Profiling the bacterial microbiome of ticks that parasitise bandicoots in Australia

Molecular methods have recently revealed novel organisms inhabiting native Australian ticks, some of which are potentially pathogenic due to their similarity to causes of known tick-borne diseases (TBDs) worldwide. Australian bandicoots (Order: Peramelemorphia) are hosts of ticks that are known to bite humans. The persistence of bandicoots in urban and peri-urban areas results in increased exposure of humans to bandicoot ticks, and the bacterial diversity of ticks parasitising bandicoots is therefore of public health interest and requires further investigation. This study analysed 290 ticks parasitising bandicoots from New South Wales (NSW; n = 125), Queensland (QLD; n = 26), Northern Territory (NT; n = 15), Tasmania (TAS; n = 80), and Western Australia (WA; n = 44). A total of seven tick species (Haemaphysalis bancrofti, H. humerosa, Ixodes australiensis, I. fecialis, I. holocyclus, I. myrmecobii and I. tasmani) were identified from four Australian bandicoot species; the eastern barred bandicoot (Perameles gunnii), the long-nosed bandicoot (P. nasuta), the northern brown bandicoot (Isoodon macrourus), and the southern brown bandicoot (I. obesulus). Next Generation Sequencing (NGS) targeting the ubiquitous bacterial 16S rRNA gene was applied to a sub-sample of ticks (n = 66). Analysis of sequence data revealed the presence of Anaplasma, Borrelia, Ehrlichia and ‘Ca. Neoehrlichia’. Anaplasma bovis was detected in two ticks (H. bancrofti and H. humerosa) from the same bandicoot in NSW. A likely novel Ehrlichia sp. was identified from a single I. fecialis tick in WA. In addition to the confirmation of the recently described ‘Ca. Neoehrlichia arcana’ and ‘Ca. N. australis’ inhabiting I. holocyclus and I. tasmani from NSW and QLD, a novel ‘Ca. Neoehrlichia’ species was detected in ticks (I. australiensis and I. fecialis) from WA. Furthermore, sequences 98.8% similar to ‘Ca. Borrelia tachyglossi’ provide the first molecular description of Borrelia inhabiting ticks (H. humerosa and I. tasmani) parasitising Australian bandicoots. This study has provided an interesting insight into the microbial communities present in ticks parasitising Australian bandicoots and raises questions about the potential for tick-associated illness in people parasitised by these ticks. An investigation into the characterisation, prevalence, pathogenicity and transmission dynamics of these candidate tick-borne pathogens is required to establish the significance of this study

Overview of the nomenclature and network of contributors to the development of bioreactors for human gut simulation using bibliometric tools: a fragmented landscape

The evolution of complex in vitro models of the human gastrointestinal system to interrogate the biochemical functionality of the gut microbiome has augmented our understanding of its role in human physiology and pathology. With 5718 authors from 52 countries, gut bioreactor research reflects the growing awareness of our need to understand the contribution of the gut microbiome to human health. Although a large body of knowledge has been generated from in vitro models, it is scattered and defined by application-specific terminologies. To better grasp the capacity of bioreactors and further our knowledge of the human gastrointestinal system, we have conducted a cross-field bibliometric search and mapped the evolution of human gastrointestinal in vitro research. We present reference material with the aim of identifying key authors and bioreactor types to enable researchers to make decisions regarding the choice of method for simulating the human gut in the context of microbiome functionality

Perception of Ticks and Tick-Borne Diseases Worldwide

In this comprehensive review study, we addressed the challenge posed by ticks and tick-borne diseases (TBDs) with growing incidence affecting human and animal health worldwide. Data and perspectives were collected from different countries and regions worldwide, including America, Europe, Africa, Asia, and Oceania. The results updated the current situation with ticks and TBD and how it is perceived by society with information bias and gaps. The study reinforces the importance of multidisciplinary and international collaborations to advance in the surveillance, communication and proposed future directions to address these challenges

