EDTA纸片法和三维试验检测阴沟肠杆菌AmpC酶的比较

目的比较EDTA纸片法及头孢西丁三维试验检测阴沟肠杆菌AmpC酶的符合程度。方法收集近几年阴沟肠杆菌株97株临床菌株,应用EDTA纸片法和三维试验分别检测97株阴沟肠杆菌的AmpC酶,并进行比较。结果 97株受检菌中,75株EDTA纸片法和三维试验均阴性,20株两种方法均阳性,2株菌EDTA纸片法阴性,而三维试验阳性。两种检测方法阳性符合率为90.9%,阴性符合率为100%,总符合率为97.9%。结论 ED-TA纸片法检测阴沟肠杆菌与三维试验的符合率高,且操作简便,较适合于临床实验室应用。     

革兰阴性杆菌产超广谱β-内酰胺酶的检测及其耐药性

目的 了解本院最近的革兰阴性杆菌中产超广谱β－内酰胺酶（ＣＳＢＬ）菌株的民生北及其耐药性情况。方法 双纸片法筛选,然后用头孢噻肟／棒酸,头孢他啶／棒权进行确证。结果 １７４株革兰阴性杆菌中有４６株是ＥＳＢＬ菌株,包括大肠埃希菌２７株,肺炎克雷伯菌１３株,阴沟肠杆菌４株,铜绿假单胞菌１侏,枸橼酸杆菌１株。本院ＥＳＢＬ株以肺炎克雷伯菌、大肠埃希菌多见,名占该种菌中的３３％、４２％。ＥＳＢＬ菌株对亚胺培     

用数值分类法解析肠杆菌的裂解色谱图

用TRS80型计算机,根据数值分类原理,对5属、10种、15株肠杆菌的58张裂解气相色谱图进行解析。结果表明：同一菌株连续多次(2—9次)分析所得裂解色谱图的符合系数为88—99％,根据符合系数可以区分不同菌株。例如,变形菌标准株和临床新分离株裂解色谱图的符合系数为．77—88％,说明在相同实验条件下用标准菌株作对照,有可能用此法对临床菌株进行鉴别。用符合系数对实验菌株的鉴别结果和传统分类法所得结果基本一致,但也有例外情况。例如,我们发现3株普通变形菌和2株奇异变形菌符合系数高达77—87％,表明二者在化学组分上极为相似,而这两种菌和摩氏、雷氏变形菌裂解色谱图的符合系数却均较低,这与Brennet根据[)NA杂交相关性的结果将变形菌重新分类的建议是一致的。     

新生儿颊粘膜定植菌株的拮抗性研究

本文分离在新生儿颊粘膜上皮细胞表面形成微菌落、且初代培养时菌落较纯的１５株ａ溶血细菌,进行对Ｂ链球菌、金黄色葡萄球菌、绿脓杆菌、大肠杆菌４种共７株菌的体外拮抗实验。１５株菌中包括８株ａＳｔｒｅｐ．,其中Ｓｔｒｅｐ．ｍｉｔｉｓ４株,Ｓｔｒｅｐ．ｏｒａｌｉｓ２株、Ｓｔｒｅｐ．Ｓａｌｉｖ．Ｓａｌｉｖａｒｉｕｓ１株、Ｓｔｒｅｐ．ｉｎｔｅｒｍｅｄｉｕｓ１株;ＬＣ．ｌａｃｔｉｓ．ｃｒｅｍｏｒｉｓ５株、Ｇｅｍｅｌａｍｏｒｂｉｌｏｒｕｍ１株、Ｇｅｍｅｌａｈａｅｍｏｌｙｓａｎｓ１株。结果约６０％（９／１５）的颊粘膜定植株对两株及两株以上的病原菌株或阴性杆菌株有拮抗作用,只对１株菌有损坏抗作用的ａ溶血菌４株,完全无拮抗作用的菌株２株;ａＳｔｒｅｐ．、ＬＣ．ｌａｃｔｉｓ．ｃｒｅｍｏｒｉｓ的拮抗作用较强;拮抗作用的有无、强弱有很强的菌株特异性     

