北京市2010-2020年多重耐药肯塔基沙门菌流行特征分析

目的 了解北京市肯塔基沙门菌临床分离株的流行情况、耐药水平及分子特征。方法 对2010-2020年分离的22株肯塔基沙门菌采用微量肉汤稀释法进行抗生素药物敏感性检测;全基因组测序进行多位点序列分型、基因组岛和耐药基因识别。采用PFGE分析菌株的分子流行病学特征。结果 22株菌对8~22种抗生素耐药,尤其是对环丙沙星、阿奇霉素和头孢菌素类等都表现为超高水平的多重耐药。21株菌超广谱β-内酰胺酶表型阳性。全基因组序列分析显示,22株肯塔基沙门菌均为ST198,携带SGI1-K基因组岛。所有菌株均有耐药基因tetA、sul1、qacE,喹诺酮耐药决定区gyrA基因存在2个突变位点（S83F、D87 N）、parC基因存在3个突变位点（T57S、S80I、T255S）。β-内酰胺类相关耐药基因（blaCTX-M-55、blaCTX-M-14b、blaTEM-141、blaTEM-206、blaTEM-209、blaTEM-214、blaTEM-1B）、氨基糖甙类耐药相关基因[aac（3）-Id、aac（3）-IId、aac（6''）-Iaa、aadA7、aadA17、aph（3''）-Ia、aph（3''）-Ib、aph（6）-Id、rmtB]以及floR、dfrA14、mphA和qnrS1等基因在不同年代菌株间存在明显差异。PFGE图谱分析显示,22株菌株之间相似性>85%,与全球广泛传播的ST198-X1流行株高度同源,在传播扩散过程中,耐药谱和PFGE图谱都发生了变化,分为两大聚类簇。结论 北京市流行的肯塔基沙门菌为多重耐药的ST198-X1-SGI-1K国际流行株,自2016年以来保持低水平流行,引起散发感染病例和聚集性腹泻事件。对氟喹诺酮类、ESBL和阿奇霉素等耐药严重,应加强多重耐药肯塔基沙门菌的监测。     

上海市2012－2013年4种致泻性大肠埃希菌监测

目的 基于临床医院开展4种致泻性大肠埃希菌(DEC)人群监测,探讨公共卫生实验室对临床实验室需求的直接技术指导的实践模式。方法 设立哨点医院,以标准化方法筛选和鉴定DEC菌型;构建DEC流行特征基线;对疑似暴发病例开展基于实验室和流行病学调查。结果 2012－2013年选择上海地区4家哨点医院检测7 204份腹泻标本确认的712例DEC感染病例,阳性率为9.9%。其中肠致病性大肠埃希菌(EPEC)感染351例;肠产毒性大肠埃希菌(ETEC)感染292例;肠侵袭性大肠埃希菌(EIEC)感染32例;产志贺样毒素大肠埃希菌(STEC/EHEC)感染6例;DEC混合感染31例。EPEC感染以1～5岁儿童最多见,菌型均为aEPEC;ETEC流行峰值在8月,阳性率>20%,感染病例2012年聚集于1～28日龄和2013年的20～60岁人群(P< 0.05),菌型以耐热肠毒素(ST)型最多(59.6%),其次为不耐热肠毒素(LT)型(27.8%)和ST/LT型(12.6%);2013年儿童感染EIEC病例明显增加(P< 0.01);未监测到EHEC O157 : H7,但确认2例EHEC O26 : H11(eae-hlyA-stx1a)儿童病例;调查确认2012年上海地区15例新生儿ETEC聚集性感染病例与四川省自贡市新生儿病例属于同一克隆(STh-CS21-CFA/I-ClyA-EatA-ST2332- SHNL0005)。结论 上海地区DEC型谱特征已发生改变,ETEC对新生儿院内感染和食源性感染性腹泻构成潜在暴发风险,需加强实验室主动监测。     

