鸡肉源沙门氏菌对喹诺酮和氟喹诺酮类抗生素耐药状况及相关基因

【目的】研究分离于陕西、河南、四川和北京四省(市)鸡肉源沙门氏菌对喹诺酮和部分氟喹诺酮类抗生素的药敏性及相关耐药基因,更好地了解耐药性的产生和传播途径,确保食品安全。【方法】用琼脂稀释法测定沙门氏菌的药敏性,用PCR和基因序列测定法确定耐药沙门氏菌中与(氟)喹诺酮类抗生素耐药相关的喹诺酮类抗性决定区基因突变及质粒携带的耐药基因。【结果】390株沙门氏菌中,63.59%的菌株对萘啶酮酸产生抗性,21.28%、16.67%和14.62%的菌株分别对环丙沙星、左氧氟沙星和加替沙星产生抗性。248株萘啶酮酸抗性菌中,aac(6’)-Ib-cr、qnrA、qnrB和qnrS基因的检出率分别为20.16%、10.89%、10.08%和1.61%。83株耐环丙沙星的菌株中,gyrA和parC基因的点突变共199个;其中gyrA基因中以Ser83Phe和Asp87Gly双突变最为常见,其次分别为Ser83Phe和Asp87Asn双突变、Ser83Tyr、Ser83Phe、Asp87Gly;parC基因的65个点突变均为Ser80Arg突变。【结论】四省市中鸡肉源沙门氏菌耐药状况严重,其解旋酶和拓扑异构酶基因突变及质粒携带的耐药基因是导致沙门氏菌耐药的重要机制。     

食源性沙门氏菌耐药性检测及相关质粒

[目的]测定390株沙门氏菌的抗生素药敏性,研究部分多重耐药株中质粒与其宿主耐药表型之间的关系及其在接合过程中对耐药性水平转移的影响.[方法]使用选择性培养基分离到沙门氏菌并通过PCR确认后,按照琼脂稀释法测定分离株对供试抗生素的药敏性,试剂盒提取代表性多重耐药株中的质粒,HindⅢ酶切,DPS软件分析电泳后质粒图谱.通过接合试验研究质粒在抗生素抗性水平转移中的作用.[结果]沙门氏菌分离株对四环素耐药最为普遍(58.2%),其次为链霉素(42.8%)、卡那霉素(39%)和氨苄青霉素(38.2%),对头孢西丁、氯霉素、庆大霉素、头孢曲松、阿莫西林甲氧苄啶、头孢替呋钠和萘啶酮酸的耐药率分别为27.2%、26.9%、21%、19%、18.2%、17.9%、14.6%和12.3%.抗性质粒编码的相同或相似沙门氏菌耐药表型与其中所含的耐药质粒并不呈现出严格的对应关系.质粒携带的抗性基因可通过接合作用转移,接合效率在2.4×10-4到5.6×10-1之间.[结论]食源性沙门氏菌对常用抗生素的多重耐药已经成为普遍现象,抗性质粒的同源性与其宿主耐药表型无直接相关性,其携带的耐药基因可通过接合作用在不同细菌种属之间高频传递.     

杭州地区多重耐药沙门氏菌的耐药特征

【背景】沙门氏菌是重要的食源性致病菌,其多重耐药现象不容忽视。【目的】分析杭州地区临床来源多重耐药沙门氏菌的耐药特征和感染状况。【方法】利用微量肉汤稀释法对339株沙门氏菌进行14类28种药物的最低抑菌浓度(Minimum Inhibitory Concentration,MIC)测定,对同时耐3类或3类以上药物的多种耐药株进行耐药特征、血清型分布等分析,并对其进行Xba I酶切及脉冲场凝胶电泳(Pulse Field Gel Electrophoresis,PFGE)。【结果】从339株沙门氏菌中检出234株多重耐药株,多重耐药率达69.03%,近3年数据比较结果显示差异无统计学意义(χ²=0.117,P=0.943);以同时耐4-8类药物的菌株多见,合计占总菌株数的56.93%(193/339);大部分多重耐药沙门氏菌(199/234,85.04%)同时耐5-13种药物;菌株的耐药模式较为分散,相对优势的耐药谱为AMP-AMS-NAl-STR-SUL(10株,4.27%)和AMP-STR-TET-MIN-DOX-SUL(7株,2.99%);鼠伤寒单相变种和德尔卑血清型的多重耐药现象较为突出,其多重耐药率分别为97.06%(66/68)和100%(11/11);234株多重耐药沙门氏菌分为162个PFGE带型,相似度为44.2%-100%,其带型呈散在多态性;PFGE带型相同的菌株,其耐药类别和耐药谱不一定相同,PFGE带型不同的菌株,其耐药类别和耐药谱也可能相同。【结论】杭州地区临床来源沙门氏菌多重耐药现象普遍,但耐药谱分散,耐药表型呈多样性,而且PFGE带型呈散在多态性,与耐药表型也不存在对应关系。其基因组特征和主要食物来源有待于进一步研究。     

