OBJECTIVE: CRISPR-Cas protects bacteria from exogenous DNA invasion and is associated with bacterial biofilm formation and pathogenicity. METHODS: We analyzed the type I-F CRISPR-Cas system of Legionella pneumophila WX48, including Cas1, Cas2-Cas3, Csy1, Csy2, Csy3, and Cas6f, along with downstream CRISPR arrays. We explored the effects of the CRISPR-Cas system on the in vitro growth, biofilm-forming ability, and pathogenicity of L. pneumophila through constructing gene deletion mutants. RESULTS: The type I-F CRISPR-Cas system did not affect the in vitro growth of wild-type or mutant strains. The biofilm formation and intracellular proliferation of the mutant strains were weaker than those of the wild type owing to the regulation of type IV pili and Dot/Icm type IV secretion systems. In particular, Cas6f deletion strongly inhibited these processes. CONCLUSION The type I-F CRISPR-Cas system may reduce biofilm formation and intracellular proliferation in L. pneumophila.
Legionella pneumophila/pathogenicity* ; CRISPR-Cas Systems ; Biofilms/growth & development* ; Phenotype ; Bacterial Proteins/metabolism* ; Gene Deletion

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Objective To investigate the differences in visual perception between children with autism spectrum disorder(ASD)and typically developing(TD)children when watching different intention videos,and to explore the feasibility of machine learning algorithms in objectively distinguishing between ASD children and TD children.Methods A total of 58 children with ASD and 50 TD children were enrolled and were asked to watch the videos containing joint intention and non-joint intention,and the gaze duration and frequency in different areas of interest were used as original indicators to construct classifier-based models.The models were evaluated in terms of the indicators such as accuracy,sensitivity,and specificity.Results When using eight common classifiers,including support vector machine,linear discriminant analysis,decision tree,random forest,and K-nearest neighbors(with K values of 1,3,5,and 7),based on the original feature indicators,the highest classification accuracy achieved was 81.90% .A feature reconstruction approach with a decision tree classifier was used to further improve the accuracy of classification,and then the model showed the accuracy of 91.43% ,the specificity of 89.80% ,and the sensitivity of 92.86% ,with an area under the receiver operating characteristic curve of 0.909(P<0.001).Conclusions The machine learning model based on eye-tracking data can accurately distinguish ASD children from TD children,which provides a scientific basis for developing rapid and objective ASD screening tools.[Chinese Journal of Contemporary Pediatrics,2024,26(2):151-157]

Objective To investigate the influences of Lycium barbarum polysaccharide on apoptosis of corneal epithelial cells induced by hypertonicity through regulating adenosine monophosphate activated protein kinase(AMPK)/uncoordinated 51-like kinase 1(ULK1)autophagy pathway.Methods The ophthalmoxerosis cell model was established by osmotic pressure of 500 mOsm·L-1 on corneal epithelial cells.They were divided into model group,positive control group(0.3％sodium hyaluronate eye drops),inhibitor group(1 mg·mL-1 Lycium barbarum polysaccharide+10 μmol·L-1compound C),experimental-L,-H groups(0.5,1.0 mg·mL 1 Lycium barbarum polysaccharide),and normal cultured CRL-11135 cells were taken as blank group(no treatment was performed).Cell apoptosis was detected by flow cytometry.Autophagy was detected by MDC staining.Western blot was used to detect the expressions of p-AMPK/AMPK and p-ULK1/ULK1.Results The apoptosis rates of experimental-L,experimental-H,positive control,inhibitor,model and blank groups were(26.47±2.13)％,(13.68±2.21)％,(12.54±2.16)％,(18.73±2.12)％,(37.56±3.25)％and(6.35±2.14)％;the relative contents of autophagosomes were(59.63±8.14)％,(89.89±9.04)％,(90.31±9.13)％,(62.75±7.26)％,(43.11±6.45)％and(100.00±0.00)％;p-AMPK/AMPK were 0.45±0.07,0.64±0.08,0.66±0.06,0.53±0.04,0.34±0.05 and 0.87±0.06;p-ULKl/ULKl were 0.54±0.06,0.75±0.05,0.77±0.03,0.65±0.04,0.46±0.04 and 0.92±0.08,respectively.The above indexes in experimental-L,-H groups and positive control group were significantly different from those in model group(all P＜0.05);the above indexes in inhibitor group were significantly different from those in experimental-H group(all P＜0.05).Conclusion Lycium barbarum polysaccharide can inhibit the apoptosis of corneal epithelial cells induced by hypertonicity by activating the AMPK/ULK1 autophagy pathway.

