In vitro activity of cefepime/taniborbactam and comparator agents against Gram-negative bacterial bloodstream pathogens recovered from patients with cancer.

Background:Taniborbactam is a β-lactamase inhibitor that, when combined with cefepime, may offer a potential treatment option for patients with serious and resistant Gram-negative bacterial (GNB) pathogens. Objectives:This study evaluated in vitro activity of cefepime/taniborbactam and comparator agents against GNB pathogens isolated from patients with cancer at our institution. Methods:A total of 270 GNB pathogens (2019-23) isolated from patients with cancer were tested against cefepime/taniborbactam and comparator agents commonly used for these patients. CLSI-approved broth microdilution methods were used. MIC50, MIC90, MIC range and percentage of susceptibility calculations were made using FDA breakpoints when available. Results:Cefepime/taniborbactam showed highly potent activity against tested Enterobacterales, including isolates producing ESBLs and carbapenem-resistant Enterobacterales. At a provisional breakpoint of ≤16/4 mg/L, cefepime/taniborbactam inhibited most tested species of GNB pathogens, with overall 98.9% susceptibility, which was significantly (P < 0.0001) higher than the susceptibility of the GNB isolates to all other tested comparator agents, ranging from 39.6% for cefepime to 86.3% for ceftazidime/avibactam. Conclusions:Our results showed that taniborbactam in combination with cefepime improved in vitro activity against GNB pathogens isolated from patients with cancer, including MDR Pseudomonas aeruginosa, carbapenem-resistant Enterobacterales, ESBL-producing Enterobacterales and Stenotrophomonas maltophilia isolates, with highest activity compared with all tested comparator agents, including other β-lactam/β-lactamase inhibitor combinations. Further studies are warranted to explore the efficacy of cefepime/taniborbactam for empirical initial treatment of GNB infections in cancer patients with high rates of febrile neutropenia requiring hospitalization.