Objective To investigate the changes in the prevalence of Babesia microti infections, spleen morphology and proportions of splenic immune cells in BALB/c mice following intravenous and intraperitoneal injections, so as to provide insights into unraveling the immune regulatory mechanisms of Babesia infections. Methods Laboratory - maintained B. microti strains were prepared into whole blood samples with 10% prevalence of B. microti infection. A total of 75 BALB/c mice were randomly divided into three groups, including the normal control group, intravenous injection group, and intraperitoneal injection group, of 25 mice in each group. Mice in the intravenous and intraperitoneal injection groups were administered 100 μL of whole blood samples with 10% prevalence of B. microti infection, with the day of injection recorded as d0, and animals in the normal control group were given no treatments. Blood was sampled from mice in each group via the tail tip on d7, d14, d21, d28 and d35, and prepared into thin-film blood smears, and B. microti infection was observed in red blood cells. Five mice were randomly sampled from each group and sacrificed on d7, d14, d21, d28 and d35, and spleen was collected for measurement of spleen size and weight. In addition, splenic cells were isolated, and the proportions of CD3e⁺ T cells, CD45R⁺ B cells, CD49b⁺ nature killer (NK) cells, and F4/80⁺ macrophages were detected in CD45⁺ lymphocytes using flow cytometry. Results The prevalence of B. microti infection in the intravenous (22.80%) and intraperitoneal injection groups (44.82%) peaked on d7 (χ² = 8.141, P < 0.01) and then rapidly decreased, and no parasites were observed on d35. The longest mouse spleen length [(32.91 ± 2.20) mm] and width [(9.82 ± 0.43) mm], and the greatest weight [(0.78 ± 0.10) g] were found on d14 in the intravenous injection group, and the longest spleen length [(32.42 ± 3.21) mm] and width [(10.25 ± 0.73) mm], and the greatest weight [(0.73 ± 0.09) g] were seen in the intra-peritoneal injection group on d21, d7 and d14, respectively. There were significant differences among the intravenous injection group, intraperitoneal injection group and the normal control group in terms of spleen length (F = 10.310, P < 0.05), width (F = 9.824, P < 0.05), and weight (F = 10.672, P < 0.05) on d21, and the mouse spleen length, width and weight were all significantly greater in the intraperitoneal injection group than in the intravenous injection group (allP values < 0.05). The proportions of splenic CD3e⁺ T cells [(60.60 ± 6.20)% and (39.68 ± 7.62)%], CD45R⁺ B cells [(43.32 ± 2.08)% and (49.53 ± 4.90)%], CD49b⁺ NK cells [(6.88 ± 1.34)% and (7.71 ± 1.59)%], and F4/80⁺ macrophages [(2.21 ± 0.29)% and (3.80 ± 0.35)%] peaked on d14, d21, d21 and d14 in the intravenous and intraperitoneal injection groups, respectively. There were significant differences in the proportions of CD3e⁺ T cells (F = 16.730, P < 0.05) and F4/80⁺ macrophages (F = 15.941, P < 0.05) among the intravenous injection group, intraperitoneal injection group and normal control group on d14, and a higher proportion of CD3e⁺ T cells and a lower proportion of F4/80⁺ macrophages were detected in the intravenous injection group than in the intraperitoneal injection group (both P values < 0.01). There were significant differences among the intravenous injection group, intraperitoneal injection group and normal control group on d21 in terms of proportions of splenic CD3e⁺ T cells (F = 9.252, P < 0.05), CD45R⁺ B cells (F = 14.349, P < 0.05), CD49b⁺ NK cells (F = 13.436,P < 0.05), and F4/80⁺ macrophages (F = 8.180, P < 0.05), and a higher proportion of CD3e⁺ T cells and lower proportions of CD45R⁺ B cells and F4/80⁺ macrophages were detected in the intravenous injection group than in the intraperitoneal injection group (all P values < 0.01). In addition, there was a significant difference in the proportion of CD3e⁺ T cells among the intravenous injection group, intraperitoneal injection group and normal control group on d28 (F = 9.772,P < 0.05), and a lower proportion of CD3e⁺ T cells was found in the intravenous injection group than in the intraperitoneal injection group (P < 0.01). Conclusions Both intraperitoneal and intravenous routes are effective to induce B. microti infections in BALB/c mice, and the prevalence of B. microti infections is higher in BALB/c mice through the intraperitoneal route than through the intravenous route. Intraperitoneal and intravenous injections with B. microti cause diverse spleen morphologies and proportions of splenic immune cells in mice, indicating routes of B. microti infections cause different impacts on immune response mechanisms in mice.

