Serological and molecular capsular typing, antibiotic susceptibility and multilocus sequence typing of Streptococcuspneumoniae isolates from invasive and non-invasive infections

Background Streptococcus pneumoniae （S.pneumoniae） is a major causative agent of severe infections,including sepsis,pneumonia,meningitis,and otitis media,and has become a major public health concern.We report the pneumococcal serotype and sequence type （ST） distribution,and antimicrobial resistance of 39 S.pneumoniae strains from seven hospitals in China.Methods Blood/cerebrospinal fluid （CSF） and sputum isolates from patients were analyzed to determine S.pneumoniae serotypes by polymerase chain reaction （PCR） and the Neufeld Quellung reaction,the multilocus sequence types （MLST） by PCR and sequencing,and susceptibility to antimicrobial agents by the VITEK Gram Positive Susceptibility Card.Results A total of 39 isolates were collected including 21 blood/CSF and 18 sputum isolates.Conventional serotyping by the Quellung reaction required 749 reactions.In contrast,PCR based typing needed only 106 PCR reactions.The most frequent serotypes from the blood/CSF isolates were 14 （38.1%）,19A （14.3%）,23F （9.5%）,and 18C （9.5%）.In the sputum isolates the most frequent serotypes were 19F （33.3%）,23F （16.7%）,19A （11.1%）,and 3 （11.1%）.The incidence of penicillin resistance in the blood/CSF and sputum isolates was 66.7% and 55.6%,respectively.Statistical analysis showed that patients ≤5 years old had a higher resistance to penicillin when they compared with the patients ≥65 years old （P=0.011）.Serotypes 14,19A and 19F were significantly associated with penicillin resistance （P 〈0.001）.ST320,ST271,and ST876 isolates showed high resistant rates to several antibiotics including penicillin （P=0.006）.All of the isolates of serotype 19A were resistant to both penicillin and erythromycin,and they were all multi-drug resistant （MDR） isolates.Conclusions The specificity and sensitivity of multiplexPCR are good,and this method represents a substantial savings of time and money,and can be widely used in the laboratory and clinical practice.Data from this research showed an extremely high prevalence of penicillin resistance and an increasing prevalence of multi-drug resistant （MDR） rate in S.pneumoniae.A distinctive emergence of serotype 19A was observed which was also associated with the increasing prevalence of antimicrobial resistance.Therefore,nationwide surveillance of pneumococcal resistance and serotypes is strongly warranted.

Multilocus sequence typing indicates diverse origins of invasive Candida tropicalis isolates in China

Background According to data from the China Hospital Invasive Fungal Surveillance Net （CHIF-NET） 2010, Candida tropica/is （C. tropica/is） is the third most common pathogen causing invasive candidiasis. Moreover, the majority of fluconazole-resistant C. tropicalis isolates were from a single hospital. Therefore, a molecular epidemiological survey is necessary to investigate the genetic relatedness of C. tropica/is isolates in China. Methods In this study, 48 C. tropicalis isolates causing invasive fungal infections from four tertiary hospitals in China were studied. All the isolates were identified by sequencing the internal transcribed spacer region. Antifungal susceptibility to triazoles, amphotericin B, and caspofungin was determined by the Clinical and Laboratory Standards Institute standard broth microdilution method. Multilocus sequence typing （MLST） was performed, and phylogenetic analysis was further performed by the eBURST and maximum parsimony （MP） methods to characterize the genetic relatedness of isolates. Results MLST discriminated 40 diploid sequence types （DSTs） among 48 isolates, including 36 novel DSTs, and the XYR1 gene showed the highest discriminatory power. The DSTs obtained from this study were compared with those of previously reported C. tropicalis isolates, and there was poor type alignment with regional strains. Nine groups and 11 singletons were identified by eBURST, whereas two groups and 10 subgroups were clustered by MP analysis. Generally, there were no obvious correlations between clonal clusters generated and the specimen source or hospital origin. Seven fiuconazole-resistant isolates were confirmed and assigned to three distinguishable branches. Conclusions The results suggested diverse origins of invasive C. tropicalis isolates in China. Although most invasive C. tropicalis strains in the mainland of China were clustered with previously characterized Asian isolates, major C. tropicalis clusters identified in this study were genetically distinct from those of other geographic regions.

