Metagenomic next-generation sequencing and proteomics analysis in pediatric viral encephalitis and meningitis.

Introduction: Early and accurate identification of pathogens is essential for improved outcomes in patients with viral encephalitis (VE) and/or viral meningitis (VM). Methods: In our research, Metagenomic next-generation sequencing (mNGS) which can identify viral pathogens unbiasedly was performed on RNA and DNA to identify potential pathogens in cerebrospinal fluid (CSF) samples from 50 pediatric patients with suspected VEs and/or VMs. Then we performed proteomics analysis on the 14 HEV-positive CSF samples and another 12 CSF samples from health controls (HCs). A supervised partial least squaresdiscriminant analysis (PLS-DA) and orthogonal PLS-DA (O-PLS-DA) model was performed using proteomics data. Results: Ten viruses in 48% patients were identified and the most common pathogen was human enterovirus (HEV) Echo18. 11 proteins overlapping between the top 20 DEPs in terms of P value and FC and the top 20 proteins in PLS-DA VIP lists were acquired. Discussion: Our result showed mNGS has certain advantages on pathogens identification in VE and VM and our research established a foundation to identify diagnosis biomarker candidates of HEV-positive meningitis based on MS-based proteomics analysis, which could also contribute toward investigating the HEV-specific host response patterns.

Dietary supplementation of probiotics fermented Chinese herbal medicine Sanguisorba officinalis cultures enhanced immune response and disease resistance of crucian carp (Carassius auratus) against Aeromonas hydrophila.

Aeromonas hydrophila, a Gram-negative bacterium, is one of the major pathogens causing bacterial sepsis in aquatic animals due to drug resistance and pathogenicity, which could cause high mortality and serious economic losses to the aquaculture. Sanguisorba officinalis (called DiYu in Chinese, DY) is well known as herbal medicine, which could inhibit the growth of pathogenic bacteria, hemostasis and regulate the immune response. Moreover, the active ingredients in DY could remarkably reduce drug resistance. In this study, we investigated the effects of probiotic fermentation cultures on A. hydrophila through in vitro and in vivo experiments. Three lactic acid bacteria, including Lactobacillus rhamnosus (LGG), Lactobacillus casei (LC) and Lactobacillus plantarum (LP), were selected to ferment the Chinese herbal medicine DY. The assays of antagonism showed that all three fermented cultures could influence the ability of A. hydrophila growth, among which L. rhamnosus fermented DY cultures appeared to be the strongest inhibitory effect. In addition, the biofilm determination revealed that L. rhamnosus fermented DY cultures could significantly inhibit the biofilm formation of A. hydrophila compared to the other groups. Furthermore, protease, lecithinase and urease activities were found in the three fermentation cultures. Three probiotics fermented DY cultures were orally administration with crucian carp to evaluate the growth performance, immunological parameters and pathogen resistance. The results showed that the three fermentation cultures could promote the growth performance of crucian carp, and the immunoglobulins, antioxidant-related enzymes and immune-related genes were significantly enhanced. Besides, the results showed that crucian carp received L. rhamnosus (60.87%), L. casei (56.09%) and L. plantarum (41.46%) fermented DY cultures had higher survival rates compared with the control group after infection with A. hydrophila. Meanwhile, the pathological tissue results revealed that the probiotic fermented cultures could largely improve the tissues damage caused by the pathogenic bacteria. In conclusion, this study proved that the fermentation cultures of three probiotics could effectively inhibit the growth of A. hydrophila, regulate the level of immune response and improve the survival rate against A. hydrophila in crucian carp. The present data suggest that probiotic fermented Sanguisorba officinalis act as a potential gut-targeted therapy regimens to protecting fish from pathogenic bacteria infection.

Construction and validation of a m6A RNA methylation and ferroptosis-related prognostic model for pancreatic cancer by integrated bioinformatics analysis.