上海市浦东新区食源性小肠结肠炎耶尔森菌耐药及分子流行病学特征

目的 了解上海市浦东新区食源性小肠结肠炎耶尔森菌耐药及分子流行病学特征。方法 2012-2016年主动、定点采集上海市浦东新区4类流通生鲜食品,使用冷增菌方法分离小肠结肠炎耶尔森菌,并分析菌株生物型、血清型、毒力基因型、耐药性和PFGE分子型别。结果 共采集食品3 900份（禽类590份、畜类1 074份、水产品1 488份、蔬菜748份）,其中111份（2.8%）检出小肠结肠炎耶尔森菌。禽类制品（5.3%,31/590）和畜类制品（4.5%,48/1 074）的检出率高于水产品（1.6%,24/1 488）和蔬菜制品（1.1%,8/748）。分离株以生物1A型（95.5%）和O：8血清型（42.3%）为主,且分离数与年总分离数呈正相关。所有菌株均缺失4种（ail、ystA、yadA和virF）产毒株标记的毒力基因,76株（68.5%）ystB基因阳性（其中35株属于1A/O：8/ystB）。分离株对氨苄西林（74.8%）和阿莫西林/克拉维酸（70.3%）的耐药率最高,对头孢西丁不敏感率超过50.0%;未发现三代头孢菌素或氟喹诺酮类抗菌药物耐药株,38.7%（43/111）的菌株为多重耐药。O：8和O：5血清型菌株分别存在44和18种PFGE分子型别。结论 上海市浦东新区食源性小肠结肠炎耶尔森菌暴露风险以禽类制品和畜类制品为主,优势菌型为1A/O：8/ystB,虽无典型产毒株特征但仍有潜在致病力。菌株耐药率处于较低水平但存在多重耐药株,PFGE分子型别提示菌株呈高度遗传多样性。     

深圳市腹泻人群致泻性大肠埃希菌流行及病原特征研究

目的 了解深圳地区腹泻患者中致泻性大肠埃希菌(DEC)的流行状况及病原特征。方法 对2014年深圳市4家哨点医院门诊急性腹泻患者粪便标本进行DEC的分离、分子鉴定、血清分群及PFGE分型。结果 1 823份粪便标本中分离到74株DEC,阳性分离率为4.06%;感染病例年龄分布以 <3岁的婴幼儿及20～39岁中青年为主,病例集中在5-9月夏秋季。以肠产毒性大肠埃希菌(ETEC)和肠致病性大肠埃希菌(EPEC)为主,分别占45.9%和31.1%。ETEC以O159最多,2株及以上PFGE带型一致的菌株有5簇;其他型别DEC血清型和PFGE带型均较分散。结论 2014年深圳地区腹泻病患者DEC的感染类型以ETEC和EPEC为主,存在年龄及季节分布特征,菌株的血清型及PFGE分子带型较分散,应警惕ETEC的暴发风险。     