Optimization of Bartonella henselae multilocus sequence typing scheme using single-nucleotide polymorphism analysis of SOLID sequence data

Background Multi-locus sequence typing （MLST） is widely used to explore the population structure of numerous bacterial pathogens. However, for genotypically-restricted pathogens, the sensitivity of MLST is limited by a paucity of variation within selected loci. For Bartonella henselae （B. henselae）, although the MLST scheme currently used has been proven useful in defining the overall population structure of the species, its reliability for the accurate delineation of closely-related sequence types, between which allelic variation is usually limited to, at most, one or two nucleotide polymorphisms. Exploitation of high-throughput sequencing data allows a more informed selection of MLST loci and thus, potentially, a means of enhancing the sensitivity of the schemes they comprise. Methods We carried out SOLID resequencing on 12 representative B. henselae isolates and explored these data using single nucleotide polymorphism （SNP） analysis. We determined the number and distribution of SNPs in the genes targeted by the established MLST scheme and modified the position of loci within these genes to capture as much genetic variation as possible. Results Using genome-wide SNP data, we found the distribution of SNPs within each open reading frame （ORF） of MLST loci, which were not represented by the established B. henselae MLST scheme. We then modified the position of loci in the MLST scheme to better reflect the polymorphism in the ORF as a whole. The use of amended loci in this scheme allowed previously indistinguishable ST1 strains to be differentiated. However, the diversity of B. henselae was still rare in China. Conclusions Our study demonstrates the use of SNP analysis to facilitate the selection of MLST loci to augment the currently-described scheme for B. henselae. And the diversity among B. henselae strains in China is markedly less than that observed in B. henselae populations elsewhere in the world.

Molecular Characteristics of Neisseria meningitidis Isolated during an Outbreak in a Jail: Association with the Spread and Distribution of ST-4821 Complex Serogroup C Clone in China

Objective To characterize the meningococcal strains isolated from cases and close contacts with meningococcal disease associated with an outbreak in a jail in May 2010 by investigating the national distribution of hyperinvasive ST-4821 serogroup C clone associated with this outbreak. Methods The cases were described based on the clinical symptoms and laboratory results. Pharyngeal swabs were cultured for N. meningitidis from men in the jail. Meningococcal isolates were identified by serogrouping, pulsed-field gel electrophoresis （PFGE） and multilocus sequence typing （MLST）, respectively. Four hundred and sixteen serogroup C N. meningitidis strains were collected from 27 provinces between 2003 and 2010 for a nationwide survey and analyzed by PFGE and MLST. Results Three persons in a jail system were infected with invasive N. meningitidis serogroup C. All isolates tested had matching PFGE patterns and belonged to the multilocus sequence type （ST） 4821 clonal complex. All 47 N. meningitidis strains were identified from the pharyngeal swabs of 166 peoples in the jail, and 26 of them belonged to ST-4821 serogroup C clone, and 90.14% （375/416） serogroup C strains identified in the nationwide survey belonged to the ST-4821 complex. The ST-4821 serogroup C clone was spread nationwide, distributed in 24 provinces, especially in eastern provinces between 2003 and 2010. Conclusion Endemic transmission and carriage rate of ST-4821 serogroup C clone are high in this jail system. The ST-4821 serogroup C clone is spreading in China and nationwide distributed despite the existence of some effective vaccines.

Genetic and Antibiotic Resistance Characteristics ofCampylobacterjejuni Isolated from Diarrheal Patients,Poultry and Cattle in Shenzhen

Objective To investigate genetic and antibiotic resistance characteristics of Campylobacter jejuni(C. jejuni) isolated from Shenzhen. Methods Multilocs sequence typing and agar dilution methods were used to define the genotype and antibiotic resistance of C. jejuni, respectively. Results In total, 126 C. jejuni strains were isolated. The prevalence of C. jejuni was 5.3% in diarrheal patients. The prevalence in poultry meat(36.5%) was higher than that in cattle meat(1.1%). However, the prevalence in poultry cloacal swabs(27.0%) was lower than that in cattle stool(57.3%). Sixty-two sequence types were obtained, among which 27 of the STs and 10 alleles were previously unreported. The most frequently observed clonal complexes were ST-21(11.9%), ST-22(10.3%), and ST-403(7.1%). ST-21, ST-45, ST-354, ST-403, and ST-443 complexes overlapped between isolates from patients and cattle, whereas ST-45 and ST-574 complexes overlapped between isolates from patients and poultry. All C. jejuni were resistant to at least one antibiotic. The highest resistance rate was toward ciprofloxacin(89.7%), followed by tetracycline(74.6%), and nalidixic acid(69.0%). Conclusion This is the first report of the genotypes and antibiotic resistance of C. jejuni in Shenzhen. Overlapping clonal complexes were found between isolates from patients and cattle, and between patients and poultry.

