Different Species of Salmonella spp and Shigella spp and Their Risk of Infection in N’Djamena Chad

Introduction: Salmonella and Shigella are gram-negative bacilli that are resistant to most antibiotics and play an important role in an etiology of diarrhea disease. The aim of the study was to determine the prevalence of Salmonella spp and Shigella spp isolated from stool and blood samples in the city of N’Djamena. Materials and Method: This was a prospective study conducted in the four district hospitals of N’Djamena from 14 July 2022 to 31 December 2022. A questionnaire form was drawn up to collect the information sent to the study patients. The samples were analyzed at the CHU de la Mère et de l’Enfant, Labo-Redes laboratory according to their protocols and the standard of the antibiogram committee of the French microbiology society. Results: Of the 803 biological samples analyzed, 39 were positive for Salmonella spp and Shigella spp, including 15 for Salmonella and 24 for Shigella, giving an overall prevalence rate of 4.85%. Borehole water, uncooked food and lack of access to a latrine constitute a risk of being infected by Salmonella spp and Shigella spp species. Of the 8 antibiotics tested, Salmonella spp and Shigella spp strains showed good sensitivity to nalidixic acid (100% for Salmonella and 90 for Shigella) and to ciprofloxacin (90.9% for Salmonella and 75% for Shigella). Resistance to ampicillin was found in 81.81% of Salmonella species and 78.57% of Shigella species, as was resistance to chloramphenicol (81.81% of Salmonella species and 67.85% of Shigella species). Similarly, cleanliness of the service and equipment is an essential factor in preventing Salmonella and Shigella infections.

青海地区不同动物源志贺菌毒力相关基因的分布研究

为了解青海省不同动物源志贺菌相关毒力基因的分布情况,试验对分离自青海省不同地区的62株不同动物源志贺菌进行了DNA提取,将其作为模板对志贺菌的毒力基因set1B、virA、set1A、ial、ipaBCD、Sen、icsP、iutA、icsA、ipaH进行了PCR检测,并统计各毒力基因在不同动物源志贺菌中的检出率、不同动物源志贺菌毒力基因携带模式及携带毒力基因种类。结果表明:62株志贺菌毒力基因set1B、virA、set1A、ial、ipaBCD、icsP、Sen、iutA、icsA、ipaH的检出率分别为6.5%、43.5%、3.2%、25.8%、37.1%、0、12.9%、22.6%、50.0%、100%。在27株猪源志贺菌中,毒力基因ipaH、VirA、icsA、ipaBCD的检出率较高,然后依次为ial、iutA、Sen,未检出icsP。在27株鸡源志贺菌中,毒力基因ipaH、icsA、virA的检出率较高,然后依次为ipaBCD、ial、Sen、iutA,未检出set1B、set1A、icsP。在4株牦牛源志贺菌中,毒力基因ipaH、icsA、ipaBCD的检出率较高,然后依次为virA、ial、iutA,未检出set1B、set1A、Sen、icsP。在4株藏羊源志贺菌中,毒力基因ipaH、ipaBCD、iutA的检出率较高;然后依次为virA、ial,未检出set1B、set1A、Sen、icsP、icsA。在62株志贺菌中,有7株菌只检出毒力基因ipaH,55株菌携带两种及以上毒力基因,共呈现出30种携带模式,其中以virA-icsA-ipaH模式的菌株最多(11.3%,7/62),然后为ipaBCD-ipaH模式(9.7%,6/62);猪源和鸡源志贺菌毒力基因的携带模式均为18种,牦牛和藏羊源志贺菌毒力基因的携带模式均为4种。在62株志贺菌中,有18株菌携带2种毒力基因,15株菌携带3种毒力基因,13株菌携带4种毒力基因,7株菌携带5种毒力基因,2株菌携带6种毒力基因。27株猪源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为3.7%、40.7%、14.8%、18.5%、14.8%、7.4%,27株鸡源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为18.5%、18.5%、29.6%、22.2%、11.1%、0,4株牦牛源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为25.0%、0、25.0%、50.0%、0、0,4株藏羊源志贺菌中携带1,2,3,4,5,6种毒力基因菌株的占比分别为0、50.0%、50.0%、0、0、0。62株志贺菌单毒力基因携带率(11.3%,7/62)<多重毒力基因携带率(88.7%,55/62),其中猪源志贺菌的多重基因携带率最高(42.0%),然后依次为鸡源(35.5%)、藏羊源(6.4%)和牦牛源(4.8%)。说明青海地区志贺菌携带多种毒力基因,携带模式呈现多样性且因动物源不同有所差异,同时应重点加强青海地区猪志贺菌病的防治工作。

