Biology subjects

Guernier-Cambert, V.

Publications and source records attributed to Guernier-Cambert, V..

5 recordsLinked to original sources

bioRxiv2026

Leptospira infection in European hedgehogs (Erinaceus europaeus): occurrence, diversity and associated risk factors in Greater Paris, France.

Background Leptospirosis is a zoonotic infectious disease whose prevalence is increasing in mainland France. While rodents are common reservoirs of pathogenic Leptospira, the pathogen diversity detected in French human clinical cases exceeds that currently identified in local rodents, suggesting that some unidentified host species may carry strains of public health importance. The aim of this study was to investigate Leptospira infection in a population of rescued injured hedgehogs (Erinaceus europaeus) in Ile-de-France, as well as to characterize the circulating genotypes and serogroups. Methodology/principal findings In 2023-2024, kidneys from 270 dead hedgehogs collected by the Veterinary University Hospital for Wild Fauna at the National Veterinary School of Alfort, France, were tested for leptospiral DNA by real-time PCR. Twenty-two percent of individuals were qPCR-positive. Positive samples were genotyped to identify circulating species and species-groups (SGs) with L. interrogans SG5 being the most common. In addition, the Microscopic Agglutination Test was performed on 245 blood samples, with Australis identified as the predominant serogroup. The effect of individual and environmental variables on Leptospira infection status of hedgehogs was assessed, with age and season identified as significant predictors of infection. Conclusions/significance Our findings suggest that hedgehogs can harbour pathogenic Leptospira in Ile-de-France. Further investigation is warranted to establish the epidemiological links between hedgehogs and other host species, including humans. A finer-scale analysis of the ecological features at the sampling sites could also help better understand the risk factors of Leptospira infection in hedgehogs at a smaller spatial scale.

molecular biology↗

bioRxiv2026

Comparative evaluation of sample preparation and enrichment methods for culture and molecular detection of Burkholderia pseudomallei in naturally contaminated soils from Thailand over one year.

Background Burkholderia pseudomallei is a soil-dwelling bacterium that causes melioidosis. Accurate environmental detection of B. pseudomallei is critical for surveillance strategies and for tracing the source of human infection. However, the detection of B. pseudomallei in soil samples, which are complex matrices with a high microbial background, remains difficult. This study aimed to compare the culture and the molecular detection of B. pseudomallei with or without pre-enrichment in naturally contaminated soils from Thailand. Methodology/principal findings In 2025, a total of 640 soil samples were collected from 10 sites from different environments and sampling periods in Amnat Charoen Province. The soils were evaluated for the presence of B. pseudomallei either without enrichment or following enrichment in Ashdown or ACER broths, using culture and real-time PCR detection methods. qPCR consistently identified a higher number of B. pseudomallei positive samples than culture regardless of the pre-treatment method and sampling period. ACER enrichment nearly doubled the odds of detection compared with no enrichment (OR = 1.90) or with Ashdown enrichment (OR = 2.09), with a model-estimated mean Ct difference of 13.6 between ACER enrichment and no enrichment. Overall, qPCR yielded higher detection rates than culture for B. pseudomallei in soil samples, particularly following enrichment. Conclusions/significance This study highlights the importance of pre-enrichment protocols with detection techniques to successfully identify B. pseudomallei in environmental samples. For both culture and molecular detection methods, B. pseudomallei was better detected when the soil samples were enriched in ACER broth compared to Ashdown broth and without enrichment. These findings highlight the need for combining optimal selective enrichment strategies with detection techniques for environmental surveillance. Although ACER enrichment improved the recovery of viable strains, culture recovered B. pseudomallei from only a fraction of qPCR-positive samples, highlighting the need for more selective media to facilitate isolation of B. pseudomallei.

microbiology↗

bioRxiv2026

Pathogenic Leptospira in dogs and rodents in Tha Wang Pha, Thailand - Prevalence, diversity and linked environments

Human leptospirosis is a disease of public health importance in Thailand, but the animal species involved in the transmission cycle have not been fully uncovered. This study investigated Leptospira infection in dogs and terrestrial micromammals in rural Nan Province, Thailand, and the pathogen diversity. Sera from 95 seemingly healthy dogs and kidney samples from 399 micromammals were analyzed using real-time PCR for Leptospira detection, followed by conventional PCR and sequencing of infecting Leptospira. We investigated environmental factors associated with Leptospira infection in micromammals, using data collected during trapping. Real-time PCR revealed ongoing infection in 8.4% (8/95) of dogs and 10.0% (40/399) of terrestrial micromammals, with 12 infected species including Bandicota indica, Berylmys berdmorei, Berylmys bowersi, Mus cervicolor, Mus cookii, and Hylomys suillus. In this qPCR-positive micromammals, three pathogenic Leptospira species were identified: L. interrogans, L. weilii, and L. borgpetersenii. This represents the first confirmed detection of L. weilii in rodents in Thailand. Infected micromammals were found in agricultural and forest habitats but not in human settlements. Our study demonstrates potential complex leptospirosis epidemiology in rural Thailand, with multiple species serving as pathogenic Leptospira reservoirs across diverse habitats, and some shared pathogen diversity with human leptospirosis cases in Thailand. Free-roaming dogs may serve as bridge hosts, transmitting zoonotic Leptospira from micromammals to humans by visiting both animal habitats and human settlements. These findings emphasize the need for integrated One Health surveillance approaches to control leptospirosis in rural communities.