广东省2013-2014年食源性疾病主动监测的病原学特征分析

目的 了解广东省腹泻病例中沙门菌、志贺菌、副溶血弧菌和4种致泻性大肠埃希菌［肠产毒性大肠埃希菌（ETEC）、肠致病性大肠埃希菌（EPEC）、产志贺毒素大肠埃希菌（STEC）、肠侵袭性大肠埃希菌（EIEC）］的感染情况及其血清型别、耐药变化和分子特征。方法 对2013-2014年广东省食源性疾病主动监测检出的沙门菌、志贺菌、副溶血弧菌和4种致泻性大肠埃希菌菌株进行血清分型、药物敏感试验和PFGE分型。结果 2013-2014年检测粪便标本57 834份,分离到3 372株致病菌,检出率为5.83%;沙门菌的检出阳性率最高,其次是副溶血弧菌、致泻性大肠埃希菌、志贺菌。3 213株沙门菌分为143种血清型,最常见的血清型为鼠伤寒、4,5,12：i：-、肠炎、斯坦利和德尔卑沙门菌。沙门菌对头孢类和氟喹诺酮类药物均较敏感;不同血清型沙门菌对抗生素的耐药率有明显差异,10种最常见血清型中,肠炎沙门菌对头孢类药物的耐药率最高,德尔卑沙门菌对环丙沙星的耐药率最高。2 289株各血清型沙门菌的PFGE型别分布多样,表现出较大的指纹图谱多态性。85株副溶血弧菌分为10种血清型,最主要的血清型为O3：K6（61.18%）,其次是O4：K8（10.59%）;tdh携带率高（81.18%）,trh携带率较低（7.06%）,有10株菌（11.76%）不携带该两种毒力基因;副溶血弧菌对亚胺培南、萘啶酸、复方新诺明、氯霉素、四环素的敏感率均>95%。13株志贺菌分别为宋内志贺菌9株、福氏志贺菌3株、鲍氏志贺菌1株;对头孢他啶、环丙沙星、氯霉素较敏感（76.92%）。检出的86株致泻性大肠埃希菌中ETEC 29株（33.72%）,EPEC 27株（31.39%）,STEC 27株（31.39%）,EIEC 3株（3.48%）。结论 2013-2014年广东省食源性疾病主动监测中沙门菌检出率最高（5.57%）,其次是副溶血弧菌、致泻性大肠埃希菌、志贺菌;沙门菌、副溶血弧菌和志贺菌对头孢类和氟喹诺酮类药物敏感;沙门菌感染中仅发现聚集性病例,但未监测到暴发。     

泰安市腹泻门诊病例粪便中肺炎克雷伯菌检出率、耐药特征和分子分型研究

目的 了解泰安市感染性腹泻病门诊病例粪便中肺炎克雷伯菌的检出率、耐药特征及分子分型特性。方法 对采自泰安市6个县（市、区）2013-2017年腹泻病症候群监测病例的866份粪便标本进行肺炎克雷伯菌的分离培养和鉴定;采用微量肉汤稀释法研究分离菌株的耐药情况;应用PFGE技术对菌株进行分子分型。结果 肺炎克雷伯菌的总检出率为7.97%（69/866）;各县（市、区）检出率差异有统计学意义（χ²=39.627,P=0.000）。耐药菌株68株的15种常用抗生素的总耐药率为98.55%（68/69）,对氨苄西林（AMP）和磺胺异恶唑（SOX）的耐药率最高,分别为84.06%（58/69）和72.46%（50/69）,共有40个耐药谱,主要耐药谱特征为AMP-SOX（n=10）;多重耐药率为33.33%（23/69）。69株分离株中共有65种PFGE型别,未发现优势带型或聚集现象。结论 肺炎克雷伯菌存在于泰安市各地区腹泻病症候群门诊病例的粪便中,能够引起社区获得性感染;对多种抗生素耐药,耐药谱广,多重耐药率高;PFGE带型呈现多样性,无耐药谱对应性。应高度重视和加强对该来源菌株的监测,防止更多的耐药菌株的产生和传播,保护易感人群。     

危重症新型冠状病毒肺炎合并多重耐药菌感染危险因素

目的 分析重型、危重型（以下简称危重症）新型冠状病毒肺炎（COVID-19）合并多重耐药菌感染的危险因素。 方法 回顾性分析某省某定点医院2020年1—4月重症隔离病区危重症COVID-19患者的临床资料,选取合并多重耐药菌感染的患者为病例组,未合并多重耐药菌感染的患者为对照组。比较两组患者临床资料,采用多因素logistic回归分析危重症COVID-19合并多重耐药菌感染的危险因素。 结果 共有62例危重症COVID-19患者。其中合并多重耐药菌感染患者10例,未合并多重耐药菌感染患者52例。62例患者中14例合并细菌或真菌感染,感染率为22.6%;10例合并多重耐药菌感染,感染率为16.1%,分别为耐碳氢霉烯类肺炎克雷伯菌（CRKP）感染4例,耐碳氢霉烯类鲍曼不动杆菌（CRAB）感染6例;合并非多重耐药菌或真菌感染共9例（11株）。单因素分析结果表明,病例组中心静脉置管比例、抗菌药物使用种类、使用抗菌药物种类≥4种比例均高于对照组;病例组清蛋白水平低于对照组;差异均有统计学意义（均P < 0.05）。多因素分析结果表明,危重症COVID-19合并多重耐药菌感染独立危险因素为抗菌药物使用种类≥4种（OR=17.104,95%CI：1.805~162.033）,清蛋白为保护因素（OR=0.834,95%CI：0.709~0.982）。 结论 危重症COVID-19患者应合理使用抗菌药物,提高清蛋白水平,有利于预防与控制危重症COVID-19合并多重耐药菌感染的发生。     