急性腹泻患儿粪便病原微生物检验结果及耐药情况分析

目的探讨急性腹泻患儿粪便病原微生物检验结果及耐药情况。方法选取2021年1月-2023年1月我院收治的167例急性腹泻患儿,采集所有患儿粪便标本送检,开展病原微生物培养与药敏试验。统计病原微生物检检验结果、分析急性病原微生物分布特点、志贺氏菌属、沙门氏菌属的耐药情况。结果167急性腹泻患儿共检出109株病原微生物,其中细菌51株(46.79%)、病毒48株(44.04%)、真菌10株(9.17%);51株细菌(46.79%)以志贺氏菌属(13.76%)、沙门氏菌(22.02%)、大肠埃希菌(4.59%)为主;48株病毒(44.04%),以轮状病毒(22.94%)、诺如病毒(15.60%)为主,真菌10株(9.17%);志贺氏菌属、沙门氏菌属对氨苄西林、哌拉西林、四环素的耐药性偏高,均>50%;对氨苄西林/舒巴坦、阿莫西林/克拉维酸、哌拉西林/他唑巴坦、头孢他啶、头孢吡肟、氯霉素、环丙沙星、左氧氟沙星、氨曲南的耐药性偏低,均﹤50%;对厄他培南、亚胺培南、美罗培南未产生耐药性。结论急性腹泻患儿粪便病原微生物以病毒、志贺氏菌属、沙门氏菌属、大肠埃希菌多见,临床需据此开展针对性治疗,以加快患者病情转归。

TaqMan探针双重荧光聚合酶链式反应技术检测食源性沙门氏菌和志贺氏菌

目的建立TaqMan探针双重荧光聚合酶链式反应(polymerase chain reaction,PCR)技术检测食源性沙门氏菌和志贺氏菌的方法。方法通过比对沙门氏菌和志贺氏菌的基因组序列,选择同源性高、保守性好的区域设计特异性引物和探针,经过引探筛选、浓度调试等一系列优化,建立了食源性沙门氏菌和志贺氏菌双重荧光PCR核酸检测方法,并对其特异性、质粒最低检出限、菌液敏感性、重复性、稳定性以及实际样品进行了验证。结果该方法与大部分食源性致病菌无交叉反应,特异性强;沙门氏菌和志贺氏菌质粒的最低检出限可达5 copies/μL,沙门氏菌菌液敏感性为1.0×10^(2) cfu/mL,志贺氏菌菌液敏感性10 cfu/mL;质粒和菌液核酸梯度的批内和批间变异系数均在0.177%~1.958%之间,小于5.0%,具有较强的稳定性;标准曲线相关系数(r^(2))均大于0.999。结论本研究成功建立了一种TaqMan探针双重荧光PCR技术同时检测食源性沙门氏菌和志贺氏菌的方法,该方法扩增时间短,只需要30 min即可,而且特异性强、稳定性好,可用于疑似沙门氏菌和志贺氏菌污染样品的检测,为食品安全的快速检测提供技术支撑。

新疆塔额垦区牛羊粪源志贺菌耐药性、毒力基因检测及其致病性分析

为了解新疆塔额垦区牛羊粪源志贺菌的耐药性、毒力基因携带情况和致病性,对从335份牛羊腹泻粪便中分离鉴定到的32株志贺菌(10株福氏志贺菌和22株宋内志贺菌)进行药敏试验、耐药基因与毒力基因检测、生物被膜形成能力和小鼠致病性检测。结果显示,32株志贺菌对四环素、多西环素和氨苄西林等药物的耐药率较高,分别为87.50%、87.50%和84.38%;29株(90.63%)呈现多重耐药。从分离株中检测到15种耐药基因,其中blaTEM(96.88%)和blaCXT-M(68.75%)基因的检出率较高;检测到14种毒力基因,其中yijP(93.75%)、ibeB(90.63%)和ipaBCD(78.13%)基因的检出率较高。部分志贺菌具有生物被膜形成能力(2/32,6.25%),并引起小鼠死亡。说明新疆塔额垦区牛羊源志贺菌具有较强的耐药性,携带多种耐药基因和毒力基因,具有一定的致病性,在牛羊健康养殖中具有潜在威胁。