Background: Both N6-methyladenosine (m6A) ribonucleic acid (RNA) methylation and ferroptosis regulators are demonstrated to have significant effects on the malignant clinicopathological characteristics of pancreatic adenocarcinoma (PAAD) patients. However, the currently available clinical indexes are not sufficient to predict precise prognostic outcomes pf PAAD patients accurately. This study aims to examine the clinicopathologic features of m6A RNA methylation and ferroptosis regulators in predicting the outcomes of different types of cancer. Methods: As the foundation for this research, the differentially expressed genes (DEGs) between PAAD tissues and adjacent normal tissues were first identified. Next, dimensional reduction analysis (DCA) based on m6A RNA methylation regulators and ferroptosis regulators were performed and DEGs between good/poor prognosis PAAD patient clusters were identified. DEGs were then screened by Cox analysis, and finally a risk signature was established by least absolute shrinkage and selection operator (LASSO) analyses. The prediction model based on risk score was further evaluated by a validation set from Gene Expression Omnibus (GEO) database. Results: In total, 4 m6A RNA methylation regulator genes and 29 ferroptosis regulator genes were found to have close causal relationships with the prognosis of PAAD, and a risk score with 3 m6A methylation regulators (i.e., IGF2BP2, IGF2BP3, and METTL16) and 4 ferroptosis regulators (i.e., ENPP2, ATP6V1G2, ITGB4, and PROM2) was constructed and showed to be highly involved in PAAD progression and could serve as effective markers for prognosis with AUC value equaled 0.753 in training set and 0.803 in validation set. Conclusions: The combined prediction model, composed of seven regulators of m6A methylation and ferroptosis, in this study more effectively reflects the progression and prognosis of PAAD than previous single genome or epigenetic analysis. Our study provides a broader perspective for the subsequent establishment of prognostic models and the patients may benefit from more precision management.

Risk factors of cervical cancer among ethnic minorities in Yunnan Province, China: a case-control study.

BACKGROUND: Cervical cancer is a common malignant tumor of the female reproductive system in the world, which is a serious threat to women's life and health. According to the latest report, the incidence of cervical cancer is 11.42 per 100 000, and the mortality rate is 3.77 per 100 000 in Yunnan Province, which is still higher than the national average. Although there have been some relevant studies on the risk factors of cervical cancer in recent years, research on ethnic minorities is lacking in Yunnan Province. OBJECTIVE: To analyze and explore the related risk factors of cervical cancer in women of ethnic minorities in Yunnan Province, to provide the scientific basis for the development of cervical cancer prevention and control strategies and measures in this region. METHODS: In total 1119 cervical cancer patients diagnosed by histopathology at the Yunnan Cancer Center (Yunnan Cancer Hospital) from January 2010 to December 2019 were selected as the case group. According to the 1:1 matching principle of the case-control study, 1119 patients with nonmalignant tumors of the same nationality, the same hospital, age difference less than 3 years old, were selected as the control group. Univariate and multivariate conditional logistic regression were used for statistical analysis. RESULTS: Basic medical insurance for rural residents (OR = 3.659; P = 0.003), human papilloma virus (HPV) infection (OR = 90.030; P < 0.001) and concurrent reproductive tract infections (OR = 1.992; P = 0.047) were risk factors for cervical cancer. Late first marriage(OR = 0.881; P = 0.032), the number of normal childbirths ≤2 (OR = 0.480, P = 0.033) and contraception (OR = 0.291; P = 0.002) were positive factors for cervical cancer. CONCLUSION: The high incidence of cervical cancer in Yunnan minority women is the result of many factors: HPV infection is the highest risk factor for cervical cancer, women with reproductive tract infections and basic medical insurance for rural residents have a higher risk for cervical cancer; Late first marriage, the number of deliveries ≤2 and contraception are positive factors for cervical cancer.

Global Genomic Characterization of Salmonella enterica Serovar Telelkebir.

