Soil contamination by Echinococcus multilocularis in rural and urban vegetable gardens in relation to fox, cat and dog faecal deposits.

Echinococcus multilocularis eggs are deposited on the ground with the faeces of the carnivore definitive hosts. A reliable assessment of the spatial distribution of E. multilocularis eggs in environments used by humans is crucial for the prevention of alveolar echinococcosis (AE). This study was conducted in 192 rural and 71 urban vegetable gardens in AE endemic areas of north-eastern France. Its objective was to explore the relationship between the spatial distribution of E. multilocularis estimated from the collection and molecular analysis of two types of samples: faeces and soil. A total of 1024 carnivore faeces and 463 soil samples were collected and analysed by real-time PCR. No fox droppings and no positive soil samples were collected from the urban gardens. Positive soil samples, positive carnivore faeces, or both, were found in 42%, 24% and 6% of the sampled rural gardens, respectively. No significant association was found between the detection of E. multilocularis in soil samples collected from 50 gardens during a single sampling session and the extent and frequency of deposits of fox and cat faeces collected during repeated sampling sessions conducted in the previous months. In 19/50 gardens, E. multilocularis was detected in the soil while no positive faeces had been collected in the previous 12 months. Conversely, in 8/50 gardens, no soil samples were positive although positive faeces had been collected in the previous months. Collecting and analysing faeces provide information on soil contamination at a given time, while analysing soil samples provides an overview of long-term contamination.

TITLE: Contamination du sol par Echinococcus multilocularis dans des jardins potagers ruraux et urbains en relation avec les dépôts fécaux de renards, de chats et de chiens. ABSTRACT: Les œufs d'Echinococcus multilocularis sont déposés sur le sol avec les fèces des carnivores hôtes définitifs. Une évaluation fiable de la distribution spatiale des œufs d'E. multilocularis dans les environnements utilisés par l'homme est cruciale pour la prévention de l'échinococcose alvéolaire (EA). La présente étude a été conduite dans 192 jardins potagers ruraux et 71 jardins potagers urbains des zones endémiques d'EA du nord-est de la France. Son objectif était d'explorer la relation entre la distribution spatiale d'E. multilocularis estimée à partir de la collecte et de l'analyse moléculaire de deux types d'échantillons : des fèces et du sol. Au total, 1024 fèces et 463 échantillons de sol ont été collectés et analysés par PCR en temps réel. Aucun excrément de renard et aucun échantillon de sol positif n'a été collecté dans les jardins urbains. Des échantillons de sol positifs, des fèces de carnivores positives ou les deux ont été trouvés dans 42 %, 24 % et 6 % des jardins ruraux échantillonnés. Aucune association significative n'a été trouvée entre la détection d'E. multilocularis dans les échantillons de sol collectés dans 50 potagers lors d'une unique session d'échantillonnage et l'importance et la fréquence des dépôts de fèces de renards et de chats collectées lors d'échantillonnages répétés conduits au cours des mois précédents. Dans 19/50 potagers, E. multilocularis a été détecté dans le sol alors qu'aucun excrément positif n'avait été collectés dans les 12 mois précédents. A l'inverse, dans 8/50 potagers aucun échantillon de sol n'était positif alors que des fèces positives avait été collectées dans les mois précédents. La collecte et l'analyse de fèces renseignent sur la contamination du sol à un instant donné, alors que l'analyse d'échantillons de sol fournissent un aperçu de la contamination à long terme.

Detection of Shiga toxin-producing Escherichia coli serotypes O26:H11, O103:H2, O111:H8, O145:H28, and O157:H7 in raw-milk cheeses by using multiplex real-time PCR.

Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are a diverse group of food-borne pathogens with various levels of virulence for humans. In this study, we describe the use of a combination of multiple real-time PCR assays for the screening of 400 raw-milk cheeses for the five main pathogenic STEC serotypes (O26:H11, O103:H2, O111:H8, O145:H28, and O157:H7). The prevalences of samples positive for stx, intimin-encoding gene (eae), and at least one of the five O group genetic markers were 29.8%, 37.3%, and 55.3%, respectively. The H2, H7, H8, H11, and H28 fliC alleles were highly prevalent and could not be used as reliable targets for screening. Combinations of stx, eae variants, and O genetic markers, which are typical of the five targeted STEC serotypes, were detected by real-time PCR in 6.5% of the cheeses (26 samples) and included stx-wzx(O26)-eae-ß1 (4.8%; 19 samples), stx-wzx(O103)-eae-ε (1.3%; five samples), stx-ihp1(O145)-eae-γ1 (0.8%; three samples), and stx-rfbE(O157)-eae-γ1 (0.3%; one sample). Twenty-eight immunomagnetic separation (IMS) assays performed on samples positive for these combinations allowed the recovery of seven eaeß1-positive STEC O26:H11 isolates, whereas no STEC O103:H2, O145:H28, or O157:H7 strains could be isolated. Three stx-negative and eaeß1-positive E. coli O26:[H11] strains were also isolated from cheeses by IMS. Colony hybridization allowed us to recover STEC from stx-positive samples for 15 out of 45 assays performed, highlighting the difficulties encountered in STEC isolation from dairy products. The STEC O26:H11 isolates shared the same virulence genetic profile as enterohemorrhagic E. coli (EHEC) O26:H11, i.e., they carried the virulence-associated genes EHEC-hlyA, katP, and espP, as well as genomic O islands 71 and 122. Except for one strain, they all contained the stx1 variant only, which was reported to be less frequently associated with human cases than stx2. Pulsed-field gel electrophoresis (PFGE) analysis showed that they displayed high genetic diversity; none of them had patterns identical to those of human O26:H11 strains investigated here.