[Preparing Bifidobacteria for Quantitative Detections].

OBJECTIVES: To compare different preparation methods for quantitative real-time PCR (qPCR) detection of Bifidobacteria. METHODS: Standard strains of Bifidobacteria were prepared with concentration gradients using strain DNA, PCR product amplification and purification, and plasmid DNA methods. The concentrations of Bifidobacteria were determined with ultraviolet spectrophotometer and real-time quantitative PCR. RESULTS: Greater than 0.99 R 2 in values of standard curves were achieved by all three preparation methods. The plasmid DNA method obtained a higher level of concentration and purity of Bifidobacteria than the other two methods ( P<0.01). CONCLUSIONS: The plasmid DNA method produces high quality preparations and is more suitable for real-time quantitative PCR, which can provide a reference for the molecular biological detection of Bifidobacteria.

[Epidemiology and Resistance Mechanisms of Group B Streptococci in Late-pregnant Maternal Birth Canal].

OBJECTIVE: To study the antibiotic-resistant rate of group B streptococci (GBS) in obstetric canal of late-pregnant women, evaluate the antibiotic-resistant status and finally to support the GBS prevention and curing by proper antibiotics. METHODS: 31 pregnant women between 35 to 37 gestational weeks were included, for whom the antibiotic sensitivity as well as the drug (erythromycin and clindamycin) resistance genes of GBS in obstetric canal was analyzed. RESULTS: 12 (38. 7%) strains of GBS were resistant to clindamycin, while 21 (67. 7%) to erythromycin, within which 12 strains were intrinsic phenotype - cMLS type-clindamycin resistance, other 9 were active efflux phenotype - MS type-clindamycin sensitive and all of which were confirmed by Double disk diffusion method. Eleven strains were mef (A) positive, and 12 strains were erm (B) positive, in which 3 with erm (C). CONCLUSIONS: In our research the GBS strains show a high erythromycin and clindamycin resistance rate. The resistance of our GBS strains are mainly caused by the ribosomal target changes induced by erm (B) and the increased efflux of clindamycin induced by mef (A).

[Clinical characteristics of children with meningitis caused by Streptococcus pneumoniae and antibiotic resistance of Streptococcus pneumoniae strains].

OBJECTIVE: To study the clinical characteristics of children with meningitis caused by Streptococcus pneumoniae (SP) and the drug sensitivity of SP strains. METHODS: A retrospective analysis was performed on the clinical data of 14 children with SP-infected meningitis between September 2008 and March 2014. RESULTS: Of the 14 cases, 8 cases (57%) aged under 2 years. 13 cases (93%) had fever, 9 cases (64%) had convulsions, and 7 cases (50%) were complicated by septicemia. Eleven cases (79%) had elevated white blood cell (WBC) counts and 10 cases (71%) had elevated serum C-reactive protein (CRP) levels. All 14 children had an elevated nucleated cell count and neutrophils were identified as the predominant cell type. CSF protein>1000 mg/dL was noted in 9 cases (64%). Ten cases (71%) were cured, 2 cases (14.2%) with sequelae and 2 cases (14.2%) died. The drug sensitivity analysis showed that SP had resistance rates of more than 60% to penicillin, erythromycin, clindamycin, tetracycline and sulfa, but it was sensitive to amoxicillin (93%), vancomycin (100%), chloramphenicol (100%) and levofloxacin (100%). CONCLUSIONS: The clinical characteristics of children with meningitis caused by SP are not different from those with meningitis caused by other bacteria. SP strains are resistant to common antibiotics used in clinical practice, so it is important to monitor the drug resistance of the strains.

[Species and drug resistance of pathogens in blood cultures from the pediatric hematology ward].

OBJECTIVE: To investigate the species and percentage changes of pathogens in blood cultures from the pediatric hematology ward, and to analyze the drug resistance of main pathogens and the risk factors for positive blood culture (sepsis). METHODS: A retrospective analysis was performed to analyze the species and drug sensitivity of the pathogens isolated from 2358 blood cultures from the pediatric hematology ward of the West China Second University Hospital between 2008 and 2011, as well as the related clinical data. RESULTS: A total of 110 strains of pathogens were isolated, with Escherichia coli (16 strains), Pseudomonas aeruginosa (12 strains) and Staphylococcus epidermidis (8 strains) being the most common ones. From 2008 to 2011, the percentage of Gram-positive bacteria decreased, while the percentage of Gram-negative bacteria increased. The detection rates of methicillin-resistant coagulase-negative Staphylococci and methicillin-resistant Staphylococcus aureus were 69% and 43% respectively, but both were sensitive to vancomycin. The detection rates of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and ESBL-producing Klebsiella pneumoniae were 69% and 62% respectively, but both were sensitive to imipenem and meropenem. Malignant tumor was a risk factor for positive blood culture (OR=3.564, P<0.05). CONCLUSIONS: A wide range of pathogens are responsible for bloodstream infection in the pediatric hematology ward and the percentages of bacteria are changing; these pathogens have a high drug resistance rate. Malignant tumor is a risk factor for positive blood culture in the pediatric hematology ward.