Altered dietary behaviour during pregnancy impacts systemic metabolic phenotypes

RationaleEvidence suggests consumption of a Mediterranean diet (MD) can positively impact both maternal and offspring health, potentially mediated by a beneficial effect on inflammatory pathways. We aimed to apply metabolic profiling of serum and urine samples to assess differences between women who were stratified into high and low alignment to a MD throughout pregnancy and investigate the relationship of the diet to inflammatory markers.MethodsFrom the ORIGINS cohort, 51 pregnant women were stratified for persistent high and low alignment to a MD, based on validated MD questionnaires. 1H Nuclear Magnetic Resonance (NMR) spectroscopy was used to investigate the urine and serum metabolite profiles of these women at 36 weeks of pregnancy. The relationship between diet, metabolite profile and inflammatory status was investigated.ResultsThere were clear differences in both the food choice and metabolic profiles of women who self-reported concordance to a high (HMDA) and low (LMDA) Mediterranean diet, indicating that alignment with the MD was associated with a specific metabolic phenotype during pregnancy. Reduced meat intake and higher vegetable intake in the HMDA group was supported by increased levels of urinary hippurate (p = 0.044) and lower creatine (p = 0.047) levels. Serum concentrations of the NMR spectroscopic inflammatory biomarkers GlycA (p = 0.020) and GlycB (p = 0.016) were significantly lower in the HDMA group and were negatively associated with serum acetate, histidine and isoleucine (p < 0.05) suggesting a greater level of plant-based nutrients in the diet. Serum branched chain and aromatic amino acids were positively associated with the HMDA group while both urinary and serum creatine, urine creatinine and dimethylamine were positively associated with the LMDA group.ConclusionMetabolic phenotypes of pregnant women who had a high alignment with the MD were significantly different from pregnant women who had a poor alignment with the MD. The metabolite profiles aligned with reported food intake. Differences were most significant biomarkers of systemic inflammation and selected gut-microbial metabolites. This research expands our understanding of the mechanisms driving health outcomes during the perinatal period and provides additional biomarkers for investigation in pregnant women to assess potential health risks

Ecology of ticks and microbes in Australian wildlife

Ticks (Ixodida) represent one of the most important vector groups affecting human and animal health, and in recent years there have been increasing concerns regarding the cause of tick-borne disease affecting Australians. Worldwide, wildlife health surveillance is recognised as a key tool for investigating tick-borne infections and a One Health approach is essential to understand the epidemiology of tick-associated microbes. Therefore, this research aimed to; i) identify ticks from Australian wildlife; ii) investigate bacteria and haemoprotozoa present in wildlife and ticks; and iii) characterise microbes and understand the interplay between host-microbetick. Molecular tools were used to assist in the identification of Australian ticks. Museum specimens of the human biting tick Amblyomma triguttatum were used to investigate the molecular systematics of this species complex. A set of molecular barcodes was developed for Australian ticks, which was important for the accurate identification of immature life stages and cryptic species. Additionally, a novel 12S rDNA metabarcoding assay was developed for high throughput identification of ticks. Free-ranging animals and their ticks were sampled from urban and periurban areas. The bacterial and haemoprotozoan diversity was characterised using a combination of amplicon high-throughput sequencing, targeted Sanger sequencing, and microscopy. Bacterial profiling generated over 100 million sequences. Statistical analysis using constrained ordination methods revealed blood, tick and tissues had distinct community signatures. A diverse range of tick associated microbes was identified, such as Anaplasmataceae, Bartonellaceae, Borreliaceae, Coxiellaceae, Midichloriaceae. Overall, these microbes were rare in wildlife hosts and generally confined to specific sample types. In addition, eight species of haemoprotozoa were identified, including species within the genera Babesia, Hepatozoon, Theileria and Trypanosoma. Lastly, this study further confirmed the absence of northern hemisphere tick-borne pathogens and provided further evidence of the unique microbes present in Australian wildlife and ticks

How significant are bats as potential carriers of zoonotic Cryptosporidium and Giardia?

Bats are known to harbour various pathogens and are increasingly recognised as potential reservoirs for zoonotic diseases. This paper reviews the genetic diversity and zoonotic potential of Cryptosporidium and Giardia in bats. The risk of zoonotic transmission of Cryptosporidium from bats to humans appears low, with bat-specific Cryptosporidium genotypes accounting for 91.5% of Cryptosporidium-positive samples genotyped from bats worldwide, and C. parvum and C. hominis accounting for 3.4% each of typed positives, respectively. To date, there have only been sporadic detections of Giardia in bats, with no genetic characterisation of the parasite to species or assemblage level. Therefore, the role bats play as reservoirs of zoonotic Giardia spp. is unknown. To mitigate potential risks of zoonotic transmission and their public health implications, comprehensive research on Cryptosporidium and Giardia in bats is imperative. Future studies should encompass additional locations across the globe and a broader spectrum of bat species, with a focus on those adapted to urban environments

Morphological and molecular characterization of Isospora elliotae n. sp. (Apicomplexa: Eimeriidae) from the Australian magpie Gymnorhina tibicen (Latham, 1801) (Passeriformes: Artamidae) in Western Australia

