First human isolation of Gibbsiella quercinecans associated with infection - significance and relevance

Gibbsiella quercinecans is a plant-associated environmental bacterium described in the context of Acute Oak Decline and has not previously been reported in human clinical samples. A previously healthy 60-year-old male developed an outdoor trauma-associated skin and soft tissue infection of a primarily sutured left-thumb wound. Surgical exploration was performed and an intraoperative specimen of representative infected tissue from the depth of the wound yielded a Gram-negative rod in pure culture. MALDI-TOF MS, automated biochemical testing, and 16S rDNA sequencing were inconclusive for species-level identification. Definitive identification as G. quercinecans was achieved by whole-genome sequencing. The isolate was susceptible to all tested antimicrobial agents and no known relevant acquired resistance genes were detected. The infection subsided after surgical debridement, irrigation, and antimicrobial therapy. This case represents, to our knowledge, the first isolation of G. quercinecans from a human infection and highlights the value of genomic methods for identifying unusual environmental pathogens at the interface of outdoor exposure and clinical microbiology.