings lay the foundations for identifying and understanding species specificity and host adaptation behind chlamydial infections affecting koalas.