福氏2c(新菌型)和福氏2a志贺菌生物学关系实验研究

目的：探讨F2c(shigella flexneri 2c,F2c)与F2a志贺菌间的相互关系（异同点），了解新菌型的各种生物学特性。方法：对上述两株志贺菌进行生化、噬菌体裂解、药敏试验及血清学凝集.结果：两株细菌生化反应、噬菌体裂解试验结果均相同。F2c同时含有群抗原3，4和7，它对庆大霉素、妥布霉素、卡那霉素、乙基西梭霉素、氧哌嗪青霉素耐药，而F2a则对以上五种药均敏感。结论：新发生的F2c与F2a在药物敏感性上存在着很大差异。     

福氏志贺菌4C亚型生物学特性研究及ipaH基因检测

目的：了解福氏志贺菌4C亚型(F4c)的生物学特性及毒力情况。方法：以生化反应、噬菌体裂解试验、血清分型鉴定菌种；按K-B法进行药敏试验；采用PCR技术检测ipaH基因；同时观察对动物的侵袭力。结果：该菌型具有志贺菌属的基本特点，靛基质等试验传代后有变化，能被Ent噬菌体溶原化而出现型抗原变异现象，ipaH基因和动物侵袭力试验阳性，对四环素、TMP等耐药。结论：F4c是一个少见的血清型，生物学特性与F2c相近，一定条件下能出现型抗原和生化特性变异。     

一株阴沟肠杆菌与福氏志贺菌4型交叉凝集的报告

目的：研究阴沟肠杆菌与福氏志贺菌4型的生物学关系。方法：采用生化试验、血清学凝集等。结果：生化试验符合阴沟肠杆菌，抗原与福氏志贺菌4型有交叉凝集。结论：阴沟肠杆菌与福氏志贺菌4型有交叉凝集。     

无锡市志贺菌血清型分布及药敏试验的研究

目的 为掌握江苏省无锡市志贺菌血清型分布和抗生素试验的耐药情况，为该市卫生防病工作提供科学依据。方法 按何晓青主编的卫生防疫细菌检验相关章节和国家卫生行业标准WS／T 125-1999纸片法抗菌药物敏感试验标准方法对2003年无锡市腹泻病门诊分离的30株志贺菌进行血清学分型和药敏试验。结果 30株志贺菌进行血清学分型，主要以B群为主，25株，占总数的83．33％；A群2株，占总数6．67％；C群2株，占总数6．67％；D群1株，占总数3．33％。在最多的B群中，福氏2型10株，占40％，福氏4型8株，占32％，福氏l型6株，占24％，福氏Y变种1株，占4％。30株菌对环丙沙星，丁胺卡那，妥布霉素为100％敏感，对复方新诺明，红霉素为100％耐药。结论 我市痢疾病人中优势流行菌型有所改变；根据药敏试验在今后的痢疾治疗用药上应首先使用环丙沙星、丁胺卡那和妥布霉素等。     

4株福志贺菌Ⅱ型不同生物学特性实验研究

[目的]探索福志贺菌Ⅱ型(Shigella flexnn2,F2)菌株间生物学关系，及时发现新菌型。[方法]用同批试剂，对4株福志贺菌Ⅱ型进行生化、噬菌体裂解、药敏及血清学凝集试验。[结果]4株福志贺菌生化反应几乎完全相同；噬菌体裂解试验结果亦完全一样。但药敏试验结果差异较大；血清学凝集结果亦有所不同。[结论]福志贺菌Ⅱ型不同菌株间对抗生素敏感性存在着较大差异；福志贺菌Ⅱ型还存在着新的菌型。     

疾病监测点痢疾感染特点及病原特性研究

目的 了解近几年志贺氏痢疾病原菌的流行优势菌型及其生物学特性；方法 对河南省监测点2000、2001分离到的68株痢疾杆菌应用血清学、生化学、药物敏感性等试验对菌种进行了系统的鉴定；结果 68株痢疾杆菌均属福氏志贺氏菌，其中福氏2a、5b分别占27．94％和26．5％；F3a占22．0％；68株菌均对多粘菌素B、头孢唑啉、丁胺卡那霉100％敏感，对头孢他啶、氨曲南、庆大霉素、环丙沙星敏感率在97％以上，对吡哌酸、四环素、氯霉素、CO.SMZ的耐药率均在87％；结论 农村近两年痢疾感染的优势菌型仍为福氏志贺氏菌，但福氏5b及3a的感染率呈逐年上升的趋势^[1][2]、药物敏感测试结果为临床合理用药提供了确切的依据。     

邵阳市首次检出福氏4c志贺菌(新菌型)

目的研究福氏志贺4c(F4c)新菌型的生物学特性及其毒力。方法采用F2a株作为参照,以生化反应、噬菌体裂解试验、血清分型进行菌种鉴定;采用K-B法进行药敏试验;对豚鼠角膜进行侵袭力测定;恢复期病人血清与分离菌进行特异性凝集试验。结果血清学反应志贺氏四种多价( )、福氏多价( )、福氏Ⅳ( )、群7( )、对四环素、氯霉素、复方新诺明、氨苄青霉素等耐药。豚鼠角膜侵袭力试验阳性,恢复期病人血清相应抗体为1:320。结论经鉴定分离的该菌为福氏志贺4c(F4c),生物学特性与F2a一致,毒力极强,是一个少见的福氏流行株,为湖南省首次检出。     