molecular biology↗

bioRxiv2024

Serological screening in animals combined with environmental surveys provides definite proof of the local establishment of Burkholderia pseudomallei in Guadeloupe

BackgroundMelioidosis is an emerging infectious disease caused by the soil-dwelling bacterium Burkholderia pseudomallei that affects both humans and animals. It is endemic in South and Southeast Asia, and northern Australia, causing an estimated 165,000 human cases annually worldwide. Human cases have been reported in the French West Indies (Martinique and Guadeloupe) since the 1990s. Conversely, no human cases have been reported in French Guiana, a French territory in South America. Our study aimed to investigate whether B. pseudomallei is locally established in Guadeloupe and French Guiana. We assessed animal exposure by serology and examined the presence of B. pseudomallei in the environment of seropositive animals. Methodology/Principal findingsBlood samples were collected from domestic animals in two goat farms in Les Saintes, Guadeloupe (n=31), and in 56 farms in French Guiana (n=670) and tested by ELISA. Serological follow up was performed on selected farms. Soil, water and goat rectal swabs were collected and analysed by culture and PCR. In French Guiana, the highest prevalence rates were observed in equids (24%) and cattle (16%), while in Les Saintes, a prevalence of 39% was observed in goats. The longitudinal study in Les Saintes revealed consistent high seropositivity in goats. A B. pseudomallei strain was isolated from the soil from one of the farms and detected in goat rectal swabs from the other farm. Conclusions/SignificanceOur environmental investigation prompted by the serologic data confirms the presence of B. pseudomallei in Les Saintes, consistent with documented human cases of melioidosis on this island. In French Guiana, our serologic results call for environmental surveys and a re-evaluation of human infections with melioidosis-like symptoms. The approach developed in this study may help to identify high-risk areas that warrant further investigation. Author summaryBurkholderia pseudomallei, an environmental bacterium, is the causative agent of melioidosis in humans and animals. If the disease has been historically reported to be endemic in South Asia and northern Australia, recent studies reveal its presence outside of these territories, both in the environment and among patients who have not travelled to endemic areas. Furthermore, the projected increase in extreme climatic events in the near future could increase the prevalence of the disease as well as cause its emergence in new territories. For these reasons, it is important to identify new areas at risk. Our study aimed to investigate the presence of the pathogen in French West Indies. We combined surveys in domestic animals (cattle, goats, horses, sheep, and pigs) and in the environment. The identification of seropositive animals without clinical signs, together with the isolation of B. pseudomallei in the environment of a goat farm in Guadeloupe, underscores the importance of including melioidosis in animal surveillance programs. The use of serologic methods can help identify animal exposure to the pathogen, thereby helping to identify areas where the pathogen may be present in the environment.

microbiology↗

bioRxiv2020

A preliminary investigation of major bacterial antibiotic resistance genes present in Australian fecal samples using shotgun metagenomics and targeted sequencing.

The gut microbiota is an immense reservoir of antimicrobial resistance genes (ARGs); however, in Australia the profile of the gut resistome, or ensemble of ARGs, has not been investigated. This study provides a first preliminary mapping of the major bacterial ARGs present in human, domestic dog and wild duck fecal samples collected from south-eastern Victoria, Australia; and evaluates the use of shotgun metagenomics sequencing (SMS) and targeted amplification of ARGs. We analysed SMS data using an in-house method and web-based bioinformatics tools: ResFinder and KmerResistance. We examined targeted sequences using One Codex or the PanBacterialAnalysis Torrent Suite plugin. All methods detected ARGs in all samples, with resistance to up to 13 classes of antibiotics detected overall. ARGs were more abundant in the human and dog samples than the duck samples. They mostly conferred resistance to three classes of antibiotics that are the most frequently prescribed in Australia: tetracycline, {beta}-lactams and MLSB (macrolide, lincosamide, streptogramin B). Targeted sequencing significantly improved sensitivity for detection of ARGs included in the panel; however, SMS provided quantitative information and allowed tentative identification of the host bacteria. For SMS, web-based and in-house methods gave comparable results, with discrepancies mostly due to different reference databases. The in-house method allowed manually checking results and potential errors, while web-based methods were user-friendlier and less time-consuming. More samples need to be investigated to fully describe the resistome in humans and animals in Australia.

genomics↗