广东省新型冠状病毒肺炎病例临床转归及其影响因素

目的 分析广东省新型冠状病毒肺炎（COVID-19）病例的临床转归及其影响因素,为优化医疗救治及疫情防控的策略提供参考依据。方法 通过流行病学调查和进程追踪,收集广东省截至2020年3月4日COVID-19确诊病例1 350例的基本人口学特征、既往病史、就诊经过和临床转归等信息,分析确诊病例的临床分型、病程特点及其相关影响因素。结果 广东省COVID-19确诊病例1 350例中,临床分型为轻型、普通型、重型和危重型（重症）分别为5.3%（72/1 350）、77.7%（1 049/1 350）、12.1%（164/1 350）和4.3%（58/1 350）,粗死亡率为0.5%（7/1 350）。病程时间中位数为23（P₂₅,P₇₅：18,31）d,住院时间中位数为20（P₂₅,P₇₅：15,27）d。出现重症时间中位数为发病第12（P₂₅,P₇₅：第9,15）天,重症持续时间中位数为8（P₂₅,P₇₅：4,14）d。1 066例已出院/死亡病例中,入院轻型病例出现普通型的占36.4%（36/99）,出现重型的占1.0%（1/99）;入院普通型病例出现重型、危重型的分别占5.2%（50/968）、0.6%（6/968）;重型病例出现危重型的占11.4%（10/88）。病例出现重症的影响因素包括男性（aHR=1.87,95% CI：1.43~2.46）、年龄较大（aHR=1.67,95% CI：1.51~1.85）、发病至首诊第2~3天就诊（aHR=1.73,95% CI：1.20~2.50）、合并糖尿病（aHR=1.75,95% CI：1.12~2.73）、合并高血压（aHR=1.49,95% CI：1.06~2.09）。结论 广东省COVID-19病例病程和住院时间普遍较长,且与其临床分型严重程度有关,重症病例主要集中在特定人群,在疫情高发时期,为确保医疗资源的合理配置,需根据隔离和救治等防控需求对病例分类管理。     

石家庄市男男性行为人群HIV自我检测及相关因素分析

目的 分析石家庄市MSM HIV自我检测（自检）及相关因素。方法 2020年8-9月,在石家庄市采用方便抽样招募MSM,利用线上调查问卷,收集其社会人口学、行为学和HIV自检等信息,采用logistic回归分析HIV自检相关因素。结果 共调查MSM 304人,最近6个月HIV自检率为52.3%（159/304）,其中95.0%（151/159）使用指尖血HIV检测试剂;获得HIV检测试剂的途径,以自己购买（45.9%,73/159）和通过MSM社会组织领取（44.7%,71/159）为主;选择HIV自检原因为检测时间不受限制（67.9%,108/159）和保护隐私（62.9%,100/159）,不选择原因为自己不会操作（32.4%,47/145）、不知道有HIV自检试剂（24.1%,35/145）和担心自检结果不准确（19.3%,28/145）。多因素logistic回归分析结果显示,18~29岁（aOR=2.68,95%CI：1.20~5.94）、最近6个月在当地领取过HIV自检包（aOR=8.61,95%CI：4.09~18.11）和主要交友途径通过互联网/社交软件（aOR=2.68,95%CI：1.48~4.88）的MSM更倾向于选择HIV自检。结论 HIV自检为MSM提供了一种更灵活、方便的检测途径,应加强HIV自检的推广,进一步提高MSM的HIV检测率。     