ObjectiveTo observe the effects of Sargassum and Glycyrrhizae Radix et Rhizoma incompatible pair with the Haizao Yuhutang （HYT） on oxidative stress in the liver of goiter rats under the condition of 2 times the dose limit of the Pharmacopoeia of the People's Republic of China 2020. MethodA total of 128 male Wistar rats were randomly divided into a blank group， a model group， a euthyrox group （20 μg·kg^-1）， a HYT group （12.06 g·kg^-1）， a HYT without Sargassum （HYT-H） group （9.90 g·kg^-1）， a HYT without Glycyrrhizae Radix et Rhizoma （HYT-G） group （10.26 g·kg^-1）， a HYT without Sargassum and Glycyrrhizae Radix et Rhizoma （HYT-HG） group （8.10 g·kg^-1）， and a Sargassum and Glycyrrhizae Radix et Rhizoma （HG） group （3.96 g·kg^-1）. The blank group was given deionized water by gavage， and the others were given propylthiouracil （PTU） to replicate the goiter pathological model. Euthyrox was taken as a positive control drug， and the rest of the Chinese medicine groups were given the corresponding decoction by gavage， the material was collected 12 hours after the last dose. The serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， alkaline phosphatase （ALP）， and the contents of superoxide dismutase （SOD）， glutathione peroxidase （GSH-Px）， malondialdehyde （MDA）， reactive oxygen species （ROS） in liver tissue were detected in each group. The pathological changes in the liver were observed via hematoxylin-eosin （HE） staining. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was utilized to detect the mRNA expressions of Kelch-like Ech-associated protein 1 （Keap1）， nuclear factor E₂-related factor 2 （Nrf2）， heme oxygenase-1 （HO-1）， p53 and Caspase-3 in liver tissues. Western blot was adopted to detect the protein expressions of Nrf2 and HO-1 in liver tissues in oxidative stress-related signaling pathways. ResultCompared with control group， the model group showed significantly increased serum ALT level and contents of MDA and ROS in liver tissues （P<0.05， P<0.01）， significantly reduced activities of SOD and GSH-Px in the liver （P<0.01）， significantly increased mRNA expression of Keap1 （P<0.01）， and significantly decreased mRNA and protein expressions of Nrf2 and HO-1 （P<0.05， P<0.01）. Compared with the model group， the HYT group manifested significantly reduced serum levels of AST， ALT， and ALP （P<0.05， P<0.01）， significantly reduced contents of MDA and ROS in liver tissue （P<0.01）， significantly increased the activities of SOD and GSH-Px （P<0.01）， significantly decreased mRNA expressions of Keap1， p53， and Caspase-3 （P<0.01）， and significantly increased mRNA and protein expressions of Nrf2 and HO-1 （P<0.05， P<0.01）. ConclusionUnder the condition of 2 times the dose limit of the Pharmacopoeia of the People's Republic of China 2020， Sargassum and Glycyrrhizae Radix et Rhizoma incompatible pair with the HYT on oxidative stress in the liver of goiter rats had different effects. The HYT that contains Sargassum and Glycyrrhizae Radix et Rhizoma has a protective effect on the liver of goiter rats， and the effect is better than that of the HG group， the euthyrox group， and the incomplete groups. Its mechanism may be related to activating the Nrf2/HO-1 signaling pathway to alleviate liver oxidative stress and inhibiting the p53/Caspase-3 signaling pathway to reduce hepatocyte apoptosis.