食源性沙门氏菌耐药性及质粒介导喹诺酮耐药基因检测

随机采集的638份食品样品中沙门氏菌总检出率为9.7%(n=62株),共检出16种不同的血清型,其中最常见的为鸭沙门氏菌。受试菌株对磺胺甲基异噁唑、复方新诺明、链霉素和环丙沙星的耐药率较高。16株耐环丙沙星沙门氏菌按GyrA和ParC喹诺酮耐药决定区(QRDR)不同氨基酸替代组合可分为5种突变型,其中GyrA亚基发生Ser83Phe和Asp87Gly变异,同时ParC亚基发生Ser80Arg变异为最常见的突变类型。62株食源性沙门氏菌中,qnr基因阳性的菌株共7株,占受试菌株的11.3%。qnrA和qnrS基因阳性菌株分别有2株和5株,没有菌株携带qnrB、qnrC和qnrD基因。aac(6')-Ib基因阳性菌株共有8株,其中3株经确认为携带其变体基因aac(6')-Ib-cr。结果表明,新乡市食源性沙门氏菌血清型分布呈多样性,耐药状况较为严重,并且一些菌株携带质粒介导喹诺酮耐药(PMQR)基因。     

2007-2008陕西部分零售畜禽肉沙门氏菌血清型和基因型

【目的】研究359株在2007-2008年分离于陕西部分地区零售畜禽肉中沙门氏菌的血清型和基因型,为确保食品安全提供依据。【方法】使用WHO指定的泰国SA公司的沙门氏菌诊断血清,采用玻片凝集法测定沙门氏菌的血清型。使用美国疾病预防控制中心推荐的脉冲场凝胶电泳方法确定沙门氏菌的DNA酶切图谱,BioNumerics软件分析电泳结果,确定沙门氏菌的基因型。【结果】359株沙门氏菌共检出24个血清型,以肠炎沙门氏菌(Salmonella Enteritidis)、鼠伤寒沙门氏菌(S.Typhimurium)、舒卜拉沙门氏菌(S.Shubra)、印第安纳沙门氏菌(S.Indiana)和德尔卑沙门氏菌(S.Derby)等为主,不常见血清型有圣保罗沙门氏菌(Salmonella Saintpaul)、里地乌沙门氏菌(S.Rideau)、田纳西沙门氏菌(S.Tennessee)、汤卜逊沙门氏菌(S.Thompson)、加里玛沙门氏菌(S.Galiema)、卡罗尔沙门氏菌(S.Kallo)、沙门氏菌Ⅲa(S.Ⅲa)、罗森沙门氏菌(S.Rissen)和布兰卡斯特沙门氏菌(S.Brancaster)等。鸡肉中最常见血清型为肠炎沙门氏菌,猪肉和羊肉中以德尔卑沙门氏菌检出率最高,而牛肉中以里地乌沙门氏菌为主。359株沙门氏菌使用XbaⅠ酶切分型后,按照88%的基因同源性,可分为7个大簇。同一血清型的沙门氏菌分型后基本位于同一大簇之中,虽然部分沙门氏菌的血清型不同,但分型后仍表现出较高的基因同源性和相似的基因型。【结论】陕西零售肉沙门氏菌的血清型和基因型表现为多样性的特征。     

沙门氏菌泛耐药基因组特征分析

[目的]分析沙门氏菌的泛耐药基因组特征.[方法]以EnteroBase数据库中16365株沙门氏菌为对象,利用课题组自主研发的泛耐药基因组分析软件(PRAP),进行泛耐药基因组结构的鉴定,通过曼-惠特尼秩和检验和皮尔逊检验,来分析耐药基因与血清型、序列型(sequence type,ST)及分离株样本来源信息间的相关性...     

