Search

International audience

The effectiveness of antibiotics has been reduced since their discovery. Surveillance and monitoring systems are key elements to collect and assess the trends of antibiotic resistance (ABR). Livestock data on ABR are traditionally collected from bacterial populations of clinical and non-clinical isolates. Resistance data on non-clinical isolates are based on the Decision 2013/652/EU in Europe. For clinical isolates, different standards, laboratory methods and methodologies are applied to collect ABR data. Further, a clinical interpretation is preferred in clinical isolates, while an epidemiological approach is frequently used in non-clinical isolates. Lack of harmonization between data types (clinical vs. non-clinical isolates) prevents the data comparison. The Normalized Resistance Interpretation (NRI) method was applied to circumvent the lack of ABR data harmonization between and within countries. Analyses were performed to identify associations between resistance to four antibiotics (ampicillin, gentamicin, nalidixic acid and tetracycline) and the data type variable per animal category (broiler, turkey and calf) within countries. Within countries, higher resistance proportions were found in clinical isolates vs commensal isolates to: gentamicin in broilers from France and in calves from Germany and France, nalidixic acid in calves from France and Germany and tetracycline for calves from France and Germany. In contrast, a higher probability of resistance in non-clinical isolates was encountered for tetracycline in broilers and turkeys from Germany and France and to gentamicin in turkeys from Germany. It seems that the higher presence of resistance in one data type (i.e. clinical or non-clinical isolates) is strongly associated with the relationship between the animal species and the antibiotic. The NRI identifies the wild-type distribution providing approximate epidemiological cut-offs that allow comparing quantitative results from different ABR systems with a different level of harmonization. This method might be regularly used in veterinary medicine and in One Health studies to compare not harmonized ABR systems until international harmonization of ABR is achieved.

National audience; Antimicrobial resistance (AMR) is increasing worldwide in humans, animals and the environment. Integrons are genetic elements involved in the dissemination of AMR, mostly among Gram-negative bacteria. Integrons are able to capture and express antibiotic resistance genes embedded within mobile gene cassettes Prevalence of integrons is well documented in Enterobacteriaceae, but data are still relatively rare in Aeromonas. Due to its ecological and genetic capabilities, Aeromonas is now proposed as an indicator of AMR dissemination in aquatic environment, and is considered, as well as integrons, as a vehicle of dissemination of antibiotic resistance genes. The aim of this study was to evaluate the prevalence of integrons in Aeromonas isolates from fishes: wild freshwater fishes, trout (fish farming) and diseased fishes (fish farming). A total of 310 Aeromonas were collected in France from wild freshwater fishes (n=109, in 2014), diseased fishes (n=124, 1985-2014), and from healthy trout coming from fish farming (n= 77, in 2014/2015). Class 1, class 2 and class 3 integrons were detected by a multiplex qPCR. Antimicrobial susceptibility of the isolates was assessed using the broth microdilution method. Eighty-one isolates harbored integrons. No integron was detected in isolates from wild freshwater fishes. Integrons were present in 54.8 % of the isolates recovered from diseased fishes and in 16.9 % of those recovered from healthy trout. Class 1 integrons were the most often detected (n=80), only one isolate recovered from trout harbored a class 2 integron. No class 3 integron was detected. In this study, we observed the highest prevalence of integrons in Aeromonas from diseased fishes and a higher prevalence in trout (fish farming) compared to isolates from wild freshwater fishes. It is assumed that this trend could be linked to the antibiotic selection pressure in fish farms, but further evaluation is necessary to investigate this point. The susceptibility profiles of the isolates and the link with integrons are under characterization.

International audience; Le Résapath joue un rôle majeur dans la surveillance de l'antibiorésistance en santé animale en France. Consolidé en plusieurs étapes depuis sa création en 1982, ce réseau de surveillance événementielle est basé sur la participation volontaire des laboratoires adhérents qui transmettent les résultats des antibiogrammes qu'ils réalisent pour leurs clients. L'objectif de cette étude était d'estimer la représentativité et la couverture du Résapath par filière animale en 2015. La proportion d'antibiogrammes collectés par le réseau par rapport à l'ensemble des antibiogrammes réalisés sur le territoire national était variable selon les espèces, s'échelonnant de 50 % pour les animaux de compagnie (chiens et chats) à 90 % pour la filière porcine. La couverture géographique du Résapath était globalement en accord avec la répartition géographique estimée des populations animales sur le territoire. Cette étude fournit les éléments pour un développement potentiel du Résapath afin d'assurer une meilleure représentativité des filières et du territoire.; Abstract Representativeness and coverage of the RESAPATH, the French surveillance network for antimicrobial resistance in pathogenic bacteria of animal origin The RESAPATH plays a major role in antimicrobial resistance surveillance in animal health in France. Consolidated since its creation in 1982, the RESAPATH is a surveillance network based on the voluntary participation of diagnostic laboratories, which transmit the results of the antibiograms performed for their clients. The objective of this study was to assess the representativeness and the coverage of the RESAPATH by animal sector in 2015. The proportion of antibiograms collected by the network compared to all the antibiograms carried out in France varied according to the sector, ranging from 50% for pets (dogs and cats), to 90% for the swine sector. The geographical coverage of the RESAPATH was broadly consistent with the geographical distribution of the estimated animal populations over the territory. This study provides key elements for a potential development of the RESAPATH in order to achieve a better representativeness of the animal sectors as well as the whole territory.

International audience; Introduction: Antimicrobial resistance is one of the major health challenges of the XXI century. In France, the “Ecoantibio” program aimed to reduce the use of veterinary drugs by 25% in 5 years. To assess the impact of this plan, an inventory of the situation is needed. In France, fish farming is a minor production not included in surveillance of antimicrobial resistance in animals. Very few data are available and the therapeutic arsenal is limited. Methodology: Three French laboratories managed a study on antimicrobial susceptibility of Aeromonas spp. isolates collected from diseased fish, by sharing their collections established since 1984. Harmonized protocols were used. The first step consisted in identifying isolates by MALDI-TOF. Motility and pigmentation reactions were also assessed to help identification at the species level. Secondly, antimicrobial susceptibility was tested by two methods: agar diffusion (AD) and broth dilution (BD). Twelve antimicrobial agents representing seven classes were chosen including agents labeled in French aquaculture (flumequine, oxolinic acid, trimethoprim-sulfamethoxazole, oxytetracycline and florfenicol). 120 isolates of Aeromonas mainly isolated from trouts (n=52, 43.3%) and turbots (n=52, 43.3%) were analyzed (27 old isolates and 93 contemporary isolates, collected in 1984–2000 and 2001–2014, respectively). Results: Aeromonas salmonicida was the most abundant species (n=77, 64.1%). Discrepancies were observed between MALDI-TOF identification and phenotypic traits. Out of the 77 isolates with A.salmonicida characteristic phenotype, the identification was confirmed for only 26 by MALDI-TOF. For the other 51 isolates, A. salmonicida identification was among the three first propositions of MALDI-TOF. Resistance to enrofloxacin, trimethoprim-sulfamethoxazole, flumequine and oxolinic acid was more frequent for the contemporary isolates compared to the oldest. In the same way, resistance to florfenicol and gentamicin was observed only in contemporary isolates whereas resistance to colistin and oxytetracycline seemed more prevalent among old isolates. AD and BD methods gave consistent results. Conclusions: A variation of antimicrobial resistance between old and contemporary isolates was observed. MALDI-TOF technology, in development in veterinary laboratories, is reliable for identification of Aeromonas spp. but the MALDI-TOF database should be improved to enable identification of Aeromonas isolates at the species level

National audience

International audience