title: AeromonasDiversity and Antimicrobial Susceptibility in Freshwater-An Attempt to Set Generic Epidemiological Cut-Off Values.
abstract: The importance of the role of environment in the dissemination of antimicrobial resistant bacteria is now well recognized. Thus, bacterial indicators to monitor the phenomena are required. TheAeromonasgenus is autochthonous in the aquatic environment and easy to detect in any water type, such as freshwater, or wastewater. These microorganisms are also causing infections in humans and animals (including fish). Furthermore, asAeromonasspp. is able to acquire antimicrobial resistance mechanisms, it is candidate for indicator bacteria to follow antimicrobial resistance dissemination in aquatic environments. Unfortunately, to date, interpretation criteria forAeromonasspp. for antimicrobial susceptibility tests are scarce in the literature. No epidemiological cut-off values forAeromonasare currently available at EUCAST to interpret Minimum Inhibitory Concentrations (MIC). The only interpretation criteria available are clinical breakpoints from CLSI that are adapted fromEnterobacteriaceae. Based on the results of MIC distributions obtained for a collection of environmental isolates ofAeromonas, this study aimed at proposing tentative epidemiological cut-off values (COWT) forAeromonasspp. assessing whether the genus is an acceptable level of definition. Thus, 233 isolates collected from 16 rivers were identified at species level using Maldi-Tof (Bruker). Eleven different species were identified, the most abundant wereA. bestiarum(n= 54),A. salmonicida(n= 45),A. sobria(n= 41), andA. eucrenophila(n= 37). 96-well micro-plates containing different concentrations of 15 antimicrobials, namely cefotaxime, ceftazidime, chloramphenicol, colistin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, nalidixic acid, oxolinic acid, streptomycin, temocillin, tetracycline, and trimethoprim-sulfamethoxazole, were prepared. The broth micro-dilution method was used to determine the antimicrobial susceptibility of each isolate. The estimation of COWTvalues was satisfactory obtained at genus level for all antimicrobials except cefotaxime and erythromycin. This first step is an invitation for other research teams to increase the amount of antimicrobial resistance data collected. Then, robustness of our proposed provisional generic epidemiological cut-off values could be assessed by testing antimicrobial susceptibility of variousAeromonascollections.
authors.affiliation: Mycoplasmology-Bacteriology Unit, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France; Bretagne-Loire UniversityRennes, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Baron
authors.affiliation: Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health and Safety (Anses), Paris-Est University Maisons-Alfort, France.
authors.forename: Sophie A
authors.initials: SA
authors.lastname: Granier
authors.affiliation: Mycoplasmology-Bacteriology Unit, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France; Bretagne-Loire UniversityRennes, France.
authors.forename: Emeline
authors.initials: E
authors.lastname: Larvor
authors.affiliation: Mycoplasmology-Bacteriology Unit, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France; Bretagne-Loire UniversityRennes, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Jouy
authors.affiliation: Mycoplasmology-Bacteriology Unit, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France; Bretagne-Loire UniversityRennes, France.
authors.forename: Maelan
authors.initials: M
authors.lastname: Cineux
authors.affiliation: Laboratory for Hydrology, French Agency for Food, Environmental and Occupational Health and Safety (Anses) Nancy, France.
authors.forename: Amandine
authors.initials: A
authors.lastname: Wilhelm
authors.affiliation: Laboratory for Hydrology, French Agency for Food, Environmental and Occupational Health and Safety (Anses) Nancy, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Gassilloud
authors.affiliation: Bretagne-Loire UniversityRennes, France; Epidemiology and Welfare in Poultry and Rabbit Farming, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Le Bouquin
authors.affiliation: Mycoplasmology-Bacteriology Unit, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France; Bretagne-Loire UniversityRennes, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Kempf
authors.affiliation: Bretagne-Loire UniversityRennes, France; Epidemiology and Welfare in Pigs, Ploufragan-Plouzané Laboratory, French Agency for Food, Environmental and Occupational Health and Safety (Anses)Ploufragan, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Chauvin
keywords: Aeromonas spp.; ECOFFinder; antimicrobial resistance; epidemiological cut-off; freshwater; minimum inhibitory concentration; normalized resistance interpretation method