美罗培南对1139株革兰阴性杆菌抗菌活性研究

目的分析美罗培南对革兰阴性杆菌的抗菌活性,为临床合理使用美罗培南提供正确依据。方法将宁波市第一医院2004年6月至2005年8月的临床各种标本分离获得的革兰阴性杆菌在VITEK-32微生物自动鉴定分析仪中进行鉴定和药敏试验。用双纸片法及2-巯基丙酸抑制试验进行ESBLs、AmpC和金属酶的检测。结果共检出临床常见的革兰阴性杆菌1139株,其中肠杆菌科559株（大肠埃希菌309株,肺炎克雷伯菌186株,阴沟肠杆菌64株）,非发酵菌580株（铜绿假单胞菌227株,嗜麦芽窄食单胞菌72株,脑膜脓毒黄杆菌44株．鲍曼不动杆菌178株．洋葱伯克霍尔德菌30株,荧光假单胞菌29株）。美罗培南对大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌、铜绿假单胞菌、鲍曼不动杆菌、嗜麦芽窄食单胞菌、脑膜脓毒黄杆菌、荧光假单胞菌的耐药率分别为0．0％、0．0％、0．0％、22．9％、23．6％、90．3％、100．0、63．3％和3．4％。结论美罗培南对革兰阴性杆菌有很强的抗菌活性,其抗菌活性要强于亚胺培南,是目前治疗肠杆菌科细菌特别是产ESBLs、AmpC酶细菌感染的危重患者的最理想用药。美罗培南耐药率呈逐年增加趋势,应引起重视。美罗培南对嗜麦芽窄食单胞菌、脑膜脓毒黄杆菌、洋葱伯克霍尔德菌活性很低,临床对于上述细菌感染不应选用美罗培南。     

阴沟肠杆菌产AmpC酶菌和非产酶菌的耐药性研究

目的：探讨阴沟肠杆菌分布特征及产AmpC酶菌和非AmpC酶菌的耐药性。方法：对临床分离的158株阴沟肠杆菌分布科室、感染部位及对16种抗生素耐药性进行分析,并通过酶粗提物头孢西丁三维试验结合PCR法检测AmpC酶。结果：标本来源主要为患者的痰液、尿液、创口分泌物等,科室以重症监护室为多,感染部位以呼吸道为主,耐药性较高的抗生素为头孢西丁、头孢噻肟、头孢曲松等,158株阴沟肠杆菌中产AmpC酶菌株共33株,产AmpC酶阳性率占总菌株数20．9％,产AmpC酶菌株对各种抗生素的耐药率比不产AmpC酶的明显增高。结论：阴沟肠杆菌的耐药与产AmpC酶有关,治疗首选亚胺培南。     

应用肠杆菌科四个属的诊断噬菌体快速诊断沙门氏菌

本文报告应用弗氏柠檬酸细萄噬菌体3组,大肠埃希氏菌噬菌体4组,阴沟肠杆菌噬菌体1组和沙门氏菌O-I噬菌体快速诊断沙门氏菌的结果。沙门氏菌0-I噬菌体可裂解沙门氏菌属地方株1393株中的1351株(97％)。柠檬酸细菌属噬菌体和共可裂解柠橡酸细菌属地方株381株中的362株(95％)。阴沟肠杆菌噬菌体Ent可裂解阴淘肠杆菌地方株l 50株中的133株(84．2％)。埃希氏菌属噬菌体E—1、E一2、E-3和E-4共可裂解埃希氏菌属地方株683株中的567株(83％)。由于E一1和E一2噬菌体的联合使用,可使o I噬菌体对埃希氏菌属地方株的误诊率从6．3％下降到0．6％。E一4噬菌体对沙门氏菌属地方株的误诊率可因与。一I噬菌体的联合使用而从0．36％下降到0．07％。     

