Rhys White

Rhys White

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

Companion animals are spillover hosts of the multidrug-resistant human extraintestinal Escherichia coli pandemic clones ST131 and ST1193

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Published:

We use whole-genome sequencing to show that companion animals represent occasional spillover hosts rather than primary reservoirs for the E. coli sequence type (ST)131 lineage.

Abstract

Escherichia coli sequence types 131 (ST131) and 1193 are multidrug-resistant extraintestinal pathogens that have recently spread epidemically among humans and are occasionally isolated from companion animals. This study characterized a nationwide collection of fluoroquinolone-resistant (FQR) E. coli isolates from extraintestinal infections in Australian cats and dogs. For this, 59 cat and dog FQR clinical E. coli isolates (representing 6.9% of an 855-isolate collection) underwent PCR-based phylotyping and whole-genome sequencing (WGS). Isolates from commensal-associated phylogenetic groups A (14/59, 24%) and B1 (18/59, 31%) were dominant, with ST224 (10/59, 17%), and ST744 (8/59, 14%) predominating. Less prevalent were phylogenetic groups D (12/59, 20%), with ST38 (8/59, 14%) predominating, and virulence-associated phylogenetic group B2 (7/59, 12%), with ST131 predominating (6/7, 86%) and no ST1193 isolates identified. In a WGS-based comparison of 20 cat and dog-source ST131 isolates with 188 reference human and animal ST131 isolates, the cat and dog-source isolates were phylogenetically diverse. Although cat and dog-source ST131 isolates exhibited some minor sub-clustering, most were closely related to human-source ST131 strains. Furthermore, the prevalence of ST131 as a cause of FQR infections in Australian companion animals was relatively constant between this study and the 5-year-earlier study of Platell et al. (2010) (9/125 isolates, 7.2%). Thus, although the high degree of clonal commonality among FQR clinical isolates from humans vs. companion animals suggests the possibility of bi-directional between-species transmission, the much higher reported prevalence of ST131 and ST1193 among FQR clinical isolates from humans as compared to companion animals suggests that companion animals are spillover hosts rather than being a primary reservoir for these lineages.

Read the full publication here: https://doi.org/10.3389/fmicb.2020.01968

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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 PRJNA627752

Raw Illumina sequence read data have been deposited to the NCBI SRA under the accession numbers SRR11608154 to SRR11608173

The high-quality draft assemblies have been deposited to GenBank under the accession numbers JAHIDC000000000 to JAHIDU000000000 and JAHIDV000000000

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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.

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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.

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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.