Study compares two antibiotics in treating severe hemorrhagic bacterial pneumonia

Stenotrophomonas maltophilia (S. maltophilia) is a multidrug-resistant bacterium that can cause severe and life-threatening hemorrhagic pneumonia in individuals with weakened immune systems. Despite this, there are limited treatment options for this bacterium and the infections it causes are extremely difficult to treat. The commonly used antibiotic, levofloxacin (LVFX), currently stands as one of the most effective, but reported evidence of S. maltophilia resistance has been increasing. Alternatively, cefiderocol (CFDC), a new antimicrobial agent, has shown effectiveness against S. maltophilia in experimental studies. However, its efficacy against hemorrhagic pneumonia remains unclear.

Therefore, a research group led by Dr. Waki Imoto at Osaka Metropolitan University's Graduate School of Medicine examined the effectiveness of CFDC and LVFX using a mouse model. After separating the mice into control, CFDC, and LVFX groups, the team administered the drugs to mice with severe hemorrhagic pneumonia caused by S. maltophilia and evaluated the effects of each treatment.

As a result, both antimicrobial treatments improved survival rates and reduced bacterial burdens in the heart and lungs. In addition, microscopic examination of lung tissue revealed reduced hemorrhage, indicating decreased lung damage. However, instances of hemorrhage differed between the LVFX and CFDC groups. In mice treated with LVFX, hemorrhage was rarely observed, whereas the CFDC group had slight occurrences.

The effects observed in this study were more pronounced with LVFX. One possible reason is that it more readily reaches the lungs, which are the primary organs infected by the bacteria. On the other hand, because the emergence of LVFX-resistant strains has been reported, it is important to select appropriate therapeutic agents depending on the clinical situation while taking antimicrobial resistance into account and using CFDC as an alternative treatment for S. maltophilia."

Dr. Waki Imoto, Osaka Metropolitan University's Graduate School of Medicine

The study was published in Antimicrobial Agents and Chemotherapy.

The authors thank Shionogi & Co., Ltd., for providing CFDC and experimental advice.