金黄色葡萄球菌荚膜分型血清研制及初步应用

为了解中国金葡菌荚膜流行型,用5型和8型国际标准菌株的菌悬液免疫家兔,吸收除去交叉凝集素研制出金葡菌5型和8型荚膜分型血清,并应用于333株临床菌株荚膜分型。该血清效价为1：1280和1：640,与本菌及其它同型菌株玻片凝集反应呈强凝集,与其它型菌株不凝集,且与美国标准血清同时对333株临床分离菌株进行分型比较的符合率为100％。333株金葡地方菌株荚膜分型结果显示,8型菌株占绝对优势,所占百分率为70．9％;5型占6．3％,5型和8型菌株共占77．2％。这与国外金葡菌荚膜5型和8型占70％-80％的报道相似。试验为金葡菌疫苗株选择提供了流行病学依据。     

基质辅助激光解吸电离飞行时间质谱对阪崎肠杆菌的鉴定

目的 利用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)法对阪崎肠杆菌进行鉴定,建立一种高效检测阪崎肠杆菌的方法,并为该技术的推广使用及阪崎肠杆菌的进一步研究提供科学依据.方法 用MALDI-TOF-MS法检测38株野生阪崎肠杆菌、2株标准菌株和1株阴沟肠杆菌,结果与常规生化鉴定结果对比;同时对在不同培养基上培养的阪崎肠杆菌进行质谱分析比较,对比不同培养基对质谱结果是否有影响;对38株野生菌株质谱图进行聚类分析.结果 38株菌株鉴定结果均为阪崎肠杆菌,与生化鉴定结果一致,且质谱鉴定分值大多在2.0以上.通过MALDI-TOF-MS鉴定方法可以很明显地将阴沟肠杆菌与阪崎肠杆菌两种菌分开.4种培养基对MALDI-TOF-MS鉴定结果的影响不是很明显,TSA比较适合作为阪崎肠杆菌MALDI-TOF-MS鉴定的培养基.通过质谱图谱和离子峰值比较得出,所有菌株在5745 m/z附近均出现高的离子峰,在2871、4740、8288、6260和9488 m/z附近出现离子峰的实验菌株达95％以上;在差异水平在0.5时,MALDI-TOF-MS的聚类分析结果可将所有实验菌株分成5个类型,结合菌株对应的来源和种类分析表明本研究所用菌株与来源和种类之间并无明显关系.结论 MALDI-TOF-MS方法具有准确且精确鉴定阪崎肠杆菌的能力;离子峰5745m/z具有作为阪崎肠杆菌的标记性离子峰的可能;差异水平为0.5进行MALDI-TOF-MS聚类分析,未发现5个类型与来源等具有一定关系,需要进一步研究.     

用纤维支气管镜检查236例肺部感染者的病原学分析

本文报告了２３６例支气管肺部感染者,用纤支镜双塞保护法采样,病原菌培养结果。总阳性率７４．６％。共分离到２２种２９１株病原菌。球茵占１６．７％、肠杆菌科占１１．７％、非发酵菌占３７．１％,厌氧菌占２２．３％、真菌占１２．７％,３９．２％的病例为复合菌感染。还报告了８种带见病原菌对２８种抗生素的敏感试验结果。对近年肺部感染的病原菌谱型变化及复合菌感染等进行了讨论。     

Selecting predictors for discriminant analysis of species performance: an example from an amphibious softwater plant

Selecting an appropriate variable subset in linear multivariate methods is an important methodological issue for ecologists. Interest often exists in obtaining general predictive capacity or in finding causal inferences from predictor variables. Because of a lack of solid knowledge on a studied phenomenon, scientists explore predictor variables in order to find the most meaningful (i.e. discriminating) ones. As an example, we modelled the response of the amphibious softwater plant Eleocharis multicaulis using canonical discriminant function analysis. We asked how variables can be selected through comparison of several methods: univariate Pearson chi-square screening, principal components analysis (PCA) and step-wise analysis, as well as combinations of some methods. We expected PCA to perform best. The selected methods were evaluated through fit and stability of the resulting discriminant functions and through correlations between these functions and the predictor variables. The chi-square subset, at P < 0.05, followed by a step-wise sub-selection, gave the best results. In contrast to expectations, PCA performed poorly, as so did step-wise analysis. The different chi-square subset methods all yielded ecologically meaningful variables, while probable noise variables were also selected by PCA and step-wise analysis. We advise against the simple use of PCA or step-wise discriminant analysis to obtain an ecologically meaningful variable subset; the former because it does not take into account the response variable, the latter because noise variables are likely to be selected. We suggest that univariate screening techniques are a worthwhile alternative for variable selection in ecology.     