上海市闵行区952株志贺菌的血清分型及耐药性分析

目的了解上海市闵行区痢疾病原菌的优胜菌型以及药物敏感特征,为痢疾预防控制提供科学依据。方法采用血清凝集试验、菌种鉴定仪系统生化鉴定和K-B法药敏试验对从腹泻病人分离的志贺菌进行流行病学分型和药物敏感试验。结果 952株志贺菌中福氏志贺菌694株,宋内志贺菌258株。福氏志贺菌共分为13个血清型,其中福氏Ⅳc 288株,福氏Ⅰa 119株,福氏Ⅱb118株,福氏Ⅱa84株,福氏X变种43株,其余8个菌型共42株。复方新诺敏耐药率91.16%,氨苄青霉素耐药率84.07%,氯霉素耐药率25.87%,庆大霉素耐药率17.03%,其余耐药率均在10%以下,头孢噻肟、丁胺卡那、头孢噻吩、头孢唑啉、氟哌酸均敏感。结论该区志贺菌感染的优势菌型为福氏Ⅳc型、宋内氏志贺菌、福氏Ⅰa型、福氏Ⅱb型和福氏Ⅱa。药物头孢噻肟、丁胺卡那霉素、头孢噻吩、头孢唑啉可作为目前临床治疗痢疾的常用药物。     

河南省痢疾感染特点及病原特性研究

〔目的〕了解志贺痢疾杆菌流行菌型变异及其生物学特性 ;〔方法〕对河南省监测点 2 0 0 1、2 0 0 2年分离的 2 14株痢疾杆菌应用血清学、生化学、药物敏感等试验进行系统的鉴定 ;〔结果〕 2 14株痢疾杆菌优势流行菌型由原来的福氏志贺 2a正逐渐向福氏 4、4c、1a、5b转变 ;2 14株菌均对头孢唑啉、诺氟沙星、多粘菌素B 10 0 %敏感 ,对头孢噻肟、头孢他啶、呋喃妥因、环丙沙星敏感率在 97%以上 ;对四环素、萘啶酸耐药高达 92 %以上。〔结论〕农村近两年痢疾感染的优势菌型仍为福氏志贺菌 ,福氏 1a、4c、4及 5b菌型的感染率呈逐年上升的趋势[2 - 3] ;药物敏感测试结果为临床合理用药提供了确切依据。     

陕西省首株福氏4c志贺菌的发现及其耐药性和毒力基因型分析

[目的]报道陕西省首株福氏4c志贺菌的发现,并分析其耐药性和毒力基园型.[方法]生化反应、血清凝集试验、噬菌体裂解试验鉴定菌株,抗生素敏感试验采用生物梅里埃GNS药敏卡,PCR法检测ipalH、shet1、ial、sen基因.[结果]该株细菌生化反应及噬菌体裂解试验菌结果均为志贺菌,血清凝集反应特殊,确定为福氏4c志贺菌;对阿莫西林、培氟沙星、替卡西林等少数抗生素耐药,对复方新诺明等敏感;该菌4种毒力基因都阳性,属Ⅰ型福氏4c志贺菌.[结论]福氏4c志贺菌在陕西首次发现,属毒力较强的Ⅰ型福氏4c志贺菌,目前尚没有形成多重耐药.应加强对这类菌株的监测,以防其继续发生甚至流行.     

Choosing the parameter for a 2 x 2 table or a 2 x 2 x 2 table analysis.

Fourteen 2 x 2 table measures of association are compared and six 2 x 2 x 2 table measures of synergism are compared. The presentation is based on a conceptual population model for the true association between the disease and the risk factor(s). Each measure is judged as to potential use and identified with the study designs under which it can be estimated. It is shown that prior information about the correct population model is required to adequately measure synergism.     

Reconsidering the odds ratio as a measure of 2x2 association in a population

The odds ratio (OR) is probably the most widely used measure of 2x2 association in epidemiology, but it often produces results that are puzzling or misleading. Receiver operating characteristic (ROC) methods are used to take a fresh look at the OR and show where and why such puzzling results arise. When researchers choose to report a summary measure of association, the OR is one of many measures of association that might be considered, not one that should be considered the 'gold standard' of 2x2 measures of association. In a randomized clinical trial with binary outcome for success, either the success or failure rates in treatment and control groups might be reported separately or the number needed to treat to achieve one extra success, to emphasize the cost of unnecessary treatment needed to achieve a success. In studies assessing reliability or heritability, we recommend the intraclass kappa. In studies in which one binary variable is assessed against a binary criterion, we recommend the weighted kappa.     

Meta-analysis for 2 x 2 tables: a Bayesian approach.

