Background Aspiration pneumonia (AP) is a common complication in the intensive care unit (ICU), which is associated with significantly increased morbidity and mortality and has a significant impact on patient prognosis. Antibiotics are commonly used in the clinical treatment of AP. However, the prognostic impact of antibiotics on patients with AP has not been adequately characterized. The purpose of this study is to illustrate the relationship between the use of antibiotics and in-hospital mortality of AP patients, as well as to analyze the effects of different antibiotic treatment regimens on the prognosis of the patients, and to further understand the distribution of pathogens and drug resistance in AP patients, so as to provide guidance information for the rational use of medication for patients in the clinic. Methods Clinical data of AP patients were extracted from the MIMIC-IV database. Statistical methods included multivariate logistic regression, propensity score matching (PSM), and inverse probability weighting (IPW) based on propensity scores to ensure the robustness of the findings. In addition, the characteristics of the medications used by patients with AP were described using statistical graphs and tables. Results A total of 4132 patients with AP were included. In-hospital mortality was significantly lower in the group using antibiotics compared to the group not using antibiotics (odds ratio [OR] = 0.44, 95% confidence interval [CI] 0.27- 0.71, P = 0.001). Furthermore, in the group using mechanical ventilation (MV), antibiotics use significantly reduced in-hospital mortality (OR = 0.30, 95% CI 0.15-0.57, P < 0.001). Vancomycin and cephalosporins are the most commonly used antibiotics to treat AP. Specifically, vancomycin in combination with piperacillin-tazobactam was used most frequently with 396 cases. The highest survival rate (97.6\%) was observed in patients treated with levofloxacin combined with metronidazole. Additionally, vancomycin combined with piperacillin-tazobactam had many inflammation related features that differed significantly from those in patients who did not receive medication. Conclusions Antibiotics use is closely associated with lower in-hospital mortality in ICU patients with AP. Moreover, understanding antibiotics use, the composition of pathogenic bacteria, and the rates of drug resistance in patients with AP can aid in disease prevention and prompt infection control.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with limited therapeutic options and a poor prognosis. Here, we identify the nuclear receptor NR4A1 as a pivotal mediator of estrogen’s antifibrotic effects through its regulation of TGF-β signaling. Clinical analysis revealed increased expression of NR4A1 and estrogen receptor α (ERα) in IPF lung tissues, with NR4A1 phosphorylation correlating with disease progression. Mechanistic investigations demonstrated that sustained TGF-β signaling induces NR4A1 phosphorylation, impairing its negative feedback regulation of fibrosis. Estrogen, acting via ERα, restored NR4A1 activity by suppressing phosphorylation, thereby reducing fibrosis both in vitro and in vivo. Overexpression of NR4A1 or inhibition of its phosphorylation attenuated fibrotic responses, whereas NR4A1 deficiency abrogated estrogen’s protective effects. These findings elucidate a previously unrecognized mechanism of estrogen-mediated antifibrotic activity and highlight NR4A1 as a promising therapeutic target for IPF.