Non-typhoidal Salmonella (NTS) is a common cause for self-limiting gastroenteritis, representing a public health concern globally. NTS is one of the leading causes of foodborne illnesses in China; however, the invasive infection caused by NTS is largely underappreciated. Here, we reported an NTS invasive infection caused by an infrequently reported serovar Telelkebir (13,23:d:e,n,z15) strain FJ001 in China, which carries antimicrobial-resistant genes [fosA7 and aac(6')-Iaa] and typhoid-toxin genes (cdtB, pltA, and pltB). By conducting the whole genomic sequencing, we also investigated the relatedness of this strain with an additional 120 global contextual Salmonella enterica serovar Telelkebir (S. Telelkebir) isolates, and assessed the antimicrobial-resistant determinants and key virulence factors using the available genomic dataset. Notably, all 121 (100%) of the S. Telelkebir strains possessed the typhoid toxin genes cdtB, pltA, and pltB, and 58.67% (71/121) of S. Telelkebir harbored antimicrobial-resistant gene fosaA7. The study by core genome multilocus sequence typing (cgMLST) and core single-nucleotide polymorphism (SNP)-based phylogenomic analysis demonstrated that the S. Telelkebir isolates from different sources and locations clustered together. This suggests that regular international travels might increase the likelihood of rapid and extensive transmissions of potentially pathogenic bacteria. For the first time, our study revealed the antimicrobial resistance, virulence patterns, and genetic diversity of the serovar S. Telelkebir isolate in humans and similar isolates over the world. The present study also suggests that genomic investigation can facilitate surveillance and could offer added knowledge of a previously unknown threat with the unique combination of virulent and antimicrobial-resistant determinants.

Discovery of Antibacterial Dietary Spices That Target Antibiotic-Resistant Bacteria.

Although spice extracts are well known to exhibit antibacterial properties, there is lack of a comprehensive evaluation of the antibacterial effect of spices against antibiotic-resistant bacteria. In the present study, ethanolic extracts from a total of 67 spices were comprehensively investigated for their in vitro antibacterial activities by agar well diffusion against two common food-borne bacteria, Staphylococcus aureus and Salmonella enteritidis, with multi-drug resistance. Results showed that S. aureus was generally more sensitive to spice extracts than S. enteritidis. Of the 67 spice extracts, 38 exhibited antibacterial activity against drug-resistant S. aureus, while only four samples were effective on drug-resistant S. enteritidis. In addition, 11 spice extracts with inhibition zones greater than 15 mm were further verified for their broad-spectrum antibacterial properties using another 10 drug-resistant S. aureus strains. It was found that five spice extracts, including galangal, fructus galangae, cinnamon, yellow mustard seed, and rosemary, exhibited the highest antibacterial capacity. Further cytotoxicity of these 11 spices was determined and LC50 values were found to be more than 100 µg/mL except for galangal, rosemary, and sage, whose LC50 values were 9.32 ± 0.83, 19.77 ± 2.17, and 50.54 ± 2.57, respectively. Moreover, the antioxidant activities (ferric-reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) values) and total phenolic content (TPC) of spice extracts were determined to establish possible correlations with the antibacterial activity. Although the antibacterial effect was positively correlated with the antioxidant activities and TPC, the correlation was weak (r < 0.5), indicating that the antibacterial activity could also be attributed to other components besides antioxidant polyphenols in the tested spice extracts. In conclusion, dietary spices are good natural sources of antibacterial agents to fight against antibiotic-resistant bacteria, with potential applications as natural food preservatives and natural alternatives to antibiotics in animal feeding.

[Assessment and application of a molecular diagnostic method on the detection of four types of diarrheagenic Escherichia coli].

OBJECTIVE: To establish and evaluate a molecular diagnostic method for routine monitoring of four types of diarrheagenic Escherichia (E.) coli (DEC)and to study the distribution of four types of DEC isolated from diarrheal patients in Shanghai. METHODS: DEC-PCR standard operation procedure(SOP)had been developed for DEC detection and isolation, using the Statens Serum Institute (SSI) DEC PCR kits with multiplex PCR technique after verification tests on reference strains. Diarrhea specimens from 3 clinical hospitals in Shanghai were tested from June to September, 2012. RESULTS: Specificity of the PCR kit was 100% by verification on the 26 DEC reference strains. A total number of 218 DEC isolates, including 181 fermented lactose and 37 unfermented lactose were identified from the 1887 stool specimens of diarrhea patients, with positive rate as 11.6%. The most common pathogen(54.1%, 118/218)was enteropathogenic E. coli(EPEC), followed by enterotoxigenic E. coli(ETEC, 41.3%, 90/218), enteroinvasive E. coli (EIEC, 4.1%, 9/ 218) and Shigatoxin-producing E. coli(STEC, 0.5%, 1/218)in addition to 18 Shigella isolates. ETEC dominated in diarrhea patients with foreign residency, as well as 1/3 were perinatal stage of neonatal ETEC of all diarrhea cases under the age of 5, while EPEC dominated in the Chinese diarrhea patients especially among young kids under the age of 2. CONCLUSION: Data was reliable after assessment on this molecular diagnostics and seperation procedures used for the routine monitoring on four types of DEC, while the diagnosis and reference ability of DEC regarding the laboratories net-working on food-borne pathogens need to be built up and improved.