印第安纳沙门氏菌对氯霉素类药物耐药性分析

[目的]调查鸡源沙门氏菌对氯霉素类药物的耐药特征和相关耐药基因的流行情况.[方法]从山东省部分地区鸡孵化场、养殖场、屠宰场分离样品进行沙门氏菌鉴定和药物敏感性试验;设计引物,对氯霉素类药物的耐药基因进行PCR扩增和序列分析.[结果]试验分离到印第安纳沙门氏菌,分离率为23.28％.孵化场、养殖场、屠宰场印第安纳沙门氏菌对氯霉素耐药率分别为50.00％、83.33％和93.30％,对氟苯尼考耐药率为83.33％、100％和100％,对甲砜霉素耐药率为63％、65％和77％.在80株氯霉素类耐药菌株中,54株检测到catA1基因,74株检测到floR基因,5株检测到cmlA基因.[结论]不同来源印第安纳沙门氏菌对氯霉素类药物耐药率存在差异,catA1和floR基因广泛存在于耐药菌株中.     

结核分枝杆菌的耐药基因及其相关分子机制

结核分枝杆菌原发性和继发性耐药是当前控帝】和治疗结核病面临的重要问题,随着分子遗传学的发展,已经阐明了结核分枝杆菌耐药的分子基础是染色体的突变,影响了药靶本身或激活了药物前体的细菌酶,造成MTB的耐药。本文主要就MTB对其常用药物的耐药机制展开讨论,以便正确认识MTB对不同药物的耐药机制,建立快速检测耐药结核分枝杆菌基因型的分子生物学方法。     

结核分枝杆菌的耐药基因及其相关分子机制

结核分枝杆菌原发性和继发性耐药是当前控制和治疗结核病面临的重要问题,随着分子遗传学的发展,已经阐明了结核分枝杆菌耐药的分子基础是染色体的突变,影响了药靶本身或激活了药物前体的细菌酶,造成MTB的耐药。本文主要就MTB对其常用药物的耐药机制展开讨论,以便正确认识MTB对不同药物的耐药机制,建立快速检测耐药结核分枝杆菌基因型的分子生物学方法。     

食源性沙门氏菌检测方法的研究进展

沙门氏菌(Salmonella)是一百多年前发现的一种病原体,是一种常见的重要人畜共患 病原菌,它不仅可以引起胃肠炎,还会引起伤寒、败血症及肠外灶性感染等多种症候群.在 世界各地的食物中毒中,沙门氏菌引起的中毒病例占首位或第二位,因而受到了人们强烈的 关注,而沙门氏菌的检测方法正是人们关注的焦点之一.近年来,沙门氏菌检测技术有了很 大的进展,由十分困难的传统分离培养法到免疫学检测方法发展成为今天的分子生物学检测 技术.毫无疑问,检测方法的进展在便利沙门氏菌检测的同时,也将为更好地了解沙门氏菌奠定基础.综述了食源性沙门氏菌的概况以及其检测方法的研究进展.     

Antimicrobial susceptibility of anaerobic bacteria in Bulgaria

ObjectivesThe antimicrobial susceptibility of anaerobic bacteria isolated from clinical specimens in the referent for Bulgaria anaerobic laboratory was studied in a period of 25 years/1983–2007/.MethodsNCCLS – recommended agar dilution methods were used. β-lactamase activity was determined with nitrocefin discs.ResultsThe 29 antimicrobial agents included in the study were divided according to their in vitro activity against the anaerobic isolates into 4 main groups for guiding empirical treatment: 1st group of metronidazole, chloramphenicol, meropenem, imipenem and combinations of β-lactam antibiotics with sulbactam – with high activity and drugs of choice for treatment; 2nd group – clindamycin, cefoxitin, carbenicillin/and azlocillin, piperacillin/ – with a good activity and low percent of resistant strains; 3rd group – of tetracycline and erythromycin with higher percent of resistant strains including the new macrolides as josamycin, clarithromycin, roxithromycin and azithromycin; 4th group – penicillins/ampicillin, amoxicillin, penicillin/and cephalosporins/cefamandole, cefazolin, cefotaxime and cefoperazone/ – not suitable for treatment of infections including Bacteroides fragilis group strains, with a very high percent of resistant strains, probably due to β-lactamase activity in most of the strains.ConclusionA continued updating and a follow-up in the changes of antibiotic susceptibility are necessary in every country as resistance patterns vary not only between geographical regions but also even among medical centers and hospitals which may be connected with differences in antibiotic usage in man and animals.     