[Clinical characteristics and pathogens of invasive fungal infections in children].

OBJECTIVE: To study the clinical characteristics and pathogens of invasive fungal infection in children. METHODS: The clinical data of 104 children who suffered from invasive fungal infections between 2008 and 2012 was retrospectively reviewed. RESULTS: Of the 104 cases, 20 occurred in neonates, 48 in infants and 36 in preschool and school-aged children (old-aged children). Prematurity (70%), hyaline membrane disease (45%) and pneumonia (30%) were commonly comorbid in the neonate group. In addition, the percentage of cases receiving total parenteral nutrition was higher in the neonate group than in the other two age groups (P<0.01). Mechanical ventilation was more frequent in neonate and infant groups than in the old-aged children (P<0.01). Hematological malignancy was the most common underlying disease, and the percentage of children who had neutropenia and accepted chemotherapy was higher in the old-aged children than in the other two age groups (P<0.05). Lung infection was the most common (61.5%), followed by sepsis (14.4%) and intestinal tract infection (12.5%), while nervous system infections were found only in old-aged children. A total of 105 strains of fungi were isolated from the 104 patients, including Candida (n=90, 85.7%), Cryptococcus (n=6) and others (n=9). The most commonly isolated species was Candida albicans (n=52, 49.5%). Non-Candida albicans Candida accounted for 36.2% (n=38). The rate of susceptibility of Candida species to 5-fluorocytosine and amphotericin B was higher than fluconazole. CONCLUSIONS: Invasive fungal infections can occur in children at various ages. There are differences in the risk factors for invasive fungal infections between age groups. Candida species are the main pathogens of childhood invasive fungal infections, and both Candida albicans and non-Candida albicans Candida are common. Fluorocytosine and amphotericin B are sensitive antifungal agents for infections caused by Candida species.

[Combined indicators for diagnosing immune thrombocytopenic purpura].

OBJECTIVE: To search for the best combined indicators for diagnosing immune thrombocytopenic purpura (ITP). METHODS: Reticulated platelet (RP), thrombopoietin (TPO), platelet-associated immunoglobulins (PAIgG, by ELISA), mean platelet volume (MPV), platelet distribution width (PDW), platelet-large cell ratio(P-LCR) by flow cytometry), and automated blood cytometer were tested in three groups of people: patients with ITP (n=45), healthy people (n=45), and patients without ITP (n=42). Receiver operating characteristic (ROC) curve, LSD-t test, logistic regression, and correlation analysis were performed to identify the best indicators for diagnosing ITP. RESULTS: The patients with ITP had higher levels of RP, MPV, PDW, P-LCR, and PAIgG than the healthy people and the patients without ITP (P<0.05). The patients without ITP had higher TPO than the healthy people and the patients with ITP (P<0.05). RP and PAIgG were sensitive indicators to ITP. PR was correlated to the diagnosis of ITP (chi2=10.458, P=0.001). CONCLUSION: Individual indicator has limited diagnostic values for ITP, which could be improved by a combination of the indicators.

[Platelet autoantibody and its impact on platelet in patients with idiopathic thrombocytopenic purpura].

OBJECTIVE: To detect the platelet autoantibody in the patients with idiopathic thrombocytopenic purpura (ITP) and to investigate the impact of the autoantibody on the count and function of platelet. METHODS: The glycoprotein specific autoantibody was measured by MAIPA in the ITP patients, non-ITP patients and healthy people. The serum of the ITP patients were added to the healthy plasma with rich platelet and the platelet aggregation function was measured. RESULTS: The platelet autoantibody was found in 65.4% of the ITP patients. The platelet counts in the ITP patients with positive autoantibody were significantly lower than those without the autoantibody. The platelet counts were negatively correlated with the levels of the autoantibody, with a correlation coefficient of -0.724 for the anti GP IIb/ IIIa autoantibody and -0.571 for the anti GP Ib/ IX autoantibody. The aggregation of normal platelets was inhibited in ten out of the 26 patients, among whom nine had platelet autoantibody. CONCLUSION: The platelet autoantibody affects not only the count but also the function of platelet.