ObjectiveTo evaluate the clinical efficacy of Fuzheng Huaji Formula （扶正化积方） for chronic hepatitis B to reduce the incidence of liver cirrhosis and hepatocellular carcinoma. MethodsA retrospective cohort study was conducted， collecting medical records of 118 patients with chronic hepatitis B and 234 patients with hepatitis B-related cirrhosis who visited the hospital between January 1， 2014， and December 31， 2018. The use of Fuzheng Huaji Formula was designated as the exposure factor. Patients receiving antiviral treatment for hepatitis B without concurrent Fuzheng Huaji Formula therapy were included in the western medicine group， while those receiving antiviral treatment combined with Fuzheng Huaji Formula for a cumulative treatment lasting longer than 3 months were included in the combined treatment group. The follow-up observation period was five years. Kaplan-Meier survival analysis was used to assess the cumulative incidence of cirrhosis in patients with chronic hepatitis B and the cumulative incidence of hepatocellular carcinoma in patients with hepatitis B-related cirrhosis. Univariate and multivariate Cox regression analyses were employed to examine the factors influencing the occurrence of cirrhosis and hepatocellular carcinoma. ResultsAmong patients with chronic hepatitis B， there were 55 cases in the combined treatment group and 63 cases in the western medicine group； among patients with hepatitis B-related cirrhosis， there were 110 cases in the combined treatment group and 124 cases in the western medicine group. Five-year follow-up outcomes for chronic hepatitis B patients showed that the cumulative incidence of cirrhosis was 5.45% （3/55） in the combined treatment group and 17.46% （11/63） in the western medicine group， with a statistically significant difference between groups （Z = 2.003， P = 0.045）. Five-year follow-up outcomes for hepatitis B-related cirrhosis patients showed that the cumulative incidence of hepatocellular carcinoma was 8.18% （9/110） in the combined treatment group and 22.58% （28/124） in the western medicine group， also showing a statistically significant difference （Z = 3.007， P = 0.003）. Univariate and multivariate Cox regression analyses indicated that treatment with Fuzheng Huaji Formula is an independent protective factor in preventing the progression of chronic hepatitis B to cirrhosis and the progression of hepatitis B-related cirrhosis to hepatocellular carcinoma （P＜0.05）. ConclusionCombining Fuzheng Huaji Formula with antiviral therapy for hepatitis B can effectively intervene in the disease progression of chronic hepatitis B， reducing the incidence of cirrhosis and hepatocellular carcinoma.

Objective To explore the relationship between education level and the risk of all-cause mortality in the middle-aged and elderly (≥45 years old) population in China. Methods Using data from five surveys from 2011-2020, years of education, age, gender, marital status, type of household, alcohol consumption status, smoking status, physical activity, limited ability to perform activities of daily living (ADLs), chronic disease status, and body mass index were collected. According to the survival status，the study participants were divided into a survival group (n=8625) and an all-cause mortality group (n=1735). Cox proportional risk regression model was used to analyze the relationship between years of education and the risk of all-cause mortality in middle-aged and elderly people with stratified analysis. Results The survey was conducted on 10360 research subjects, including 4 983 males and 5 377 females, with an age M(Q_R) of 59(8) years old. A total of 88 187 person years (average 8.512 person years) were followed up, and a total of 1735 deaths were reported over 9 years. The all-cause mortality rate was 19.674 ‰, with an education period M(Q_R) of 5(8) years and a survival time M(Q_R) of 9 (0) years. After adjusting for confounding factors, for every 1 year increase in education, the risk of all-cause mortality decreased by 2.60% [HR=0.974, 95% CI (0.960-0.988)]. The stratified analysis results showed that in the population aged 45-59, for every 1 year increase in education, the risk of all-cause mortality decreased by 1.00% [HR=0.990, 95% CI (0.959,1.021)]; In the population aged 60-74 and over 75, for every 1 year increase in education, the risk of all-cause mortality decreased by 2.70% [HR=0.973, 95% CI (0.948, 0.999)] and 3.50% [HR=0.965, 95% CI (0.929, 1.003)], respectively. Conclusion Improving the education level of middle-aged and elderly people (≥ 45 years old) in China can reduce the risk of all-cause mortality, and elderly education should be vigorously promoted.

