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.

Objective To explore the clinical manifestations,endoscopic findings,histopathological changes,treatment,and prognosis of eosinophilic gastrointestinal disease(EGID)in children,with the aim of enhancing awareness among pediatricians about this condition.Methods Data of 267 children with EGID were prospectively collected from January 2019 to July 2022 at Jiangxi Children's Hospital,Hunan Children's Hospital,and Henan Children's Hospital.The age of onset,symptoms,physical signs,laboratory examination results,endoscopic findings,histopathological changes,and treatment outcomes were observed.Results Among the 267 children with EGID,the majority had mild(164 cases,61.4% )or moderate(96 cases,35.6% )clinical severity.The disease occurred at any age,with a higher prevalence observed in school-age children(178 cases).The main symptoms in infants were vomiting and hematemesis,while in toddlers,vomiting and bloody stools were prominent.Abdominal pain and vomiting were the primary symptoms in preschool and school-age children.Nearly half(49.4% )of the affected children showed elevated platelet counts on hematological examination,but there was no significant difference in platelet counts among children with mild,moderate,and severe EGID(P>0.05).Endoscopic findings in EGID children did not reveal significant specificity,and histopathological examination showed no specific structural damage.Among them,85.0% (227 cases)received acid suppression therapy,34.5% (92 cases)practiced dietary avoidance,20.9% (56 cases)received anti-allergic medication,and a small proportion(24 cases,9.0% )were treated with prednisone.Clinical symptoms were relieved in all patients after treatment,but three cases with peptic ulcers experienced recurrence after drug discontinuation.Conclusions Mild and moderate EGID are more common in children,with no specific endoscopic findings.Dietary avoidance,acid suppression therapy,and anti-allergic medication are the main treatment methods.The prognosis of EGID is generally favorable in children.[Chinese Journal of Contemporary Pediatrics,2024,26(2):139-144]

Objective To study the clinical characteristics of children with anti-neutrophil cytoplasmic antibody(ANCA)-associated vasculitis(AAV).Methods A retrospective analysis was conducted on the clinical data of 25 children diagnosed with AAV at the Second Xiangya Hospital of Central South University from January 2010 to June 2022.Results Among the AAV children,there were 5 males and 20 females,with a median age of onset of 11.0 years.Involvement of the urinary system was seen in 18 cases(72%);respiratory system involvement in 10 cases(40%);skin involvement in 6 cases(24%);eye,ear,and nose involvement in 5 cases(20%);joint involvement in 4 cases(16%);digestive system involvement in 2 cases(8%).Eleven cases underwent kidney biopsy,with 5 cases(46%)showing focal type,2 cases(18%)showing crescentic type,2 cases(18%)showing mixed type,and 2 cases(18%)showing sclerotic type.Immune complex deposits were present in 5 cases(45%).Seven cases reached chronic kidney disease(CKD)stage Ⅴ,with 2 cases resulting in death.Two cases underwent kidney transplantation.At the end of the follow-up period,2 cases were at CKD stage Ⅱ,and 1 case was at CKD stage Ⅲ.Of the 16 cases of microscopic polyangiitis(MPA)group,13(81%)involved the urinary system.Of the 9 cases of granulomatosis with polyangiitis(GPA),6 cases(66%)had sinusitis.Serum creatinine and uric acid levels were higher in the MPA group than in the GPA group(P<0.05),while red blood cell count and glomerular filtration rate were lower in the MPA group(P<0.05).Conclusions AAV is more common in school-age female children,with MPA being the most common clinical subtype.The onset of AAV in children is mainly characterized by renal involvement,followed by respiratory system involvement.The renal pathology often presents as focal type with possible immune complex deposits.Children with MPA often have renal involvement,while those with GPA commonly have sinusitis.The prognosis of children with AAV is poor,often accompanied by renal insufficiency.