云南省2016—2022年志贺氏菌分子分型及耐药性分析

目的对云南省2016—2022年食源性疾病主动监测分离的志贺氏菌进行血清、分子分型和药敏试验等分析,了解云南省志贺氏菌的病原学特性,为志贺氏菌感染的防控和治疗提供数据支持。方法2016年1月至2022年12月从患者粪便中分离志贺氏菌,采用玻片凝集法进行血清学分型,脉冲场凝胶电泳(PFGE)进行分子分型分析,微量肉汤稀释法进行药敏试验。结果共分离志贺氏菌89株,其中福氏志贺氏菌占52.81%,宋内志贺氏菌占47.19%。PFGE分析发现,2种志贺氏菌均分为A和B 2个聚类簇,B簇为优势簇。47株福氏志贺氏菌分为30种PFGE带型,有3组优势带型,42株宋内志贺氏菌分为22种PFGE带型,有4组优势带型,并识别两起疑似暴发事件。志贺氏菌对13种抗生素存在不同程度的耐药,78.65%的菌株为多重耐药菌株。结论云南省志贺氏菌PFGE优势带型明显,部分带型聚集分布。耐药形势严峻,多重耐药现象严重。福氏志贺氏菌和宋内志贺氏菌耐药表型存在差异。

重组酶介导的等温扩增结合CRISPR/Cas12a检测志贺氏菌和克罗诺杆菌

目的应用重组酶介导的等温扩增技术(recombinase-aided amplification,RAA)结合成簇规则的间隔短回文重复序列(clustered regularly interspaced short palindromic repeats,CRISPR),建立志贺氏菌和克罗诺杆菌的快速检测方法。方法通过筛选志贺氏菌和克罗诺杆菌特异性基因,设计特异扩增引物、CRISPR脱氧核糖核酸(CRISPR deoxyribonucleic acid,crDNA)和探针,将靶标进行RAA扩增后,建立CRISPR检测方法。对方法的灵敏度、特异性和应用性进行评价,并与国标检测方法进行对比。结果本研究对志贺氏菌和克罗诺杆菌纯菌液DNA最低检出限分别为4.9×10^(3) CFU/mL、4.4×10^(4) CFU/mL,基因组DNA最低检出限为6.8×10^(‒3) ng/μL、5.7×10^(‒3 )ng/μL,特异性好,与其他病原菌无交叉反应。同时,该方法成功检测出加标猪肉样品和人工污染奶粉中的志贺氏菌和克罗诺杆菌,比国家标准检出限更低。结论本研究建立的RAA-CRISPR方法可有效应用于志贺氏菌和克罗诺杆菌的检测,这为快速筛查食品中是否污染这两种病原菌提供重要价值。

《细菌性痢疾诊疗方案(2023年版)》解读

细菌性痢疾是我国规定的法定传染病之一。近几十年来,随着卫生设施的改善、水源和食品安全的管理加强以及积极的公共卫生措施,我国细菌性痢疾的发生率和死亡率大幅下降,但志贺菌仍是引起急性感染性腹泻的常见致病菌。为进一步规范细菌性痢疾临床诊疗工作,国家卫生健康委员会医疗应急司组织制定《细菌性痢疾诊疗方案(2023年版)》,现对该指南的部分意见进行分析,以促进细菌性痢疾治疗的规范化。

耐高浓度氨氮微生物Y5的脱氮特性及应用研究

污水脱氮是污水净化处理的关键步骤之一。为去除水体中高浓度氨氮,于某化工污水中筛选出一株具有异养硝化-好氧反硝化性能的菌株鲍氏志贺菌(Shigella boydii Y5),通过单因素实验研究其最佳生存环境,并考察其应用于实际废水中的脱氮性能。结果表明,其最佳生存环境是碳源为蔗糖,C/N为10,pH为7,转速为140 r/min,此环境下生长的菌株Y5对初始质量浓度为1000 mg/L氨氮废水具高效的脱氮能力,且菌株Y5为嗜盐菌。将菌株Y5应用于核酸废水,对氨氮和总氮的最大降解率达98.22%和90.27%。通过高通量测序分析废水脱氮过程中Y5菌株的作用和稳定性,结果表明,与只添加碳源处理组相比,添加碳源和菌株Y5处理组废水中微生物多样性水平出现显著性差异,表明Shigella boydii Y5在实际废水处理中有巨大应用价值。