Development and application of a real-time polymerase chain reaction method for Campylobacter jejuni detection.

AIM: To develop a real-time polymerase chain reaction (PCR) method to detect and quantify Campylobacter jejuni (C. jejuni) from stool specimens. METHODS: Primers and a probe for real-time PCR were designed based on the specific DNA sequence of the hipO gene in C. jejuni. The specificity of the primers and probe were tested against a set of Campylobacter spp. and other enteric pathogens. The optimal PCR conditions were determined by testing a series of conditions with standard a C. jejuni template. The detection limits were obtained using purified DNA from bacterial culture and extracted DNA from the stool specimen. Two hundred and forty-two specimens were analyzed for the presence of C. jejuni by direct bacterial culture and real-time PCR. RESULTS: The optimal PCR system was determined using reference DNA templates, 1 × uracil-DNA glycosylase, 3.5 mmol/L MgCl2, 1.25 U platinum Taq polymerase, 0.4 mmol/L PCR nucleotide mix, 0.48 µmol/L of each primer, 0.2 µmol/L of probe and 2 µL of DNA template in a final volume of 25 µL. The PCR reaction was carried as follows: 95 °C for 4 min, followed by 45 cycles of 10 s at 95 °C and 30 s at 59 °C. The detection limit was 4.3 CFU/mL using purified DNA from bacterial culture and 10(3) CFU/g using DNA from stool specimens. Twenty (8.3%, 20/242) C. jejuni strains were isolated from bacterial culture, while 41 (16.9%, 41/242) samples were found to be positive by real-time PCR. DNA sequencing of the PCR product indicated the presence of C. jejuni in the specimen. One mixed infection of C. jejuni and Salmonella was detected in one specimen and the PCR test for this specimen was positive. CONCLUSION: The sensitivity of detection of C. jejuni from stool specimens was much higher using this PCR assay than using the direct culture method.

Regenerative endodontic treatment of an immature permanent tooth at an early stage of root development: a case report.

INTRODUCTION: Regenerative endodontic treatment (RET) has been used in treating nonvital immature permanent tooth whose root formation ranged from approximately two-thirds of the full root length to almost completely developed root with open apex at least 1.1 mm in diameter according to the reported cases. However, this case report was to introduce RET in an affected tooth at an early stage of root development. METHODS: The premolar #29 in an 8-year-old girl had pulpal necrosis and apical periodontitis caused by the fracture of dens evaginatus. Its root was at the beginning of formation. Copious hemorrhagic drainage was observed after preparing of an access cavity. The canal was irrigated with 3% NaOCl solution, sterile normal saline, and chlorhexidine. Root dressing with triple antibiotic was then performed and left for 4 weeks. We used a K-file to create bleeding into the canal after flushing and drying the root canal. Mineral trioxide aggregate was carefully placed over the formed blood clot. RESULTS: Clinical examination at 1, 3, 6, 9, and 12 months revealed an asymptomatic tooth. Radiographic examination revealed resolution of periapical radiolucency, increased thickening of the canal wall, and lengthening of the root, which demonstrated the continual development of the tooth root. Noticeably, the first-month postoperative radiograph showed radiopaque image in the root canal like an isolated island, which was gradually obvious during follow-up. Cone-beam computed tomography revealed that the calcification was attached with dentin wall in buccolingual direction, and the root canal was not completely obliterated. CONCLUSIONS: RET is feasible for a tooth at an early stage of root development that has necrotic pulp and periapical lesion.

