Staphylococcus epidermidis bacteremia from transfusion of contaminated platelets: application of bacterial DNA analysis

Septicemia is a rare complication of platelet transfusion. A case is reported of transfusion-associated septicemia in a 66-year-old man who received a 10-unit pool of platelets. During transfusion, he experienced rigors, wheezing, dyspnea, and fever. A total of four blood cultures drawn 10 and 36 hours after discontinuation of the transfusion grew Staphylococcus epidermidis. Culture of the residual platelet pool yielded S. epidermidis with a colony count of 10(5) organisms per mL. Strain identity of all four blood isolates and the platelet pool isolate was confirmed by gel electrophoresis of EcoRI and HindIII restriction digests of whole-cell DNA. There have been 31 prior reported cases of platelet transfusion-associated septicemia, of which 9 have been caused by coagulase-negative staphylococci. Systemic reactions to platelet transfusions should prompt consideration of transfusion-associated bacteremia as the cause.     

A prospective microbiologic surveillance program to detect and prevent the transfusion of bacterially contaminated platelets

After two patients received bacterially contaminated platelet transfusions, a prospective surveillance program was instituted to perform Gram staining and microbiologic culturing of platelets at the time of transfusion. In 12 months, 3141 random-donor platelet pools (prepared from 14,481 units) and 2476 single-donor apheresis units were cultured. All single-donor apheresis units were sterile, but 6 (0.19%) of the random-donor pools were found to be bacterially contaminated, with 1 unit of 5 in the pool being the source in each case. Contaminants were Staphylococcus epidermidis (4 cases), Bacillus cereus (1), and Staphylococcus aureus (1) at counts of 0.5 × 10(2) to 10(11) colony-forming units per mL in platelet pools and 10(3) to 10(13) colony-forming units per mL in source units. The contamination rate for units transfused at < or = 4 days (1.8/10,000) was significantly lower than that at 5 days (11.9/10,000; p < 0.05), as was the magnitude of contamination (p < 0.05). Use of the pretransfusion Gram stain on 4- and 5-day-old platelet pools was 100 percent sensitive (4/4 true positives) and 99.93 percent specific (1 false positive) in detecting contaminated pools. These data define the extent and magnitude of platelet bacterial contamination and demonstrate the efficacy of the pretransfusion Gram stain on platelet units stored for 4 and 5 days in preventing the transfusion of heavily contaminated units. It is concluded that the risk of platelet contamination is related to the duration of component storage.(ABSTRACT TRUNCATED AT 250 WORDS)     

实时荧光PCR熔解曲线法快速鉴定嗜肺军团菌

摘要：目的：建立特异、快速、敏感的实时荧光PCR熔解曲线基因分型方法,并探讨该法在鉴定嗜肺军团菌中的应用价值。 方法：根据嗜肺军团菌16S rRNA基因保守序列设计引物和猝灭FRET探针建立实时荧光PCR熔解曲线方法,优化引物与探针浓度,用15株嗜肺军团菌、30株非嗜肺军团菌及7株其他病原菌标准菌株验证该方法的特异性、敏感性和重复性,用该法检测117例临床痰标本并进行基因测序。 结果：15株不同血清型的嗜肺军团菌Tm值均为57 ℃;7株非嗜肺军团菌Tm值为43 ℃,1株Tm值为45 ℃;其余22株非嗜肺军团菌和7株其他病原菌均无明显Tm值。该方法最低检出限可达0.1 pg/μL。检测117例痰标本发现3株嗜肺军团菌,与PCR基因测序法检测结果一致。 结论：实时荧光PCR熔解曲线法可特异、快速和敏感地检测嗜肺军团菌,适用于临床痰标本的嗜肺军团菌检测。     

采用PCR与RFLP方法快速诊断细菌感染

目的:探讨PCR与RFLP方法快速诊断细菌感染的临床应用价值.方法:选取14种下呼吸道常见病原茵制成DNA模板,用16S rRNA基因保守区建立一对通用引物对其进行PCR扩增,再分别用限制性内切酶Hae Ⅲ,Mnl Ⅰ,Alu Ⅰ,Dde Ⅰ和BstBⅠ酶切,根据RFLP分析鉴定细菌.结果:所有待测细菌经通用引物PCR扩增和HaeⅢ酶切后的电泳图谱呈现多态性,但有部分细茵图谱相同或相似,再分别用MnlⅠ、AluⅠ、DdeⅠ和BstBⅠ酶切,其产生的酶切图谱各异,可以相互区分,从而鉴定出痛原菌.结论:PCR与RFLP分析方法检测病原茵快速简便,是一种具有临床应用价值的快速诊断方法.     