山东省艾滋病病毒感染者抗病毒治疗继发性耐药影响因素的病例对照研究

目的 了解HIV感染者抗病毒治疗发生继发性耐药的影响因素,为提高山东省抗病毒治疗效果提供依据。方法 按照病例对照研究设计,1∶2匹配病例组和对照组,2015年10月进行入户面对面调查。根据山东省级实验室自建的HIV感染者抗病毒治疗耐药数据库和艾滋病综合防治数据信息系统,筛选研究对象。样本量估计为330例（病例110例、对照组220例）,研究对象为在山东省存活的HIV感染者、年龄≥15岁、参加抗病毒治疗≥6个月并检测病毒载量（VL）。针对VL>1 000拷贝/ml者进行实验室耐药检测,筛选出继发性耐药者作为病例组,非继发性耐药者为对照组。采用EpiData 3.1软件和SPSS 22.0软件建立数据库,运用非条件逐步logistic回归分析继发性耐药的影响因素。结果 研究对象共288例（病例组103例、对照组185例）。病例组年龄为（37.62±1.06）岁,对照组年龄为（37.90±0.74）岁,以男性、已婚/同居者、高中及以下文化程度、汉族为主。多因素logistic回归分析结果显示,与治疗时间<1年相比,治疗时间1～3年和>3年的OR值分别为8.80（95% CI：3.69～21.00）、3.00（95% CI：1.20～7.53）;与未漏服相比,漏服比例>25.0%的OR值为15.41（95% CI：4.59～51.71）;本人领药OR值为0.22（95% CI：0.07～0.74）。结论 HIV感染者的治疗时间、漏服比例、本人领药为其抗病毒治疗继发性耐药的影响因素。治疗时间≥1年、漏服药物比例>25%为继发性耐药的危险因素,本人领药为继发性耐药的保护因素。应加强治疗优化的干预力度,提高HIV感染者本人对服药的认知水平。     

Serotypes and colonization factors of enterotoxigenic Escherichia coli isolated in various countries

One hundred and six enterotoxigenic E. coli (ETEC) isolated from many geographical areas were serotyped and investigated for the presence of colonization factor antigens CFA/I and CFA/II, the expression of mannose-resistant haemagglutination (MRHA) and the levels of surface hydrophobicity. CFA/I was found in 6 (17%) of 36 LT⁺STa⁺ strains and in 15 (54%) of 28 STa⁺ strains; CFA/II was found in 16 (44%) of 36 LT⁺STa⁺ strains. None of 42 LT⁺ strains showed CFA/I or CFA/II. CFA/I was found in ETEC of serotypes O63:K?:H?, O78:K80, O128:K67 and O153:K?:H45, whereas CFA/II was found in serotypes O6:H?, O6:K15:H16 and 06:K?:H40. Of the 69 CFA/I^? CFA/II^? ETEC strains, 9 (13%) showed MRHA with some of the seven erythrocyte species used and 21 (30%) were hydrophobic. Among the 21 hydrophobic strains CFA-negative we have detected: (i) 6 LT⁺ strains of serogroup O25 negative for MRHA, (ii) 5 strains O159 (4 LT⁺ and 1 LT⁺ STa⁺) also negative for MRHA, and (iii) 3 STa⁺ strains of serotype O27:K?:H7 that haemagglutinated calf and sheep erythrocytes when grown on Minca-Is. The 106 ETEC strains belonged to 20 different 0 serogroups. However, 77 (73%) were of one of nine serogroups (O6, O8, O25, O27, O78, O148, O153, O159 and O167). E. coli strains belonging to O6 and O153 groups predominated among ETEC isolated in Spain, O159 strains in the Central African Republic, O25 and O148 strains in Japan, and O15 and O78 strains in India.     

