Characterization of the Salmonella enterica Serotype Isangi Isolated from Patients for the First Time in China.

No studies have reported the isolation of serotype Salmonella Isangi from cases of salmonellosis in mainland China. We investigated an outbreak of foodborne disease with salmonella and collected the samples from the patients and surplus foods. Salmonella strains were isolated and the serotype was identified according to the Kauffmann-White scheme. The relatedness of the isolates was determined using pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Antimicrobial susceptibility was conducted by the broth microdilution method. There were 74 diners in the case, 33 of which got ill, with an attack rate of 44.6% (33/74). A total of 24 samples were collected from the outbreak cases, six Salmonella Isangi strains were isolated and susceptible to all tested drugs. PFGE and WGS analysis suggested that the pathogen dissemination through a single or limited vector(s), the steamed fish and mixed food (fry spicy chicken, braised pork ribs, and goose leg), may be the source of infection or be cross-contaminated. We first report the characteristics of an outbreak and molecular strain relatedness of Salmonella Isangi in mainland China.

Surveillance and molecular typing of Cronobacter spp. in commercial powdered infant formula and follow-up formula from 2011 to 2013 in Shandong Province, China.

BACKGROUND: Infection with Cronobacter spp. leads to neonatal meningitis, necrotizing enterocolitis and bacteremia. Cronobacter spp. are reported to comprise an important pathogen contaminating powdered infant formula (PIF) and follow-up formula (FUF), although little is known about the contamination level of Cronobacter spp. in PIFs and FUFs in China. RESULTS: In total, 1032 samples were collected between 2011 and 2013. Forty-two samples were positive, including 1.6% in PIFs and 6.5% in FUFs. The strains were susceptible to most antibiotics except for cefoxitin. Pulsed-field gel electrophoresis after XbaI digestion produced a total of 36 banding patterns. The 38 strains were found in 27 sequence types (STs), of which nine types (ST454 to ST462) had not been reported in other countries. The clinically relevant strains obtained from the 38 isolates in the present study comprised three ST3, two ST4, two ST8 and one ST1. CONCLUSION: The contamination rate in the PIF and FUF has stayed at a relatively high level. The contamination rate of PIF was significantly lower than FUF. The isolates had high susceptibility to the antibiotics tested, except cefoxitin. There were polymorphisms between the Cronobacter spp. as indicated by pulsed-field gel electrophoresis and multilocus sequence typing. Therefore, contamination with Cronobacter spp. remains a current issue for commercial infant formulas in China. © 2016 Society of Chemical Industry.

Continuous detection and genetic diversity of human rotavirus A in sewage in eastern China, 2013-2014.

BACKGROUND: Rotavirus is the leading viral agent for pediatric gastroenteritis. However, the case-based surveillance for rotavirus is limited in China, and its circulation in the environment is not well investigated. METHODS: From 2013 to 2014, rotavirus was detected in raw sewage samples of Jinan and Linyi by quantitative PCR (qPCR) and conventional reverse transcription PCR (RT-PCR). After sequenced and genotyped, sequences analysis was conducted. RESULTS: A total of 46 sewage samples were collected monthly for the detection of rotavirus, and rotavirus was positive in 43 samples (93.5 %, 43/46). By quantitative assessment, the concentrations of rotavirus in raw sewage ranged from 4.1 × 10(3) to 1.3 × 10(6) genome copies (GC)/L in Jinan, and from 1.5 × 10(3) to 3.0 × 10(5) GC/L in Linyi. A total of 318 sequences of 5 G-genotypes and 318 sequences of 5 P-genotypes were obtained. G9 (91.8 %, 292/318) and P[8] (56.0 %, 178/318) were the most common G- and P-genotype, respectively. Multiple transmission lineages were recognized in these genotypes. Interestingly, an intragenic recombination event between two G9 lineages was observed. CONCLUSIONS: This study provided the first report of comprehensive environmental surveillance for rotavirus in China. The results suggest that the concentration of rotavirus in raw sewage was high, and multiple rotavirus transmission lineages continuously co-circulated in Shandong.

[Contaminant levels and drug resistance analysis of Salmonella isolated from broiler production and processing course in Shandong Province in 2012].