Background As a pillar industry in China, the manufacturing sector has a high incidence of non-fatal occupational injuries. The factors influencing non-fatal occupational injuries in this industry are closely related at various levels, including individual, equipment, environment, and management, making the analysis of these influencing factors complex. Objective To identify influencing factors of non-fatal occupational injuries among manufacturing workers, providing a basis for targeted interventions and surveillance. Methods A total of 2243 frontline workers from cable and shipbuilding enterprises were selected as study subjects to investigate the incidence of non-fatal occupational injuries and collect information at four levels: individual, equipment, management, and environment in past 12 months. Data balancing was performed using resampling, and LASSO regression was used to select factors of non-fatal occupational injuries. The influence degree and type of variables were judged based on the magnitude of the estimated coefficients of each variable, where variables with estimated coefficients > 0 are risk factors, and those <0 are protective factors. The area under the receiver operating characteristic (ROC)curve (AUC) was used to test the performance of the model, with an AUC value > 0.7 indicating good model performance. Results Among the 2243 frontline workers, males accounted for 77.7% (1742 out of 2243), with the main age range being 40-49 years old, representing 29.5% (661 out of 2243), 82.7% of the workers (1854 out of 2243) were married, and 55.6% (1248 out of 2243) had a junior middle school education level. The average monthly income for 51.0% (1144 out of 2243) of the workers was between 5000 and 6999 Chinese Yuan. The incidence of non-fatal occupational injuries among the manufacturing workers was 8.4% (189/2243) in the past 12 months. Among the 22 factors associated with the occurrence of non-fatal occupational injuries (P<0.05), 10 were individual-level factors, including gender, smoking, alcohol consumption, colleague relationships, average exercise duration, job burnout, work fatigue, musculoskeletal disorders, cardiovascular diseases, and neurological and sensory organ diseases; 3 were equipment-level factors, including equipment operability, hazardous workpieces, and safety hazards; 5 were environmental-level factors, including low temperatures, special operations, noise, workspace size, and dirty and disorderly environment; and 4 were management-level factors, including daily working hours, weekly working days, overtime, and pre-job technical training. The AUC value of the LASSO regression model was 0.704 and the final model retained a total of 10 variables. Among them, there were 7 risk factors for non-fatal occupational injuries (coefficient > 0), including safety hazards, musculoskeletal disorders, dangerous workpieces, job burnout, dirty and disorderly environment, smoking, and male gender; and 3 protective factors (coefficient < 0), including pre-job technical training, good colleague relationship, and long working days per week. Conclusion Manufacturing enterprises need to focus on the incidence of non-fatal occupational injuries and conduct targeted interventions for non-fatal occupational injuries by controlling potential safety hazards, providing pre-job technical training, reducing dangerous workpieces, rectifying working environment, and reasonably arranging working hours.

Objective:To investigate the risk factors associated with post-prematurity respiratory disease (PPRD) in very preterm infants.Methods:A prospective cohort study was conducted, enrolling 369 very preterm infants who were admitted to the neonatal intensive care unit of Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, within one week of birth from January 2019 to June 2023. Data on maternal and infant clinical characteristics, neonatal morbidities, and treatments during hospitalization were collected. The very preterm infants were divided into 2 groups based on whether they developed PPRD. Continuous variables were compared using Mann-Whitney U test, while categorical variables were compared using χ2 tests or continuity correction χ2 test. Multivariate Logistic regression analysis was used to identify the independent risk factors for PPRD in very preterm infants. Results:Among the 369 very preterm infants, 217 cases(58.8%) were male, with a gestational age of 30 (28, 31) weeks at birth and a birth weight of 1 320 (1 085, 1 590) g. Of these, 116 cases (31.4%) developed PPRD, while 253 cases (68.6%) did not. The very preterm infants in the PPRD group had a lower gestational age and lower birth weight (both, P<0.001). The PPRD group also had a higher proportion of males, lower Apgar scores at the 1 th minute after birth and the 5 th minutes after birth, a higher rate of born via cesarean delivery, and a higher incidence of bronchopulmonary dysplasia, more pulmonary surfactant treatment, longer durations of mechanical ventilation, longer total oxygen therapy, and lower Z-score for weight at discharge (all P<0.05). Multivariate Logistic regression analysis showed that gestational age ( OR=0.85, 95% CI 0.73-0.99, P=0.037), born via cesarean delivery ( OR=2.23, 95% CI 1.21-4.10, P=0.010), a duration of mechanical ventilation ≥7 days ( OR=2.51, 95% CI 1.43-4.39, P=0.001), and a Z-score for weight at discharge ( OR=0.82, 95% CI 0.67-0.99, P=0.040) were all independent risk factors for PPRD in very preterm infants. Conclusion:Very preterm infants with a small gestational age, born via cesarean section, mechanical ventilation ≥7 days, and a low Z-score for weight at discharge should be closely monitored for PPRD, and provided with standardized respiratory management after discharge.

