Uncovering hidden threats: prevalence, antibiotic resistance and virulence gene profiles of Escherichia coli strains isolated from Testudines and their aquatic habitats.

Background: The gut microbiota of Testudines is fundamental to their digestion and overall health, yet remains a poorly investigated area in their biology, particularly in wild freshwater turtle (terrapins) and tortoise populations within South Africa. This study investigated the occurrence, diversity, virulence genes and antibiotic resistance of Escherichia coli isolated from Testudine gut microbiota and sediments at Timbavati Private Nature Reserve, South Africa.

Methods And Results: Cloacal swab samples were collected from 36 wild Testudines and 20 sediment samples from temporary and permanent water bodies.

Archival mitogenomes identify invasion by the CAPE lineage caused an African amphibian extinction in the wild.

Outbreaks of emerging infectious diseases are influenced by local biotic and abiotic factors, with host declines occurring when conditions favour the pathogen. Deterioration in the population of the micro-endemic Tanzanian Kihansi spray toad () occurred after the construction of a hydropower dam, implicating habitat modification in this species decline. Population recovery followed habitat augmentation; however, a subsequent outbreak of chytridiomycosis caused by () led to the spray toad's extinction in the wild.

Environment predicts lineage distribution and zones of recombination in South Africa.

The amphibian-infecting chytrid fungus, (), is widespread throughout Africa and is linked to declines of populations and species across the continent. While it is well established that the lineage of encodes traits which determine disease severity, knowledge around how lineages are distributed according to environmental envelope is unclear. We here studied the distribution of in South Africa based on the two lineages found, GPL and CAPE, in terms of their genome and environmental envelope statistically associated with their distribution.

Occurrence, Antimicrobial Resistance, and Virulence Profiles of Serovars Isolated from Wild Reptiles in South Africa.

Reptiles are carriers of an array of microorganisms, including significant zoonotic bacteria of the genus , which cause a disease referred to as salmonellosis that affects both animals and humans. This study investigated the occurrence of serovars in wild reptiles at Timbavati Private Game Reserve in Limpopo Province, South Africa, and examined their virulence and antimicrobial resistance gene profiles. A total of 19 wild reptiles were sampled, which resulted in 30 presumptive isolates.

Comparison of RPMI 2650 cell layers and excised sheep nasal epithelial tissues in terms of nasal drug delivery and immunocytochemistry properties.

Nasal drug administration has been identified as a potential alternative to oral drug administration, especially for systemic delivery of large molecular weight compounds. Major advantages of nasal drug delivery include high vascularity and permeability of the epithelial membranes as well as circumvention of first-pass metabolism. RPMI 2650 cell layers (in vitro cell model) and excised sheep nasal mucosal tissues (ex vivo sheep model) were evaluated with regard to epithelial thickness, selected tight junction protein expression (i.

Discriminating lineages of Batrachochytrium dendrobatidis using quantitative PCR.

The ability to detect and monitor infectious disease in a phylogenetically informative manner is critical for their management. Phylogenetically informative diagnostic tests enable patterns of pathogen introduction or changes in the distribution of genotypes to be measured, enabling research into the ecology of the pathogen. Batrachochytrium dendrobatidis (Bd), a causative agent of chytridiomycosis in amphibian populations, emerged worldwide in the 21st century and is composed of six lineages which are display varying levels of virulence in their hosts.

Response to Comment on "Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity".

Lambert question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts.

Capsaicin and Piperine as Functional Excipients for Improved Drug Delivery across Nasal Epithelial Models.

The fruit from various pepper plants has been employed for the seasoning of food, as perfuming agents, and also as traditional medicines. Phytochemicals isolated from different pepper species have been found to modulate the pharmacokinetics of orally administered drugs. This study investigated the possibility to apply capsaicin and piperine (extracted alkaloids) as modulators for drug delivery across the nasal epithelium.

Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity.

Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia.

Genetic variability and ontogeny predict microbiome structure in a disease-challenged montane amphibian.