OBJECTIVE: To investigate the Salmonella contamination and its antibiotic resistance spectrum in the whole process of broiler hatching, cultivation, slaughtering, processing, distribution and retail in Shandong Province. METHODS: 2496 samples were collected from the chicken farms, hatching factory, breeding farm, slaughterhouse, large supermarkets and farmers' market in Jinan and Zibo City. All samples were tested according to GB 4789.4-2010 and the antimicrobial susceptibilities by the broth microdilution method. RESULTS: The positive rate of the hatching process was 2.39%, the breeding process was 12.67%, the slaughter process was 27.00%, the distribution and retail process was 22.72%. There were 32 serotypes, the Indiara and Enteritidis Salmorella accounted for 42.25% and 34.21% respectively. 95.91% of the Salmorella strains were resistant to at least one antibiotic, 71.37% of the strains were resistant to at least three antibiotics, 28.21% of the strains were resistant to at least ten antibiotics, 7 strains were resistant to fourteen antibiotics, all of them are Indiana Salmonella. CONCLUSION: In Jinan and Zibo City, it is seriously contaminated by various aspects of Salmonella in broiler production and processing. The contamination rate of slaughter and Salmonella distribution is higher than the links of hatching process and breeding. The situation of broiler Salmonella is becoming severe.

Integrated Bioinformatics Exploration and Preliminary Clinical Verification for the Identification of Crucial Biomarkers in Severe Cases of COVID-19.

Background: Coronavirus disease 2019 (COVID-19) is a respiratory infectious illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The objective of this study is to identify reliable and accurate biomarkers for the early stratification of disease severity, a crucial aspect that is currently lacking for the impending phases of the next COVID-19 pandemic. Methods: In this study, we identified important module and hub genes related to clinical severe COVID-19 using differentially expressed genes (DEGs) screening combing weighted gene co-expression network analysis (WGCNA) in dataset GSE213313. We further screened and confirmed these hub genes in another two new independent datasets (GSE172114 and GSE157103). In order to evaluate these key genes' stability and robustness for diagnosing or predicting the progression of illness, we used RT-PCR validation of selected genes in blood samples obtained from hospitalized COVID-19 patients. Results: A total of 968 and 52 DEGs were identified between COVID-19 patients and normal people, critical and non-critical patients, respectively. Then, using WGCNA, 10 modules were constructed. Among them, the blue module positively associated with clinic disease severity of COVID-19. From overlapped section between DEGs and blue module, 12 intersected common differential genes were obtained. Subsequently, these hub genes were validated in another two new independent datasets as well and 9 genes that overlapped showed a highly correlation with disease severity. Finally, the mRNA expression levels of these hub genes were tested in blood samples from COVID-19 patients. In severe cases, there was increased expression of MCEMP1, ANXA3, CD177, and SCN9A. In particular, MCEMP1 increased with disease severity, which suggested an unfavorable development and a frustrating prognosis. Conclusion: Using comprehensive bioinformatical analysis and the validation of clinical samples, we identified four major candidate genes, MCEMP1, ANXA3, CD177, and SCN9A, which are essential for diagnosis or development of COVID-19.

TREM-1, TREM-2 and their association with disease severity in patients with COVID-19.

BACKGROUND: Delayed diagnosis and inadequate treatment caused by limited biomarkers are associated with the outcomes of COVID-19 patients. It is necessary to identify other promising biomarkers and candidate targets for defining dysregulated inflammatory states. METHODS: The triggering receptors expressed on myeloid cell (TREM)-1 and TREM-2 expression from hospitalized COVID-19 patients were characterized using ELISA and flow cytometry, respectively. Their correlation with disease severity and contrast with the main clinical indicators were evaluated. RESULTS: Increased expression of soluble TREM-1 and TREM-2 in the plasma of COVID-19 patients was found compared to the control group. Moreover, membrane-bound TREM-1 and TREM-2 expression was upregulated on the cell surface of circulating blood T cells from COVID-19 patients. Correlation analysis showed that sTREM-2 levels were negatively correlated with PaO2/FiO2, but positively correlated with C-reactive protein (CRP), procalcitonin (PCT) and interleukin (IL)-6 levels. Receiver operating characteristic curve analysis indicated that the predictive efficacy of sTREM-1 and sTREM-2 was equivalent to CRP and IL-6, and a little better than absolute leukocyte or neutrophil count and PCT in distinguishing disease severity. CONCLUSION: TREM-2 and TREM-1 are critical host immune factors that response to SARS-COV-2 infection and could serve as potential diagnostic biomarkers and therapeutic targets for COVID-19.