Rapid, simple, and low-cost identification of Candida species using high-resolution melting analysis

The feasibility of using high-resolution melting analysis (HRMA) was examined for its rapid and simple detection of 5 clinically relevant Candida species (C. albicans, C. glabrata, C. kefyr, C. parapsilosis, and C. guilliermondii). HRMA was able to differentiate clinical Candida species and resulted in being sensitive, reproducible, and inexpensive.     

Rapid and highly sensitive determination of trace proteins using dibromomethyl carboxyazo-Pb(II) complex as a spectroscopic reagent

BACKGROUND: The concentration of protein in body fluids is an important measure in disease diagnosis and in analytical biochemistry. Searching for a sensitive and rapid method for proteins is an ongoing subject of investigation. We describe the reaction of dibromomethyl carboxyazo-Pb(II) with proteins found in urine. METHODS: In a buffer containing of HCl and KCl at pH 1.80, dibromomethyl carboxyazo-Pb(II) complex combined with proteins to form a colored compound. The reaction was completed in 2 min and remained stable for 80 min. Under optimum conditions, the product of reaction between protein and dibromomethyl carboxyazo-Pb(II) absorbed at 530 nm and was linear in the range of 0-50 microg/ml of BSA. Moreover, the maximum binding number was defined to express the binding ability of dibromomethyl carboxyazo-Pb(II) to protein under a given set of conditions. RESULTS: The method was applied to the determination of urine proteins. The recovery of protein from human urine was 97.6-103% and the precision was <4.8%. Results compared favorably to the Biuret and Bradford protein methods on 50 urine samples. CONCLUSIONS: This method had high sensitivity and specificity and may be applicable to clinical analysis.     

Rapid screening of high-risk patients for disorders of purine and pyrimidine metabolism using HPLC-electrospray tandem mass spectrometry of liquid urine or urine-soaked filter paper strips

BACKGROUND: A rapid and specific screening method for patients at risk of inherited disorders of purine and pyrimidine metabolism is desirable because symptoms are varied and nonspecific. The aim of this study was to develop a rapid and specific method for screening with use of liquid urine samples or urine-soaked filter paper strips. METHODS: Reverse-phase HPLC was combined with electrospray ionization (ESI), tandem mass spectrometry (MS/MS), and detection performed by multiple reaction monitoring. Transitions and instrument settings were established for 17 purines or pyrimidines. Stable-isotope-labeled reference compounds were used as internal standards when available. RESULTS: Total analysis time of this method was 15 min, approximately one-third that of conventional HPLC with ultraviolet detection. Recoveries were 96-107% in urine with added analyte, with two exceptions (hypoxanthine, 64%; xanthine, 79%), and 89-110% in urine-soaked filter paper strips, with three exceptions (hypoxanthine, 65%; xanthine, 77%; 5-hydroxymethyluracil, 80%). The expected abnormalities were easily found in samples from patients with purine nucleoside phosphorylase deficiency, ornithine transcarbamylase deficiency, molybdenum cofactor deficiency, adenylosuccinase deficiency, or dihydropyrimidine dehydrogenase deficiency. CONCLUSIONS: HPLC-ESI MS/MS of urine allows rapid screening for disorders of purine and pyrimidine metabolism. The filter paper strips offer the advantage of easy collection, transport, and storage of the urine samples.     

MAP-based kinetic analysis for voxel-by-voxel compartment model estimation: detailed imaging of the cerebral glucose metabolism using FDG

We propose a novel algorithm for voxel-by-voxel compartment model analysis based on a maximum a posteriori (MAP) algorithm. Voxel-by-voxel compartment model analysis can derive functional images of living tissues, but it suffers from high noise statistics in voxel-based PET data and extended calculation times. We initially set up a feature space of the target radiopharmaceutical composed of a measured plasma time activity curve and a set of compartment model parameters, and measured the noise distribution of the PET data. The dynamic PET data were projected onto the feature space, and then clustered using the Mahalanobis distance. Our method was validated using simulation studies, and compared with ROI-based ordinary kinetic analysis for FDG. The parametric images exhibited an acceptable linear relation with the simulations and the ROI-based results, and the calculation time took about 10 min. We therefore concluded that our proposed MAP-based algorithm is practical.     

