Culturomics Profiling of Nasal Cavities of European Wild Rabbits on the Iberian Peninsula: Antimicrobial Resistance and Detection of Microorganisms of Public Health Interest

Background: European wild rabbits (Oryctolagus cuniculus) are closely connected to the natural environment and might be a potential source of pathogenic bacteria and/or antimicrobial-resistant bacteria. The objective was to identify the bacterial community (species and genera) that colonizes the nasal cavities of European wild rabbits as well as to study the antimicrobial resistance (AMR) phenotypes of bacteria of public health interest. Methods: A total of 147 nasal swabs individually collected from wild rabbits in Spain and Portugal (between 2022 and 2024) were studied. Samples were inoculated in different culture media, and isolates were identified by MALDI-TOF. The AMR phenotypes of staphylococci, mammaliicocci, enterococci and Enterobacterales were evaluated by the disk-diffusion method. Results: Overall, 557 non-repetitive isolates were obtained (1 isolate per species and AMR phenotype of each animal). A wide diversity of genera (n = 40) and species (n = 90) was found. Staphylococcus (21.2%), Mammaliicoccus (11.7%), Enterococcus (23.3%), Enterobacter (9.2%), Citrobacter (4.5%) and Escherichia (5.9%) were the most detected genera. Most animals presented more than one genera (78.9%), and in 15.7% of them, at least five genera were identified. Susceptibility to all antimicrobials tested was found in 37.2%, 38.5% and 51.6% of staphylococci/mammaliicocci, enterococci and Escherichia coli isolates: moreover, multidrug resistance was detected in 10.4%, 14.6% and 9.6% of these groups of bacteria. Moreover, important species of pathogenic bacteria were found, such as Yersinia enterolocolitica (0.5%) and Bordetella bronchiseptica (0.2%), among others. Conclusions: A high bacterial diversity was detected in the nasal cavities of European wild rabbits from the Iberian Peninsula, including pathogenic species and/or resistant strains of public health interest.