CRISPR/Cas system, an adaptive immune system with clustered regularly interspaced short palindromic repeats, may interfere with exogenous nucleic acids and protect prokaryotes from external damages, is an effective gene editing and nucleic acid detection tools. The CRISPR/Cas system has been widely applied in virology and bacteriology; however, there is relatively less knowledge about the application of the CRISPR/Cas system in parasitic diseases. The review summarizes the mechanisms of action of the CRISPR/Cas system and provides a comprehensive overview of their application in gene editing and nucleic acid detection of parasitic diseases, so as to provide insights into future studies on parasitic diseases.

Objective To analyze the correlations of the expressions of miR-4500 and nerve growth factor(NGF)in breast cancer patients with preoperative magnetic resonance(MR)signs.Methods A total of 105 patients with breast cancer admitted to our hospital were selected,the mRNA expression levels of miR-4500 and NGF in breast cancer tissues and adjacent tissues of patients were detected by qRT-PCR,and the positive expression rates of NGF in breast cancer tissues and adjacent tissues were determined by immunohistochemistry method.The correlations of the expressions of miR-4500 and NGF in breast cancer tissues with clinicopathological features and MR signs of patients were analyzed.The targeting relationship between miR-4500 and NGF was predicted by the bioinformatics website,and the correla-tion between the expressions of the two was analyzed.Results Compared with the adjacent tissues,the expression level of miR-4500 in breast cancer tissue decreased(P<0.05),while the level of NGF mRNA and the positive expression rate of NGF increased(P<0.05).There was no significant difference in age,pathological type,tumor classification,parenchymal background,apparent diffusion coefficient or enhancement curve among different expressions of miR-4500 and NGF(P>0.05).The histological grade,lymph node metastasis,tumor diameter,tumor morphology,ring-like enhancement,and peritu-moral brain edema were related to the expressions of miR-4500 and NGF(P<0.05).The bioinformatics website prediction showed that miR-4500 and NGF had binding sites,and the expressions of miR-4500 and NGF mRNA in breast cancer tissues were negatively correlated(r=-0.576,P<0.05).Conclusion The expression of miR-4500 in breast cancer tissue is low,and the expression of NGF is high,which are correlated with the preoperative MR signs in patients,providing a molecu-lar basis for MR signs.

Objective To explore the correlation of MPV,NLR,PT,APTT and FIB with early pro-gression of ACI in patients with BAD.Methods A total of 303 ACI patients with BAD admitted in our department of neurology from October 2021 to September 2023 were consecutively recrui-ted,and according to their progression within 7 d of onset,they were divided into progression group(89 cases)and un-progression group(214 cases).The general clinical data,blood routine re-lated indicators(MPV,NLR)and coagulation related indicators(PT,APTT,FIB)were compared between the two groups.Multivariate logistic regression analysis was applied to identify the rela-tionship of above indicators with early progression of ACI in BAD patients.ROC curve was plot-ted to analyze the predictive value of the indictors for disease progression in these patients.Results The progression group had significantly advanced age,larger proportions of diabetes,hyperlipi-demia and stroke history,and increased levels of uric acid,LDL-C,homocysteine,MPV,platelet distribution width,NLR,D-dimer and FIB,and shorter TT,PT and APTT when compared with the un-progressed group(P＜0.05,P＜0.01).Multivariate logistic regression analysis showed that MPV,NLR,PT,APTT,and FIB were all independent influencing factors for early disease pro-gression of ACI in patients with BAD(P＜0.05,P＜0.01).ROC curve indicated that the AUC value of combined MPV,NLR,PT,APTT and FIB in detecting early disease progression was 0.859(95％CI:0.813-0.905).Conclusion Blood routine(MPV,NLR)and coagulation related indicators(PT,APTT,FIB)are closely associated with the early disease progression of ACI in BAD patients,and these indicators are of high value in predicting the early disease progression.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.