Objective To evaluate the in vitro effect of combinations of 5 β-lactam antibiotics with different β-lac-tamase inhibitors on the activity of multidrug-resistant Mycobacterium tuberculosis(MDR-TB),and identify the most effective combination of β-lactam antibiotics and β-lactamase inhibitors against MDR-TB.Methods MDR-TB strains collected in Henan Province Antimicrobial Resistance Surveillance Project in 2021 were selected.The mini-mum inhibitory concentrations(MIC)of 5 β-lactam antibiotics or combinations with different β-lactamase inhibitors on clinically isolated MDR-TB strains were measured by MIC detection method,and the blaC mutation of the strains was analyzed by polymerase chain reaction(PCR)and DNA sequencing.Results A total of 105 strains of MDR-TB were included in the analysis.MIC detection results showed that doripenem had the highest antibacterial activity against MDR-TB,with a MIC50 of 16 μg/mL.MIC values of most β-lactam antibiotics decreased significantly after combined with β-lactamase inhibitors.A total of 13.33％(n=14)strains had mutations in blaC gene,mainly 3 nu-cleotide substitution mutations,namely AGT333AGG,AAC638ACC and ATC786ATT.BlaC proteins Ser111 Arg and Asn213Thr enhanced the synergistic effect of clavulanic acid/sulbactam and meropenem on MDR-TB compared with synonymous single-nucleotide mutation.Conclusion The combination of doripenem and sulbactam has the strongest antibacterial activity against MDR-TB.Substitution mutations of BlaC protein Ser111 Arg and Asn213Thr enhances the sensitivity of MDR-TB to meropenem through the synergy with clavulanic acid/sulbactam.

Objective:To study the clinical characteristics of congenital esophageal atresia (CEA) and risk factors of mortality associated with esophageal repair (ER) surgery.Methods:From January 2010 to December 2022, patients diagnosed of CEA using chest and abdomen X-ray and esophagography in our hospital were retrospectively reviewed. The patients were assigned into ER group and non-ER group according to the treatments. The ER group was subgrouped into survival group and death group according to the prognosis. Clinical data and outcomes were collected and compared between the groups.Results:A total of 553 cases were enrolled. According to Gross classification, 29 patients (5.2%) were type A, 2 patients (0.4%) were type B, 504 patients (91.1%) were type C, 6 patients (1.1%) were type D and 11 patients (2.0%) were type E. One patient had simple transluminal septal atresia of the esophagus. 406 patients were in ER group and 147 in non-ER group. Compared with ER group, non-ER group had significantly higher incidences of preterm birth, low birth weight and overall malformations (all P<0.05). In ER group, 152 patients (37.4%) received open thoracic surgery (OTS), 243 (59.9%) had video-assisted thoracoscopic surgery (VATS) and 11 (2.7%) were VATS converted to OTS. Postoperative anastomotic leakage (PAL) occurred in 92 patients (22.7%) and 15 patients (3.7%) died after surgery. The median length of hospital stay was 23 (17, 36) d. Compared with the survival group, the death group had higher incidences of preterm birth, low birth weight, VATS converted to OTS, mechanical ventilation after ER, and shorter length of hospital stay (all P<0.05). After adjusted for birth weight, VATS converted to OTS ( OR=9.585, 95% CI 1.899-48.374) and mechanical ventilation after ER ( OR=7.821, 95% CI 1.002-61.057) were risk factors of mortality in ER patients. Conclusions:Non-ER patients have higher incidences of preterm birth, low birth weight and overall malformations than ER patients. VATS is the method of choice for CEA. Preterm birth, low birth weight, VATS converted to OTS and mechanical ventilation after ER are risk factors of mortality in ER patients.

AIM To identify the endophytic fungus G-(JK)-2 from Orixa japonica Thunb.and to study its secondary metabolites and their α-glucosidase inhibitory activities.METHODS Through the ITS sequence,the evolutionary tree that identifies the endophytic fungus G-(JK)-2 was established.Then 45 days rice solid medium of endophytic fungus G-(JK)-2 was extracted by methanol,and then by ethyl acetate.The ethyl acetate extract was separated and purified by silica gel chromatography,Sephadex LH-20,and semi-preparative HPLC.The structures of obtained compounds were identified by physicochemical properties and spectral data.Their α-glucosidase inhibitory activities were evaluated by PNPG method.RESULTS The endophytic fungus G-(JK)-2 from O.japonica was identified as Fusarium nematophilum.Thirteen compounds were isolated and identified as p-hydroxybenzaldehyde(G1),4-hydroxyacetophenone(G2),anhydromevalonolactone(G3),flazine(G4),salicylic acid(G5),p-hydroxybenzoic acid(G6),di-(2-ethylhexyl)-phthalate(G7),terephthalic acid bis(2-ethyl-hexyl)ester(G8),thymine(G9),uridine(G10),adenosine(G11),2′-deoxyuridine(G12),nicotinic acid(G13).The inhibitory effect of each compound on α-glucosidase was in sequence of G4>G11>G10>G13>G12.CONCLUSION All compounds are first isolated from the endophytic fungi of the O.japonica,and G10,G11,G13 are first isolated from the endophytic fungi of Fusarium.G4 and G11 have mild inhibition to α-glucosidase.

