Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective To investigate the changing distribution and antibiotic resistance profiles of clinical isolates of Staphylococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Staphylococcus according to the unified protocol of CHINET(China Antimicrobial Surveillance Network)using disk diffusion method and commercial automated systems.The CHINET antimicrobial resistance surveillance data from 2015 to 2021 were interpreted according to the 2021 CLSI breakpoints and analyzed using WHONET 5.6.Results During the period from 2015 to 2021,a total of 204,771 nonduplicate strains of Staphylococcus were isolated,including 136,731(66.8％)strains of Staphylococcus aureus and 68,040(33.2％)strains of coagulase-negative Staphylococcus(CNS).The proportions of S.aureus isolates and CNS isolates did not show significant change.S.aureus strains were mainly isolated from respiratory specimens(38.9±5.1)％,wound,pus and secretions(33.6±4.2)％,and blood(11.9±1.5)％.The CNS strains were predominantly isolated from blood(73.6±4.2)％,cerebrospinal fluid(12.1±2.5)％,and pleural effusion and ascites(8.4±2.1)％.S.aureus strains were mainly isolated from the patients in ICU(17.0±7.3)％,outpatient and emergency(11.6±1.7)％,and department of surgery(11.2±0.9)％,whereas CNS strains were primarily isolated from the patients in ICU(32.2±9.7)％,outpatient and emergency(12.8±4.7)％,and department of internal medicine(11.2±1.9)％.The prevalence of methicillin-resistant strains was 32.9％in S.aureus(MRSA)and 74.1％in CNS(MRCNS).Over the 7-year period,the prevalence of MRSA decreased from 42.1％to 29.2％,and the prevalence of MRCNS decreased from 82.1％to 68.2％.MRSA showed higher resistance rates to all the antimicrobial agents tested except trimethoprim-sulfamethoxazole than methicillin-susceptible S.aureus(MSSA).Over the 7-year period,MRSA strains showed decreasing resistance rates to gentamicin,rifampicin,and levofloxacin,MRCNS showed decreasing resistance rates to gentamicin,erythromycin,rifampicin,and trimethoprim-sulfamethoxazole,but increasing resistance rate to levofloxacin.No vancomycin-resistant strains were detected.The prevalence of linezolid-resistant MRCNS increased from 0.2％to 2.3％over the 7-year period.Conclusions Staphylococcus remains the major pathogen among gram-positive bacteria.MRSA and MRCNS were still the principal antibiotic-resistant gram-positive bacteria.No S.aureus isolates were found resistant to vancomycin or linezolid,but linezolid-resistant strains have been detected in MRCNS isolates,which is an issue of concern.

This study was aimed at creating an engineered strain of Bacillus subtilis for efficient expression of biologically active type 2 toxin B(TcdB2)derived from a highly virulent strain of Clostridium difficile.The TcdB2 gene was cloned from ST1/RT027 strain genome DNA,incorporated into the PHT01 vector,and then transformed into B.subtilis strain WB800N for prokaryotic expression.Cell toxicity assays revealed that the recombinant TcdB2 exhibited cytotoxic effects in various cells.The engineered B.subtilis strain effectively expressed biologically active TcdB2,thus providing a basis for further exploration of the pathogenic mechanisms of highly virulent strains of C.difficile and establishing a foundation for potential vaccine can-didate targets.

The regulatory requirements of 3D printing products were introduced.The risks during the production of 3D printed navigational template for orthopedic surgery were summarized in terms of data acquisition,medical-industrial intera-ction design,3D printing,post-processing and sterilization.Some quality control measures were proposed from the aspects of quality control of raw materials,validation of data and software,verification of printing process parameters,post-processing method and verification,sterilization verification and testing of semi-finished and final products,so as to enhance the safety and effectiveness of 3D printed navigational template for orthopedic surgery.[Chinese Medical Equipment Journal,2024,45(5):80-85]

With the widespread use of carbapenem antibiotics,the clinical detection rate of carbapenem-resistant Gram-negative bacilli has shown a significant increase.Carbapenem-resistant Gram-negative bacilli isolates are often extensively or fully resistant,resulting in limited antimicrobial treatment options and high morbidity and mortality rates,posing a serious public health threat.The clinical treatment of carbapenem-resistant Gram-negative bacilli includes the use of single or combination antimicrobials such as polymyxin,tigecycline,and fosfomycin.A number of new antimicrobials and therapeutic approaches are under development.The clinical management of carbapenem-resistant Gram-negative infections is severely challenged by the limited choice of antimicrobial agents.Therefore,this article reviews the current status and progress of antimicrobial treatment for carbapenem-resistant Gram-negative bacilli to providing clinical reference.

