Biology subjects

Power, M. L.

Publications and source records attributed to Power, M. L..

4 recordsLinked to original sources

bioRxiv2022

Does ivermectin treatment for endemic hookworm infection alter the gut microbiota of endangered Australian sea lion pups?

The gut microbiota is essential for the development and maintenance of the hosts immune system, and disturbances can impact host health. This study aimed to determine if topical ivermectin treatment for endemic hookworm (Uncinaria sanguinis) infection in Australian sea lion (Neophoca cinerea) pups causes gut microbial changes. The gut microbiota was characterised for untreated (control) (n=23) and treated (n=23) pups sampled during the 2019 and 2020/21 breeding seasons at Seal Bay, Kangaroo Island. Samples were collected pre- and post-treatment on up to four occasions. The gut microbiota of both untreated (control) and treated pups was dominated by five bacterial phyla, Fusobacteria, Firmicutes, Proteobacteria, Actinobacteria and Bacteroides. There was a significant difference in alpha diversity between treatment groups in 2020/21 (p = 0.008), with greater diversity in treated pups. Modelling the impact of host factors on beta diversity revealed that pup ID accounted for most of the variation with pup ID, age and capture being the only significant contributors to microbial variation (p < 0.05). There were no statistically significant differences in microbial composition between treatment groups in both breeding seasons, indicating that ivermectin treatment did not alter microbial composition. To our knowledge, this is the first study to consider the impact of parasitic treatment on overall diversity and composition of the gut microbiota. Importantly, the lack of compositional changes in the gut microbiota with topical treatment support the utility of topical ivermectin as a safe and minimally invasive management strategy to enhance pup survival in this endangered species. ImportanceDisturbances to the gut microbiota in early life stages can have life-long impacts on host health. Australian sea lions are endangered and declining, and pups are endemically infected with hookworm (Uncinaria sanguinis) which contributes to pup mortality. Treatment with topical ivermectin has been shown to effectively eliminate hookworm infection and to improve pup health, but the impact on the gut microbiota was previously unknown, representing a key knowledge gap. The results from this study show that topical ivermectin treatment does not alter the gut microbiota of Australian sea lion pups, indicating that it is a safe and minimally invasive treatment that can aid in disease mitigation and conservation of this endangered species.

microbiology↗

bioRxiv2021

Transmission of Klebsiella strains and plasmids within and between Grey-headed flying fox colonies

The Grey-headed flying fox (Pteropus poliocephalus) is an endemic Australian fruit bat, known to carry pathogens with zoonotic potential. We recently showed these bats harbour the bacterial pathogens Klebsiella pneumoniae and closely related species in the K. pneumoniae species complex (KpSC). However, the dynamics of Klebsiella transmission and gene flow within flying fox colonies were not explored and remain poorly understood. Here we report a high-resolution genomic comparison of 39 KpSC isolates from Greyheaded flying foxes. Illumina whole genome sequences (n=39) were assembled de novo and the Kleborate genotyping tool was used to infer sequence types (STs). Oxford Nanopore sequences were generated for 13 isolates (one for each distinct ST) in order to generate high-quality completed reference genomes. Read mapping and variant calling was used to identify single nucleotide variants (SNVs) within each ST, using the relevant reference genome. In silico genome-scale metabolic models were generated to predict and compare substrate usage to 59 previously published KpSC models for isolates from human and environmental sources, which indicated no distinction on the basis of metabolic capabilities. High-resolution genome comparisons identified five putative strain transmission clusters (four intra- and one inter-colony, n=2-15 isolates each, [≤]25 pairwise SNVs). Inter-colony transmission of Klebsiella africana was found between two flying fox populations located within flying distance. The 13 completed genomes harboured 11 plasmids, all of which showed 37-98% coverage (mean 73%) and [≥]95% identity to those previously reported from human-associated KpSC. Comparison of plasmids from different flying fox associated KpSC indicated an interspecies horizontal plasmid transmission between K. pneumoniae and K. africana for a 98 kbp plasmid, pFF1003. These data indicate that KpSC are able to transmit directly via flying fox populations or indirectly via a common source, and that these isolates can harbour plasmids with similarity to those found in human derived KpSC, indicating gene flow is occurring between isolates from Grey-headed flying fox KpSC and human clinical isolates.

microbiology↗

bioRxiv2021

Novel strains of Klebsiella africana and Klebsiella pneumoniae in Australian Fruit Bats (Pteropus poliocephalus)

Over the past decade human associated multidrug resistant (MDR) and hypervirulent Klebsiella pneumoniae lineages have been increasingly detected in wildlife. This study investigated the occurrence of K. pneumoniae species complex (KpSC) in grey-headed flying foxes (GHFF), an Australian fruit bat. Thirty-nine KpSC isolates were cultured from 275 GHFF faecal samples (14.2%), comprising K. pneumoniae (sensu stricto) (n=30), Klebsiella africana (n=8) and Klebsiella variicola subsp. variicola (n=1). The majority (79.5%) of isolates belonged to novel sequence types (ST), including two novel K. africana STs. This is the first report of K. africana outside of Africa and in a non-human host. A minority (15.4%) of GHFF KpSC isolates shared STs with human clinical K. pneumoniae strains, of which, none belonged to MDR clonal lineages that cause frequent nosocomial outbreaks, and no isolates were characterised as hypervirulent. The occurrence of KpSC isolates carrying acquired antimicrobial resistance genes in GHFF was low (1.1%), with three K. pneumoniae isolates harbouring both fluoroquinolone and trimethoprim resistance genes. This study indicates that GHFF are not reservoirs for MDR and hypervirulent KpSC strains, but they do carry novel K. africana lineages. The health risks associated with KpSC carriage by GHFF are deemed low for the public and GHFF.

microbiology↗

bioRxiv2020

Genome Methylation Predicts Age and Longevity of Bats

Exceptionally long-lived species, including many bats, rarely show overt signs of aging, making it difficult to determine why species differ in lifespan. Here, we use DNA methylation (DNAm) profiles from 712 known-age bats, representing 26 species, to identify epigenetic changes associated with age and longevity. We demonstrate that DNAm accurately predicts chronological age. Across species, longevity is negatively associated with the rate of DNAm change at age-associated sites. Furthermore, analysis of several bat genomes reveals that hypermethylated age- and longevity-associated sites are disproportionately located in promoter regions of key transcription factors (TF) and enriched for histone and chromatin features associated with transcriptional regulation. Predicted TF binding site motifs and enrichment analyses indicate that age-related methylation change is influenced by developmental processes, while longevity-related DNAm change is associated with innate immunity or tumorigenesis genes, suggesting that bat longevity results from augmented immune response and cancer suppression.

genomics↗