29株食源性志贺氏菌病原学特征和耐药特性分析

目的:分析29株食源性志贺氏菌的病原学特征和耐药特性。方法:利用《食品安全国家标准食品微生物学检验志贺氏菌检验》(GB 4789.5—2012)中的血清学方法对29株食源性志贺氏菌进行分群血清凝集实验;利用高通量测序技术对菌株进行全基因组测序和生物信息学分析,确定其群型和血清型;利用微量肉汤稀释法对菌株进行药敏实验。结果:通过血清学鉴定和wgSNP分析,29株食源性志贺氏菌中仅有2株为福氏志贺氏菌,其余27株均为宋内氏志贺氏菌;29株菌均对氨苄西林、氨苄西林舒巴坦、氯霉素、环丙沙星、头孢噻肟、萘啶酸、复方新诺明和四环素有不同程度的耐药特性,对复方新诺明和萘啶酸耐药率最高(100.00%),对头孢噻肟和环丙沙星的耐药率较低,分别为6.90%和3.45%。结论:临沂市食源性志贺氏菌流行优势菌株为宋内氏志贺氏菌,耐药形势严峻,针对志贺氏菌感染病例应采用更加个性化的治疗方案。

常见细菌性食源性疾病研究进展

细菌性食源性疾病在全球范围内非常普遍,并对公共卫生和个人健康造成了影响。常见的3种食源性病原菌分为沙门氏菌、大肠杆菌和志贺氏菌,本文针对其形态特征和食源性致病机制,以及诊断细菌性食源性疾病的方法、有关细菌性食源性疾病治疗方案等进行综述,以期为临床实践和预防措施的制定提供理论依据。

志贺氏杆菌分泌蛋白Dnak的表达纯化与多克隆抗体的制备及应用

目的表达轮状病毒感染的乳鼠体内志贺氏杆菌分泌蛋白Dnak(Hsp70),并制备Dnak多克隆抗体。方法以提取的志贺氏杆菌基因组为模板PCR扩增Dnak片段,与pET-24a(+)和PCDNA3.1分别连接构建原核表达质粒pET24a(+)-Dnak和真核表达质粒PCDNA3.1-Dnak;pET24a(+)-Dnak原核表达质粒转化至E.coli BL21(DE3)感受态细胞,IPTG诱导表达,经镍柱纯化Dnak蛋白。以纯化后的重组蛋白为免疫原免疫C57BL/6小鼠制备多克隆抗体,采用间接ELISA检测效价,Western Blot法检测灵敏度和特异性。利用制备的多克隆抗体在GST Pull-down实验中检测Dnak与轮状病毒非结构蛋白Nsp2的相互作用。真核表达质粒PCDNA3.1-Dnak转染至HEK293T细胞,以制备的DnaK多克隆抗体为一抗,Western blot法检测Dnak在细胞中的表达。利用MEGA11及Genedoc软件分析此志贺氏杆菌与志贺菌属其他细菌Dnak氨基酸序列同源性。结果重组质粒pET24a(+)-Dnak与PCDNA3.1-Dnak经测序比对包含与此志贺氏杆菌(Shigella:PRJNA804371)序列一致的基因,证明质粒构建成功。诱导表达的重组Dnak蛋白主要以可溶性形式存在,相对分子质量约为75 kDa,浓度可达0.62 mg/mL;Dnak鼠多克隆抗体可与重组Dnak蛋白发生特异性反应,效价为1∶32000,至少可以在1∶6000稀释度下检测到Dnak蛋白。GST Pull-down实验可以检测到Dnak与轮状病毒非结构蛋白Nsp2发生相互作用。转染PCDNA3.1-Dnak重组质粒的HEK293T细胞可以表达Dnak蛋白。经MEGA11和Genedoc软件比对PRJNA804371株与宋内志贺菌(Shigella sonnei)、痢疾志贺菌(Shigella dysenteriae)、鲍氏志贺菌(Shigella boydii)、福氏志贺菌(Shigella flexneri)Dnak氨基酸序列同源性较高。结论成功表达志贺氏杆菌Dnak蛋白,具有良好反应性与免疫原性;制备的鼠多克隆抗体效价及灵敏度较高可满足后续实验需要。