BACKGROUND:The micro/nanostructured gradient biomimetic surface of implant materials can simulate the structure of the extracellular environment in human bone tissue,thereby achieving perfect bone integration function.However,further research is needed on the mechanisms by which the surface microstructure of bone implant materials regulates cell function and promotes osteogenesis. OBJECTIVE:To analyze the effect of titanium sheet microstructure surface on osteogenic differentiation of MC3T3-E1 osteoblasts. METHODS:(1)At a constant voltage of 5 V or 20 V,nanotube arrays of different diameters were prepared on the surface of titanium sheets by acid etching and anodic oxidation techniques,and were recorded as group R5 and group R20,respectively.The surface morphology,roughness,and hydrophilicity of pure titanium sheet(without acid etching or anodizing treatment)were measured in group R5 and group R20.(2)MC3T3-E1 osteoblasts of logarithmic growth stage were inoculated on the surface of pure titanium sheets,R5 group and R20 group respectively.After 24 hours of osteogenic induction culture,the expression of mechanical sensitive channel protein 1 was analyzed by RT-PCR and immunofluorescence staining.Osteoblast inducible base with or without the mechanosensitive channel protein 1 activator Yada1 was added,and alkaline phosphatase staining was performed after 7 days of culture.Alizarin red staining was performed after 14 days of culture. RESULTS AND CONCLUSION:(1)The surface of pure titanium sheets was smooth under scanning electron microscope.Relatively uniform and orderly nanotube arrays with average diameters of about 30 nm and 100 nm were observed on the surface of titanium sheets of groups R5 and R20,respectively.The results of scanning electron microscope were further verified by atomic force microscopy.The surface roughness of titanium sheet of group R5 was higher than that of pure titanium(P<0.05),and the water contact angle was lower than that of pure titanium(P<0.05).The surface roughness of titanium sheet in group R20 was higher than that in group R5(P<0.05),and the water contact angle was lower than that in group R5(P<0.05).(2)RT-PCR and immunofluorescence staining showed that the expression of mechanosensitive channel protein 1 in group R5 was higher than that in pure titanium group(P<0.05),and the expression of mechanosensitive channel protein 1 in group R20 was higher than that in group R5(P<0.05).Under the osteogenic induction,compared with the condition without Yada1,there were no significant changes in the activity of alkaline phosphatase and the deposition of calcified nodules in pure titanium group after Yada1 addition,while the activity of alkaline phosphatase and the deposition of calcified nodules in groups R5 and R20 after Yada1 addition were significantly increased(P<0.05).With or without Yada1,the alkaline phosphatase activity and calcified nodule deposition in group R5 were higher than those in pure titanium group(P<0.05),and the alkaline phosphatase activity and calcified nodule deposition in group R20 were higher than those in group R5(P<0.05).(3)The results show that the surface microstructure of titanium sheet can promote the osteogenic differentiation of osteoblast MC3T3-E1 by activating mechanosensitive channel protein 1.

BACKGROUND:Metal-organic frameworks exhibited great potential for bone tissue engineering and bone disease treatment because of its unique merits including tunable porosity,a large specific surface area,good biocompatibility,and easy structure modification. OBJECTIVE:To review the advancements,application,strengths,and weaknesses of metal-organic framework materials in bone repair,arthritis,bone infection,and bone tumors,offering guidance and strategies for future research. METHODS:Web of Science,PubMed,and CNKI databases were searched using Chinese and English keywords"metal-organic frameworks,MOFs,orthopedics,bone repair,bone regeneration,orthopaedic applications,bone tissue engineering,bone infection,arthritis,bone tumor,osteosarcoma"for related literature published from 2015 to 2023.Following initial screening based on inclusion and exclusion criteria,72 articles were finally included for review. RESULTS AND CONCLUSION:(1)During bone repair,metal ions of metal-organic frameworks can induce bone formation by activating specific signaling pathways,which include stimulating osteogenic gene expression,inhibiting osteoclasts,encouraging blood vessel formation,and speeding up bone mineralization.Hence,metal-organic frameworks with metals like calcium,strontium,cobalt,copper,and magnesium ions show significant potential in enhancing bone implant performance.(2)Metal-organic framework materials,especially zinc/cobalt-based metal-organic frameworks,exhibit enzyme-like activities and promote cartilage regeneration by scavenging reactive oxygen species.Compared with natural enzymes,it has the advantages of not easy inactivation and better stability.(3)Zinc-based metal-organic framework materials characterized with wide band gaps,efficient separation and migration of photogenerated carriers,and high stability,the enhancement of photocatalytic activity results from enhancing the excited electron-hole widely used for the eradication of bacteria and tumor cells.(4)Bimetallic metal-organic frameworks,the doping of additional metals,showed critical advantages in optimizing structural performance,such as zinc/magnesium-based metal-organic framework 74 offering increased stability for durable antibacterial activity,and the light absorption capacity and photocatalytic efficiency of tantalum/zirconium-based metal-organic framework greatly improved and thus enhancing the radiation therapy.(5)However,metal-organic framework materials still face challenges in clinical applications,such as the uncertainty of drug release,in vivo safety,and potential immune responses from long-term presence.