The expression of soluble TREM-1 and TREM-2 in plasma and membrane-bound TREM-1 and TREM-2 on the cell surface was upregulated in COVID-19 patients.sTREM-2 level was negatively correlated with PaO₂/FiO₂, but positively correlated with CRP, PCT and IL-6 level, respectively.sTREM-1 and sTREM-2 exhibited potential predictive abilities, and their expression was equivalent to CRP and IL-6, and better than the absolute leukocytes or neutrophil counts and PCT in distinguishing disease severity.

Gut microbiota composition is associated with disease severity and host immune responses in COVID-19.

Background: Human gut microbiota play a crucial role in the immune response of the host to respiratory viral infection. However, evidence regarding the association between the gut microbiome, host immune responses, and disease severity in coronavirus disease 2019 (COVID-19) remains insufficient. Methods: To better comprehend the interactions between the host and gut microbiota in COVID-19, we conducted 16S rRNA sequencing and characterized the gut microbiome compositions in stool samples from 40 COVID-19 patients and 33 non-pneumonia controls. We assessed several hematological parameters to determine the immune status. Results: We found that the gut microbial composition was significantly changed in COVID-19 patients, which was characterized by increased opportunistic pathogens and decreased commensal bacteria. The frequency of prevalent opportunistic pathogens Enterococcus and Lactobacillus increased, especially in severe patients; yet the abundance of butyrate-producing bacteria, Faecalibacterium, Roseburia, and Anaerostipes, decreased significantly, and Faecalibacterium prausnitzii might help discriminate severe patients from moderate patients and non-pneumonia people. Furthermore, we then obtained a correlation map between the clinical characteristics of COVID-19 and severity-related gut microbiota. We observed a notable correlation between the abundance of Enterococcus faecium and abnormal neutrophil or lymphocyte percentage in all COVID-19 patients. Faecalibacterium was positively correlated with lymphocyte counts, while negatively correlated with neutrophil percentage. Conclusion: These results suggested that the gut microbiome could have a potential function in regulating host immune responses and impacting the severity or consequences of diseases.

[Study of molecular subtypes of biotype 1A Yersinia enterocolitica in Shandong province from 2008 to 2009].

OBJECTIVE: To investigate the molecular subtypes of 73 strains of Yersinia enterocolitica biotype 1A isolated in Shandong province by PFGE, and thereby to analyze the relationship between PFGE typing and biological characteristics. METHODS: Seventy-three strains of Yersinia enterocolitica biotype 1A were isolated from animal feces and meat products in Gaomi city and Wulian county in Shandong province from 2008 to 2009. Motility test, serum agglutination and virulent genes detection by PCR were used to learn the biological characteristics of the isolated strains. The molecular subtypes were determined by PFGE, whose relationships with motility, serotypes and virulent genotypes were also analyzed. RESULTS: Out of the 73 strains of Yersinia enterocolitica, 5 showed medium-active motility while the other 68 showed well-active motility. The dominated serotypes were O:5(17/73) and O:8(14/73), followed by O:9(5/73) and O:7, 8(1/73), and there was no O:3 serotype found. Meanwhile, 36 strains couldn't be serotyped. All the strains were negative with the gene ail, ystA, yadA and virF, yet the positive rate of ystB gene was 72.6% (53/73). The 73 strains of Yersinia enterocolitica isolated could be subtyped into 54 PFGE patterns (K6GN11SD0001-K6GN11SD0054), most of which only had 1 or 2 isolated strains, and no pattern was dominant. The strains in the same or similar cluster were from different hosts; each serotype and toxic genotype scattered in the clustering trees, without specific correlation with PFGE subtypes. 4 out of 5 strains, which showed medium-active motility, belonged to one branch, with the similarity coefficient at 80.9% - 100.0%; while all the toxic genotype belonged to type B. CONCLUSION: Biotype 1A Yersinia enterocolitica has many clones, whose PFGE types had relations with motility, but no relations with virulent genotype and host.

Corrigendum: Genomic Investigation Reveals a Community Typhoid Outbreak Caused by Contaminated Drinking Water in China, 2016.

[This corrects the article DOI: 10.3389/fmed.2022.753085.].

Genomic Investigation Reveals a Community Typhoid Outbreak Caused by Contaminated Drinking Water in China, 2016.