Objective To assess the effectiveness and safety of prone positioning in the treatment of neonatal respiratory distress syndrome(NRDS)using invasive respiratory support.Methods A prospective study was conducted from June 2020 to September 2023 at Suining County People's Hospital,involving 77 preterm infants with gestational ages less than 35 weeks requiring invasive respiratory support for NRDS.The infants were randomly divided into a supine group(37 infants)and a prone group(40 infants).Infants in the prone group were ventilated in the prone position for 6 hours followed by 2 hours in the supine position,continuing in this cycle until weaning from the ventilator.The effectiveness and safety of the two approaches were compared.Results At 6 hours after enrollment,the prone group showed lower arterial blood carbon dioxide levels,inspired oxygen concentration,oxygenation index,rates of tracheal intubation bacterial colonization,and Neonatal Pain,Agitation and Sedation Scale scores compared to the supine group(P<0.05).There were no significant differences between the groups in terms of pH,arterial oxygen pressure,positive end-expiratory pressure,duration of mechanical ventilation,accidental extubation,ventilator-associated pneumonia,air leak syndrome,skin pressure sores,feeding intolerance,and grades II-IV intraventricular hemorrhage(P>0.05).Conclusions Compared to supine positioning,prone ventilation effectively improves oxygenation,increases comfort,and reduces tracheal intubation bacterial colonization in neonates requiring mechanical ventilation for NRDS,without significantly increasing adverse reactions.

Objective To explore the establishment of a risk prediction model for concurrent bronchiolitis obliterans(BO)in children with refractory Mycoplasma pneumoniae pneumonia(RMPP).Methods A retrospective study included 116 RMPP children treated in the Department of Pediatrics of Xiangya Changde Hospital from June 2021 to December 2023.Eighty-one cases were allocated to the training set and thirty-five cases to the validation set based on a 7:3 ratio.Among them,26 cases in the training set developed BO,while 55 did not.The multivariate logistic regression was used to select variable factors for constructing the BO risk prediction model.Nomograms were drawn,and the receiver operating characteristic(ROC)curve was used to assess the discriminative ability of the model,while calibration curves and Hosmer-Lemeshow tests evaluated the model's calibration.Results Multivariate logistic regression analysis indicated that several factors were significantly associated with concurrent BO in RMPP children,including length of hospital stay,duration of fever,atelectasis,neutrophil percentage(NEUT%),peak lactate dehydrogenase(LDH),ferritin,peak C reactive protein(CRP),oxygenation index(PaO2/FiO2),≥2/3 lung lobe consolidation,pleural effusion,bronchial mucous plugs,bronchial mucosal necrosis,and arterial oxygen partial pressure(PaO2)(P<0.05).ROC curve analysis for the training set indicated an area under the curve of 0.904 with 88%sensitivity and 83%specificity;the validation set showed an area under the curve of 0.823 with 76%sensitivity and 93%specificity.The Hosmer-Lemeshow test's Chi-square values for the training and validation sets were 2.17 and 1.92,respectively,with P values of 0.221 and 0.196,respectively.Conclusions The risk prediction model for BO in RMPP children based on logistic regression has good performance.Variables such as length of hospital stay,duration of fever,atelectasis,peak LDH,peak CRP,NEUT%,ferritin,≥2/3 lung lobe consolidation,pleural effusion,bronchial mucous plugs,bronchial mucosal necrosis,PaO2/FiO2,and PaO2 can be used as predictors.

Aim To explore the mechanism of hydroxy-a-sanshool in the treatment of diabetic cardiomyopathy ( DCM) based on label-free quantitative proteomics detection technique. Methods DCM model was established by high fat diet and intraperitoneal injection of streptozotocin ( STZ) . They were divided into control group ( CON group ) , diabetic cardiomyopathy group (DCM group) and hydroxy-a-sanshool treatment group ( DCM + SAN group) . The cardiac function of mice was evaluated by echocardiography, the myocardial morphology was observed by pathology staining, the protective mechanism of hydroxy-a-sanshool on diabetic cardiomyopathy was speculated by proteomic technique , and the expression level of cAMP/PKA signaling pathway and key proteins were verified by Western blotting. Results Cardiac ultrasound and pathology staining showed that hydroxy-a-sanshool had protective effect on the heart of DCM mice. Label-free quantitative proteomic analysis was carried out between DCM + SAN group and DCM group, and 160 differential pro-teins were identified by proteomics, in which 127 proteins were up-regulated and 33 proteins were down regulated ; GO secondary functional annotations showed the biological process, molecular function and cellular component; KEGG enrichment analysis showed that cAMP signaling pathway was the most abundant; protein interaction network showed that PKA as the central node interacted with many proteins in the cAMP signaling pathway. Western blot showed that the relative expression of с AMP, PKA protein in DCM group was significantly lower than that in CON group ( P < 0. 05 ) , while the relative expression of cAMP, PKA protein in DCM + SAN group was significantly higher than that in DCM group ( P < 0. 05 ) . Conclusions Hydroxy-a-sanshool has protective effect on heart function of mice with diabetes, which plays a role through cAMP signaling pathway.