BACKGROUND:Spleen has the functions of blood storage,hematopoiesis,and immunity.With the increase of age,the structural degeneration and functional decline of spleen lead to the impairment of immune system function,thus accelerating the aging process of the body.The treatment of spleen aging in tree shrews with highly active umbilical cord mesenchymal stem cells has not been reported. OBJECTIVE:To explore the intervention effect and mechanism of highly active umbilical cord mesenchymal stem cells on spleen aging in tree shrews. METHODS:Highly active umbilical cord mesenchymal stem cells were isolated,cultured,and obtained from the umbilical cord tissue of newborn tree shrews by caesarean section.The differentiation abilities of adipogenesis,osteogenesis,and chondrogenesis were detected by three-line differentiation kit.Cell cycle and surface markers were detected by flow cytometry.The second generation of highly active umbilical cord mesenchymal stem cells were transfected with Genechem Green Fluorescent Protein with infection complex values of 100,120,140,160,180,and 200,respectively,to screen the best transfection conditions.After transfection,the fourth generation of highly active umbilical cord mesenchymal stem cells was injected into the tail vein of tree shrews in the elderly treatment group.The young control group and the aged model group were not given special treatment.After 4 months of treatment,the spleen tissue was taken and the structure of the spleen was observed by hematoxylin-eosin staining.β-Galactosidase staining was used to detect the activity of aging-related galactosidase.Immunohistochemical staining was used to detect the expression levels of p21 and p53 proteins.Ki67 and PCNA immunofluorescence staining was used to detect cell proliferation activity.Immunofluorescence staining was used to detect the expression levels of spleen autophagy protein molecules Beclin 1 and APG5L/ATG5.Reactive oxygen species fluorescence staining was used to detect the content of reactive oxygen species in spleen tissue.CD3 immunofluorescence staining was used to detect the change of the proportion of total T lymphocytes.The secretion levels of interleukin 1β and transforming growth factor β1 in spleen were detected by enzyme linked immunosorbent assay.The distribution of highly active umbilical cord mesenchymal stem cells labeled with green fluorescent protein in spleen tissue was observed by DAPI double staining of nucleus. RESULTS AND CONCLUSION:(1)Highly active umbilical cord mesenchymal stem cells grew in a short spindle shape with fish-like growth,with a large proportion of G0/G1 phase,and had the potential to differentiate into adipogenesis,osteogenesis,and chondrogenesis.(2)Multiplicity of infection=140 and transfection for 72 hours were the best conditions for labeling tree shrews highly active umbilical cord mesenchymal stem cells with Genechem Green Fluorescent Protein.(3)Compared with the aged model group,in the aged treatment group,the spleen tissue cells of tree shrews were arranged closely,and the area of white pulp was increased(P<0.01);the boundary between red pulp and white pulp was clear;the proportion of germinal centers did not show statistically significant difference(P>0.05).The activity level of galactosidase related to spleen tissue aging was decreased(P<0.001),and the expression levels of aging protein molecules p21 and p53 were down-regulated(P<0.001).The expression levels of proliferation-related molecules Ki67 and PCNA were up-regulated(P<0.001,P<0.05);expression levels of autophagy-related molecules Beclin 1 and APG5L/ATG5 were up-regulated(P<0.001),and the content of reactive oxygen species decreased(P<0.001),and the proportion of CD3+T cells increased(P<0.05).The secretion level of interleukin 1β in the aging-related secretion phenotype decreased(P<0.001);no significant difference was found in transforming growth factor β1 level(P>0.05).Compared with the young control group,the above indexes were significantly different in the elderly treatment group(P<0.05).(4)Green fluorescent cells labeled with green fluorescent protein were observed in spleen tissue of tree shrews the elderly treatment group by frozen tissue section observation.The results show that intravenous infusion of highly active umbilical cord mesenchymal stem cells can migrate to spleen tissue,inhibit the production of reactive oxygen species,down-regulate the expression of aging-related proteins,induce autophagy,promote cell proliferation,reduce chronic inflammation,and then improve the structure and function of spleen tissue.