Typhoid fever is a life-threatening disease caused by Salmonella enterica serovar Typhi (S. Typhi) and remains a significant public health burden in developing countries. In China, typhoid fever is endemic with a limited number of reported outbreaks. Recently, Chinese local Center for Disease Prevention and Control is starting to apply whole genome sequencing for tracking the source of outbreak isolates. In this study, we conducted a retrospective investigation into a community outbreak of typhoid fever in Lanling, China, in 2016. A total of 26 S. Typhi isolates were recovered from the drinking water (n = 1) and patients' blood (n = 24) and stool (n = 1). Phylogenetic analysis indicated the persistence of the outbreak isolates in drinking water for more than 3 months. The genomic comparison demonstrated a high similarity between the isolate from water and isolates from patients in their genomic content, virulence gene profiles, and antimicrobial resistance gene profile, indicating the S. Typhi isolate from drinking water was responsible for the examined outbreak. The result of pulsed-field gel electrophoresis (PFGE) revealed these isolates had identical PFGE pattern, indicating they are clonal variants. Additionally, phylogeographical analysis of global S. Typhi isolates suggested the outbreak isolates are evolutionarily linked to the isolates from the United Kingdom and Vietnam. Taken together, this study highlights the drinking water and international travel as critical control points of mitigating the outbreak, emphasizing the necessity of regular monitoring of this pathogen in China.

High Prevalence and Persistence of Escherichia coli Strains Producing Shiga Toxin Subtype 2k in Goat Herds.

Shiga toxin (Stx)-producing Escherichia coli (STEC) is a zoonotic pathogen with the ability to cause severe diseases like hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Shiga toxin (Stx) is the key virulence factor in STEC and can be classified into two types, Stx1 and Stx2, and different subtypes. Stx2k is a newly reported Stx2 subtype in E. coli strains from diarrheal patients, animals, and raw meats exclusively in China so far. To understand the reservoir of Stx2k-producing E. coli (Stx2k-STEC), we investigated Stx2k-STEC strains in goat herds and examined their genetic characteristics using whole-genome sequencing. A total of 448 STEC strains were recovered from 2,896 goat fecal samples, and 37.95% (170/448) were Stx2k-STEC. Stx2k-STEC strains of serotype O93:H28 and sequence type 4038 (ST4038) were the most predominant and were detected over several years. Notably, 55% of Stx2k-STEC strains carried the heat-labile toxin (LT)-encoding gene (elt) defining enterotoxigenic E. coli (ETEC), thereby exhibiting the hybrid STEC/ETEC pathotype. Stx2k-converting prophage genomes clustered into four groups and exhibited high similarity within each group. Strains from patients, raw meat, sheep, and goats were intermixed distributed in the phylogenetic tree, indicating the risk for cross-species spread of Stx2k-STEC and pathogenic potential for humans. Further studies are required to investigate the Stx2k-STEC strains in other reservoirs and to understand the mechanism of persistence in these hosts. IMPORTANCE Strains of the recently reported Stx2k-STEC have been circulating in a variety of sources over time in China. Here, we show a high prevalence of Stx2k-STEC in goat herds. More than half of the strains were of the hybrid STEC/ETEC pathotype. Stx2k-STEC strains of predominant serotypes have been widespread in the goat herds over several years. Stx2k-converting prophages have exhibited a high level of similarity across geographical regions and time and might be maintained and transmitted horizontally. Given that goat-derived Stx2k-STEC strains share similar genetic backbones with patient-derived strains, the high prevalence of Stx2k-STEC in goats suggests that there is a risk of cross-species spread and that these strains may pose pathogenetic potential to humans. Our study thus highlights the need to monitor human Stx2k-STEC infections in this region and, by extension, in other geographic locations.

High prevalence and pathogenic potential of Shiga toxin-producing Escherichia coli strains in raw mutton and beef in Shandong, China.

Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen that can cause severe human diseases such as hemolytic uremic syndrome (HUS). Human STEC infections are frequently caused through consumption of contaminated foods, especially raw meats. This study aimed to investigate the prevalence of STEC in raw meats and to characterize the meat-derived STEC strains using whole genome sequencing. Our study showed that 26.6% of raw mutton, and 7.5% of raw beef samples were culture-positive for STEC. Thirteen serotypes were identified in 22 meat-derived isolates in this study, including the virulent serotypes O157:H7 and O26:H11. Seven Shiga toxin (Stx) subtypes were found in 22 isolates, of these, stx1c and stx1c + stx2b were predominant. The recently-reported stx2k subtype was found in three mutton-sourced isolates. A number of other virulence genes such as genes encoding intimin (eae), enterohemorrhagic E. coli (EHEC) hemolysin (ehxA), EHEC factor for adherence (efa1), heat-stable enterotoxin 1 (astA), type III secretion system effectors, were detected in meat-derived STEC strains. One mutton-sourced isolate was resistant to three antibiotics, i.e., tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole. Whole-genome phylogeny indicated the genomic diversity of meat-derived strains in this study. O157:H7 and O26:H11 isolates in this study were phylogenetically grouped together with strains from HUS patients, suggesting their pathogenic potential. To conclude, our study reported high STEC contaminations in retail raw meats, particularly raw mutton, genomic characterization indicated pathogenic potential of meat-derived STEC strains. These findings highlight the critical need for increased monitoring of STEC in retail raw meats in China.

[Antibiotic resistance and molecular typing of Listeria monocytogenes from foods in Shandong province from 2009 to 2010].

OBJECTIVE: To know the antibiotic resistance and molecular characteristics of Listeria monocytogenes in Shandong province and to study the relationship between antibiotic resistance phenotypes and genome types. METHODS: From 2009 to 2010, a total of 80 Listeria monocytogenes isolates were collected from raw meat, cooked meat, aquatic products and other foods in 6 cities of Shandong province. The antibiotic susceptibility was measured by broth microdilution method, PFGE was performed for molecular typing and the relationship between antimicrobial resistance and PFGE patterns was analyzed. RESULTS: 16.25% (13/80) of the isolates were drug-resistant. Imipenem resistance was the most prevalent (12.50%, 10/80), followed by tetracycline and doxycycline (3.75%, 3/80 and 2.50%, 2/80). A total of the 80 isolates were subtyped into 9 antibiotic resistance patterns and 34 PFGE types which were largely dominated by the type 17 and 29. Antibiotic resistance pattern A corresponded to 79.41% (27/34) of PFGE types. CONCLUSION: The antibiotic resistance of Listeria monocytogenes in Shandong province is serious from 2009 to 2010 and there is no correlation between PFGE types and antibiotic resistance patterns.

Nosocomial cross-infection of hypervirulent Listeria monocytogenes sequence type 87 in China.

BACKGROUND: To investigate the epidemiological and phenotypic characteristics and molecular relatedness of L. monocytogenes, which were cultured from the blood and cerebrospinal fluid (CSF) samples isolated from two neonates. METHODS: In the present case study, two infected neonates were interviewed and epidemiological investigation performed. The phenotypic characteristics and molecular relatedness of L. monocytogenes was characterized by serotyping, pulsed-field gel electrophoresis and whole-genome sequencing (WGS). RESULTS: The field investigation found that the two neonates were born in the same hospital (Hospital B) and admitted to the neonatal department through different channels within half an hour by different nurses, where they were weighed and placed in different but adjacent incubators. Then they were cared for by the same group of nurses that evening. It is worth noting that there was no record of sanitation of the neonatal incubator of neonate-1. The serotype of the two isolated L. monocytogenes were 1/2b, with an indistinguishable pulsotypes and were sequence type (ST) 87. WGS showed that there were no core SNP differences identified. In order to explore the genomic traits associated with L. monocytogenes virulence genes, we identified the Listeria pathogenicity island 4 and found that the genome was devoid of any stress islands. There are no positive results from the environmental samples. Considering the genomic data together with epidemiological evidence and clinical symptoms, insufficient surface cleaning along with the nursing staff caring for these neonates was considered as cross-infection factors. CONCLUSIONS: To our knowledge, this is the first report of a nosocomial cross-infection of L. monocytogenes ST87 between two neonates, which carries the recently identified gene cluster expressing the cellobiose-family phosphotransferase system (PTS-LIPI-4) between two neonates. The test results of environmental samples in the hospital indicate that strict sterilization and patient isolation measures cannot be emphasized enough in neonatal nursing.

Emergence of NDM-1- and CTX-M-3-Producing Raoultella ornithinolytica in Human Gut Microbiota.