Objective To investigate the distribution and antimicrobial resistance of bacterial isolates from blood samples in the hospitals participating in China Antimicrobial Surveillance Network (CHINET) from 2015 to 2021.Methods Bacterial strains isolated from blood samples were collected from 52 medical centers participating in CHINET from 2015 to 2021 for analysis of bacetrial distribution and antimicrobial resistance.Results A total of 153591 isolates were collected,48.8％ of which were gram-positive bacteria and 51.2％ were gram-negative bacteria.The top five bacterial strains were coagulase negative Staphylococcus (28.2％),Escherichia coli (20.7％),Klebsiella (13.7％),Enterococcus (7.2％),and Staphylococcus aureus (6.6％).Compard to female patients,male patients showed lower proportion of E.coli and higher proportions of other bacterial species in all the bacterial isolaets from blood samples.The proportions of Streptococcus pneumoniae and Salmonella in all the bacterial isolaets from blood samples were higher in children compared to adults.Enterobacterales species showed various resistance rates to antimicrobial agents.Overall,≥58.0％,≥36.8％ and ≥56.8％ of E.coli strains were resistant to cefotaxime,gentamicin and levofloxacin respectively over the 7-year period.However,less than 2.5％ of the E.coli strains were resistant to carbapenems.K.pneumoniae showed higher resistance rates to imipenem and meropenem than other Enterobacterales species.During the 7-year period,the prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae increased from 21.4％ and 19.9％ in 2015 to 25.7％ and 26.6％ in 2021,respectively.However,carbapenems still maintained good antibacterial activity against other Enterobacterales,associaetd with lower resistance rates.In the 7-year period,Acinetobacter baumannii showed a dwonward trend in the resistance rates to imipenem and meropenem,but remained 72.9％ and 73.2％ respectively in 2021.The prevalence of imipenem-resistant and meropenem-resistant P.aeruginosa decreased from 26.7％ and 22.9％ in 2015 to 18.5％ and 14.7％ in 2021,respectively.The prevalence of PRSP was 1.5％ in the isolaets from adults and and 0.8％ in the isolates from children.Less than 3.0％ of the Enterococcus faecium and Enterococcus faecalis strains were resistant to vancomycin,teicolanin,or linezolid.The prevalence of methicillin-resistant S.aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) was 32.1％ and 81.0％,respectively.The prevalence of MRSA was relatively stable,28.5％ in 2015 and 28.0％ in 2021.Conclusions Coagulase negative Staphylococcus,E.coli and K.pneumoniae were the main bacterial species isolated from blood samples in the hospitals participaing in the CHINET from 2015 to 2021.Significant sex and age differences were found in the distribution of bcterial isolates from blood samples.The overall resistance rates of the top bacetrial strains from blood samples to antimicrobial agents showed a downward trend.Ongoing surveillance of antimicrobial resistance for the isolates from blood samples is still essential for prescribing rational antimicrobial therapies and curbing bacterial resistance.

Objective To investigate the distribution and antimicrobial resistance of bacterial isolates from blood samples in the hospitals participating in China Antimicrobial Surveillance Network (CHINET) from 2015 to 2021.Methods Bacterial strains isolated from blood samples were collected from 52 medical centers participating in CHINET from 2015 to 2021 for analysis of bacetrial distribution and antimicrobial resistance.Results A total of 153591 isolates were collected,48.8％ of which were gram-positive bacteria and 51.2％ were gram-negative bacteria.The top five bacterial strains were coagulase negative Staphylococcus (28.2％),Escherichia coli (20.7％),Klebsiella (13.7％),Enterococcus (7.2％),and Staphylococcus aureus (6.6％).Compard to female patients,male patients showed lower proportion of E.coli and higher proportions of other bacterial species in all the bacterial isolaets from blood samples.The proportions of Streptococcus pneumoniae and Salmonella in all the bacterial isolaets from blood samples were higher in children compared to adults.Enterobacterales species showed various resistance rates to antimicrobial agents.Overall,≥58.0％,≥36.8％ and ≥56.8％ of E.coli strains were resistant to cefotaxime,gentamicin and levofloxacin respectively over the 7-year period.However,less than 2.5％ of the E.coli strains were resistant to carbapenems.K.pneumoniae showed higher resistance rates to imipenem and meropenem than other Enterobacterales species.During the 7-year period,the prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae increased from 21.4％ and 19.9％ in 2015 to 25.7％ and 26.6％ in 2021,respectively.However,carbapenems still maintained good antibacterial activity against other Enterobacterales,associaetd with lower resistance rates.In the 7-year period,Acinetobacter baumannii showed a dwonward trend in the resistance rates to imipenem and meropenem,but remained 72.9％ and 73.2％ respectively in 2021.The prevalence of imipenem-resistant and meropenem-resistant P.aeruginosa decreased from 26.7％ and 22.9％ in 2015 to 18.5％ and 14.7％ in 2021,respectively.The prevalence of PRSP was 1.5％ in the isolaets from adults and and 0.8％ in the isolates from children.Less than 3.0％ of the Enterococcus faecium and Enterococcus faecalis strains were resistant to vancomycin,teicolanin,or linezolid.The prevalence of methicillin-resistant S.aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) was 32.1％ and 81.0％,respectively.The prevalence of MRSA was relatively stable,28.5％ in 2015 and 28.0％ in 2021.Conclusions Coagulase negative Staphylococcus,E.coli and K.pneumoniae were the main bacterial species isolated from blood samples in the hospitals participaing in the CHINET from 2015 to 2021.Significant sex and age differences were found in the distribution of bcterial isolates from blood samples.The overall resistance rates of the top bacetrial strains from blood samples to antimicrobial agents showed a downward trend.Ongoing surveillance of antimicrobial resistance for the isolates from blood samples is still essential for prescribing rational antimicrobial therapies and curbing bacterial resistance.