云南省猪源志贺菌分离株耐药特点和毒力基因分析

旨在研究云南省猪源志贺菌的流行情况以及耐药情况,分析志贺菌分离株耐药基因和毒力基因。采集云南省5个地州共300份猪肛门拭子样品进行志贺菌的分离、生化鉴定及PCR鉴定,通过K-B药敏纸片法和PCR分别检测分离菌的耐药性、耐药基因及毒力基因。结果:志贺菌阳性检出率20.7%(62/300),其中楚雄、红河、大理、昭通、澜沧阳性率分别为18.9%、21.8%、18.8%、21.9%和22%;62株志贺菌对14种抗生素均有不同程度的耐药,对萘啶酸耐药率最高为96.8%,对头孢西丁的耐药率最低为3.2%;以链霉素-氨苄西林耐药谱为主;喹诺酮类耐药基因gyrA的检出率最高为79%,qnrA的检出率最低为1.6%;毒力基因ipaH、ial、shet1A的检出率依次为100%、77.4%和40.3%。研究表明,云南省猪源志贺菌对多种抗生素均产生耐药性,耐药基因检出率均较高,毒力基因以ipaH为主。

菌株Shigella flexneri FB5响应氟磺胺草醚蛋白质组学分析

为明确氟磺胺草醚降解菌的蛋白质组学相关机理,针对实验室前期筛选得到的高效降解菌Shigella flexneri FB5,在明确菌株对氟磺胺草醚高效降解的基础上,研究进行了蛋白提取和双向电泳试验。结果发现氟磺胺草醚诱导下菌株差异蛋白点13个,使用质谱技术对它们进行鉴定。通过生物信息学比对得到其功能,并对目标蛋白的基因进行PCR扩增与测序。结果表明:研究得到氟磺胺草醚诱导下菌株两个相关基因,测序后发现基因F3序列与E.coli结合蛋白dps基因同源性是100%,基因F6序列与沙门氏菌肠溶亚种血清变型索菲亚菌S1635外膜蛋白基因和E.coli SYW004外膜蛋白基因A相似度是87%,同时对这两个基因所在家族功能进行分析,并且推测出基因的理化性质。

Multi-drug Resistance and Characteristic of Integrons in Shigella spp.Isolated from China

Objective To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp. Methods Ninety Shigella strains （83 S. flexneri and 7 S. sonnei） were isolated from the stools of patients in China. Susceptibility to 8 antimicrobials was tested for all isolated strains. PCR, RFLP and sequencing analysis of integrons were applied to all of them. Results High prevalence of multi‐drug resistance （95.6%） was identified. Of the isolates 79 （87.8%） carried integrase genes of class 1 integron （3.3%）, class 2 integron （10.0%） or both （74.4%）. No intI3 was detected in the tested isolates. The prevalence of intI2 was significantly higher in isolates with multi‐drug resistance to at least 3 antibiotics than that in isolates with resistance to 2 and less antibiotics （P0.05）. Gene cassettes dfrA17‐aadA5, dfrA12‐orfF‐aadA2 of class 1 integron and dfrA1‐sat1‐aadA1 of class 2 integron were identified. Conclusion The class 2 integron may play a role in the emergence of multi‐drug resistance in Shigella spp.

Prevalence and trends of aminoglycoside resistance in Shigella worldwide, 1999-2010

Shigellosis causes diarrheal disease in humans in both developed and developing countries, and multi-drug resistance in Shigella is an emerging problem. Understanding changing resistance patterns is important in determining appropriate antibiotic treatments. This meta-analysis systematically evaluated aminoglycoside resistance in Shigella. A systematic review was constructed based on MEDLINE and EMBASE databases. Randomeffect models or fixed-effect models were used based on P value considering the possibility of heterogeneity between studies for meta-analysis. Data manipulation and statistical analyses were performed using software STATA 11.0. By means of meta-analysis, we found a lower resistance to three kinds of aminoglycosides in the Europe-America areas during the 12 year study period than that of the Asia-Africa areas. Kanamycin resistance was observed to be the most common drug resistance among Shigella isolates with a prevalence of 6.88% （95%CI： 6.36%-7.43%）. Comparison of data from Europe-America and Asia-Africa areas revealed that Shigella flexneri resistance was greater than the resistance calculated for Shigella sonnei. Importantly, Shigella sonnei has played a significant role in aminoglycoside-resistance in recent years. Similarly, data showed that resistance to these drugs in children was higher than the corresponding data of adults. In conclusion, aminoglycoside-resistant Shigella is not an unusual phenomenon worldwide. Distribution in Shigella resistance differs sharply based on geographic areas, periods of time and subtypes. The results from the present study highlight the need for con- tinuous surveillance of resistance and control of antibiotic usage.