This paper develops and implements a fully Bayesian approach to meta-analysis, in which uncertainty about effects in distinct but comparable studies is represented by an exchangeable prior distribution. Specifically, hierarchical normal models are used, along with a parametrization that allows a unified approach to deal easily with both clinical trial and case-control study data. Monte Carlo methods are used to obtain posterior distributions for parameters of interest, integrating out the unknown parameters of the exchangeable prior or 'random effects' distribution. The approach is illustrated with two examples, the first involving a data set on the effect of beta-blockers after myocardial infarction, and the second based on a classic data set comprising 14 case-control studies on the effects of smoking on lung cancer. In both examples, rather different conclusions from those previously published are obtained. In particular, it is claimed that widely used methods for meta-analysis, which involve complete pooling of 'O-E' values, lead to understatement of uncertainty in the estimation of overall or typical effect size.     

2 × 2 Tables: a note on Campbell's recommendation

For 2 × 2 tables, Egon Pearson's N ? 1 chi‐squared statistic is theoretically more sound than Karl Pearson's chi‐squared statistic, and provides more accurate p values. Moreover, Egon Pearson's N ? 1 chi‐squared statistic is equal to the Mantel‐Haenszel chi‐squared statistic for a single 2 × 2 table, and as such, is often available in statistical software packages like SPSS, SAS, Stata, or R , which facilitates compliance with Ian Campbell's recommendations. Copyright © 2015 John Wiley & Sons, Ltd.     

Cellular and humoral immunity following vaccination with two different PCV2 vaccines (containing PCV2a or PCV2a/PCV2b) and challenge with virulent PCV2d

Porcine Circovirus type 2 (PCV2) associated disease is one of the most economically important swine diseases worldwide. Vaccines reduce PCV2 disease by inducing humoral immunity (neutralizing antibodies) and cell-mediated immunity (CMI) but may be improved by optimizing the immune response they induce. This study evaluated immune responses to a trivalent inactivated Porcine Circovirus (PCV) Type 1-Type 2a chimera (cPCV2a), cPCV2b and Mycoplasma hyopneumoniae (MH) (an experimental serial of Fostera® Gold PCV MH, also marketed as Circomax® Myco) vaccine or a bivalent recombinant PCV2a baculovirus expressed ORF2 capsid plus MH vaccine (Circumvent® PCV-M G2). Treatment Groups (T) received two doses of placebo (T01), one full or two split doses of the trivalent vaccine (T02, T03) or two split doses of the bivalent vaccine (T04) where two doses were given, there was a three-week period between administrations. All pigs were challenged with a virulent field isolate of PCV2d. CMI was measured as PCV2-specific IFN-γ secreting cells in blood and lymph node. Humoral immunity was measured as PCV2 antibodies. Vaccine efficacy was determined as viremia and fecal shedding of virus. There was a robust antibody response in T02 and T04 post the second vaccination and all vaccinated groups post challenge. There was a robust PCV2-specific IFN-γ response following the 1^st dose in T02 and T03 and after the second dose in T02. T04 induced a low but detectable PCV2-specific IFN-γ response only after the 2^nd dose. Among lymph node cells (study day 52), there was a significantly higher PCV2-specific, IFN-γ response to replicase and PCV2d capsid peptides in T01, consistent with active viral replication in non-vaccinated pigs. The trivalent chimeric vaccine induced robust CMI and protective efficacy, following a one dose regimen or splitting the dose into two vaccine administrations.     

A PCV2 vaccine based on genotype 2b is more effective than a 2a-based vaccine to protect against PCV2b or combined PCV2a/2b viremia in pigs with concurrent PCV2, PRRSV and PPV infection

The predominant genotype of porcine circovirus (PCV) in the pig population today is PCV2b yet PCV2a-based commercial vaccines are considered effective in protecting against porcine circovirus associated disease. The objective of this study was to compare the ability of PCV2a- and PCV2b-based vaccines to control PCV2b viremia in a challenge model that mimics the U.S. field situation. Sixty-three pigs were randomly assigned to one of eight groups. Sixteen pigs were vaccinated with an experimental live-attenuated chimeric PCV1-2a vaccine based on genotype 2a and another 16 pigs with a chimeric PCV1-2b vaccine based on genotype 2b. Challenge was done 28 days post vaccination (dpv) using PCV2b (or a combination of PCV2a and PCV2b), porcine reproductive and respiratory syndrome virus (PRRSV), and porcine parvovirus (PPV) to mimic what commonly occurs in the field. The experiment was terminated 21 days post challenge (dpc) or 49 dpv. Pigs vaccinated with the chimeric PCV1-2b vaccine had significantly higher levels of PCV1-2b viremia and shedding of the PCV1-2b vaccine virus in feces and nasal secretions but also a more robust humoral immune response as evidenced by significantly higher ELISA S/P ratios compared to the PCV1-2a vaccination. Regardless of challenge, the PCV1-2b vaccination significantly reduced the prevalence and amount of PCV2 viremia compared to the PCV1-2a vaccination. Interestingly, in the non-vaccinated pigs concurrent PCV2a infection resulted in clinical disease and increased macroscopic lung lesions compared to pigs challenged with PCV2b alone, further supporting the idea that concurrent PCV2a/PCV2b infection is necessary for optimal PCV2 replication.