MLST analysis of genetic diversity of Bacillus coagulans strains to evaluate effects on constipation model

Bacillus coagulans can help ameliorate or prevent gastrointestinal diseases, but the genetic relationships among B. coagulans isolates are not well studied. Multilocus sequence typing analysis was conducted on 57 isolates of B. coagulans from 22 provinces or autonomous regions in China. B. coagulans isolates were highly diverse and a total of 33(sequence typings) STs were found. These isolates had a weak clonal population structure and strong indications of intraspecies recombination. The evolution direction of B. coagulans was not correlated with geography or isolation source. Fifteen strains were selected for further analysis based on proximity relationships from the phylogenetic tree. Five isolates(B. coagulans-1, B. coagulans-10, B. coagulans-39, B. coagulans-70 and B. coagulans-71) with good spore-forming ability relative to the rest of the isolates were evaluated for constipation relief. B. coagulans-39 significantly relieved constipation symptoms in mice by regulating intestinal flora, increasing the production of short-chain fatty acids and restoring the level of gastrointestinal regulatory peptides. Comparative genomic analysis showed the beneficial effects of B. coagulans-39 might be associated with specific functional genes that are involved in the utilization of various carbohydrates as primary substrates and short-chain fatty acid production.

Prevalence and fuoroquinolone resistance of Campylobacter spp.isolated from beef cattle in Japan

Beef is a source of human Campylobacter infections.Antimicrobial treatment is needed when patients are immuno‑compromised or have other comorbidities.Therefore,we investigated the prevalence and antimicrobial resistance of Campylobacter spp.in beef cattle in Japan.Rectal swab samples were collected from 164 beef cattle at an abattoir between March 2021 and August 2021,and Campylobacter spp.were isolated from 94(57.3%)cattle.C.jejuni and C.coli were isolated from 68 and 26 cattle,respectively.For Campylobacter jejuni,the resistant rates against ampicillin,tetracycline and ciprofoxacin were 20.6,75.0 and 64.7%,respectively.For C.coli,the resistant rates against ampicil‑lin,tetracycline and ciprofoxacin were 53.8,76.9 and 88.5%,respectively.No Campylobacter isolates were resistant to erythromycin.By multilocus sequence typing,C.jejuni and C.coli isolates were classifed into 22 and 2 sequence types(STs).The top three STs of C.jejuni were ST806(12 isolates),ST21(nine isolates),and ST459(eight isolates).The most frequent ST of C.coli was ST1068(23 isolates).The results suggest that Campylobacter spp.are prevalent in the gastrointestinal tract of beef cattle slaughtered at abattoirs.Furthermore,the administration of erythromycin is efec‑tive against human campylobacteriosis caused by beef consumption.Monitoring the prevalence and antimicrobial resistance of Campylobacter spp.in beef cattle could be useful for managing the risk of human campylobacteriosis.

Molecular Diversity of <i>Staphylococcus aureus</i>from the Nares of Hospital Personnel, HIV-Positive and Diabetes Mellitus Patients in Yaounde Cameroon

Nasal carriage of Staphylococcus aureus has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic diversity of Staphylococcus aureus is relevant for managing epidemiological and clinical challenges resulting from the evolutionary differences of this bacterium. The objective of this study was to determine and compare the molecular diversity of Staphylococcus aureus isolates from three high-risk populations in Yaounde, Cameroon. Molecular analysis confirmed that 95% of 100 tested isolates were S. aureus. The mecA and Panton Valentine-Leukocidin (PVL) genes (lukS/F-PV) were detected in 37% (35/95) and 43% (41/95) of isolates respectively and 18% (17/95) of the isolates harboured both the mecA and lukS/F-PV genes. A mixed distribution of both methicillin sensitive S. aureus (MSSA)/PVL and methicillin resistant S. aureus (MRSA)/PVL strains were detected within the study population. Community associated MRSA accounted for 94% (33/35) of the isolates, further classified into allotypes SCCmec type IV 54% (19/35) and SCCmec type V 40% (14/35), while two isolates were hospital associated SCCmec type II strains. A majority of the isolates harboured a single aggressive gene regulator allele agr type I. Pulsed Field Gel Electrophoresis (PFGE) generated 18 pulsotypes that grouped isolates irrespective of the study population. Multilocus Sequence Typing (MLST) of 12 selected isolates was assigned to six pandemic clonal complexes (CC): CC5 (ST5), CC8 [ST8, (n = 3)], CC15 (ST 15), CC25 (ST 25), CC72 [ST72 (n = 2)] and CC121 [ST 121 (n = 2)] and three atypical sequence types ST 508, ST 699 (CC45) and ST 1289 (CC 88). The study population represents an important reservoir for MRSA, MRSA-PVL and MSSA-PVL which could serve as focal point for further dissemination bringing about significant clinical and epidemiological implications. The predominance of SCCmec IV and agr types in this setting warrants further investigation. Isolates were genetically diverse with MLST indicating that pandemic ST8 was predominant. Detection of atypical STs has provided an insight into the necessity for constant monitoring.