Amphibian populations worldwide are at risk of extinction from infectious diseases, including chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Amphibian cutaneous microbiomes interact with Bd and can confer protective benefits to the host. The composition of the microbiome itself is influenced by many environment- and host-related factors.

Amphibian skin defences show variation in ability to inhibit growth of isolates from the Global Panzootic Lineage.

The fungal pathogen has caused declines and extinctions in hundreds of amphibian species across the world. Virulence varies among and within lineages; the Global Panzootic Lineage (GPL) is the most pathogenic, although there is also variation in lethality among GPL isolates. Amphibians have a number of defences against pathogens, and skin products including the microbiota and host peptides have considerable influence over disease progression.

Estimating Herd Immunity to Amphibian Chytridiomycosis in Madagascar Based on the Defensive Function of Amphibian Skin Bacteria.

For decades, Amphibians have been globally threatened by the still expanding infectious disease, chytridiomycosis. Madagascar is an amphibian biodiversity hotspot where () has only recently been detected. While no -associated population declines have been reported, the risk of declines is high when invasive virulent lineages become involved.

Mitigating amphibian chytridiomycoses in nature.

Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife.

Widespread presence of the pathogenic fungus Batrachochytrium dendrobatidis in wild amphibian communities in Madagascar.

Amphibian chytridiomycosis, an emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), has been a significant driver of amphibian declines. While globally widespread, Bd had not yet been reported from within Madagascar. We document surveys conducted across the country between 2005 and 2014, showing Bd's first record in 2010.

Spatial assessment of amphibian chytrid fungus (Batrachochytrium dendrobatidis) in South Africa confirms endemic and widespread infection.

Chytridiomycosis has been identified as a major cause of global amphibian declines. Despite widespread evidence of Batrachochytrium dendrobatidis infection in South African frogs, sampling for this disease has not focused on threatened species, or whether this pathogen poses a disease risk to these species. This study assessed the occurrence of Bd-infection in South African Red List species.

West Africa - a safe haven for frogs? A sub-continental assessment of the chytrid fungus (Batrachochytrium dendrobatidis).

A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd). While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species) for the presence of Bd.

Morphology of the elygium and developing umbraculum in the eye of Amietia vertebralis tadpoles.

The elygium is a darkly pigmented projection over the pupil of the tadpoles of certain species that live mostly at high altitudes. It has been suggested that this structure shades the retina, protecting it from high UV levels. In post-metamorphic individuals, the elygium is replaced by a structure known as an umbraculum.

Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage.

Batrachochytrium dendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. Despite widespread effort to understand the emergence of this panzootic, the origins of the infection, its patterns of global spread, and principle mode of evolution remain largely unknown. Using comparative population genomics, we discovered three deeply diverged lineages of Bd associated with amphibians.

Rapid global expansion of the fungal disease chytridiomycosis into declining and healthy amphibian populations.

The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis, is enigmatic because it occurs globally in both declining and apparently healthy (non-declining) amphibian populations. This distribution has fueled debate concerning whether, in sites where it has recently been found, the pathogen was introduced or is endemic. In this study, we addressed the molecular population genetics of a global collection of fungal strains from both declining and healthy amphibian populations using DNA sequence variation from 17 nuclear loci and a large fragment from the mitochondrial genome.

The challenge of conserving amphibian megadiversity in Madagascar.

Highly diverse and so far apparently untouched by emergent diseases, Malagasy frogs nevertheless are threatened by ongoing habitat destruction, making pro-active conservation actions especially important for preserving this unique, pre-decline, amphibian fauna.

Relationships among size, development, and Batrachochytrium dendrobatidis infection in African tadpoles.

The fungal pathogen Batrachochytrium dendrobatidis contributes to the global decline of amphibians. Although mortality from B. dendrobatidis infections occurs primarily in postmetamorphic individuals, infected tadpoles may suffer reduced growth and developmental rates as a result of oral chytridiomycosis, possibly affecting adult fitness.