Ceftazidime Combined with Bifico Improves Therapeutic Efficacy and Intestinal Safety in a Mouse Model of Pseudomonas aeruginosa Pneumonia.

Bacterial pneumonia is a serious infectious disease with high morbidity and mortality, particularly in elderly and immunocompromised individuals. Ceftazidime is a first-line treatment, but its use is limited by adverse effects on gut health. In a murine model of Pseudomonas aeruginosa pneumonia, we evaluated the efficacy and intestinal safety of combining Ceftazidime with Bifico. The results revealed that, Bifico alone showed limited therapeutic efficacy against Pseudomonas aeruginosa-induced bacterial pneumonia, whereas its combination with Ceftazidime significantly enhanced treatment outcomes, particular in reducing lung injury scores (Ceftazidime-Bifico combination treatment: mean ± SD = 1.42 ± 0.23 vs. Ceftazidime treatment: mean ± SD = 1.94 ± 0.53, p < 0.05). While Bifico alone exerted weak anti-inflammatory effects, its combination with Ceftazidime produced significantly stronger anti-inflammatory effects than Ceftazidime alone (p < 0.05). Notably, Ceftazidime-induced gut dysbiosis was alleviated by Bifico, which mitigated intestinal inflammation and restored microbial diversity, as reflected by a Chao index comparable to control and higher than Ceftazidime alone (Ceftazidime-Bifico combination treatment: mean ± SD = 482.22 ± 73.21 vs. Ceftazidime treatment: mean ± SD = 349.64 ± 61.14, p < 0.05). These findings indicate that the Ceftazidime-Bifico combination enhances therapeutic efficacy while preserving gut homeostasis, representing a promising and safer strategy for managing bacterial pneumonia.