Public health implications of Yersinia enterocolitica investigation:an ecological modeling and molecular epidemiology study

Background Yersinia enterocolitica has been sporadically recovered from animals,foods,and human clinical samples in various regions of Ningxia,China.However,the ecological and molecular characteristics of Y.enterocolitica,as well as public health concerns about infection in the Ningxia Hui Autonomous Region,remain unclear.This study aims to analyze the ecological and molecular epidemiological characteristics of Y.enterocolitis in order to inform the public health intervention strategies for the contains of related diseases.Methods A total of 270 samples were collected for isolation[animals(n=208),food(n=49),and patients(n=13)],then suspect colonies were isolated and identified by the API20E biochemical identification system,serological tests,biotyping tests,and 16S rRNA-PCR.Then,we used an ecological epidemiological approach combined with machine learning algorithms(general linear model,random forest model,and eXtreme Gradient Boosting)to explore the associations between ecological factors and the pathogenicity of Y.enterocolitis.Furthermore,average nucleotide identity(ANI)estimation,single nucleotide polymorphism(SNP),and core gene multilocus sequence typing(cgMLST)were applied to characterize the molecular profile of isolates based on whole genome sequencing.The statistical test used single-factor analysis,Chi-square tests,t-tests/ANOVA-tests,Wilcoxon rank-sum tests,and Kruskal–Wallis tests.Results A total of 270 isolates of Yersinia were identified from poultry and livestock(n=191),food(n=49),diarrhoea patients(n=13),rats(n=15),and hamsters(n=2).The detection rates of samples from different hosts were statistically different(χ^(2)=22.636,P<0.001).According to the relatedness clustering results,270 isolates were divided into 12 species,and Y.enterocolitica(n=187)is a predominated species.Pathogenic isolates made up 52.4%(98/187),while non-pathogenic isolates made up 47.6%(89/187).Temperature and precipitation were strongly associated with the pathogenicity of the isolates(P<0.001).The random forest(RF)prediction model showed the best performance.The prediction result shows a high risk of pathogenicity Y.enterocolitica was located in the northern,northwestern,and southern of the Ningxia Hui Autonomous Region.The Y.enterocolitica isolates were classified into 54 sequence types(STs)and 125 cgMLST types(CTs),with 4/O:3 being the dominant bioserotype in Ningxia.The dominant STs and dominant CTs of pathogenic isolates in Ningxia were ST429 and HC100_2571,respectively.Conclusions The data indicated geographical variations in the distribution of STs and CTs of Y.enterocolitica isolates in Ningxia.Our work offered the first evidence that the pathogenicity of isolates was directly related to fluctuations in temperature and precipitation of the environment.CgMLST typing strategies showed that the isolates were transmitted to the population via pigs and food.Therefore,strengthening health surveillance on pig farms in high-risk areas and focusing on testing food of pig origin are optional strategies to prevent disease outbreaks.

