ObjectiveTo compare the differences between clinical and environmental sources of Acinetobacter baumannii （AB） at a tertiary hospital in Guangzhou in terms of molecular epidemiological characteristics， antimicrobial resistance， disinfectant tolerance， virulence and the distribution of related genes， as well as plasmid epidemiological characteristics； and to assess the association between environmental and clinical strains and the potential transmission risks associated with environmental contamination. MethodsA total of 118 clinical and 102 environmental AB isolates were collected from a tertiary hospital in Guangzhou between 2024 and 2025. Species identification was performed using mass spectrometry and 16S rRNA sequencing； minimum inhibitory concentrations （MICs） for eight antimicrobial agents were determined using the agar dilution method； biofilm formation capacity was assessed using the crystal violet staining method； A Galleria mellonella infection model was used to evaluate the virulence； whole-genome sequencing was employed for multilocus sequence typing （MLST）， phylogenetic analysis， and studies on the distribution of resistance， disinfectant resistance and virulence genes， and plasmid screening. ResultsA total of 38 known ST types were identified among the 220 AB strains， with ST2 and ST40 being the predominant lineages. Antimicrobial susceptibility testing revealed that the clinical infection group exhibited resistance to minocycline， imipenem and other antibiotics， as well as the tolerance levels to the disinfectants triclosan and benzalkonium bromide， were generally higher than those in the environmental group （P＜0.001）， and the detection rates of drug resistance genes such as bla_OXA-23 and adeB all exceeded 70.0%. Statistical analysis confirmed that the MIC values of TCS and BAB were significantly positively correlated with various antibiotic resistance phenotypes （P＜0.05）. In biofilm experiments， the proportion of strong biofilm-forming strains in the environmental group （64.7%） was significantly higher than that in the clinical infection group （11.9%；χ²=69.06， df=2， P＜0.000 1）， and the mortality rate of the strains increased with enhanced biofilm-forming ability. Furthermore， a total of 41 plasmid lineages and 219 insertion sequences were detected； ISs such as IS1006 and IS1007 were frequently co-occurring with resistance and virulence genes including bla_OXA-23 and katA. ConclusionsThe predominant lineages of AB in this tertiary hospital were ST2 and ST40. The clinical infection group generally exhibits higher levels of antibiotic resistance and tolerance to disinfectants compared to the environmental group， while biofilm-forming ability differs ： the environmental group dominates in strong biofilm formation， and the clinical group dominates in weak to moderate biofilm formation. Plasmids and ISs may be involved in the co-occurrence and dissemination control strategies and for the molecular epidemiological surveillance of multidrug-resistant bacteria.

Breast cancer is one of the most common cancers in women， which seriously threatens women's health. Early diagnosis and precise treatment of breast cancer are helpful to improve the prognosis of patients. This article summarizes the research status of bacteria and their metabolites in the development and treatment of breast cancer， and discusses in detail the role and mechanism of bacteria and their metabolites in the development and intervention of breast cancer. These mechanisms include regulation of inflammation and immune response， DNA damage， and regulation of cell biological characteristics. Engineering bacteria have become one of the hotspots in the field of breast cancer treatment in recent years due to their natural advantages in targeting tumors and activating immunity. This article further summarizes the research progress of engineered bacteria in the treatment of breast cancer， aiming to provide an important reference for formulating targeted treatment strategies and improving the prognosis of patients. Although bacteria and their metabolites affect the development and treatment of breast cancer through a variety of mechanisms， and can enhance the therapeutic effect of cancer and reduce the adverse effects of treatment， the clinical application of bacteria in anti-breast cancer therapy still faces numerous challenges. The highly individualized composition of bacteria leads to the lack of universality of treatment， and the complex interaction between bacteria and host further increases the difficulty of research. In the future， it is urgent to further explore the mechanism of bacteria and their metabolites affecting the development and treatment of breast cancer， and promote the clinical application of bacteria in anti-breast cancer treatment.

[Objective]Depression is a common mental illness with a profound impact on physical health.Depression has been associated with a higher risk of bacterial infection;however,whether this relationship is causal and how depression affects infection remains unclear.Therefore,we aimed to investigate the effects of depressive phenotype in infected mice by constructing a chronic unpredictable mild stress(CUMS)model.[Methods]Mice were induced with CUMS for 4 weeks.The depressive phenotype was evaluated using behavioral tests.Subsequently,the mice were intraperitoneally injected with Klebsiella pneumoniae to establish bacterial infection.Serum and abdominal tissues were collected 48 h after infection.Hematoxylin-eosin(HE)staining was used to observe the pathological changes in the tissues,and enzyme-linked immunosorbent assay(ELISA)was used to measure the levels of inflammatory factors.In addition,the fecal samples collected before infection were analyzed for 16S rDNA gene of gut microbiota,and the expression levels of NF-κB/NLRP3 signaling pathway in colon tissues of uninfected mice were detected.[Results]Behavioral tests showed that compared with the control mice,CUMS mice had significantly lower body weight(P<0.0001,t=5.426),lower sucrose preference rate(P<0.001,t=4.937),increased swimming stationary time(P<0.001,t=16.37),and decreased time spent in the central area of the open field(P<0.01,t=3.575).Survival analysis showed that compared with the control mice,the survival rate of CUMS mice significantly decreased after infection(P<0.05).Additionally,histochemical staining showed that tissue damage in the liver(P<0.05,t=4.025),kidney(P<0.05,t=2.828),and mesentery(P<0.01,t=5.367)significantly increased.Furthermore,ELISA results showed that the levels of the inflammatory cytokines IL-6(P<0.01,t=3.365),IL-1β(P<0.01,t=4.061),TNF-α(P<0.01,t=4.460)and LPS(P<0.0001,t=27.24)were elevated.The difference was statistically significant.According to 16S rDNA sequencing,CUMS-induced changes in the intestinal bacterial community structure of mice,making them significantly different from the control mice.Compared with the control mice,the expression levels of NF-κB(P<0.01,t=6.825)and NLRP3(P<0.001,t=9.561)were upregulated in CUMS mice.[Conclusion]The CUMS model was successfully constructed and CUMS mice developed more severe bacterial infection.Gut microbiota was dysregulated and the expression of NF-κB/NLRP3 signaling pathway was up-regulated in CUMS mice,which was related to the susceptibility to bacterial infection.