Insulin control of glucose metabolism in man: a new kinetic analysis

Analyses of the control of glucose metabolism by insulin have been hampered by changes in bloog glucose concentration induced by insulin administration with resultant activation of hypoglycemic counterregulatory mechanisms. To eliminate such mechanisms, we have employed the glucose clamp technique which allows maintenance of fasting blood glucose concentration during and after the administration of insulin. Analyses of six studies performed in young healthy men in the postabsorptive state utilizing the concurrent administration of [14C]glucose and 1 mU/kg per min (40 mU/m2 per min) porcine insulin led to the development of kinetic models for insulin and for glucose. These models account quantitatively for the control of insulin on glucose utilization and on endogenous glucose production during nonsteady states. The glucose model, a parallel three-compartment model, has a central compartment (mass = 68 +/- 7 mg/kg; space of distribution = blood water volume) in rapid equilibrium with a smaller compartment (50 +/- 17 mg/kg) and in slow equilibrium with a larger compartment (96 +/-21 mg/kg). The total plasma equivalent space for the glucose system averaged 15.8 liters or 20.3% body weight. Two modes of glucose loss are introduced in the model. One is a zero-order loss (insulin and glucose independent) from blood to the central nervous system; its magnitude was estimated from published data. The other is an insulin-dependent loss, occurring from the rapidly equilibrating compartment and, in the basal period, is smaller than the insulin-independent loss. Endogenous glucose production averaged 1.74 mg/kg per min in the basal state and enters the central compartment directly. During the glucose clamp experiments plasma insulin levels reached a plateau of 95 +/-8 microU/ml. Over the entire range of insulin levels studied, glucose losses were best correlated with levels of insulin in a slowly equilibrating insulin compartment of a three-compartment insulin model. A proportional control by this compartment on glucose utilization was adequate to satisfy the observed data. Insulin also rapidly decreased the endogenous glucose production to 33% of its basal level (0.58 mg/kg per min), this suppression being maintained for at least 40 min after exogenous insulin infusion was terminated and after plasma insulin concentrations had returned to basal levels.The change in glucose utilization per unit change in insulin in the slowly equilibrating insulin compartment is proposed as a new measure for insulin sensitivity. This defines insulin effects more precisely than previously used measures, such as plasma glucose/plasma insulin concentration ratios.Glucose clamp studies and the modeling of the coupled kinetics of glucose and insulin offers a new and potentially valuable tool to the study of altered states of carbohydrate metabolism.     

Rapid and visual detection of Group B streptococcus using recombinase polymerase amplification combined with lateral flow strips

Conventional culture method for detecting Group B streptococcus (GBS), a common pathogen of neonatal meningitis and sepsis, is time-consuming and unsensitive. Even though real-time fluorescence PCR-based molecular method is more accurate, it need special instrument and elaborate protocol. Here, we established a novel molecular method combining recombinase polymerase amplification with lateral flow strips for detecting GBS. The cAMP factor (cfb) gene is a highly specific and sensitive biomarker to identify GBS and is detectable by using 100 genomic copies as the amplification template. Clinical performance of this assay was evaluated by testing 130 samples, in comparison with culture method and real-time fluorescence PCR, and the results achieved 100% accuracy, which were the same with those of real-time fluorescence PCR, and were better than those of culture method with false-negative detection. This study provides a rapid and visual method, with clinical potential, for the detection of GBS infection of patients.     