[The fundamental role of stage control technology on the detectability for Salmonella networking laboratory].

OBJECTIVE: To evaluated the fundamental role of stage control technology (SCT) on the detectability for Salmonella networking laboratories. METHODS: Appropriate Salmonella detection methods after key point control being evaluated, were establishment and optimized. Our training and evaluation networking laboratories participated in the World Health Organization-Global Salmonella Surveillance Project (WHO-GSS) and China-U.S. Collaborative Program on Emerging and Re-emerging infectious diseases Project (GFN) in Shanghai. Staff members from the Yunnan Yuxi city Center for Disease Control and Prevention were trained on Salmonella isolation from diarrhea specimens. Data on annual Salmonella positive rates was collected from the provincial-level monitoring sites to be part of the GSS and GFN projects from 2006 to 2012. RESULTS: The methodology was designed based on the conventional detection procedure of Salmonella which involved the processes as enrichment, isolation, species identification and sero-typing. These methods were simultaneously used to satisfy the sensitivity requirements on non-typhoid Salmonella detection for networking laboratories. Public Health Laboratories in Shanghai had developed from 5 in 2006 to 9 in 2011, and Clinical laboratories from 8 to 22. Number of clinical isolates, including typhoid and non-typhoid Salmonella increased from 196 in 2006 to 1442 in 2011. The positive rate of Salmonella isolated from the clinical diarrhea cases was 2.4% in Yuxi county, in 2012. At present, three other provincial monitoring sites were using the SBG technique as selectivity enrichment broth for Salmonella isolation, with Shanghai having the most stable positive baseline. CONCLUSION: The method of SCT was proved the premise of the network laboratory construction. Based on this, the improvement of precise phenotypic identification and molecular typing capabilities could reach the level equivalent to the national networking laboratory.

[Initial study of biological characterization and virulence of Porphyromonas gingivalis PG0839-defective mutant].

PURPOSE: To study the effect of PG0839 gene form Porphyromonas gingivalis (P. gingivalis) on biological characterization and virulence in a murine model of soft tissue destruction, and further to provide evidence for clarifying the gene function of PG0839. METHODS: P. gingivalis W83 and PG0839-defective mutant strains were plated on brain heart infusion (BHI). Colonial formation, micromorphology and growth curve of the two strains were observed. The two strains cells were mixed respectively with sheep erythrocytes, which were prepared to a final concentration of 1% in 1×PBS, to assess hemagglutination activity. The mice were challenged with subcutaneous injections of bacterial suspension,which were P. gingivalis W83 and PG0839-defective mutant strains at the doses of 2×10(10), 1×10(10), 5×10(9) CFU/mL respectively, on the dorsal surface. Difference in survival situation of mice in various groups was examined using Pearson Chi-square and log rank test with SPSS 13.0 software package. RESULTS: In contrast to the wild-type W83 strain, PG0839-defective mutant strain was nonpigmented and the hemagglutinin activities reduced. However, the growth rate of PG0839-defective mutant strain was not affected (U=25.50, P=0.19). Results of the mice subcutaneous infection model indicated that the virulence of the PG0839-defective mutant strain was significantly lower than P. gingivalis W83 strain (P<0.05). CONCLUSIONS: Absence of PG0839 gene altered several biological characteristics of P. gingivalis W83 strain, suggesting that PG0839 gene may regulate the expression of certain gene or gene product of P. gingivalis W83 strain. Moreover, PG0839 gene may contribute to the virulence of P. gingivalis W83.

[Effect of PG0839 gene of Porphyromonas gingivalis on inflammatory cytokine in human oral epidermoid carcinoma KB cell].