Isolation of enterotoxigenic Escherichia coli from British troops in Saudi Arabia.

Specimens from 181 patients with diarrhoea were examined by a Military General Hospital in a 3-month period during deployment of troops to Saudi Arabia in 1990/1. DNA probes for heat labile (LT) and heat stable (ST) enterotoxin genes identified enterotoxigenic Escherichia coli (ETEC) in 47 of the specimens (26%) and 49 ETEC strains were isolated. The majority (55%) belonged to a novel ETEC serotype having the O-antigen 159 and a flagellar antigen designated as a provisional new type. They produced ST and the coli surface associated antigen (CS)6. Strains of serotype O6:H16 represented 22% of the ETEC examined. They produced ST, LT and CS3 together with either CS1 or CS2. The remaining ETEC belonged to seven O:H serotypes. Overall, ST was the only enterotoxin gene identified in 73% of the ETEC and 67% of the strains expressed CS6 in the absence of other colonization antigens. Resistance to three or more antibiotics was observed in 53% of the ETEC, including most of the O159 strains.     

Outbreaks of cholera-like diarrhoea caused by enterotoxigenic Escherichia coli in the Brazilian Amazon Rainforest

The relationship between enteropathogens and severe diarrhoea in the Brazilian Amazon is poorly understood. In 1998, outbreaks of acute diarrhoea clinically diagnosed as cholera occurred in two small villages localized far from the main cholera route in the Brazilian rainforest. PCR was performed on some enteropathogens and heat-labile (LT) and/or heat-stable (STh) toxin genes, the virulence determinants of enterotoxigenic Escherichia coli (ETEC), were detected. Further characterization of ETEC isolates revealed the presence of two clones, one from each outbreak. One presenting serotype O167:H5 harboured LT-I and STh toxin genes and expressed the CS5CS6 colonization factor. The other, a non-typeable serotype, was positive for the LT-I gene and expressed the CS7 colonization factor. The current study demonstrates the importance of molecular diagnosis in regions such as the Amazon basin, where the enormous distances and local support conditions make standard laboratory diagnosis difficult. Here we also show that the mis-identified cholera cases were in fact associated with ETEC strains. This is the first report of ETEC, molecularly characterized as the aetiological agent of severe diarrhoea in children and adults in the Brazilian Amazon Rainforest.     

Antibodies derived from an enterotoxigenic Escherichia coli (ETEC) adhesin tip MEFA (multiepitope fusion antigen) against adherence of nine ETEC adhesins: CFA/I,CS1, CS2, CS3, CS4, CS5, CS6, CS21 and EtpA

Diarrhea continues to be a leading cause of death in children younger than 5 years in developing countries. Enterotoxigenic Escherichia coli (ETEC) is a leading bacterial cause of children's diarrhea and travelers’ diarrhea. ETEC bacteria initiate diarrheal disease by attaching to host receptors at epithelial cells and colonizing in small intestine. Therefore, preventing ETEC attachment has been considered the first line of defense against ETEC diarrhea. However, developing vaccines effectively against ETEC bacterial attachment encounters challenge because ETEC strains produce over 23 immunologically heterogeneous adhesins. In this study, we applied MEFA (multiepitope fusion antigen) approach to integrate epitopes from adhesin tips or adhesive subunits of CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS21 and EtpA adhesins and to construct an adhesin tip MEFA peptide. We then examined immunogenicity of this tip MEFA in mouse immunization, and assessed potential application of this tip MEFA for ETEC vaccine development. Data showed that mice intraperitoneally immunized with this adhesin tip MEFA developed IgG antibody responses to all nine ETEC adhesins. Moreover, ETEC and E. coli bacteria expressing these nine adhesins, after incubation with serum of the immunized mice, exhibited significant reduction in attachment to Caco-2 cells. These results indicated that anti-adhesin antibodies induced by this adhesin tip MEFA blocked adherence of the most important ETEC adhesins, suggesting this multivalent tip MEFA may be useful for developing a broadly protective anti-adhesin vaccine against ETEC diarrhea.     

