Objective To investigate the clonal types of Staphylococcus aureus collected from 2004to 2010 in patients with blood stream infection from a Grade A tertiary care hospital in Shanghai as well as the dynamic changes and to detect the variation in antimicrobial resistance and virulence-gene content in different strain types.Methods A total of 103 nonduplicate S.aureus isolates were collected from 2004 to 2010 from inpatients with S.aureus blood stream infection from Shanghai Huashan hospital.Determination of oxacillin MICs and the type of SCCmec gene were used to screen MRSA.Typing of S.aureus isolates was identified by using multilocus sequence typing(MLST) and S.aureus-specific staphylococcal protein A typing(spa typing),PCR was used to detect the antimicrobial resistance and virulence-gene.Results Sixtysix isolates(64.1%) MRSA were detected in 103 nonduplicate S.aureus isolates,and 35 isolates were MRSA with SCCmec type Ⅱ ,Twenty-nine isolates were MRSA with SCCmec type Ⅱ,two isolates were MRSA with SCCmec type Ⅳ,Thirty-seven isolates(35.9%) were MSSA.Thirty-three MRSA isolates were ST5,Twenty-nine MRSA isolates were ST239,two MRSA isolates were ST59,one MRSA isolates was ST641 and one MRSA isolates was ST6.All of the other clones belonged to MSSA.The percentage of ST5 and ST239 were decreased significantly after 2009(ST5 was decreased from 52.9% to 15.4%; ST239 was decreased from 61.1% to 15.4%),and new clonal types MSSA increased significantly(in 2009,the percentage of ST7 was 41.7%; new clonal types such as ST188 and ST15 were detected in 2010).In 2010,it was shown that 84.6% of MSSA were isolated from S.aureus blood stream infection,nineteen isolates(18.4%) harbored mupA gene and 41 isolates(39.8%) harbored qacA/B gene in 103 nonduplicate S.aureus isolates.It was shown that 70.6% ST239 harbored qacA/B gene.Four isolates of ST398 and 1 isolates of ST9were detected which were originally from animal.There was no significant difference of the virulence gene presence in the same strain types except sasX、lukSF and arcA genes,but there were a lot of genes which were restricted to different genomic background.Conclusions The percentage of ST5 and ST239 were decreased and new clonal types of MSSA were increased significantly in S.aureus blood stream infection,antimicrobial resistance and virulence-gene were restricted to different clonal types.

Objective To determine whether the novel surface-anchored protein SasX promotes aggregation of S.aureus and adherence of S.aureus to human nasal epithelial cells.Methods MRSA ST-239 HS770 sasX gene mutant ( HS770 △sasX) and complement [ HS770 △sasX (pRBsasX) ] were gotten by gene knock-out and complement methods.The aggregation ability of S.aureus was observed through microscope.By adherence assay which was used for detection of the adherence ability of wild type and mutant to human nasal epithelial cells and blocking experiments which detected the ability of the purified recombinant SasX protein in blocking the adherence of S.aureus to human nasal epithelial cells,we investigated the influence SasX on colonization of S.aureus.Results Compared to wild type,HS770△sasX showed a reduction in cell aggregation,while the complement had no difference with wild type in aggregation. HS770 △sasX showed a significant reduction of adherence to human nasal epithelial cells compared to wild type ( P＜0.01 ),and the complement showed a very clear increasement of adherence to human nasal epithelial cells compared to wild type(P＜0.01 ).Preincubation of nasal epithelial cells with the purified recombinant SasX protein inhibited S.aureus binding significantly.Conclusion SasX had an influence in aggregation of S.aureus and its adherence to human nasal epithelial cells.By acquiring sasX,S.aureus colonized more easily to the susceptible sites of the host,and thus caused infection.