Objective To examine the changing antimicrobial resistance profile of Enterobacter spp.isolates in 53 hospitals across China from 2015 t0 2021.Methods The clinical isolates of Enterobacter spp.were collected from 53 hospitals across China during 2015-2021 and tested for antimicrobial susceptibility using Kirby-Bauer method or automated testing systems according to the CHINET unified protocol.The results were interpreted according to the breakpoints issued by the Clinical & Laboratory Standards Institute(CLSI)in 2021(M100 31st edition)and analyzed with WHONET 5.6 software.Results A total of 37 966 Enterobacter strains were isolated from 2015 to 2021.The proportion of Enterobacter isolates among all clinical isolates showed a fluctuating trend over the 7-year period,overall 2.5％in all clinical isolates amd 5.7％in Enterobacterale strains.The most frequently isolated Enterobacter species was Enterobacter cloacae,accounting for 93.7％(35 571/37 966).The strains were mainly isolated from respiratory specimens(44.4±4.6)％,followed by secretions/pus(16.4±2.3)％and urine(16.0±0.9)％.The strains from respiratory samples decreased slightly,while those from sterile body fluids increased over the 7-year period.The Enterobacter strains were mainly isolated from inpatients(92.9％),and only(7.1±0.8)％of the strains were isolated from outpatients and emergency patients.The patients in surgical wards contributed the highest number of isolates(24.4±2.9)％compared to the inpatients in any other departement.Overall,≤ 7.9％of the E.cloacae strains were resistant to amikacin,tigecycline,polymyxin B,imipenem or meropenem,while ≤5.6％of the Enterobacter asburiae strains were resistant to these antimicrobial agents.E.asburiae showed higher resistance rate to polymyxin B than E.cloacae(19.7％vs 3.9％).Overall,≤8.1％of the Enterobacter gergoviae strains were resistant to tigecycline,amikacin,meropenem,or imipenem,while 10.5％of these strains were resistant to polycolistin B.The overall prevalence of carbapenem-resistant Enterobacter was 10.0％over the 7-year period,but showing an upward trend.The resistance profiles of Enterobacter isolates varied with the department from which they were isolated and whether the patient is an adult or a child.The prevalence of carbapenem-resistant E.cloacae was the highest in the E.cloacae isolates from ICU patients.Conclusions The results of the CHINET Antimicrobial Resistance Surveillance Program indicate that the proportion of Enterobacter strains in all clinical isolates fluctuates slightly over the 7-year period from 2015 to 2021.The Enterobacter strains showed increasing resistance to multiple antimicrobial drugs,especially carbapenems over the 7-year period.

Objective To understand the changing distribution and antimicrobial resistance profiles of Proteus,Morganella and Providencia in hospitals across China from January 1,2015 to December 31,2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods Antimicrobial susceptibility testing was carried out following the unified CHINET protocol.The results were interpreted in accordance with the breakpoints in the 2021 Clinical & Laboratory Standards Institute(CLSI)M100(31 st Edition).Results A total of 32 433 Enterobacterales strains were isolated during the 7-year period,including 24 160 strains of Proteus,6 704 strains of Morganella,and 1 569 strains of Providencia.The overall number of these Enterobacterales isolates increased significantly over the 7-year period.The top 3 specimen source of these strains were urine,lower respiratory tract specimens,and wound secretions.Proteus,Morganella,and Providencia isolates showed lower resistance rates to amikacin,meropenem,cefoxitin,cefepime,cefoperazone-sulbactam,and piperacillin-tazobactam.For most of the antibiotics tested,less than 10％of the Proteus and Morganella strains were resistant,while less than 20％of the Providencia strains were resistant.The prevalence of carbapenem-resistant Enterobacterales(CRE)was 1.4％in Proteus isolates,1.9％in Morganella isolates,and 15.6％in Providencia isolates.Conclusions The overall number of clinical isolates of Proteus,Morganella and Providencia increased significantly in the 7-year period from 2015 to 2021.The prevalence of CRE strains also increased.More attention should be paid to antimicrobial resistance surveillance and rational antibiotic use so as to prevent the emergence and increase of antimicrobial resistance.

Objective To understand the changing distribution and antimicrobial resistance profiles of Klebsiella strains in 52 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Antimicrobial susceptibility testing was carried out according to the unified CHINET protocol.The susceptibility results were interpreted according to the breakpoints in the Clinical & Laboratory Standards Institute(CLSI)M100 document.Results A total of 241,549 nonduplicate Klebsiella strains were isolated from 2015 to 2021,including Klebsiella pneumoniae(88.0％),Klebsiella aerogenes(5.8％),Klebsiella oxytoca(5.7％),and other Klebsiella species(0.6％).Klebsiella strains were mainly isolated from respiratory tract(48.49±5.32)％.Internal medicine(22.79±3.28)％,surgery(17.98±3.10)％,and ICU(14.03±1.39)％were the top 3 departments where Klebsiella strains were most frequently isolated.K.pneumoniae isolates showed higher resistance rate to most antimicrobial agents compared to other Klebsiella species.Klebsiella isolates maintained low resistance rates to tigecycline and polymyxin B.ESBLs-producing K.pneumoniae and K.oxytoca strains showed higher resistance rates to all the antimicrobial agents tested compared to the corresponding ESBLs-nonproducing strains.The K.pneumoniae and carbapenem-resistant K.pneumoniae(CRKP)strains isolated from ICU patients demonstrated higher resistance rates to majority of the antimicrobial agents tested than the strains isolated from non-ICU patients.The CRKP strains isolated from adult patients had higher resistance rates to most of the antimicrobial agents tested than the corresponding CRKP strains isolated from paediatric patients.Conclusions The prevalence of carbapenem-resistant strains in Klebsiella isolates increased greatly from 2015 to 2021.However,the Klebsiella isolates remained highly susceptible to tigecycline and polymyxin B.Antimicrobial resistance surveillance should still be strengthened for Klebsiella strains.

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.