Yokenella regensburgei, an environmental organism, is an emerging pathogen in patients chiefly with immune suppression. We report the draft genome of Y. regensburgei, strain UU2206353, isolated from the urinary tract of an immunocompetent individual. The assembled genome consisted of 4,669,536 bp distributed over 20 contigs with 4,283 protein-coding genes.

Yokenella regensburgei , belonging to the order Enterobacterales , is a rare and emerging human pathogen reported to cause both superficial and invasive infections. The 13 case reports in the literature worldwide highlight blood, bone and wound infections. To our knowledge this is the first case description of Y. regensburgei causing a urinary tract infection in a 69-year-old immunocompetent patient which was isolated in two separate specimens and identified using matrix-assisted laser desorption ionization time-of-flight MS. It was found to be susceptible to most antimicrobials but resistant to penicillin, amoxicillin-clavulanate, cefoxitin and colistin. Inducible chromosomal ampC resistance was demonstrated on disc approximation testing, and blaYOC-1 class C beta-lactamase, beta lactamase superfamily and MBL fold metallo-hydrolase genes were found on whole genome sequencing.

Freshwater mussels (Unionida) are suffering mass mortality events worldwide, but the causes remain enigmatic. Here, we describe an analysis of bacterial loads, community structure, and inferred metabolic pathways in the hemolymph of pheasantshells (Actinonaias pectorosa) from the Clinch River, USA, during a multi-year mass mortality event. Bacterial loads were approximately 2 logs higher in moribund mussels (cases) than in apparently healthy mussels (controls). Bacterial communities also differed between cases and controls, with fewer sequence variants (SVs) and higher relative abundances of the proteobacteria Yokenella regensburgei and Aeromonas salmonicida in cases than in controls. Inferred bacterial metabolic pathways demonstrated a predominance of degradation, utilization, and assimilation pathways in cases and a predominance of biosynthesis pathways in controls. Only two SVs correlated with Clinch densovirus 1, a virus previously shown to be strongly associated with mortality in this system: Deinococcota and Actinobacteriota, which were associated with densovirus-positive and densovirus-negative mussels, respectively. Overall, our results suggest that bacterial invasion and shifts in the bacterial microbiome during unionid mass mortality events may result from primary insults such as viral infection or environmental stressors. If so, bacterial communities in mussel hemolymph may be sensitive, if generalized, indicators of declining mussel health.