Identification of a 28 kDa lychee allergen as a triose-phosphate isomerase

The aim of this study was to investigate the allergenic potency of the exotic fruit lychee (Litchi chinensis SONN.). For this purpose the lychee protein extract was separated by ion exchange chromatography and a purified allergen with a molecular weight of 28 kDa was identified by N-terminal sequencing and peptide mass fingerprinting. Both methods determined the lychee allergen as a triose-phosphate isomerase. To this protein 67% of patients showed allergic reactions respectively IgE binding of their sera. Similar enzymes from other plants were also recognized as allergens.     

Postoperative Paenibacillus thiaminolyticus Wound Infection,Switzerland

Paenibacillus thiaminolyticus is a nonvirulent organism found in human and ruminant microbiota. However, P. thiaminolyticus can act as an opportunistic pathogen in humans. We describe a case of abdominal wall hematoma secondarily infected by P. thiaminolyticus. Our findings emphasize the risk for unusual Paenibacillus infections in otherwise healthy persons.     

Purification and characterization of Moran 20K fromMorus alba

A new glycoprotein was purified from the aqueous methanolic extract of the root bark ofMorus alba which has been used as a component of antidiabetic remedy in Oriental Medicine. SDS-PAGE result shows that the molecular weight of the glycoprotein was approximately 20 kDa. This new glycoprotein was named as Moran 20K. The protein lowered blood glucose level in streptozotocin-induced hyperglycemic mice model and it also increased the glucose transport in cultured epididymis fat cells. The amino acid composition of the protein was analyzed, and the protein contained above 20% serine and cysteine such as insulin. The actual molecular weight of the protein was determined as 21,858 Da by MALDI-TOF mass spectroscopy.     

利用磁珠法结合MALDI-TOF MS进行慢性心衰气阴虚证血液蛋白质组学研究的方法学探讨

目的:建立磁珠法结合MALDI-TOF MS进行慢性心衰气阴虚证血液蛋白质组学研究的实验方法。方法:采用MALDI-TOF-MS技术检测不同磁珠分离的患者血液蛋白质谱,从采集、蛋白提取、反复冻融、重复性、基质样品比例等方面分析其影响。结果:血清质谱峰均多于血浆,弱阳离子磁珠出峰数量优于铜螯合磁珠,气阴虚证患者与健康组比较蛋白表达有明显差异。结论:该方法作为一种高通量、快速分离、制备和鉴定的蛋白质组学技术,整个实验体系稳定、可靠、重复性好,适用于中医证候蛋白质组学的研究。     

Emerging methodologies for pathogen identification in positive blood culture testing

Bloodstream infections (BSIs) represent a major cause of death in developed countries and are associated with long-term loss of functions. Blood culture remains the gold standard for BSI diagnosis, as it is easy to perform and displays a good analytical sensitivity. However, its major drawback remains the long turnaround time, which can result in inappropriate therapy, fall of survival rate, emergence of antibiotic resistance and increase of medical costs. Over the last 10 years, molecular tools have been the alternative to blood cultures, allowing early identification of pathogens involved in sepsis, as well detection of critical antibiotic resistance genes. Besides, the advent of MALDI-TOF revolutionized practice in routine microbiology significantly reduced the time to result. Reviewed here are recent improvements in early BSI diagnosis and these authors’ view for the future is presented, including innovative high-throughput technologies.     

基质辅助激光解吸／电离飞行时间质谱仪快速鉴别甲氧西林耐药和甲氧西林敏感金黄色葡萄球菌的研究

目的：分析基质辅助激光解吸／电离飞行时间质谱仪（ matrix-assisted laser desorption／ionization time-of-flight mass spectrometry , MALDI-TOF MS）快速鉴别甲氧西林耐药和甲氧西林敏感金黄色葡萄球菌。方法收集浙江大学医学院附属第二医院已保存的临床分离的耐甲氧西林金黄色葡萄球菌（MRSA）25株和甲氧西林敏感金黄色葡萄球菌（MSSA）30株用于模型的建立。同时选取34株临床分离株（12株MRSA和22株MSSA）用做模型验证菌株。 MALDI-TOF MS对所有菌株进行鉴定,ClinProTools 3．0软件对MALDI-TOF MS鉴定细菌所产生的质谱峰图进行分析。结果 ClinPro-Tools软件的4种算法所得出的结果基本一致,灵敏度均大于95．0％,其中遗传算法（GA）的灵敏度最高（100．0％）;除监督式神经网络算法（ SNN）外,其余3种算法的特异性均大于90．0％。质荷比为3279、6485、6555和3299 m／z的质谱峰是用于区分MRSA和MSSA的最为主要的特征性峰。受试者工作特征曲线（ ROC）显示,这4个特征性峰的曲线下面积（ AUC）均大于0．9;凝胶浏览图显示,MSSA组的3279、6485、6555 m／z峰的蛋白强度高于MRSA组,而3299 m／z峰的蛋白强度低于MRSA组。外部验证显示,GA模型对MRSA组的准确鉴定率为83．3％,对MSSA组的准确鉴定率为90．9％。结论在严格控制实验条件的情况下,MALDI-TOF MS可快速准确地鉴别MRSA和MSSA,具有耗时短,灵敏性高,特异性高的优点。准确鉴定的同时区分MRSA和MSSA,尽早为临床防治MRSA提供参考依据,限制其传播及暴发流行。     