Abstract A new coccidian species, Isospora elliotae n. sp., from the Australian magpie Gymnorhina tibicen (Latham, 1801) in Western Australia, is described and characterized morphologically and molecularly. Microscopic analysis of a faecal sample identified subspheroidal oocysts (n = 20), 20–22 × 18–20 (20.7 × 18.7); length/width (L/W) ratio 1.05–1.14 (1.10). Wall bi‐layered, 1.0–1.3 (1.2) thick, outer layer smooth, c. 2/3 of total thickness. Micropyle and oocyst residuum absent, but usually two polar granules are present. Sporocysts (n = 28) ovoidal, 12–13 × 9–11 (12.6 × 9.7); L/W ratio 1.22–1.35 (1.30). Stieda body present, flattened to half‐moon‐shaped, c. 0.5 deep × 2.0 wide; sub‐Stieda indistinct or barely discernible, c. 1.0 deep × 2.5 wide; para‐Stieda body absent; sporocyst residuum present, composed of granules dispersed among the sporozoites. Sporozoites vermiform, with anterior and posterior refractile bodies and nucleus. Segments of three gene loci (18S rRNA, 28S rRNA and COI) were sequenced and I. elliotae n. sp. exhibited 99.8% genetic similarity to Isospora sp. MAH‐2013a (KF648870) followed by 99.7% genetic similarity to Isospora neochmiae (Yang, Brice & Ryan, 2016) (KT224380) at the 18S rRNA gene locus. It shared 97.0% genetic similarity with an unnamed Isospora sp. (AY283852) at the 28S rRNA gene locus and it also shared the highest genetic similarity of 99.8% with the unnamed Isospora sp. from an American crow (OL999120) at the COI gene locus. Based on morphological and molecular data, this isolate is a new species named as I. elliotae n. sp

Cryptosporidium and Giardia in cats and dogs: What is the real zoonotic risk?

Due to the close bond between humans and companion animals, a thorough understanding of the diversity of Cryptosporidium species and Giardia assemblages in cats and dogs is essential to determine the potential zoonotic risks. Analysis of molecular studies shows that C. felis and C. canis are the main species infecting cats and dogs, respectively. These species are largely host-specific, as despite intense association with humans, prevalence of C. felis and C. canis in humans is low and predominantly in immunocompromised individuals and low-income countries. There have been reports of C. parvum in cats and dogs and two reports of C. hominis in dogs. In most studies conducted to date, however, the prevalence of zoonotic species was low and may be associated with coprophagy and or/spillback, but this remains to be determined. Results of subtyping studies suggest that for C. felis and C. canis, some zoonotic transmission may occur but host-adapted subtypes also exist. Giardia duodenalis assemblages C and D are commonly reported in dogs, with assemblages F and A most common in cats. Assemblages C, D and F are largely host-specific as there are only a handful of reports of them in humans. Reports of assemblage A and B in cats and dogs may be due to coprophagy or spillback from owners. Despite the extent of pet ownership and the close contact between humans and companion animals worldwide, the overall risk of zoonotic transmission from cats and dogs to humans is uncertain but thought to be low due to C. canis, C. felis and G. duodenalis assemblages C, D and F being predominantly host-specific, the relatively low prevalence of C. parvum (and C. hominis) in cats and dogs (which may be due to mechanical carriage), and low oo/cyst shedding. Carefully designed epidemiological studies of cats and dogs and their owners using subtyping tools are essential to better quantify the extent of spillover and spillback of Cryptosporidium and Giardia between pets and their owners

Exploiting the Potential of Bioreactors for Creating Spatial Organization in the Soil Microbiome: A Strategy for Increasing Sustainable Agricultural Practices

Industrial production of synthetic nitrogen fertilizers and their crop application have caused considerable environmental impacts. Some eco-friendly alternatives try to solve them but raise some restrictions. We tested a novel method to produce a nitrogen bioinoculant by enriching a soil microbial community in bioreactors supplying N2 by air pumping. The biomass enriched with diazotrophic bacteria was diluted and applied to N-depleted and sterilized soil of tomato plants. We estimated microbial composition and diversity by 16S rRNA metabarcoding from soil and bioreactors at different run times and during plant uprooting. Bioreactors promoted the N-fixing microbial community and revealed a hided diversity. One hundred twenty-four (124) operational taxonomic units (OTUs) were assigned to bacteria with a greater Shannon diversity during the reactor’s steady state. A total of 753 OTUs were found in the rhizospheres with higher biodiversity when the lowest concentration of bacteria was applied. The apparent bacterial abundance in the batch and continuous bioreactors suggested a more specific functional ecological organization. We demonstrate the usefulness of bioreactors to evidence hidden diversity in the soil when it passes through bioreactors. By obtaining the same growth of inoculated plants and the control with chemical synthesis fertilizers, we evidence the potential of the methodology that we have called directed bioprospecting to grow a complex nitrogen-fixing microbial community. The simplicity of the reactor’s operation makes its application promising for developing countries with low technological progress