Epidemiology and properties of heat-stable enterotoxin-producing Escherichia coli serotype O169:H41.

Enterotoxigenic Escherichia coli (ETEC) serotype O169:H41 organisms have become the most prevalent ETEC in Japan since the first outbreak in 1991. It was assumed that the outbreaks were due to clonal spread of this new ETEC serotype. The relationship of 32 strains isolated from 6 outbreaks were examined for biotype, antibiotic susceptibility, enterotoxigenicity, protein banding pattern, lipopolysaccharide banding pattern, plasmid analysis, and ribotyping. Further, the strains were examined by haemagglutination, surface hydrophobicity, and the ability to adhere to HEp-2 cells. The present study suggests that the outbreaks were caused by multiple clones of STp-producing O169:H41 since they showed differences in ribotype and outer membrane protein banding patterns. The strains did not agglutinate human or bovine red blood cells in a mannose-resistant manner. They adhered to HEp-2 cells in a manner resembling enteroaggregative E. coli. Five strains were examined by dot-blot tests for the colonization factor antigens CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS7, PCFO159, PCFO166 and CFA/III. Although four strains expressed CS6, no structure for CS6 was identified. A strain that the anti-CS6 MAbs did not react with could adhere to HEp-2 cells in mannose resistant manner; thus, it is unlikely that CS6 play an important role in the adhesion to the cells. Electron microscopy studies of the O169:H41 strains suggested that curly fimbriae, a possible new colonization factor, may be playing an important role in the adhesion of the bacteria to HEp-2 cells. In conclusion, outbreaks due to ETEC O169:H41 were caused by multiple clones, and the strains should be examined in detail for a possible new colonization factor.     

上海市2013-2016年门诊腹泻患者弯曲菌流行特征及耐药研究

目的 了解2013-2016年上海市门诊腹泻患者弯曲菌流行特征及耐药情况。方法 2013-2016年,采用膜过滤法对上海市23家医院肠道门诊腹泻病例粪便肛拭标本开展弯曲菌检测,并用常规生化试验和PCR方法鉴定分离菌株。采用微量肉汤稀释法对弯曲菌进行8种抗菌药物（阿奇霉素、环丙沙星、红霉素、庆大霉素、四环素、萘啶酸、泰利霉素、克林霉素）敏感试验。结果 在10 444例腹泻患者粪便肛拭标本中共分离到179株弯曲菌,检出率为1.7%,其中空肠弯曲菌占94.4%,结肠弯曲菌占5.6%。不同年龄人群弯曲菌检出率存在差异,儿童的检出率比成年人高。4-6月和10-12月是弯曲菌的发病高峰。空肠弯曲菌对环丙沙星、四环素、萘啶酸的耐药率高,为96.4%、83.4%、81.7%,结肠弯曲菌耐药率高于空肠弯曲菌,人源弯曲菌存在多重耐药菌株。结论 弯曲菌是上海市腹泻病门诊重要病原体之一,存在不同年龄人群、不同季节的分布差异。上海市人源弯曲菌对环丙沙星、四环素、萘啶酸的耐药情况严重。     