AIM To evaluate the quality of Beidougen Formula Granules.METHODS Fifteen batches of standard decoctions and three batches of formula granules were prepared,after which paste rate and contents,transfer rates of magnoflorine,daurisoline,dauricine were determined.HPLC specific chromatograms were established,and cluster analysis was adopted in chemical pattern recognition.RESULTS For three batches of formula granules,the paste rates were 15.1%-16.6%,the contents of magnoflorine,daurisoline,dauricine were 18.93-19.39,9.42-9.60,6.79-6.85 mg/g with the transfer rates of 34.42%-35.25%,43.81%-44.65%,27.27%-27.51%from decoction pieces to formula granules,respectively,and there were seven characteristic peaks in the specific chromatograms with the similarities of more than 0.95,which demonstrated good consistence with those of standard decoctions and accorded with related limit requirements.Fifteen batches of standard decoctions were clustered into two types,and the medicinal materials produced from Jilin,Hebei,Shangdong could be used for the preparation of formula granules.CONCLUSION This reasonable and reliable method can provide references for the quality control and clinical application of Beidougen Formula Granules.

Objective To investigate the therapeutic effect of hesperidin(Hsp)on mammary gland hyperplasia(MGH)rats and the possible mechanism.Methods Sixty female rats were randomly divided into blank,model,control and experimental-L,-M,-H groups.Except for blank group,all other groups were injected intramuscularly with estrogen and progestin to induce MGH model in rats.The experimental-L,-M and-H groups were given 25,50,100 mg·kg-1 Hsp by gavage.The control group was given 5 mg·kg-1 tamoxifen by gavage.The blank and control groups were given an equal volume of 0.9％NaCl by gavage.Six groups of rats were administered once a day for 30 days.After the administration,the height and diameter of nipples and the uterine coefficient were measured.The serum sex hormone content was detected using enzyme-linked immunosorbent assay,the levels of oxidative stress indicators were detected using corresponding kits,and the expressions of related proteins were detected using Western blot.Results The nipple diameters of rats in experimental-M and-H groups,control group,model group and blank group were(1.41±0.20),(1.18±0.21),(1.23±0.20),(1.75±0.13)and(1.02±0.06)mm;the nipple heights were(1.62±0.24),(1.41±0.19),(1.47±0.16),(1.87±0.32)and(1.23±0.14)mm;the uterine indexes were(0.55±0.08),(0.37±0.05),(0.41±0.04),(0.72±0.11)and(0.34±0.03)mg·g-1;the relative expression levels of estrogen receptor alpha(ERα)were 0.54±0.05,0.13±0.02,0.13±0.03,0.89±0.08 and 0.10±0.02;the relative expression levels of progesterone receptor(PR)were 0.43±0.03,0.08±0.01,0.87±0.07,0.20±0.04 and 0.14±0.03;the phosphorylated-extracellular-regulated kinase 1/2(ERK1/2)/ERK1/2 were 0.50±0.03,0.06±0.02,0.83±0.05,0.09±0.04 and 0.04±0.01,respectively.Compared with model group,the differences of above indexes in the experimental-M,-H groups and control group were statistically significant(all P＜0.05).Conclusion Hsp could reduce nipple diameter,height,and uterine coefficient,regulate sex hormone levels,resist oxidative stress,and inhibit the expression of ERα,PR and p-ERK1/2 proteins in rats.