Multiclass linear discriminant analysis with ultrahigh‐dimensional features

Within the framework of Fisher's discriminant analysis, we propose a multiclass classification method which embeds variable screening for ultrahigh‐dimensional predictors. Leveraging interfeature correlations, we show that the proposed linear classifier recovers informative features with probability tending to one and can asymptotically achieve a zero misclassification rate. We evaluate the finite sample performance of the method via extensive simulations and use this method to classify posttransplantation rejection types based on patients' gene expressions.     

Secrets in the eyes of Black Oystercatchers: a new sexing technique

ABSTRACT.   Sexing oystercatchers in the field is difficult because males and females have identical plumage and are similar in size. Although Black Oystercatchers ( Haematopus bachmani ) are sexually dimorphic, using morphology to determine sex requires either capturing both pair members for comparison or using discriminant analyses to assign sex probabilistically based on morphometric traits. All adult Black Oystercatchers have bright yellow eyes, but some of them have dark specks, or eye flecks, in their irides. We hypothesized that this easily observable trait was sex-linked and could be used as a novel diagnostic tool for identifying sex. To test this, we compared data for oystercatchers from genetic molecular markers (CHD-W/CHD-Z and HINT-W/HINT-Z), morphometric analyses, and eye-fleck category (full eye flecks, slight eye flecks, and no eye flecks). Compared to molecular markers, we found that discriminant analyses based on morphological characteristics yielded variable results that were confounded by geographical differences in morphology. However, we found that eye flecks were sex-linked. Using an eye-fleck model where all females have full eye flecks and males have either slight eye flecks or no eye flecks, we correctly assigned the sex of 117 of 125 (94%) oystercatchers. Using discriminant analysis based on morphological characteristics, we correctly assigned the sex of 105 of 119 (88%) birds. Using the eye-fleck technique for sexing Black Oystercatchers may be preferable for some investigators because it is as accurate as discriminant analysis based on morphology and does not require capturing the birds.     

Conditional Quadratic Discrimination in the Identification of Biological Markers for Disease Screening

Conditional multivariate normal density functions are used to construct conditional quadratic discriminant functions that adjust for covariate differences between disease groups. An expected actual error rate for the conditional discriminant function is defined. The purpose of this paper is to use the conditional quadratic discriminant function and its misolassification error rate in order to help determine if a set of discriminators is a good biological marker for disease screening. The conditional quadratic discriminant analysis is illustrated using data from two alcoholism classification problems. It is shown how the discriminant functions can identify a set of variables that can be used as biological markers.     

Special Properties in Selection Performance of Qualitative Variables in Discriminant Analysis

The paper deals with the optimal Bayes discriminant rule for qualitative variables. The performance of variable selection is investigated under strong assumptions like the restriction to dichotomous variables, which are assumed to be independent or dependent with fixed dependence structure, and all parameters known. Differences in comparison with normal variables in linear discriminant analysis can be shown. This is a further reason for applying special methods of discriminant analysis in the case of qualitative variables.     

