Objective To evaluate the capability of multilocus variable-number tandem-repeat ( VNTR) analysis ( MLVA) and pulsed-field gel electrophoresis ( PFGE) for genotyping Salmonella enterica serovar Typhi (S.Typhi) isolates.Methods Five polymorphic VNTRs (SAL02,SAL11,SAL16,SAL20, and TR4699 ) that were observed in S.Typhi strains from previous studies were selected to establish MLVA . Twenty-one epidemiologically unrelated S.Typhi strains that were isolated from Shenzhen ,China from 2002 to 2007 were genotyped by the established MLVA , and the results were compared with those by PFGE . Results The Simpson′s index of diversity ( D value ) for all five different VNTRs ranged from 0.838 to 0.943 .A total of 19 MLVA profiles and 19 PFGE profiles were found , respectively .The D value for both MLVA and PFGE were 0.99 and the test results from two analyses were identical .Conclusion The five polymorphic VNTRs analysis could be used as an alternative typing scheme for epidemiologic investigation of S.Typhi infection .

Objective To investigate the prevalence and molecular characteristics of the extended -spectrum β-lactamase ( ESBL) and AmpC enzyme-producing Proteus mirabilis ( P.mirabilis) strains isola-ted in Shenzhen People′s Hospital.Methods The production of ESBLs and AmpC enzymes by P.mirabilis isolates were detected by a screening and confirmatory test for ESBLs and AmpC disk test , respectively .The PCR assays followed by DNA sequencing of the products were employed to analyze the multiple genes inclu -ding the ESBLs genes, AmpC genes, insertion sequences (ISs) upstream of the ESBLs or AmpC genes, plasmid -mediated quinolone resistance ( PMQR ) determinants , quinolone resistance-determining region (QRDR) genes , the integrase genes, and class1 integron cassette.The epidemiological analysis of the iso-lates was performed by pulsed field gel electrophoresis .Results There were 130 P.mirabilis clinical iso-lates collected from Shenzhen People′s Hospital in China during the year 2004 to 2010.Among them, 13 isolates (10%) produced ESBLs, that accounted for 0%-9.1%in the year 2004-2009 and up to 29.4%in 2010, and 3 isolates (2.3%) produced AmpC enzymes.The predominant genotype of ESBLs -producing isolateswas b al CTX-M-14(n=7), followed by blaCTX-M-65(n=3), blaCTX-M-55(n=1), blaCTX-M-24(n=1) and blaPER-1 (n =1).The clinical isolate of PER-1-producing P.mirabilis was reported for the first time in China.Twoisolates carried an AmpC β-lactamase gene of blaCMY-2 and one isolate carried an unidentified AmpC gene .ISEcp1 located upstream of blaCTX-M and blaCMY-2 were detected in 91.7% (11/12) of CTX-M-producing isolatesand one CMY-2-producing isolate, respectively.ISPa12 was present upstream of blaPER-1 in one studiedisolate.Approximately 66.7% (10/15) of ESBL and /or AmpC-producing isolates harbored PMQR genes including2 carrying qnrD, 5 carrying aac-Ib-cr and 3 carrying both qnrD and aac-Ib-cr.Twelve ESBL and /orAmpC-producers with high level of resistance to ciprofloxacin carried the similar mutation profiles of S 83I inGyrA, S80I or S80R in ParC and among them, six strains showed E466D mutation in GyrB.Approximately86.7% (13/15) of ESBL and/or AmpC-producing isolates carried class 1 integron.Fourteen PFGE typeswere observed among 15 ESBL and/or AmpC-producers.Conclusion The prevalence of CTX-M β-lactamasesin P.mirabilis isolates contributed to the increased resistance to extended -spectrum cephalosporins.The qnrD and/or aac-Ib-cr genes were detected among the most of ESBL and /or AmpC-producing P.mirabilis clinical isolates.

