IDSA Updates Guidance for Managing Resistant Gram-Negative Infections
核心洞察
A randomized trial in Bangkok compared oral fosfomycin 3 g every 48 hours with IV carbapenem (搜索) step-down in hospitalized adults with complicated UTI caused by resistant Enterobacterales (搜索).
Clinical cure at day 7 reached 98.4% in both arms, with no differences in clinical or microbiological cure, readmissions or adverse events at day 28.
Eleven patients with non-E. coli pathogens were successfully treated with oral fosfomycin, though bacteremic patients were excluded, leaving step-down necessity uncertain.
A randomized study published in the International Journal of Infectious Diseases compared oral fosfomycin with continued IV carbapenem (搜索) therapy in hospitalized men and women in Bangkok, Thailand, with complicated urinary tract infection (搜索) caused by third-generation cephalosporin-resistant E. coli, C. freundii, E. cloacae or P. mirabilis. After three days of IV carbapenem, patients received either an IV carbapenem or oral fosfomycin 3 g every 48 hours to complete a seven-day total antibiotic course. Patients with pregnancy, concurrent bacteremia, co-infections in other organs, CrCl < 10, or urinary bacteria resistant to study drugs were excluded.
Among 124 cases meeting inclusion criteria, the primary endpoint of clinical cure at day 7 was achieved in 98.4% of patients in both groups, with no difference between arms for primary or secondary outcomes, including day 28 clinical cure, microbiological cure, hospital readmissions and adverse events. Eleven patients with non-E. coli pathogens were successfully treated with oral fosfomycin, which the authors said supports susceptibility testing of urinary isolates of C. freundii, E. cloacae and P. mirabilis.
The authors noted that bacteremic patients were not included, so the comparable outcomes may reflect that only three days of IV therapy is needed for complicated UTI without bacteremia and that step-down therapy may not be necessary. Updated 2026 IDSA guidance recommends oral fosfomycin for uncomplicated E. coli UTI but cautions against its use in complicated E. coli UTI because of limited renal parenchymal and serum concentrations, and warns of high FosA (搜索) gene prevalence in non-E. coli Enterobacterales (搜索).