ObjectiveTo investigate the distribution and effect on antibiotic resistance of the novel cell wall anchored protein-encoding gene sasX.MethodsA total of 300 S.aureus isolates were randomly collected from inpatients with S.aureusinfection in ShanghaiHuashanhospitalin 2004, 2007and 2010.Meanwhile,170 S.aureus isolates from the nasal swabs of healthy people were collected as part of a population-based community prevalence study.Typing of S.aureus isolates were identified by using multilocus sequence typing (MLST) and S.aureus-specific staphylococcal protein A typing (spa typing).Determination of oxacillin MICs was used to screen MRSA.PCR and sequencing were used to analyze sasX gene.The effect on antibiotic resistance of sasX gene was detect by disc agar diffusion drug sensitive test.ResultsThe major clonal types of the 300 S.aureus isolates collected from inpatients with S.aureus infection were ST239 ( 110,36.7％) and ST5 (122,40.7％).From 2004 to 2010,the percentage of isolates from inpatients with S.aureus infection was increased from 17％ to 39％,but sasX was only found in 0.59％ of the S.aureus isolates from the nasal swabs of healthy people.The percentage of sasX positive was increased from 47.2％ to 83.8％ in ST239.The percentage of sasX positive MRSA was increased from 26.4％ to 50.8％,but the percentage of sasX positive MSSA was about 10％.Antibiotic resistance of sasX positive strains were higher than that of sasX negative strains.Conclusions SasX gene is mainly detected in nosocomial pathogenic S.aureus and it is a possible virulence factor of S.aureus in hosptal setting.The presence of sasX gene is related to antibiotic resistance.For better understanding the real function of this novel gene,further studies such as expression of the encoded protein should be carried out.

Objective To Analyze the clinical outcomes of pediatric liver transplantation (LT) for liver-based metabolic disorders.Methods We conducted a retrospective analysis on 42 pediatric patients with liver-based metabolic disorders from June 2013 to March 2017,and analyzed the pediatric end stage liver disease model (PELD),growth and development,type of transplant,postoperative complications and prognosis of patients.Results There were 42 children with liver-based metabolic disorders (15.56%) out of all the 270 children who underwent LT.The median age was 51.0 months (range,3.4-160.9 months).Of the 42 children,19 received living donor liver transplantation (LDLT),18 cases received deceased donor liver transplantation (DDLT) and 5 cases received domino liver transplantation.1-,2-and 3-year cumulative survival rate of 42 recipients was 97.7%,93.6% and 93.6%,and that of the grafts was 95.3%,91.4% and 91.4%,respectively.As compared with the 194 children with biliary atresia who underwent LT,significant difference was found in PELD and weight Z-score between the two groups.Conclusion Liver transplantation is a valuable option for children with metabolic disorders,and it has gained a better prognosis.

Objective According investigate the expression of NLRP3 in liver tissues of mice with hepatic ischemia-reperfusion injury (HIRI),to determin the role of NLRP3 in the process of HIRI.Methods Established mice model of partial HIRI.Forty-two male C57BL/6 mice (aged 7 to 8 weeks,weight 20 to 25 g) were respectively divided into 7 groups:no-treatment control group,sham operation group,HIRI groups (2、6、12、24 h) and CY-09 group,6 mice in each group.The injury of the hepatic tissues in the 7 groups was analyzed based on detecting the levels of alanine transaminase (ALT),aspartate transaminase (AST),interleukin-1β (IL-1β),interleukin-18 (IL-18),tumor necrosis factor-α (TNF-α) by ELISA.HE and TUNEL staining were used to observe the pathological changes of liver tissues after HIRI.Western blotting assay were carried out to detect the expressions of NLRP3 and Caspase-1.Measurement data were expressed as mean ± standard deviation (Mean ± SD),and one-way variance analysis was used for comparison between groups.If the variance was not uniform,Dunnett C test was used.Results Serum ALT,AST,IL-1 β,IL-18 and TNF-α of mice detected in HIRI groups were higher than no-treatment control group and sham operation group at all endpoints (P ＜ 0.05).The relative expression of NLRP3 and Caspase-1 in the liver tissues of mice in the HIRI groups were significantly higher than that in the no-treatment control group and sham operation group.Serum ALT,AST,IL-1β,IL-18 and TNF-α of mice detected in CY-09 group were lower than HIRI groups at all endpoints (P ＜ 0.05).Less hepatocellular necrosis were exhibited in CY-09 group,comparing to HIRI groups.The hepatocyte apoptosis rate of mice in the CY-09 group was significantly lower than that in the 12 h HIRI group (P ＜ 0.05).The relative expression of NLRP3 in the liver tissues of mice in the CY-09 group was significantly lower than that in other groups.The relative expression of Caspase-1 in the liver tissues of mice in the CY-09 group was significantly lower than that in other groups except the no-treatment control group and sham operation group.Conclusions HIRI cause an increase in NLRP3 expression.The inhibition of NLRP3 can reduce HIRI.