Based on the implementation of GMP, comprehensive improvement of quality control measures, and consideration of the 3Rs principle for experimental animals, Several years ago, WHO, the European Pharmacopoeia and the FDA gradually abolished the testing for abnormal toxicity of biological products, and the Chinese Pharmacopoeia 2025 Edition(Volume Ⅲ)also revised the testing for abnormal toxicity of biological products. In order to help users of the Chinese Pharmacopoeia(Volume Ⅲ) better understand and implement this pharmacopoeia, this article provides a detailed review of the changes in regulatory concepts for abnormal toxicity test in various countries and the process of gradually phasing out abnormal toxicity test, as well as the actual situation of China’s pharmaceutical industry. It also interprets the ideas and considerations for revising the Chinese Pharmacopoeia 2025 Edition(Volume Ⅲ) on abnormal toxicity test for biological products.

Background Di(2-ethylhexyl) phthalate (DEHP) is the most prevalent environmental endocrine disruptor among phthalate acid esters (PAEs) worldwide. Previous studies have indicated that exposure to DEHP may disrupt glucose metabolism. Objective To investigate the impact of DEHP on glucose homeostasis in rats, focusing on oxidative stress-induced impairment of autophagy in islet β cells. Methods Forty male SD rats were randomly assigned to four groups, receiving DEHP doses of 0, 187, 375, and 750 mg·kg⁻¹ for 12 weeks. Oral glucose tolerance (OGTT) and insulin tolerance tests (ITT) were conducted 24 h after the final exposure. Pancreatic microstructural alterations were assessed using hematoxylin and eosin (HE) staining and transmission electron microscopy (TEM). Commercial ELISA kits were employed to quantify the levels of insulin, adenosine triphosphate (ATP), and adenosine monophosphate (AMP) in rat serum, as well as the protein expression level of activated caspase-3 in pancreatic tissue. Additionally, commercial microplate kits were utilized to measure the concentration of reduced glutathione (GSH) in serum, the activity of superoxide dismutase (SOD) using water-soluble tetrazolium salt-1, the content of malondialdehyde (MDA) by thiobarbituric acid method, and the level of reactive oxygen species (ROS) in pancreatic tissue by chemical fluorescence method. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure sequestosome1 (SQSTM1/p62), Beclin1, microtubule-associated protein 1 light chain 3 (LC3), and cysteinyl aspartate specific proteinase-8 (Caspase-8) mRNA levels. Western blot analysis was applied to detect the protein relative expression levels of p62, Beclin-1, LC3-I, LC3 II, AMPK, p-AMPK, mTOR, p-mTOR, ULK1, and Caspase-8. Results Compared to the 0 mg·kg⁻¹ DEHP group, the 750 mg·kg⁻¹ DEHP group exhibited a significant increase in fasting blood glucose levels at 2, 4, 6, and 12 weeks (P<0.05). The OGTT showed that, following high-glucose gavage, the 187 mg·kg⁻¹ DEHP group had elevated blood glucose at 30 min (P<0.05), the 375 mg·kg⁻¹ DEHP group showed increased glucose levels at 15, 30, and 180 min (P<0.05), and the 750 mg·kg⁻¹ DEHP group exhibited elevated levels at 15, 30, 60, and 180 min (P<0.05). The 375 and 750 mg·kg⁻¹ DEHP groups demonstrated significantly increased OGTT area under the curve (AUC) values (P<0.05). In contrast, ITT results indicated no significant differences in blood glucose levels or AUC among the DEHP exposure groups at all time points (P>0.05). Compared to the 0 mg·kg⁻¹ DEHP group, the 750 mg·kg⁻¹ DEHP group exhibited significantly higher HOMA-IR levels and markedly lower HOMA-ISI values (P<0.05). HE and TEM showed that in each DEHP exposure group, the number of islet cells decreased, the islet area reduced, and chromatin condensation occurred. The endocrine granules in the cytoplasm of islet β cells decreased, and there were varying degrees of widening of the nuclear membrane gap, flattening and expansion of the Golgi complex, and expansion of the endoplasmic reticulum. Ribosome separation was observed, and autophagosomes were visible. In the 375 and 750 mg·kg⁻¹ DEHP groups, the mitochondria were deformed to varying degrees, and some cristae structures disappeared, presenting vacuolization. Moreover, the chromatin condensation in the nuclei was more severe in the 750 mg·kg⁻¹ DEHP group. The serum SOD activity was significantly elevated in the 750 mg·kg⁻¹ DEHP group (P<0.05). Both the 375 mg·kg⁻¹ and 750 mg·kg⁻¹ DEHP groups exhibited a significant