OBJECTIVETo study the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in children.

METHODA total of 37 MRSA strains were isolated from hospitalized patients in Children's Hospital of Fudan University from March 2009 to November 2011. The clinical characteristics were investigated by a cohort study. Furthermore, the mecA, Panton-Valentine leucocidin (PVL) genes were detected by polymerase chain reaction (PCR), and the genotypes of SCCmec were determined by multiplex PCR.

RESULT(1) Among the 37 MRSA isolates, infections with 21 were acquired from hospital (HA-MRSA), and 16 isolates were acquired from community (CA-MRSA). (2) In the study, MRSA frequently caused respiratory tract infection, and most of the strains were isolated from intensive care unit (ICU). (3) CA-MRSA was most frequently associated with skin and soft tissue infections (SSTI), suppurative tonsillitis, even pneumonia and septicemia. HA-MRSA infection was more aggressive, most frequently associated with pneumonia, septicemia, and central nervous system (CNS) infections, such as meningitis. In children with fever caused by HA-MRSA or CA-MRSA infection, HA-MRSA showed a longer duration of fever, for 10.5 days. C-reactive protein (CRP) level caused by HA-MRSA (63.00 mg/L) was higher than CA-MRSA (9.50 mg/L) , and there were statistically significant differences between the groups (t = 2.5670, P < 0.05). However, there were no statistically significant differences between the groups in white blood cell count (WBC) or procalcitonin (PCT) level. (4) Among 37 MRSA isolates, the whole isolates were mecA gene positive (100%). SCCmec genotyping results showed that the most frequent SCCmec types were type III, 17 isolates, the others including type IV 8 isolates, type II1 isolates, nontypable 11 isolates, type I and type V were not found in this group. Therein, among 21 HA-MRSA isolates, SCCmec III was the most common, 15 isolates, type IV 1 isolates, nontypable 5 isolates; among 16 CA-MRSA isolates, SCCmec type IV was the most common, 7 isolates, type III 2 isolates, type II 1 isolate, nontypable 6 isolates. (5) Among the 37 MRSA isolates, 28 were PVL gene positive; and among 21 HA-MRSA isolates, 17 were PVL gene positive; Among 16 CA-MRSA isolates, 11 were PVL gene positive; There were no statistically significant differences between the groups (χ(2) = 0.735, P > 0.05) .

CONCLUSIONCompared with CA-MRSA, HA-MRSA infection was more aggressive, and induced higher C reactive protein; the dominant epidemic strains of CA-MRSA was SCCmec type IV, and HA-MRSA was SCCmec type III; the positive rate of PVL gene was high.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Bacterial Toxins ; genetics ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; Cohort Studies ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; epidemiology ; microbiology ; DNA, Bacterial ; genetics ; Female ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin ; pharmacology ; Methicillin Resistance ; genetics ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Penicillin-Binding Proteins ; Staphylococcal Infections ; epidemiology ; microbiology

Zinc oxide nanoparticle (nano-ZnO) has a size between 1 and 100 nm. Nano-ZnO has some special effects, such as small size effect, surface effect, quantum size effect, which makes it different from the ordinary ZnO, and is widely used in rubber industry, food processing, cosmetics and pharmaceutical fields. It has been reported that nano-ZnO has toxic effects in vitro and in vivo, but the mechanism of toxicity is still unclear. Therefore, it is important to evaluate the safety nano-ZnO by studying its biological toxic effects and related mechanisms. In this paper, we summarize the characterization, ingestion pathway, metabolism, systematic toxicity of nano-ZnO and its mechanisms, which may provide us with new strategy for the toxic research of nano-ZnO.
Animals ; Humans ; Metal Nanoparticles ; toxicity ; Zinc Oxide ; toxicity

OBJECTIVE: To explore the optimal culture conditions in vitro and the biological characterizations of the QY1 pluripotential mesenchymal stem cell (MSC) line from Sprague-Dawley rat bone marrow and to analyze the biological stability of this MSC line so as to provide an ideal cell model for the further differentiation and actual application. METHODS: The methods and technologies of cell biology and stem cell tissue engineering were used to purify MSCs. We determined the effects of morphology of cell proliferation, the time of change medium, growth curves, doubling time, adhesive rates, chromosome, culture conditions, and repeated frost on the biological characterizations of MSCs. RESULTS: The cells had a fibroblastic-like morphology and were well spread out; 80% - 90% cells became confluent between 10 and 12 days in primary culture. The growth curves of Passage 1, 3, 10, and 20 were quite similar (P>0.05). The doubling time of passage 1, 3, 10, and 20 were 34.2, 33.9, 31.8, and 30.6 hours, respectively. The adhesive rates of Passage 1, 3, 10, and 20 were very much similar (P>0.05) and about 89% subcultured cells adhered to the wall in 10 hours. The most appropriate concentration of serum was 20% and the most appropriate concentration of cell number was 8 x 10(4)/mL. The cells of Passage 8 showed light red cytoplasm and heavy blue nuclear stained by Giemsa staining. The chromosomes of Passage 8 and 20 were normal in appearance and their karyotypes were 42, XY. The cells were resuscitable after repeated frozen, and more than 85% cells were alive. The cells had been continuously cultured for more than 10 months so far. CONCLUSION The QY1 MSCs line from Sprague-Dawley rat bone marrow is a purified cell line, which can maintain its undifferentiation and the stable biological characterizations for the long term.
Animals ; Bone Marrow Cells ; cytology ; Cell Line ; Cell Proliferation ; Cells, Cultured ; Mesenchymal Stem Cells ; cytology ; Pluripotent Stem Cells ; cytology ; Rats ; Rats, Sprague-Dawley

Objective To investigate the presence and genetic background of 16S rRNA methylase gene and Aminoglycoside modifying enzymes(AMEs) genes in Klebsiella pneumoniae isolated from the People's Liberation Army 98th HospitaI,Huzhou district,Zhejiang province,China.Methods 25 strains of Klebsiella pneumoniae were isolated from the inpatienta between September,2005 and April,2006.6 kinds of 16S rRNA methylase gene (including armA,rmtA,rmtB,rmtC,rmtD and npmA ),6 kinds of AMEs genes [ including aac (3)-Ⅰ,sac (3)-Ⅱ,sac (6')-Ⅰ,aac (6')-Ⅱ,ant (3")-Ⅰand ant(2")-Ⅰ],intI1,intI2,intI3,mercuric reductase gene merA (merA gene were the collective genetic markers of transposona of Tn21 and Tn501 ) and tnpA ( tnpA gene were the collective genetic markers of transposons of Tn1,Tn2,Tn3 and Tn1000) were analyzed by PCR and verificated by DNA sequencing.Results In 25 strains of Klebsiella pneumoniae,the positive rate of genes of rmtB,sac (3)-Ⅱ,sac (6')-Ⅰ,ant(3")-Ⅰ and intI1 were 60.0%(15/25),4.0%(1/25),48.0%(12/25),60.0%(15/25) and 96.0%(24/25),respectively.The rest 12 kinds of genes were all tested negative.The total positive rate of 6 kinds of AMEs gene was 84.0%(21/25).Conclusion There were very high positive rate on both genes of rmtB and AMEs genotypes in Klebsiella pneumoniae isolated from inpatients,and this was the first report of the emergence of 16S rRNA methylase gene rmtB in Klebsiella pneumoniae identified in Zhejiang province,China.

Child ; Humans ; Liver Failure, Acute/therapy* ; Liver Transplantation/adverse effects*