Immunoproteome analysis of soluble and membrane proteins of Shigella flexneri 2457T

AIM: To profile the immunogenic proteins of Shigella flexneri (S. flexneri) expressed during human infection using a proteomic approach. METHODS: Soluble and membrane protein extractions of S. flexneri 2457T were separated by two-dimensional gel electrophoresis (2-DE). Proteins were transferred to PVDF membrane and immunoblotted with sera from shigellosis patients. Reactive protein spots were matched to Coomassie stained gels run in parallel, cut out and trypsin digested. Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS) was used to determine the peptide mass fingerprints, which were searched in the MASCOT database to identify the protein. RESULTS: A total of 8 immunoreactive proteins were successfully identified from the Coomassie stained gels in three repeats. Six of these proteins have not previously been reported as immunogenic in S. flexneri. These proteins could be potential candidates for vaccine or attenuation studies. CONCLUSION: Soluble and membrane proteins of S. flexneri 2457T have been screened by 2-DE and immunoblotting with sera from shigellosis patients. Eight proteins are identified as immunogenic.

Immunoproteomics of membrane proteins of Shigella flexneri 2a 2457T

AIM： To screen the immunogenic membrane proteins of Shigella Aexneri 2a 2457T. METHODS： The routine two-dimensional polyacrylamide gel electrophoresis （2-DE） and Western blotting were combined to screen immunogenic proteins of S. Aexneri 2a 2457T. Serum was gained from rabbits immunized with the same bacteria. Immunogenic spots were cut out from the polyacrylamide gel and digested by trypsin in-gel. Matrix-assisted laser desorption/ionization time of flight-mass spectrometry （MALDI-TOF-MS） was performed to determine the molecular weight of peptides. Electrospray ionization （ESI-MS/MS） was performed to determine the sequences of the interesting peptides. RESULTS： A total of 20 spots were successfully identified from Coomassie brilliant blue stained gels representing 13 protein entries, 5 known antigens and 8 novel antigens. A hypothetical protein （YaeT） was detected, which might be a candidate target of vaccine. CONCLUSION： Membrane proteins of S. flexneri 2a 2457T were successfully observed by 2-DE. Several known and novel antigens were identified by mass spectrum.

Construction of a novel Shigella live-vector strain co-expressing CS3 and LTB/STm of enterotoxigenic E.coli

AIM: To construct and evaluate a polyvalent recombinant vaccine strain Shigella flexneri2a T32 against enterotoxigenic E.coli/(ETEC). METHODS: By using a host-plasmid balanced lethal system based on asd gene, a polyvalent recombinant strain was constructed to highly express CS3 and regularly express fusion enterotoxin of LIB subunit and mutant ST (LTB/STm) in a vaccine strain Shigella flexneri 2a T32 with specific deletion of asd gene. Fimbria CS3 was observed by immunofluorescence and electron microscopy assay. The security of LTB/STm was examined by ileal loop assay and suckling mouse assay. To evaluate this new candidate vaccine, it was compared with a previous vaccine strain in plasmid and protein level, growth assay and immunogenicity in Balb/c mice. RESULTS: The newly constructed vaccine expressed CS3 and grew better than the previously constructed vaccine except for the lower expression of LTB/STm. Serum IgG and mucosal IgA against CS3, LTB, ST, and host lipopolysaccharide (LPS) were produced after immunization of Balb/c mice by oral route with the new strain. The titers were not significantly different from the Balb/c mice with the previous strain. CONCLUSION: This novel candidate diarrheal vaccine can effectively induce serum and mucosal antibody responses against ETEC and Shigella.

In vitro activity of allicin combined with two antibiotics on intestinal Shigella

Objective: We aimed to evaluate the combined antibacterial effects of allicin in combination with levofloxacin and ceftriaxone on Shigella isolated from the intestinal tract in vitro. Materials and Methods: Using a checkerboard design, broth microdilution assay was used to test the effects of the compounds on the organism. We also determined the MIC of the two groups of antibacterial drugs against 30 strains of Shigella and calculated the fractional inhibitory concentration(FIC) index, to judge the combination effect. Result: After the combined application of allicin and ceftriaxone the MIC decreased significantly. Distribution of the FIC index was as follows: FIC ≤0.5, accounting for 10%; 0.5< FIC ≤1.0, accounting for 60%; 1 < FIC ≤2, accounting for 30%; FIC >2, percentage is zero. After combined application of allicin and levofloxacin, distribution of FIC index was as follows: FIC≤0.5, ratio is zero; 0.5< FIC ≤1, accounting for 56.7%; 1 < FIC ≤2, accounting for 43.3%; FIC >2, ratio is zero. Conclusion: After the combined use of ceftriaxone, levofloxacin, and allicin, most of the tests showed synergistic effects and additive effects on Shigella, while some of them showed no correlation and no antagonistic effect.