increase in the relative ROS content in pancreatic tissue (P<0.05). In DEHP-treated groups, the MDA content increased (P<0.05), while the GSH content decreased (P<0.05). Additionally, in the 750 mg·kg⁻¹ DEHP group, the AMP/ATP ratio in serum was significantly raised (P<0.05), and the expression of cleaved Caspase-3 protein in pancreatic tissue was also significantly increased (P<0.05). The relative mRNA levels of p62, Beclin-1, LC3, and Caspase-8 in the pancreatic tissue of rats exposed to DEHP were significantly elevated (P<0.05). The relative expression levels of p-AMPK/AMPK, p-ULK1/ULK1, and Beclin-1 proteins in the DEHP-treated groups were significantly increased (P<0.05). In the 375 mg·kg⁻¹ and 750 mg·kg⁻¹ DEHP treatment groups, the relative expression levels of p62, LC3 II/LC1, and Caspase-8 proteins were significantly increased (P<0.05), while the relative expression level of p-mTOR/mTOR was significantly decreased (P<0.05). Conclusion DEHP can disrupt glucose homeostasis by inducing oxidative stress, which subsequently activates autophagy via the ROS/AMPK/ULK1 pathway, impairing autophagic flux and promoting apoptosis of islet β cells, ultimately decreasing their function and number.

Background A diverse cohort of patients and susceptible individuals congregate in healthcare facilities, where exposure to pathogenic microorganisms associated with respiratory infectious diseases constitutes a significant risk factor for cross-infection. Central air-conditioning ventilation systems improve some indoor environment indicators while exacerbating the risk of transmission of respiratory infectious diseases. Objective To investigate the distribution characteristics of microbial communities in the central air-conditioning ventilation systems of hospitals, providing a scientific basis for the selection of microbial indicators in hygiene standards for hospital central air-conditioning ventilation systems and for hospital risk early warning systems. Methods In October 2023, two central air-conditioning ventilation systems were selected from a Grade 3A hospital in Shanghai: one was an all-air air-conditioning system serving the waiting area on the ground floor, and the other was a fan coil plus fresh air system serving the outpatient area on the third floor. Samples from four different components of the ventilation systems—air outlets, filters, surface coolers, and condensate trays—were collected for high-throughput sequencing of the 16S rRNA gene to analyze bacterial communities. Alpha-diversity and beta-diversity analyses were performed to investigate the microbial community composition and diversity characteristics of the hospital central air-conditioning ventilation systems. Functional analysis was conducted to determine the relative abundance of bacterial functions in these systems.Results A total of 528 operational taxonomic units (OTUs) were identified, encompassing 20 bacterial phyla, 37 classes, 79 orders, 123 families, and 240 genera. The analysis revealed that the bacterial community was predominantly composed of Proteobacteria, Gemmatimonadates, Bacteroidetes, and Actinobacteria. The diversity analysis indicated that bacterial community richness and diversity were highest in the condensate trays, while no statistically significant differences (P > 0.05) were observed in the bacterial community composition among the air outlets, filters, and surface coolers. The functional analysis showed that the bacterial communities in the central air-conditioning ventilation systems primarily exhibited chemoheterotrophic, oxidative energy-dependent heterotrophic, and ureolytic functional characteristics. Conclusion The dominance of Proteobacteria suggests that this phylum exhibits strong adaptability in the central air-conditioning ventilation systems, possibly related to its ability to survive and reproduce under varying environmental conditions. The diversity analysis indicates that the condensate tray is a critical area for bacterial proliferation in the central air-conditioning ventilation systems. The similarity in environmental conditions among the air outlets, filters, and surface coolers result in similar bacterial community structures. The functional analysis reveals that the bacterial communities possess robust energy conversion and metabolic capabilities, potentially contributing to processes such as organic matter decomposition and nitrogen cycling within the central air-conditioning ventilation systems.