Optimal treatment of Imipenem and meropenem against bloodstream infections caused by the Citrobacter spp.

Abstract

Objectives: This work was to investigate the optimal treatments of imipenem (IPM) and meropenem (MEM) against bloodstream infections (BSIs) caused by Citrobacter spp.

Methods: A total of 230 nonduplicate BSIs Citrobacter spp. were collected from 2014 to 2020 in three hospitals in Zhejiang Province in China. The minimum inhibitory concentrations (MICs) of 17 antibiotics were determined. Monte Carlo simulation (MCS) was used to investigate the cumulative fraction of response (CFR) of 8 regimens of IPM and 10 regimens of MEM.

Results: C. freundii (Cfr) was the predominant epidemic isolate (83.9%, 193/230). The resistance rates to IPM and MEM showed an increasing trend from 2015 to 2019. Fosfomycin showed excellent activity from 2014 to 2020. The probability of target attainment of IPM and MEM by prolonged 3 h infusion therapy (PIT) was higher than that by traditional 0.5 h (h) infusion therapy (TIT) during the same administration dosage. The CFR of all IPM regimes was above 90%, while MEM with 500 mg q8h was lower than 90%, especially for Cfr.

Conclusions: Cfr is the most common BSIs. Citrobacter spp. PIT is more adequate to provide activity against BSIs Citrobacter spp., especially for IPM.