Sex determination of African Penguins Spheniscus demersus using bill measurements: method comparisons and implications for use

African Penguins Spheniscus demersus are sexually dimorphic; on average, males are larger than females but measurements overlap making sex determination difficult through observations alone. We developed a discriminant function, using bill length and depth from a sample of birds sexed from gonad visualisation during post-mortem, which correctly classified 93% of the individuals. Cross-validation correctly assigned 90% of DNA-sexed birds and 91% of birds sexed by partner measurement comparisons. The use of discriminant function score cutpoints, while leaving 16% and 29% of birds unclassified, improved accuracy of birds sexed by DNA to 97% and of those sexed by partner comparison to 99%. Bill depth was found to be a discriminating variable. However, two techniques for measuring bill depth are currently in use for African Penguins. While these measurements are correlated (r = 0.85), they differ on average by 1.4?mm hindering accuracy of sex determination when using a discriminant function developed from the other bill depth measurement. Exploration of adult bill morphology of birds sexed from DNA at different colonies suggests the discriminant functions can be applied throughout the African Penguins’ South African range.     

太行山猕猴掌骨性别判别分析

为了了解成年太行山猕猴5根掌骨的性差大小。本文对太行山猕猴掌骨标本40例(雄:10, 雌:30)进行观察并选择掌骨的9项形态变量进行测量。数据用SPSS19.0软件进行多变量判别分析。结果表明: 5根掌骨长度等变量在性别之间有明显差异。用全模型法5根掌骨的性别正确判别率范围为94.1%~100.0%, 用逐步判别法掌骨性别正确判别率范围为93.8%~97.5%。有关掌骨的9个形态变量, 长度变量首先被挑选出来, 说明在性别判别中起重要作用。分别用左右侧掌骨的判别函数来判别性别时侧别差异不明显。结论: 用每根掌骨的形态变量建立判别函数可以有效地区分性别, 对非人灵长类掌骨标本的性别鉴定有一定的理论意义和应用价值。     

Predicting class II MHC/peptide multi-level binding with an iterative stepwise discriminant analysis meta-algorithm.

MOTIVATION: Predicting peptides that bind to both Major Histocompatibility Complex (MHC) molecules and T cell receptors provides crucial information for vaccine development. An agretope is that portion of a peptide that interacts with an MHC molecule. The identification and prediction of agretopes is the first step towards vaccine design. RESULTS: An iterative stepwise discriminant analysis meta-algorithm is utilized to derive a quantitative motif for classifying potential agretopes as high-, moderate- or non-binders for HLA-DR1, a class II MHC molecule. A large molecular online database provides the input for this data-driven algorithm. The model correctly classifies over 85% of the peptides in the database. AVAILABILITY: Stepwise discriminant analysis software is available commercially in SPSS and BMDP statistical software packages. Peptides known to bind MHC molecules can be downloaded from http://wehih.wehi.edu.au/mhcpep/. Peptides known not to bind HLA-DR1 are available from the author upon request. CONTACT: ronna@ucsfresno.edu.     

Predictive score of uncomplicated falciparum malaria patients turning to severe malaria

In acute uncomplicated falciparum malaria, there is a continuum from mild to severe malaria. However, no mathematical system is available to predict uncomplicated falciparum malaria patients turning to severe malaria. This study aimed to devise a simple and reliable model of Malaria Severity Prognostic Score (MSPS). The study was performed in adult patients with acute uncomplicated falciparum malaria admitted to the Bangkok Hospital for Tropical Diseases between 2000 and 2005. Total 38 initial clinical parameters were identified to predict the usual recovery or deterioration to severe malaria. The stepwise multiple discriminant analysis was performed to get a linear discriminant equation. The results showed that 4.3% of study patients turned to severe malaria. The MSPS = 4.38 (schizontemia) + 1.62 (gametocytemia) + 1.17 (dehydration) + 0.14 (overweight by body mass index; BMI) + 0.05 (initial pulse rate) + 0.04 (duration of fever before admission) - 0.50 (past history of malaria in last 1 year) - 0.48 (initial serum albumin) - 5.66. Based on the validation study in other malaria patients, the sensitivity and specificity were 88.8% and 88.4%, respectively. We conclude that the MSPS is a simple screening tool for predicting uncomplicated falciparum malaria patients turning to severe malaria. However, the MSPS may need revalidation in different geographical areas before utilized at specific places.