Biochemical and molecular characterization of Campylobacter fetus isolates from bulls subjected to bovine genital campylobacteriosis diagnosis in Spain

Authors’ contributions: GA and ECF conceived the study and participated in its design. NPF performed the biochemical and PCR tests and interpreted the results with NK. NPF, MO and AH performed the whole genomes analysis and interpreted the results. MF isolated the Campylobacter spp. strains from bull preputial samples and identifed them by MALDI-TOF. NPF and NK wrote the manuscript, with interpretation of results, material and methods and discussion inputs from GA, ECF, MO, AH, MF and IP. All authors read and approved the fnal manuscript. Esther Collantes-Fernández and Gorka Aduriz contributed equally to this work and share last authorship.Bovine genital campylobacteriosis (BGC) is caused by Campylobacter fetus subsp. venerealis (Cfv) including its biovar intermedius (Cfvi). This sexually transmitted disease induces early reproductive failure causing considerable economic losses in the cattle industry. Using a collection of well-characterized isolates (n=13), C. fetus feld isolates (n=64) and saprophytic isolates resembling Campylobacter (n=75) obtained from smegma samples of breeding bulls, this study evaluated the concordance of the most used phenotypic (H2S production in cysteine medium and 1% glycine tolerance) and molecular (PCR) methods for the diagnosis of BGC and assessed possible cross-reactions in the molecular diagnostic methods. Characterization at the subspecies level (fetus vs. venerealis) of C. fetus isolated from bull preputial samples using phenotypic and molecular (PCR targeting nahE and ISCfe1) methods showed moderate concordance (κ=0.462; CI: 0.256–0.669). No cross-reactions were observed with other saprophytic microaerophilic species or with other Campylobacter species that can be present in preputial samples. Whole genome sequencing (WGS) of discrepant isolates showed 100% agreement with PCR identifcation. For the diferentiation of Cfv biovars, comparison of the H2S test (at 72 h and 5 days of incubation) and a PCR targeting the L-cysteine transporter genes showed higher concord‑ ance when H2S production was assessed after 5 days (72 h; κ=0.553, 0.329–0.778 CI vs. 5 days; κ=0.881, 0.631–1 CI), evidencing the efcacy of a longer incubation time. This study confrmed the limitations of biochemical tests to correctly identify C. fetus subspecies and biovars. However, in the case of biovars, when extended incubation times for the H2S test (5 days) were used, phenotypic identifcation results were signifcantly improved, although PCR-based methods produced more accurate results. Perfect agreement of WGS with the PCR results and absence of cross-reactions with non-C. fetus saprophytic bacteria from the smegma demonstrated the usefulness of these methods. Nevertheless, the identifcation of new C. fetus subspecies-specifc genes would help to improve BGC diagnosis.Depto. de Sanidad AnimalFac. de VeterinariaTRUEpu

Exploring the Prevalence and Resistance of Campylobacter in Urban Bird Populations

The increasing urbanization of ecosystems has had a significant impact on wildlife over the last few years. Species that find an unlimited supply of food and shelter in urban areas have thrived under human presence. Wild birds have been identified as amplifying hosts and reservoirs of Campylobacter worldwide, but the information about its transmission and epidemiology is still limited. This study assessed the prevalence of Campylobacter in 137 urban birds admitted at a wildlife rescue center, with 18.8% of individuals showing positive. C. jejuni was the most frequent species (82.6%), followed by C. coli and C. lari (4.3% each). The order Passeriformes (33.3%) showed significant higher presence of Campylobacter when compared to orders Columbiformes (0%) and Ciconiiformes (17.6%), as well as in samples collected during the summer season (31.9%), from omnivorous species (36.8%) and young individuals (26.8%). Globally, Campylobacter displayed a remarkable resistance to ciprofloxacin (70.6%), tetracycline (64.7%), and nalidixic acid (52.9%). In contrast, resistance to streptomycin was low (5.8%), and all the isolates showed susceptibility to erythromycin and gentamycin. The results underline the importance of urban birds as reservoirs of thermophilic antimicrobial-resistant Campylobacter and contribute to enhancing the knowledge of its distribution in urban and peri-urban ecosystems.Simple Summary: Wildlife has been described as a sylvatic reservoir for a multitude of pathogens. The interactions between wild birds, domestic animals, and humans in urban areas are high, so monitoring urban birds is key for the surveillance of zoonosis such as campylobacteriosis. This infection is mainly caused by thermophilic Campylobacter spp., and it is the most reported foodborne zoonosis in the European Union. This study aimed to evaluate the prevalence of thermophilic Campylobacter isolates and their antimicrobial resistance pattern in urban wild birds. Results showed that 16.8% of birds were positive for Campylobacter, with 82.4% of the isolates resistant to at least one antimicrobial. The taxonomic order of individuals, main diet, age, and season of sampling were significant factors associated with Campylobacter spp. carriage. Although the prevalence of Campylobacter was low, the rate of antimicrobial-resistant isolates is worrying, so similar studies should be included in the antimicrobial resistance surveillance programs.Ministerio de Transición Ecológica (España)Sección Deptal. de Fisiología (Veterinaria)Sección Deptal. de Farmacología y Toxicología (Veterinaria)Depto. de Nutrición y Ciencia de los AlimentosFac. de VeterinariaTRUEpu

Exploring the Prevalence and Resistance of Campylobacter in Urban Bird Populations

Wildlife has been described as a sylvatic reservoir for a multitude of pathogens. The interactions between wild birds, domestic animals, and humans in urban areas are high, so monitoring urban birds is key for the surveillance of zoonosis such as campylobacteriosis. This infection is mainly caused by thermophilic Campylobacter spp., and it is the most reported foodborne zoonosis in the European Union. This study aimed to evaluate the prevalence of thermophilic Campylobacter isolates and their antimicrobial resistance pattern in urban wild birds. Results showed that 16.8% of birds were positive for Campylobacter, with 82.4% of the isolates resistant to at least one antimicrobial. The taxonomic order of individuals, main diet, age, and season of sampling were significant factors associated with Campylobacter spp. carriage. Although the prevalence of Campylobacter was low, the rate of antimicrobial-resistant isolates is worrying, so similar studies should be included in the antimicrobial resistance surveillance programs.Ministry of Ecological Transition (MITECO) of Spain2.4 Q1 JCR 20220.552 Q1 SJR 2023No data IDR 2023UE

Prevalence and antimicrobial resistance of Campylobacter from wild birds of prey in Spain

Wild birds have been identified as a relevant reservoir of Campylobacter spp., therefore, a potential source of infection in humans and domestic animals. The objective of this study was to determine the occurrence of Campylobacter spp. on birds of prey in Spain. In addition, antibiotic resistance profiles of the isolates were evaluated. A total of 689 specimens of 28 raptor species were analyzed, with a resulting individual prevalence of 7.5%. C. jejuni was the most frequently isolated species (88.5%), followed by C. coli and C. lari (3.8% each). The occurrence of Campylobacter was significantly higher (p < 0.05) in nocturnal birds of prey (15.3%), in spring season (12.2%) and in carnivorous species (9.4%). Isolates displayed a remarkable resistance to nalidixic acid (69.9%), ciprofloxacin (69.9%), and tetracycline (55.6%), and a low resistance to streptomycin (6.7%). Our findings highlight the importance of birds of prey as reservoirs of Campylobacter strains and their significant role as carriers of antimicrobial resistance.Depto. de FisiologíaFac. de VeterinariaTRUEpu