OBJECTIVE: To investigate the effect of PG0839 gene form Porphyromonas gingivalis (Pg) on inflammatory cytokine expression in human oral epidermoid carcinoma KB cell. METHODS: A mutant in the PG0839 gene of Pg was created by insertional inactivation. Group 1 was chanllenged with PgW83 strain, group 2 with PG0839-defective mutant, and the control group with Dulbecco's modified Eagle's medium only. KB cells were co-cultured with presence of bacteria for 24 h. At the time point of 0.5, 2, 6, 12 and 24 h, cells were stored in Trizol. The mRNA expression of interleukin-1ß (IL-1ß) and Toll like recepector-4 (TLR-4) was examined by reverse transcription polymerase chain reaction. RESULTS: At 2 h and 6 h, IL-1ß mRNA expression was lower in group 2 than in group 1 (2 h: 0.31 ± 0.11 versus 0.95 ± 0.48, P < 0.05; 6 h: 0.57 ± 0.20 versus 1.29 ± 0.55, P < 0.05). At 0.5 h and 6 h, TLR-4 mRNA expression was lower in group 2 than in group 1 (0.5 h: 0.20 ± 0.09 versus 0.58 ± 0.09, P < 0.05; 6 h: 0.34 ± 0.04 versus 0.71 ± 0.18, P < 0.05). CONCLUSIONS: PG0839 gene may play an important role in Pg-induced inflammatory effects of KB cell.

[Characteristics of Salmonella enterica serovar Senftenberg lacking Salmonella pathogenicity island 1].

OBJECTIVE: To study the characteristics of the strains of Salmonella enterica (S. enterica) serovar Senftenberg lacking Salmonella pathogenicity island 1 (SPI-1). METHODS: A total of 10 strains of S. enterica serovar Senftenberg were isolated from 10 cases of diarrhea patients. Pulsed field gel electrophoresis (PFGE), PCR, sequencing techniques and cell invasion test were adapted to study the molecular types and invasiveness of the genes and cells; and made a comparison between the 10 strains and the strains (C02013) isolated in Shenzhen in 2002. RESULTS: The 10 Senftenberg isolated (S09007-S09012, S09014-S09017) in Shanghai showed three PFGE patterns, which were significantly different from the strains isolated in Shenzhen. PCR-amplified results indicated the invasion gene (invA), secreted effector protein gene (sipA) and gene fragments as fhlA-hilA, hilA-spaP and spaP-invH in the 10 strains of SPI-1 were all negative. The sequencing results revealed that the 10 strains isolated in Shanghai lacked most parts of SPI-1 genes, as fragments from orgA to invH and parts of orgA gene itself; however, compared with strains isolated in Shenzhen, the sprB-orgC gene existed. The missing parts of genes were replaced by a simple insertion sequence (IS) of 1000 bp in the strains isolated both in Shenzhen in 2002 and in Shanghai in 2006. The invasiveness rates of the 10 strains (S09007-S09012, S09014-S09017) towards Hela cells were (0.0053 ± 0.0024)%, (0.0046 ± 0.0006)%, (0.0047 ± 0.0003)%, (0.0064 ± 0.0012)%, (0.0065 ± 0.0011)%, (0.0070 ± 0.0020)%, (0.0115 ± 0.0030)%, (0.0099 ± 0.0039)%, (0.0180 ± 0.0135)% and (0.0031 ± 0.0012)%, respectively; which were all significantly lower than the rate of invA-positive control strain STM1344 ((5.0800 ± 0.6333)%); lower or close to the rate of invA-lacked artificial-mutated strain STMinvA-((0.0193 ± 0.0045)%). CONCLUSION: SPI-1 genes are not essential for the diarrhea caused by S. enterica serovar Senftenberg.

[Study on the epidemiological characteristics and molecular typing of Salmonella enterica subsp. enterica serovar Senftenberg in Shanghai].