Preliminary molecular epidemiology of the Staphylococcus aureus in lower respiratory tract infections： a multicenter study in China

Background Staphylococcus aureus （S. aureus） remains as an important microbial pathogen resulting in community and nosocomial acquired infections with significant morbidity and mortality. Few reports for S. aureus in lower respiratory tract infections （LRTIs） have been documented. The aim of this study was to explore the molecular epidemiology of S. aureus in LRTIs in China.Methods A multicenter study of the molecular epidemiology of S. aureus in LRTIs was conducted in 21 hospitals in Beijing, Shanghai and twelve other provinces from November 2007 to February 2009. All the collected S. aureus strains were classified as minimum inhibitory concentration （MIC）, mecA gene, virulence genes Panton-Valentine Leukocidin （PVL） and y-hemolysin （hlg）, staphylococcal cassette chromosome mec （SCCmec） type, agr type, and Multilocus Sequence Typinq （MLST）.Results Totally, nine methicillin-sensitive S. aureus （MSSA） and 29 methicillin-resistant S. aureus （MRSA） strains were isolated after culture from a total of 2829 sputums or bronchoalveolar lavages. The majority of MRSA strains （22/29） had a MIC value of 〉512 μg/ml for cefoxitin. The mecA gene acting as the conservative gene was carried by all MRSA strains. PVL genes were detected in only one S. aureus strain （2.63%, 1/38）. The hlg gene was detected in almost the all S. aureus （100% in MSSA and 96.56% in MRSA strains）. About 75.86% of MRSA strains carried SCCmec Ⅲ. Agr type 1 was predominant （78.95%） among the identified three agr types （agr types 1,2, and 3）. Totally, ten sequence type （ST） of S. aureus strains were detected. A new sequence type （ST1445） was found besides confirming ST239 as the major sequence type （60.53%）. A dendrogram generated from our own MLST database showed all the bootstrap values 〈50%. Conclusion Our preliminary epidemiology data show SCCmec Ⅲ, ST239 and agr type 1 of S. aureus as the predominant strains in LRTIs in Mainland of China.

A first meningococcal meningitis case caused by serogroup X Neisseria meningitidis strains in China

Neisseria meningitidis is the leading cause of bacterial meningitis and classified into 13serogroups based on the immunological reactivity of the capsular polysaccharide.1 Serogroups A, B, C, W135 and Y are the most common causes of meningitis.2 Among them, serogroup A and C are the major causes of epidemics in Africa and Asia.2 Most of the epidemic outbreaks of meningococcal meningitis are caused by serogroup A Neisseria meningitidis strain from the 1950s to the 1980s in China.3 During the years 2003 and 2005, a new sequence type （ST-4821） of serogroup C was identified in the Anhui and 11 other provinces of China.4

Comparative analysis of whole genome structure of Streptococcus suis using whole genome PCR scanning

An outbreak associated with Streptococcus suis infection in humans emerged in Sichuan province, China in 2005. The outbreak is atypical for the apparent large number of human cases, high fatality rate and geographical spread. To determine whether the bacterium has changed, we compared both human and animal isolates from the Sichuan outbreak with those collected previously within China and in other countries using whole genome PCR scanning (WGPScaning) comparative sequencing of several known virulence factor genes and multilocus sequence typing (MLST) analysis. WGPScanning analysis showed that all primer pairs yielded PCR products of the expected sizes in all four strains tested. The nucleotide sequences of all the detected virulence factor genes are identical in the four strains and MLST results showed that the four isolates studied and reference strain all belonged to the ST1 com-plex. No new genetic changes were found in the genome structure of the isolates from this Sichuan outbreak.

Tracing enterococci persistence along a pork production chain from feed to food in China

The prevalence and transmission of vancomycin-resistant Enterococcus(VRE)in enterococci being as probiotics has been neglected in the scientific literature.The application of enterococci in feed,food and health products may cause VRE transmission through the food chain.This study evaluated phenotypic resistance of Enterococcus species to 20 antibiotics along a pork production chain from feed to food.It also assessed the genetic diversity of Enterococcus faecium isolates.A total of 510 samples(feed,n=70;swine manure,n=400;swine carcasses,n=20,and retail pork,n=20)were collected in Beijing,China.A total of 328 enterococci isolates with 275 E.faecium and 53 Enterococcus faecalis were identified using 16 S rRNA.Antimicrobial susceptibility to all enterococci isolates was conducted using the KeB method for 20 antibiotics from 9 categories.Multilocus sequence typing(MLST)was conducted on the E.faecium isolates to survey the dissemination of enterococci in the pig industry.The results showed that only 26 enterococci isolates were sensitive to the 20 antibiotics,while half of the isolates(164/328)had acquired multi-drug resistance.The resistant rate to furazolidone was 68.60%,followed by 42.99%to tetracycline.One vancomycin-resistant E.faecium isolates were isolated from feed origin and 2 from manure origin,with minimum inhibitory concentrations to vancomycin of 1,024,64,and 64 mg/mL,respectively.The MLST outcomes showed that the 275 E.faecium isolates belonged to 11 sequence types(ST)including ST40,ST60,ST94,ST160,ST178,ST296,ST361,ST695,ST726,ST812 and ST1014.The ST of the feedsourced VRE was ST1014,while the 2 manure-sourced VRE was ST69.ST1014 evolved from ST78,which was the dominant clonal complex in most cities of China,leading to the spreading of VRE.These findings revealed the potential safety hazards of commercial probiotic enterococci in China and showed that there is a risk of the VRE horizontally transferring from feed to food.