Adiponectin and other adipocytokines as predictors of markers of triglyceride-rich lipoprotein metabolism

BACKGROUND: Adipocytokines are bioactive peptides that may play an important role in the regulation of glucose and lipid metabolism. In this study, we investigated the association of plasma adipocytokine concentrations with markers of triglyceride-rich lipoprotein (TRL) metabolism in men. METHODS: Fasting adiponectin, leptin, resistin, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), apolipoprotein (apo) B-48, apo C-III, and remnant-like particle (RLP)-cholesterol concentrations were measured by immunoassays and insulin resistance by homeostasis assessment (HOMA) score in 41 nondiabetic men with a body mass index of 22-35 kg/m2. Visceral and subcutaneous adipose tissue masses (ATMs) were determined by magnetic resonance imaging and total ATM by bioelectrical impedance. RESULTS: In univariate regression, plasma adiponectin and leptin concentrations were inversely and directly associated with plasma apoB-48, apoC-III, RLP-cholesterol, triglycerides, VLDL-apoB, and VLDL-triglycerides (P <0.05). Resistin, IL-6, and TNF-alpha were not significantly associated with any of these variables, except for a direct correction between apoC-III and IL-6 (P <0.05). In multivariate regression including HOMA, age, nonesterified fatty acids, and adipose tissue compartment, adiponectin was an independent predictor of plasma apoB-48 (beta coefficient = -0.354; P = 0.048), apoC-III (beta coefficient = -0.406; P = 0.012), RLP-cholesterol (beta coefficient = -0.377; P = 0.016), and triglycerides (beta coefficient = -0.374; P = 0.013). By contrast, leptin was not an independent predictor of these TRL markers. Plasma apoB-48, apoC-III, RLP-cholesterol, and triglycerides were all significantly and positively associated with plasma insulin, HOMA, and visceral, subcutaneous, and total ATMs (P <0.05). CONCLUSIONS: These data suggest that the plasma adiponectin concentration may not only link abdominal fat, insulin resistance, and dyslipidemia, but may also exert an independent role in regulating TRL metabolism.     

Metabolomics-driven identification of perturbations in amino acid and sphingolipid metabolism as therapeutic targets in a rat model of anorexia nervosa disease using chemometric analysis and a multivariate analysis platform

It is important to explore novel therapeutic targets and develop an effective strategy for the treatment of anorexia nervosa. In this work, serum samples were analyzed using ultra-performance liquid chromatography coupled with quadrupole time-of flight mass spectrometry (UPLC/Q-TOF MS) coupled with chemometric analysis and multivariate analysis to obtain the metabolites and their corresponding pathways. In addition, knock-in and knock-down of the key enzyme in vivo was performed to verify the reliability of the obtained metabolic pathway, which is closely associated with the anorexia nervosa pathomechanism and the potential targets. There were significant differences in the biochemical parameters between the model group and the control group. A total of 26 potential biomarkers were identified to resolve the difference between the control and model rats, which were closely related to amino acid metabolism, sphingolipid metabolism, arachidonic acid metabolism, the citrate cycle, and so forth. According to the ingenuity pathway analysis, we further elucidated the relationship between the gene, protein, and metabolite alteration in anorexia nervosa, which are involved in cellular compromise, lipid metabolism, small molecule biochemistry, cell signaling, molecular transport, nucleic acid metabolism, cell morphology, cellular function and maintenance. Arginosuccinate synthetase (ASS) deficiency was accompanied by a significant downregulation of the β-endorphin and ghrelin in the animal models. The metabolites and pathways obtained using the metabolomics strategy may provide valuable information for the early treatment for anorexia nervosa.

It is important to explore novel therapeutic targets and develop an effective strategy for the treatment of anorexia nervosa.     

阴道炎患者细菌性阴道病的快速检测及结果分析

目的探讨青岛地区女性阴道炎患者滴虫和假丝酵母菌以及细菌性阴道病的感染情况。方法采集妇科门诊就诊的阴道炎患者的阴道分泌物,用生理盐水涂片法进行滴虫和假丝酵母菌检测,用唾液酸酶法进行细菌性阴道病的快速检测。结果在6 345例标本中,共检出阳性标本2 878例,阳性检出性率为45.4%,其中检出滴虫145例,检出率为2.3%;检出假丝酵母菌1 671例,检出率为26.3%;细菌性阴道病阳性1 697例,检出率为26.7%。结论青岛地区阴道炎患者细菌性阴道病的感染率较高,应加强对该病的检测,以便更全面地反映阴道炎患者的病原体感染状况,协助临床医生做出正确诊断和治疗。