[Genomic characteristics of extraintestinal pathogenic <i>Escherichia coli</i>/ST88 and monophasic <i>Salmonella Typhimurium</i>/ST34 in a patient with double bacteremia].

To analyze the genomic characteristics of patients with double bacteremia caused by extraintestinal pathogenic <i>Escherichia coli</i> (ExPEC)/sequence type(ST)88 and monophasic <i>Salmonella Typhimurium</i> (MST)/ST34. The clinical data of a female patient admitted to Shanghai Huashan Hospital on July 25, 2024 were retrospectively analyzed, and the clinical diagnosis was pelvic abscess secondary to soft tissue infection, pulmonary infection and double bacteremia. The whole-genome sequencing results of the strains were ExPEC/ST88 and MST/ST34, respectively, with resistance to 15 antibiotics belonging to 8 classes for ExPEC/ST88 and 18 antibiotics belonging to 10 classes for MST/ST34. ResFinder and CARD database predicted that 12 resistance mechanisms or microstructures of the two strains overlapped or crossed to varying degrees. ExPEC/ST88 had 84 virulence genes in 19 species. MST/ST34 had 150 virulence genes in 27 species. The patient's temperature returned to normal after anti-infection treatment with linezolid and glucose injection, imipenem and cistatin, and meropenem successively. ExPEC/ST88 is the primary pathogen causing bloodstream infection in this patient, marking the first case reported in Asia, and the coexistence with colistin-resistant MST makes this case even more rare. ExPEC/ST88 has the characteristics of high antibiotic resistance, high virulence, and high recombination of zoonotic and foodborne invasive diseases.