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Macrolides are the first-line compounds used for the treatment of campylobacteriosis. Macrolide resistance remains low in France, with mutations in 23S rDNA being the main associated resistance mechanism. However, two erythromycin methyltransferases have also been identified : erm (B), which is mainly described in animal reservoirs, and erm (N), which is strictly described in humans. In France, between 2018 and 2023, erythromycin-resistant Campylobacter species strains were systematically sequenced and analyzed via an in-house bioinformatics pipeline, leading to the identification of the resistomes, MLST and cgMLST, as well as the characterization of the source of contamination. In this study, the genomes of 280 erythromycin-resistant strains were sequenced over a 6-year period. The identification of erythromycin-associated resistance markers revealed a predominance of 23S rDNA mutations, in 90% of cases, but also erm -type methyltransferases in 10% of cases: 75% for erm (N) and 25% for erm (B). Over this period, an important increase in the rate of erm -positive isolates was observed: 2% in 2018 compared with 13% in 2023, with 10% for erm (N) and 3% for erm (B). erm (N) has been found exclusively within a CRISPR-Cas9 operon, whereas erm (B) has been found within diverse types of resistance genomic islands. Each erm (N)- or erm (B)-positive isolate had at least two other resistance markers (mostly ciprofloxacin, tetracycline, or ampicillin) and often carried aminoglycoside-associated resistance genes. The majority of the erm -positive isolates were obtained from chicken. The increasing rates of erm -positive and multiresistant isolates make the monitoring of erythromycin-resistant Campylobacter strains, specifically within the chicken meat production, a topic of serious importance., Competing Interests: The authors declare no conflict of interest.

Purpose: In 2023, Helicobacter zhangjianzhongii was proposed as a new species in the Helicobacter genus. We here describe two human cases of H. zhangjianzhongii bacteremia., Methods: Four clinical strains from the Helicobacter genus isolated from blood culture between 2017 and 2023 were studied. They were initially identified as H. canis by MALDI-TOF and 16S rDNA sequencing. The strains were biochemically characterized and tested at different temperatures and atmospheres. Two databases were used to characterize the isolates: the Bruker® MBT compass Version 4.1.1 database and a in-house spectrum-enriched database. After bacterial DNA extraction the genomes were sequenced on NovaSeq 6000 (Illumina) and analyzed using an in-house pipeline., Results: Case 1 involved a 58-year-old woman who was hospitalized in a thoracic oncology unit because her general condition deteriorated in a setting of small-cell carcinoma. She presented with abdominal pain associated with significant hepatomegaly. Case 2 involved a 78-year-old woman on rituximab who was hospitalized to treat chest pain, anemia, and inflammatory syndrome. Both strains exhibited very similar microbiological and genomic characteristics, thus growth in a microaerobic atmosphere at 37°C and 42°C, oxidase-positivity, and urease- and catalase-negativity. Both were formally identified by whole-genome sequencing as H. zhangjianzhongii (ANI > 99% and DDH > 94%)., Conclusion: This proposed species is associated with bacteremia in humans. It is thus likely to be a novel human pathogen. Dogs may have been the source of infection., Competing Interests: Declarations. Conflict of interest: The authors declare no competing interests. Human ethics and consent to participate: All diagnostic methods were routine. As the strains were sent to the NRCCH for research purposes, there was no need for ethical approval or informed patient consent. The need for scrutiny by an ethics committee was deemed unnecessary because the scientific mission of the national reference center is mandated by Santé Publique France ( www.spf ). All information that could possibly identify patients was removed. Consent for publication: Not applicable., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)