Human carboxylesterase 2A (hCES2A) plays pivotal roles in prodrug activation and hydrolytic metabolism of ester-bearing chemicals. Targeted inhibition of intestinal hCES2A represents a feasible strategy to mitigate irinotecan-triggered gut toxicity (ITGT), but the orally active, selective, and efficacious hCES2A inhibitors are rarely reported. Here, a novel drug-like hCES2A inhibitor was developed via three rounds of structure-based drug design (SBDD) and structural optimization. Initially, donepezil was identified as a moderate hCES2A inhibitor from 2000 US Food and Drug Administration (FDA)-approved drugs. Following two rounds of SBDD and structural optimization, a donepezil derivative (B7) was identified as a strong reversible hCES2A inhibitor. Subsequently, nine B7 carbamates were rationally designed, synthesized and biologically assayed. Among all synthesized carbamates, C3 showed the most potent time-dependent inhibition on hCES2A (IC₅₀ = 0.56 nmol/L), excellent specificity and favorable drug-like properties. C3 could covalently modify the catalytic serine of hCES2A with high selectivity, while this agent also showed favorable safety profiles, high intestinal exposure, and impressive effects for ameliorating ITGT in both human intestinal organoids and tumor-bearing mice. Collectively, this study showcases a rational strategy for developing drug-like and serine-targeting covalent inhibitors against target serine hydrolase(s), while C3 emerges as a promising orally active drug candidate for ameliorating ITGT.

Objective:To understand the clinical manifestations, laboratory characteristics, and treatment of Staphylococcus aureus ( Sa) infection in children, and explore the predictive value of lymphocyte count, neutrophil to lymphocyte ratio(NLR), and high-sensitivity C-reactive protein to albumin ratio(CAR) in patient with secondary bloodstream infection(BSI). Methods:A retrospective analysis was conducted on 72 children with Sa infection admitted to the Nanchong Hospital of Beijing Anzhen Hospital Affiliated to Capital Medical University from January 2020 to April 2024. Clinical data including basic information, drug resistance, antibiotic treatment were collected. Differences in laboratory test results and inflammatory indicators were analyzed. The influencing factors of Staphylococcus aureus bacteraemia(SAB) in pediatric patients were analyzed using univariate/multivariate Logistic regression and correlation analysis. The predictive value was analyzed by receiver operating characteristic curve (ROC) and area under curve (AUC). Results:Seventy-two patients were selected, of whom 60 (83.33%) had skin and soft tissue infections (SSTIs), mainly community-associated Staphylococcus aureus(CA-SA)(50 cases), including 16 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) cases (32.00%, 16/50). The detection rate of MRSA was 37.50% (27/72). The resistance rates of Sa to penicillin, clindamycin, and erythromycin were 97.22%(70/72), 69.44%(50/72), and 69.44%(50/72), respectively. Compared with the SSTIs group, the levels of lymphocyte count in children with bone and joint infections were significantly lower, while NLR and CAR levels were higher ( P<0.05). Fourteen patients had secondary SAB. In the secondary SAB group, lymphocyte counts were lower, while inflammatory indicators (NLR, CAR), and D-dimer were higher. CAR and NLR are positively correlated with the occurrence of bloodstream infections ( P<0.05). CAR ( OR=4.866, 95% CI: 1.37-17.25) and NLR ( OR=1.293, 95% CI: 1.032-1.620) were independent risk factors for secondary bloodstream infection, and ROC curve results showed that the combination of the two indicators had a higher sensitivity (0.929) and AUC (0.909) than individual testing. After undergoing effective treatment, the levels of CAR and NLR in the children in the secondary SAB group were significantly reduced. Wound infection patients underwent debridement treatment in 38 cases (52.78%, 38/72), while antibiotic treatment still primarily used first- and second-generation cephalosporins. For patients with secondary bloodstream infection, vancomycin was the first choice. Conclusions:Children′s wound infections with Sa primarily involve skin and soft tissue infections, commonly seen in CA-SA. NLR and CAR are independent risk factors for children with secondary bloodstream infection, and their combined detection has certain value for early diagnosis.

Objective:To understand the clinical manifestations, laboratory characteristics, and treatment of Staphylococcus aureus ( Sa) infection in children, and explore the predictive value of lymphocyte count, neutrophil to lymphocyte ratio(NLR), and high-sensitivity C-reactive protein to albumin ratio(CAR) in patient with secondary bloodstream infection(BSI). Methods:A retrospective analysis was conducted on 72 children with Sa infection admitted to the Nanchong Hospital of Beijing Anzhen Hospital Affiliated to Capital Medical University from January 2020 to April 2024. Clinical data including basic information, drug resistance, antibiotic treatment were collected. Differences in laboratory test results and inflammatory indicators were analyzed. The influencing factors of Staphylococcus aureus bacteraemia(SAB) in pediatric patients were analyzed using univariate/multivariate Logistic regression and correlation analysis. The predictive value was analyzed by receiver operating characteristic curve (ROC) and area under curve (AUC). Results:Seventy-two patients were selected, of whom 60 (83.33%) had skin and soft tissue infections (SSTIs), mainly community-associated Staphylococcus aureus(CA-SA)(50 cases), including 16 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) cases (32.00%, 16/50). The detection rate of MRSA was 37.50% (27/72). The resistance rates of Sa to penicillin, clindamycin, and erythromycin were 97.22%(70/72), 69.44%(50/72), and 69.44%(50/72), respectively. Compared with the SSTIs group, the levels of lymphocyte count in children with bone and joint infections were significantly lower, while NLR and CAR levels were higher ( P<0.05). Fourteen patients had secondary SAB. In the secondary SAB group, lymphocyte counts were lower, while inflammatory indicators (NLR, CAR), and D-dimer were higher. CAR and NLR are positively correlated with the occurrence of bloodstream infections ( P<0.05). CAR ( OR=4.866, 95% CI: 1.37-17.25) and NLR ( OR=1.293, 95% CI: 1.032-1.620) were independent risk factors for secondary bloodstream infection, and ROC curve results showed that the combination of the two indicators had a higher sensitivity (0.929) and AUC (0.909) than individual testing. After undergoing effective treatment, the levels of CAR and NLR in the children in the secondary SAB group were significantly reduced. Wound infection patients underwent debridement treatment in 38 cases (52.78%, 38/72), while antibiotic treatment still primarily used first- and second-generation cephalosporins. For patients with secondary bloodstream infection, vancomycin was the first choice. Conclusions:Children′s wound infections with Sa primarily involve skin and soft tissue infections, commonly seen in CA-SA. NLR and CAR are independent risk factors for children with secondary bloodstream infection, and their combined detection has certain value for early diagnosis.