First Description of Mergibacter septicus Isolated from a Common Tern (Sterna hirundo) in Germany

Mergibacter septicus (M. septicus), previously known as Bisgaard Taxon 40, is a recently described species within the Pasteurellaceae family. In this study, we present a M. septicus strain isolated from a common tern (Sterna hirundo) chick that died just after fledging from the Banter See in Wilhelmshaven, Germany. The recovered M. septicus strain underwent microbiological phenotypic characterization, followed by whole genome sequencing on Illumina and Nanopore platforms. Phenotypically, M. septicus 19Y0039 demonstrated resistance to colistin, cephalexin, clindamycin, oxacillin, and penicillin G. The genome analysis revealed a circular 1.8 Mbp chromosome without any extrachromosomal elements, containing 1690 coding DNA sequences. The majority of these coding genes were associated with translation, ribosomal structure and biogenesis, followed by RNA processing and modification, and transcription. Genetic analyses revealed that the German M. septicus strain 19Y0039 is related to the American strain M. septicus A25201^T. Through BLAST alignment, twelve putative virulence genes previously identified in the M. septicus type strain A25201^T were also found in the German strain. Additionally, 84 putative virulence genes distributed across nine categories, including immune modulation, effector delivery system, nutrition/metabolic factors, regulation, stress survival, adherence, biofilm, exotoxin, and motility, were also identified.