Objective To compare the regulating effect of electrically stimulating different parts of the auri-cle on the cardiac vagus nerve in rats, and to explore the basic neural mechanism. Methods The tragus, concha auriculae and helix of 24 male Sprague-Dawley rats were stimulated at different intensities ( 0-16 mA) and with differ-ent durations ( 0-15 min) and any changes in the heart rate were observed. One week later, the rats were randomized into a tragus injection group, a concha auriculae injection group, a helix injection group and a control group, each of 6. The rats of the first three groups were injected with 2 μL of cholera toxin subunit B conjugate AF555 ( CTB-AF555) at the right auricle, while the control group was injected with the same amount of aseptic phosphate-buffered saline at the right tragus. Five days later, all of the rats were sacrificed and their right superior and inferior ganglia and the whole bulbus medullae were resected to observe the fluorescent labeling sites. Results The rats'heart rate declined with longer and more intense stimulation of the tragus or concha auriculae, but not with stimulation of the he-lix. With stimulation of the same duration, a significant decrease was observed in the heart rate when the tragus and concha auriculae were stimulated at 10, 12, 14 or 16 mA compared with when the helix was stimulated at the same intensities. The heart rate when the concha auriculae was stimulated at 12 mA was significantly slower than when the tragus was stimulated at the same intensity. At identical stimulus intensities, the heart rate slowed significantly more when the tragus was stimulated for 6 to 15 minutes and the concha auriculae for 4 to 15 minutes compared with stimu-lating the helix for the same length of time. And compared with stimulating the tragus for 6 to 10 minutes, the heart rate decreased significantly more when the concha auriculae was stimulated for the same length of time. All of the rats in the tragus and concha auriculae injection groups displayed nerve tracer in their superior and inferior ganglia. In the tragus injection group, CTB-AF555 was observed in the nucleus tractus solitarius ( NTS) of 3 of the 6 rats. In the concha auriculae injection group it was observed in 4 of the 6. In the helix injection group, CTB-AF555 was observed in the nucleus of the spinal tract in 5 of the 6 rats, but no nerve tracer was found in their superior or inferior ganglia or in the NTS. Conclusion Electrical stimulation of the tragus and concha auriculae can regulate the functioning of the cardiac vagus nerve, but stimulating the helix cannot. This is partly because the nerve signals in tragus or concha auriculae stimulation and the cardiac sensory nerve signal are integrated in the inferior ganglion and then analyzed and processed in the bulbar center to monitor the heart.

OBJECTIVETo analyze the dynamic pattern and the distributive characteristics of neutralizing antibody against enterovirus 71 (EV-A71 ) in children aged 6-35 months in Jiangsu province from 2012 to 2014.

METHODSFrom March, 2012 to March, 2014, a total of 1 276 children aged between 6 and 35 months were regularly followed up on day 0, year 1 and year 2 for EV-A71 neutralizing antibody test based on the enterovirus surveillance system, with the method of reporting by their guardian or being visited in Ganyu Sheyang Taixing Donghai Pizhou and Baoying in Jiangsu province. At the same time, samples were taken from the suspected persons infected by enterovirus. The χ(2) test or variance analysis was used to compare the difference of the positive rates and the geometric mean titer(GMT) of EV-A71 neutralizing antibody in different subjects.

RESULTSIn 2 years follow-up, the positive rates of EV-A71 antibody increased as the growth of the age,and the positive rates on day 0, year 1 and year 2 were 22.57% (288/1 276), 37.72%(444/1 177) and 42.84%(422/985), respectively (χ(2) values were 39.33, 56.41, 32.25; P< 0.001).The GMTs were 9.95, 15.37 and 24.05, respectively (F values were 22.90,46.36,41.58;P<0.001). In 2 years, the annually new infection rates were 13.47%(158/1 173) and 20.73%(192/926),respectively, and the annually decay rates of EV-A71 antibody were 2.81%(33/1 173) and 8.10%(75/926).

CONCLUSIONSIn 2012 to 2014, the positive rates and the GMTs of EV-A71 antibody of children increased as the growth of the age in Jiangsu. The higher annually new infection rate was in children aged 3 to 4 years. The EV-A71 neutralizing antibody level could maintain at least two years after natural infection.

Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Child, Preschool ; China ; epidemiology ; Enterovirus A, Human ; Enterovirus Infections ; blood ; Humans ; Infant ; Seroepidemiologic Studies

As a carbon-storage compound and osmoprotectant in brown algae, mannitol is synthe-sized and then accumulated at high levels in Saccharina japonica (Sja);however, the underlying con-trol mechanisms have not been studied. Our analysis of genomic and transcriptomic data from Sja shows that mannitol metabolism is a cyclic pathway composed of four distinct steps. A mannitol-1-phosphate dehydrogenase (M1PDH2) and two mannitol-1-phosphatases (M1Pase1 and MIPase2) work together or in combination to exhibit full enzymatic properties. Based on comprehensive tran-scriptomic data from different tissues, generations, and sexes as well as under different stress con-ditions, coupled with droplet digital PCR (ddPCR) and proteomic confirmation, we suggest that SjaM1Pase1 plays a major role in mannitol biosynthesis and that the basic mannitol anabolism and the carbohydrate pool dynamics are responsible for carbon storage and anti-stress mechanism. Our proteomic data indicate that mannitol metabolism remains constant during diurnal cycle in Sja. In addition, we discover that mannitol-metabolism-associated (MMA) genes show differential expression between the multicellular filamentous (gametophyte) and large parenchymal thallus (sporophyte) generations and respond differentially to environmental stresses, such as hyposalineand hyperthermia conditions. Our results indicate that the ecophysiological significance of such dif-ferentially expressed genes may be attributable to the evolution of heteromorphic generations (fil-amentous and thallus) and environmental adaptation of Laminariales.

Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.

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.