OBJECTIVE: To study the molecular epidemiological characteristics of Salmonella enterica subsp. enterica serovar Senftenberg (Salmonella senftenberg) in Shanghai, from 2006 to 2007. METHODS: A retrospective analysis in 2006 and 2007 was performed to explore the source of food-borne Salmonella senftenberg. The isolates from diarrhea patients between 2006 and 2007 were identified, including biochemical test, hilA and invA gene phenotyping, drug susceptibility, Riboprinter((R)) (RP) and pulsed-field gel electrophoresis (PFGE). RESULTS: Of the diarrhea patients isolates in the monitoring program on non-typhi Salmonella infection in the year of 2006 in Shanghai, number of patients caused by Salmonella senftenberg ranked the third. The stock of Salmonella senftenberg food-born isolates were derived from swine and beef products between 2003 and 2005. All of the strains from diarrhea patients were susceptible to antibiotics except tetracylina (75.6%). With RP and PFGE molecular typing, the two groups (with hydrogen sulfide and hilA, invA gene or without) could be divided into two different independent clone cluster in genetics. 34 strains of diarrhea were divided into 16 PFGE typing-pattern, and among them 12 strains including type 4 (4 strains), type 5 (1 strains), type 6 (6 strains), type 7 (1 strains) and 13 strains including type 11 (3 strains), type 17 (5 strains), type 23 (5 strains) were two different dominant clone cluster. CONCLUSION: The epidemic of Salmonella senftenberg within 2006 might have been the result of a long period of case occurrence in Shanghai. This rare outbreak belonged to a cluster of outbreaks caused by two different PFGE clone clusters. Data suggested that the genetic clone of Salmonella senftenberg might have been unstable and the source of contamination were complicated, with the characteristics as the obvious decreasing number of patients, with no food-borne isolates in 2007.

[Study of caries polarization in 2-5 year-old children of Shenyang, China].

OBJECTIVE: To investigate dental caries polarization in 2-5 year-old children. METHODS: 3 799 random samples of 2-5 year-old children from attending kindergarten in Shenyang were selected. Means of dmft index and SiC index for each age group were calculated by WHO Collaborating Center. The subjects of each age group were further divided into subgroups of different level of dmft: the dmft of subgroup I was 0, the dmft of subgroup II was 1, the dmft of subgroup III was 2, the dmft of sub-group IV was equal to or more than 3. The obtained data were analyzed statistically with SPSS 10.0. RESULTS: 4.5% of 2-year-old children were carriers of 60.0% of the total dmft in that age group, 13.2% of 3-year-old children were carriers of 69.4% of the total dmft in that age group, 34.4% of 4-year-old children were carriers of 86.6% of the total dmft in that age group, and 47.8% of 5-year-old children were carriers of 89.8% of the total dmft of that age group. CONCLUSION: This study supports the assertion that a small percentage of persons with high dental caries rate and a large percentage of caries-free persons of early childhood caries.

[Detection of Porphyromonas gingivalis in the subgingival plaque of puberty gingivitis].

PURPOSE: To detect the presence of Porphyromonas gingivalis (Pg) in the subgingival plaque of puberty gingivitis and to investigate its relationship with gingival health. METHODS: The subjects of 14- to 17-year-old children in this study were divided into two groups, puberty gingivitis group and gingival healthy group, with 36 in each group. Periodontal parameters were recorded. A 16S rRNA-based polymerase chain reaction (PCR) detection method was used to determine the prevalence of Pg in the subgingival plaque samples. The AVG of positive band in the agarose gel electrophoresis was analyzed using the automatic gel documentation and image analyzer software. The relative quantity of Pg was determined. The data were statistically analyzed using SPSS11.5 software. Chi-square test was used to compare the prevalence of Pg in the two groups. Wilcoxon rank sum test was used to analyze the relative quantity of Pg and the severity between the Pg-positive and the Pg-negative subjects. Spearman correlation analysis was used to test the relationship between the relative quantity of Pg and periodontal parameters. RESULTS: The prevalence of Pg in the puberty gingivitis group and gingival healthy group was 47.22% and 25.00%, respectively (P<0.05). The relative quantity of Pg in the two groups was 48.02% and 21.46%, respectively(P<0.01). In all the Pg-positive subjects of puberty gingivitis group, there was positive correlation between the relative quantity of Pg and the gingival index (GI),sulcus bleeding index (SBI) and the probe depth (PD). There were statistically differences between them. The GI and SBI index of the Pg-positive subjects were statistically higher than that of the Pg-negative subjects in the puberty gingivitis group (P<0.01). CONCLUSION: Periodontal pathogens can colonize in the subgingival plaque in puberty subjects and colonization of Pg is relevant to the status of gingival health.