# Efficacy of cefiderocol and levofloxacin against Stenotrophomonas maltophilia in a hemorrhagic pneumonia mouse model

## TL;DR

This study compares cefiderocol and levofloxacin in treating Stenotrophomonas maltophilia-induced pneumonia in mice, finding that both drugs improve survival but with different effectiveness and risks.

## Contribution

The study provides the first evidence of cefiderocol's efficacy against S. maltophilia-induced hemorrhagic pneumonia in a mouse model.

## Key findings

- Cefiderocol improved survival and reduced bacterial load and hemorrhage in infected mice.
- Levofloxacin showed greater efficacy than cefiderocol in this model, possibly due to better tissue penetration.
- Cefiderocol may be preferable for treating resistant pathogens despite lower efficacy compared to levofloxacin.

## Abstract

Cefiderocol (CFDC) is a promising drug for treating infections caused by Stenotrophomonas maltophilia, a multidrug-resistant pathogen. However, no evidence of its efficacy against S. maltophilia-induced hemorrhagic pneumonia has been reported. We compared the effects of CFDC and levofloxacin (LVFX) on improving survival as well as reducing bacterial load and pathological effects in a mouse model of S. maltophilia hemorrhagic pneumonia. The dosage of LVFX and CFDC was determined using a previously described method to establish S. maltophilia-induced hemorrhagic pneumonia in mice. CFDC and LVFX were administered intraperitoneally 3 h after bacterial infection. Treatment was administered using the calculated dosages. CFDC significantly improved survival, showed a tendency to reduce bacterial load in the blood and lungs, and revealed that hemorrhage was suppressed in pathological analysis compared with the control group. These results support the current recommendation for CFDC as a treatment option for S. maltophilia infections. However, its efficacy in our model was lower than that of LVFX. This may be due to the superior pulmonary tissue penetration of LVFX. Treatment strategies that consider tissue penetration are necessary for severe S. maltophilia infections. However, the use of LVFX must consider the risk of resistance development, whereas CFDC may be advantageous for treating resistant pathogens.