广东省和广西壮族自治区部分地区2014-2016年宋内志贺菌病原学特征分析

目的 了解2014-2016年广东省和广西壮族自治区部分地区宋内志贺菌暴发分离株及散发分离株的病原学特征。方法 对2014-2016年广东省和广西壮族自治区柳州市分离的14株宋内志贺菌暴发菌株和6株散发菌株进行抗生素敏感性试验和PFGE分析,并选择其中6株代表菌株进行全基因组测序,与NCBI上获取的51株国内外宋内志贺菌的基因组进行遗传进化分析。结果 抗生素敏感性检测结果显示,试验菌株对氨苄西林、四环素、庆大霉素、复方新诺明和萘啶酸有较高的耐药性,对阿奇霉素、氯霉素和亚胺培南完全敏感。PFGE分子分型显示,不同地区不同来源的分离株之间PFGE指纹图谱有很高的相似度（93.2%）,基于全基因组的遗传进化分析显示,广东省和广西壮族自治区柳州市的宋内志贺菌分离株同处在一个进化分支上,与来自韩国的菌株亲缘关系最为接近。结论 广东省和广西壮族自治区部分地区分离的宋内志贺菌对常用抗生素具有较高的耐药性,对阿奇霉素、氯霉素和亚胺培南有较高的敏感性。试验菌株之间具有相似的PFGE指纹图谱,遗传进化关系相近。     

Evaluation of the immunogenicity and protective efficacy of a recombinant CS6-based ETEC vaccine in an Aotus nancymaae CS6 + ETEC challenge model

Colonization factors or Coli surface antigens (CFs or CS) are important virulence factors of Enterotoxigenic E. coli (ETEC) that mediate intestinal colonization and accordingly are targets of vaccine development efforts. CS6 is a highly prevalent CF associated with symptomatic ETEC infection both in endemic populations and amongst travelers. In this study, we used an Aotus nancymaae non-human primate ETEC challenge model with a CS6 + ETEC strain, B7A, to test the immunogenicity and protective efficacy (PE) of a recombinant CS6-based subunit vaccine. Specifically, we determined the ability of dscCssBA, the donor strand complemented recombinant stabilized fusion of the two subunits of the CS6 fimbriae, CssA and CssB, to elicit protection against CS6 + ETEC mediated diarrhea when given intradermally (ID) with the genetically attenuated double mutant heat-labile enterotoxin LT(R192G/L211A) (dmLT). ID vaccination with dscCssBA + dmLT induced strong serum antibody responses against CS6 and LT. Importantly, vaccination with dscCssBA + dmLT resulted in no observed diarrheal disease (PE = 100%, p = 0.03) following B7A challenge as compared to PBS immunized animals, with an attack rate of 62.5%. These data demonstrate the potential role that CS6 may play in ETEC infection and that recombinant dscCssBA antigen can provide protection against challenge with the homologous CS6 + ETEC strain, B7A, in the Aotus nancymaae diarrheal challenge model. Combined, these data indicate that CS6, and more specifically, a recombinant engineered derivative should be considered for further clinical development.     

Construction of a non-toxigenic Escherichia coli oral vaccine strain expressing large amounts of CS6 and inducing strong intestinal and serum anti-CS6 antibody responses in mice

Coli surface antigen 6 (CS6) is one of the most prevalent non-fimbrial colonization factors (CFs) of enterotoxigenic Escherichia coli (ETEC) bacteria, which are the most common cause of diarrhea among infants and children in developing countries. Since immune protection against ETEC is mainly mediated by locally produced IgA antibodies in the gut, much effort is focused on the development of an oral CF-based vaccine. Previous work has described the preparation of candidate E. coli vaccine strains expressing immunogenic amounts of fimbrial CF antigens such as CFA/I and CS2, which are retained after formalin treatment. However, attempts to generate E. coli expressing immunogenic amounts of CS6 and to preserve the immunological activity of the CS6 protein in a killed whole-cell vaccine have failed until now. Here we describe the construction of a recombinant non-toxigenic E. coli strain, with thyA as a non-antibiotic-based selection, which expresses large amounts of CS6 antigen on the bacterial surface, and show that phenol inactivation of the bacteria does not destroy the CS6 antigen properties. Oral immunization of mice with such phenol-killed CS6 over-expressing E. coli bacteria induced strong fecal and intestinal IgA and serum IgG + IgM antibody responses to CS6 that exceeded the responses induced by an ETEC reference strain naturally expressing CS6 and previously used as a vaccine strain. Our data indicate that the described phenol-inactivated non-toxigenic and CS6 over-expressing E. coli strain may be a useful component in an oral ETEC vaccine.