AIM To investigate the effects of Zhuangyao Shuanglu Tongnao Formula on neuronal apoptosis in rats with cerebral ischemia-reperfusion injury based on the study of oxidative stress and inflammatory response.METHODS The rats were randomly divided into the sham operation group,the model group,the edaravone group(3.0 mg/kg),the low,medium and high dose groups(9.0,18.0,36.0 g/kg)of Zhuangyao Shuanglu Tongnao Formula,with 18 rats in each group.The middle cerebral artery occlusion/reperfusion was conducted by thread embolism method to simulate cerebral ischemia reperfusion injury in rats followed by 6 days corresponding drugs administration.Subsequently,the rats had their neurological function deficit scored by Zeal Longa scoring method;their sizes of cerebral infarction areas measured by TTC staining;their pathological damage and apoptosis of neurons in hippocampal CA1 area of ischemic penumbra of the brain tissue detected by HE staining and TUNEL staining;their SOD activity and levels of GSH,MDA,IL-6,IL-1β,TNF-α in brain tissue detected by kits;and their protein expressions of Bax,Bcl-2,caspase-3,cleaved-capase-3,TLR4,NF-κB p65,Nrf2,HO-1 in rat brain tissue determined by Western blot.RESULTS Compared with the model group,the groups intervened with edaravone,medium and high dose of Zhuangyao Shuanglu Tongnao Formula displayed improvements in the scores of nerve function defects,the rate of cerebral infarction,the rate of neuronal apoptosis,the levels of IL-6,IL-1β,TNF-α and MDA in the ischemic penumbra of brain tissues,the protein expressions of Bax and TLR4,the ratio of cleaved-capase-3/caspase-3 and p-NF-κB p65/NF-κB p65(P＜0.05),the levels of GSH,the activity of SOD and the protein expressions of Bcl-2,Nrf2 and HO-1(P＜0.05).CONCLUSION Being an inhibitor of oxidative stress and inflammatory response,Zhuangyao Shuanglu Tongnao Formula can alleviate brain injury in rats with cerebral ischemia reperfusion injury through the inhibition of neuronal apoptosis and improvement of neural function mediated by the inhibition of TLR4/NF-κB signal pathway and activation of Nrf2/HO-1 signal pathway.

OBJECTIVE To investigate the effect of pachymic acid （PA） on renal function and fibrosis in chronic renal failure （CRF） rats and its potential mechanism based on the Ras homolog gene family member A （RhoA）/Rho-associated coiled-coil forming protein kinase （ROCK） signaling pathway. METHODS Using male SD rats as subjects， the CRF model was established by 5/6 nephrectomy； the successfully modeled rats were divided into model group， PA low-dose， medium-dose and high-dose groups （5， 10， 20 mg/kg PA）， high-dose PA+ROCK pathway activator lysophosphatidic acid （LPA） group （20 mg/kg PA+1 mg/kg LPA）， with 15 rats in each group. Another 15 rats were selected as the sham operation group with only the kidney exposed but not excised. The rats in each drug group were gavaged and/or injected with the corresponding liquid via the caudal vein， once a day， for 12 consecutive weeks. During the experiment， the general condition of rats was observed in each group. After the last administration， the serum renal function indexes （blood urea nitrogen， serum creatinine， uric acid） of rats in each group were detected， the renal histopathological changes were observed； the renal tubule injury score and the area of renal fibrosis were quantified. The levels of oxidative stress indexes [malondialdehyde （MDA）， superoxide dismutase （SOD）] and inflammatory factors （tumor necrosis factor-α， interleukin-1β， interleukin-6）， the positive expression rates of connective tissue growth factor （CTGF） and collagen Ⅰ were detected as well as the expression levels of pathway-related proteins （RhoA， ROCK1） and fibrosis- related proteins （transforming growth factor-β1， bare corneum homologs 2， α-smooth muscle actin） were determined. RESULTS Compared with the sham operation group， the rats in model group had reduced diet， smaller body size， listless spirit and sluggish response， reduced and atrophied glomeruli， dilated renal tubules with chaotic structure， and a large number of inflammatory cells infiltrated interstitium； the serum levels of renal function indexes， renal tubule injury score， renal fibrosis area proportion， the levels of MDA and inflammatory factors， the positive expression rates of CTGF and collagen Ⅰ， and the expression levels of pathway-related proteins and fibrosis-related proteins in renal tissues were significantly increased， while SOD level was significantly decreased （P＜0.05）. Compared with the model group， the general condition and pathological injuries of kidney tissue of rats in PA groups were improved to varying degrees，and the above quantitative indexes were significantly improved in a dose-dependent manner （P＜0.05）. LPA could significantly reverse the improvement effect of PA on the above indicators （P＜0.05）. CONCLUSIONS PA can improve renal function and alleviate renal fibrosis in CRF rats， which may be related to inhibiting the activation of RhoA/ROCK signaling pathway.