Raoultella ornithinolytica is an opportunistic pathogen of the Enterobacteriaceae family and has been implicated in nosocomial infections in recent years. The aim of this study was to characterize a carbapenemase-producing R. ornithinolytica isolate and three extended-spectrum ß-lactamase (ESBL)-producing R. ornithinolytica isolates from stool samples of adults in a rural area of Shandong Province, China. The species were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rDNA sequence analysis. Antimicrobial susceptibility test showed that all four isolates were multidrug-resistant (MDR). The whole genome sequence (WGS) of these isolates was determined using an Illumina HiSeq platform, which revealed MDR-related genes. The S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) was used to characterize the plasmids carried by the R. ornithinolytica isolates. The bla NDM-1 and bla CTX-M-3 genes were probed using Southern blotting, which confirmed the location of both genes on the same plasmid with molecular weight of 336.5-398.4 kb. The transferability of bla NDM-1 and bla CTX-M was also confirmed by conjugation assays. Finally, BLAST analysis of both genes showed that mobile genetic elements were associated with the spread of drug resistance genes. Taken together, we report the presence of conjugative bla NDM-1 and bla CTX-M plasmids in R. ornithinolytica isolates from healthy humans, which indicate the possibility of inter-species transfer of drug resistance genes. To the best of our knowledge, this is the first study to isolate and characterize carbapenemase-producing R. ornithinolytica and ESBL-producing R. ornithinolytica isolates from healthy human hosts.

Prevalence of Foodborne Pathogens in Cooked Meat and Seafood from 2010 to 2013 in Shandong Province, China.

BACKGROUND: Current food safety issues are deleteriously reshaping the lifestyle of the population in the developing world. The globalization of food supply impacts patterns of foodborne disease outbreaks worldwide, and consumers are having increased concern about microbiological food safety. METHODS: A total of 2305 samples including sauced meat, sausage, smoked meat, shrimp, sashimi and shellfish were collected from different farmer's markets and supermarkets. The prevalence of selected foodborne pathogens was evaluated in cooked meat and seafood from 2010 to 2013 in Shandong Province, China. RESULTS: The average contamination rate was 6.39% (93.1456) for the selected pathogens in cooked meat and 16.84% (143.849) for V. parahaemolyticus in seafood. For the selected pathogens, 0.55%, 1.03%, 1.17%, 3.64% and 16.84% samples were contaminated with E.coli O157: H7, Salmonella spp., L. monocytogenes, S. aureus and VP, respectively. There was a significant (P<0.05) difference in the contamination rate between the farmer's markets and supermarkets. CONCLUSION: The contamination was decreasing in cooked meat and maintaining a relatively high level in seafood from 2010 to 2013. E. coli O157: H7, S. aureus, L. monocytogenes and Salmonella spp. existed at a relatively low rate in retail foods. For VP, the contamination rate has been maintained at a relatively high level in Shandong Province in China. Moreover, cooked meat and seafood obtained from farmer's markets are more susceptible to be contaminated compared to those from supermarkets.

[Distribution and molecular epidemiologic characterizes of insertion sequence IS1301 in neisseria meningitidis isolated from China].

OBJECTIVE: To research the distribution and molecular epidemiology of insertion sequence IS1301 in Neisseria (N.) meningitidis strains in China, so as to provide scientific and available evidence for a new method of genotyping in N. meningitidis strains with IS1301. METHODS: Examined the IS1301 by PCR in 219 N.meningitidis strains from 16 provinces and 3 cities during 2007 and 2008 in China, productions of amplification were sent for sequencing. The positive N. meningitidis strains were analyzed by pulse field gel electrophoresis (PFGE) and nucleic acid blotting hybridization(Southern blot) by electrophoresis. RESULTS: The positive rates with IS1301 were 15.53%, 11.11%, 20.75%,6.17% and 28.57% for four serotypes (A, B, C, N) respectively. The sequence comparability between the amplification productions and No.Z49092.1 N. meningitidis which registered in GenBank was 94%-100%. There were two types of clusters divided by cladogram analysis. There appeared large IS1301 sequence difference between the serotype C and others. The number of IS1301 replica ranged from 6-17 per strain at least. The number of IS1301 replica changed in the same type of PFGE N. meningitidis respectively. CONCLUSION: Typing by IS1301 combined with PFGE could comprehend the homology and genetic polymorphism of N.meningitidis epidemic strains at the molecular level.