Species identification and antifungal susceptibility of uncommon blood yeast isolates

Background/PurposeAccurate identification of Candida species is increasingly important in the era of emergence of Candida auris. We aimed to compare the identification performance of two matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems (Vitek MS and Bruker biotyper MS) and an oligonucleotide array for uncommon blood yeast isolates and demonstrate the susceptibilities among those isolates.MethodCandida species isolates from blood culture other than Candida albicans, Candida parapsilosis, Candida tropicalis, Candida glabrata, and Candida krusei identified by biochemical methods were collected from multiple hospitals and further identified by an oligonucleotide array based on the internal transcribed spacer-1 (ITS-1) and ITS-2 sequences of the rRNA genes, Vitek MS and Bruker biotyper MS. The minimal inhibitory concentrations (MICs) of these clinical isolates were determined by the Sensititre YeastOne (SYO) system.ResultsAmong 136 isolates, Candida guilliermondii was most common (52, 38.2%), followed by C. lusitaniae (13, 9.6%) and C. haemulonii (12, 8.8%). The oligonucleotide array, Vitek MS and Bruker biotyper MS correctly identified 89.7% (122), 90.4% (123), and 92.6% (126) of these isolates, respectively. Elevated minimal inhibitory concentrations (MICs) of fluconazole were observed for C. haemulonii (MIC₉₀: 256 mg/L), and C. guilliermondii (MIC₉₀: 16 mg/L) with 28.4% of uncommon Candida isolates with MIC ≧ 8 mg/L.ConclusionsFor uncommon Candida species, the unmet need for current databases of two commercial MALDI-TOF MS systems is highlighted, and the oligonucleotide array may serve as a supplement.     

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting

IntroductionThe incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing.Material and methodsFifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA).ResultsForty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates.ConclusionsRoutine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.     

Use of MALDI-TOF MS (Bruker Daltonics) for identification of Mycobacterium species isolated directly from liquid medium

ObjectivesThe aim of this study was to describe the evaluation of the use of MALDI-TOF MS for the identification of non-tuberculous mycobacteria (NTM) and Mycobacterium tuberculosis directly from liquid MGIT cultures from January 2017 to December 2017.Material/methodsA total of 155 isolates (mainly respiratory) were analyzed by MALDI-TOF MS (Bruker Daltonics) directly from MGIT liquid medium with a previous extraction procedure.ResultsMALDI-TOF MS generated acceptable scores for 152 isolates (98.06%). Fifty isolates were identified as M. tuberculosis complex and the remaining 105 as NTM (M. abscessus subsp. abscessus, M. avium, M. celatum, M chelonae, M. chimaera, M. fortuitum, M. gordonae, M. intracellulare, M. kansasii, M. lentiflavum, M. mageritense, M. mucogenicum and M. xenopi).ConclusionsThese results indicate that MALDI-TOF MS can be useful to identify mycobacteria directly from MGIT cultures and is an accurate, rapid and cost-effective system to be used as a routine method.     

T-2毒素、脱氧雪腐镰刀菌烯醇全抗原的合成及鉴定

目的分别合成T-2毒素、脱氧雪腐镰刀菌烯醇(DON)的全抗原。方法采用琥珀酸酐法对分子结构进行修饰,产生易反应的官能团,并与载体蛋白偶联,从而具备免疫条件,用高性能基质辅助激光解吸电离-飞行时间质谱仪MALDI-TOF检测偶联物及偶联蛋白的分子量,用商品化的T-2和DON免疫试剂盒与偶联物进行棋盘滴定验证。结果T-2和DON的全抗原及BSA的分子量分别为67641.6、66680.4、66297.7,偶联物与免疫试剂盒中T-2和DON的抗体均呈阳性反应。结论合成的T-2、DON全抗原为相应抗体的制备和免疫学方法的建立奠定了基础。