Objective To explore the overall level,distribution characteristics,and differences in household fine particulate matter (PM_2.5) pollution caused by fuel burning in urban and rural areas in China. Methods The relevant articles published from 1991 to 2021 were retrieved and included in this study.The data including the average concentration of household PM_2.5 and urban and rural areas were extracted,and the stoves and fuel types were reclassified.The average concentration of PM_2.5 in different areas was calculated and analyzed by nonparametric test. Results The average household PM_2.5 concentration in China was (178.81±249.91) μg/m³.The mean household PM_2.5 concentration was higher in rural areas than in urban areas[(206.08±279.40) μg/m³ vs. (110.63±131.16) μg/m³;Z=-5.45,P<0.001] and higher in northern areas than in southern areas[(224.27±301.66) μg/m³ vs.(130.11±140.61) μg/m³;Z=-2.38,P=0.017].The north-south difference in household PM_2.5 concentration was more significant in rural areas than in urban areas[(324.19±367.94) μg/m³ vs.(141.20±151.05) μg/m³,χ²=-5.06,P<0.001].The PM_2.5 pollution level showed differences between urban and rural households using different fuel types (χ²=92.85,P<0.001),stove types (χ²=74.42,P<0.001),and whether they were heating (Z=-4.43,P<0.001).Specifically,rural households mainly used solid fuels (manure,charcoal,coal) and traditional or improved stoves,while urban households mainly used clean fuels (gas) and clean stoves.The PM_2.5 concentrations in heated households were higher than those in non-heated households in both rural and urban areas (Z=-4.43,P<0.001). Conclusions The household PM_2.5 pollution caused by fuel combustion in China remains a high level.The PM_2.5 concentration shows a significant difference between urban and rural households,and the PM_2.5 pollution is more serious in rural households.The difference in the household PM_2.5 concentration between urban and rural areas is more significant in northern China.PM_2.5 pollution in the households using solid fuel,traditional stoves,and heating is serious,and thus targeted measures should be taken to control PM_2.5 pollution in these households.
Humans ; Particulate Matter/analysis* ; Air Pollution, Indoor/analysis* ; Cooking ; Environmental Exposure/analysis* ; China ; Rural Population

Animals ; SARS-CoV-2 ; Antibodies, Neutralizing ; Macaca mulatta ; COVID-19/prevention & control* ; Antibodies, Viral ; Vaccines

Objective: To investigate the clinicopathological characteristics of reactive epithelial hyperplasia and dysplasia in the stomach, as well as the clinical value of mucin special staining and proliferating cell nuclear antigen (Ki-67) in distinguishing the two gastric lesions. Methods: The clinical pathological data of 63 patients with gastric reactive epithelial hyperplasia, 54 patients with low-grade dysplasia, and 63 patients with high-grade dysplasia diagnosed from May 2018 to May 2021 in Beijing Chaoyang Hospital, Capital Medical University, Beijing, China were analyzed. Alcian blue periodic acid Schiff (AB-PAS) and Ki-67 staining were performed to examine the mucin staining pattern, number of Ki-67 positive cells, Ki-67 staining patterns in the three groups of lesions, and histopathologic characteristics. Results: The positive rates of AB-PAS in the reactive epithelial hyperplasia and gastric dysplasia groups were 87.3%(55/63) and 10.3%(12/117), respectively. The expression of AB-PAS in the reactive epithelial hyperplasia was gradually increased from the base to the surface of the epithelium. In low-grade dysplasia and high-grade dysplasia, there was no mucin present in the dysplasia epithelium. The difference between the two groups was statistically significant (P<0.01). The positive rate of Ki-67 in the epithelial reactive hyperplasia (>10%) was 81.0% (51/63), and the positive cells were mainly located in the neck and middle parts of the mucosal glands (58/63, 92.1%). In the low-grade dysplasia group, the positive rate of Ki-67 (>10%) was 90.7%(49/54); the positive cells were mainly located in the upper mucosa (33/54, 61.1%), showing a banded distribution pattern; in the high-grade dysplasia group, the positive rate (>10%) was 95.2%(60/63), and the positive cells were mainly located in the whole mucosa (49/63, 77.8%), showing a diffuse/diffuse scattered distribution pattern. The three groups had statistically different rates and distribution patterns of Ki-67 expression (P<0.01). Conclusion: The gastric epithelial reactive hyperplasia and dysplasia can be differentiated using clinicopathological features, AB-PAS staining and Ki-67 expression pattern.
Alcian Blue ; Humans ; Hyperplasia ; Ki-67 Antigen/metabolism* ; Periodic Acid ; Staining and Labeling ; Stomach Neoplasms/diagnosis*