Genetic diversity of Listeria monocytogenes isolates from farm products in Shanghai,China

Farm products are considered important vehicles for the transmission of Listeria monocytogenes(L.monocytogenes).The typing of L.monocytogenes from farm products contributes to the surveillance and source tracing of the pathogen.In this study,77 L.monocytogenes strains from seven farm product categories in Shanghai were analyzed by serological typing,multilocus sequence typing(MLST),pulsed-field gel electrophoresis(PFGE),and whole-genome nucleotide polymorphism(wgSNP).The results showed that the 77 isolates were classified into four serovars(1/2a,1/2c,1/2b,and 4b),and of these,1/2a(n=47)was the most prevalent.Seventeen sequence types(STs)were generated by MLST with two novel STs(ST1402 and ST1403),and 20 of 77 L.monocytogenes isolates had high genetic identity with previously documented outbreak isolates according to the minimum spanning tree from the MLST results.Moreover,34 PFGE patterns(PF1-PF34)were differentiated,and based on a similarity value higher than 80%by the unweighted pair group method dendrogram,the discriminatory index was relatively low(equal to 0.775).Furthermore,14 isolates were chosen and further analyzed by wgsNP based on the previous typing results,which demonstrated that wgSNP and MLST yielded mostly consistent typing results but higher resolution than PFGE.In conclusion,77 L.monocytogenes isolates from farm products collected in nine districts in Shanghai were highly genetically diverse,and 20 of these isolates had high relatedness with previously documented outbreak strains worldwide.The results indicate a possible cross-contamination risk of L.monocytogenes and a potential public health concern resulting from farm products during the supply chain in Shanghai,China.

Characterization of the first Wolbachia from the genus Scaptodrosophila,a male-killer from the rainforest species S.claytoni

The Scaptodrosophila genus represents a large group of drosophilids with a worldwide distribution and a predominance of species in Australia,but there is little information on the presence and impacts of Wolbachia endosymbionts in this group.Here we describe the first Wolbachia infection from this group,wClay isolated from Scaptodrosophila claytoni(van Klinken),a species from the east coast of Australia.The infection is polymorphic in natural populations,occurring at a frequency of around 6%–10%.wClay causes male killing,producing female-biased lines;most lines showed 100%male killing,though in 1 line it was<80%.The lines need to be maintained through the introduction of males unless the infection is removed by tetracycline treatment.wClay is transmitted at a high fidelity(98.6%)through the maternal lineage and has been stable in 2 laboratory lines across 24 generations,suggesting it is likely to persist in populations.The infection has not been previously described but is closely related to the male-killing Wolbachia recently described from Drosophila pandora based on multilocus sequence typing and the wsp gene.Male-killing Wolbachia are likely to be common in drosophilids but remain difficult to detect because the infections can often be at a low frequency.

PulseNet China,a model for future laboratory-based bacterial infectious disease surveillance in China

Surveillance is critical for the prevention and control of infectious disease.China’s real-time web-based infectious disease reporting system is a distinguished achievement.However,many aspects of the current China Infectious Disease Surveillance System do not yet meet the demand for timely outbreak detection and identification of emerging infectious disease.PulseNet,the national molecular typing network for foodborne disease surveillance was first established by the Centers for Disease Control and Prevention of the United States in 1995 and has proven valuable in the early detection of outbreaks and tracing the pathogen source.Since 2001,the China CDC laboratory for bacterial pathogen analysis has been a member of the PulseNet International family;and has been adapting the idea and methodology of PulseNet to develop a model for a future national laboratory-based surveillance system for all bacterial infectious disease.We summarized the development progress for the PulseNet China system and discussed it as a model for the future of China’s national laboratory-based surveillance system.