用荧光标记O-I噬菌体快速检测食品源沙门氏菌

[目的]利用O-I噬菌体几乎可裂解沙门氏菌属细菌的特性建立快速检测食品中沙门氏菌的方法.[方法]用核酸荧光染料SYBR gold染料标记O-I噬菌体侵染100株试验菌及120份食品样品菌,荧光显微镜鉴定沙门氏菌;并测灵敏度.[结果]100株试验菌中40株沙门氏菌可见杆状荧光,而10株变形杆菌、20株志贺氏菌、20株大肠杆菌和10株葡萄球菌均无荧光;沙门氏菌检测灵敏度达10 CFU/100 μL;120份食品样品中沙门氏菌的O-I噬菌体检测与生化鉴定结果的阳性率分别为9.17%和10%,符合率为91.7%.[结论]试验表明用荧光标记的O-I噬菌体可以快速、直观、准确、大量地检测食品中沙门氏菌.     

Characterization of antimicrobial susceptibility and virulence genes of Salmonella serovars collected at a commercial turkey processing plant

Aims:  To determine the antimicrobial susceptibility profiles, distribution of class 1 integrons, virulence genes and genes encoding resistance to tetracycline ( tetA , tetC , tetD and tetE ) and streptomycin ( strA , strB and aadA1 ) in Salmonella recovered from turkeys.
Methods and Results:  The antimicrobial susceptibility of 80 isolates was determined using National Antimicrobial Resistance Monitoring System. The distribution of resistance genes, class 1 integrons and virulence genes was determined using PCR. Resistances to tetracycline (76·3%) and streptomycin (40%) were common. Sixty-two (77·5%) isolates displayed resistance against one or more antimicrobials and 33 were multi-drug resistant. tetA was detected in 72·5% of the isolates, while tetC , tetD and tetE were not detected. The strA and strB genes were detected in 73·8% of the isolates. Two isolates possessed class 1 integrons of 1 kb in size, containing the aadA1 gene conferring resistance to streptomycin and spectinomycin. Fourteen of the virulence genes were detected in over 80% of the isolates.
Conclusions:  This study shows that continuous use of tetracycline and streptomycin in poultry production selects for resistant strains. The Salmonella isolates recovered possess significant ability to cause human illness.
Significance and Impact of the Study:  Information from this study can be employed in guiding future strategies for the use of antimicrobials in poultry production.     

食源性相关腹泻肠炎沙门菌感染抗菌药物敏感性

目的 了解食源性相关腹泻非伤寒沙门菌感染的菌种分布及其对抗菌药物敏感性,为控制该类细菌的感染及传播提供技术支持。方法 对2015‒2017年本系统2家社区卫生服务中心就诊的食源性相关腹泻患者粪便（或肛拭子）标本采用直接分离与增菌分离相结合的方法常规培养分离获得42株沙门菌;采用血清凝集法进行快速血清分型,并自动化生化鉴定及抗菌药物敏感性试验;通过现况调查进行流行病学危险因素分析。结果 自动化生化鉴定结果能够覆盖常规血清学快速鉴定结果,同属沙门菌群;42株沙门菌以肠炎沙门菌、鼠伤寒沙门菌和斯坦利沙门菌为主,其中肠炎沙门菌占全部菌株的23.81%,鼠伤寒沙门菌占19.06%,斯坦利沙门菌占14.29%;其中肠炎沙门菌可对氟喹诺酮类、三四代头孢菌素类与碳青霉烯类等敏感（敏感率可达97.00%以上）,而对氨基糖苷类可产生双向耐药。通过现况调查,发现患者有腹痛、腹泻等胃肠道症状,可伴有发热,所有患者48 h内有可疑食物暴露史,无水源性案例,均为散发。结论 菌种鉴定应以常规快速血清学凝集结果为准,自动化生化鉴定仅供参考,并将鉴定菌种与药敏报告相关联,可根据药敏结果合理选用敏感抗菌药物;应对社区居民开展针对性的健康宣教。     

Antimicrobial peptides isolated from insects and their potential applications

Antimicrobial peptides (AMPs) in insects have the potential to be developed as chemotherapy agents against numerous microbial species. This article reviewed the existing knowledge of what have been focused so far on published materials related to AMPs isolated from insects. Previous studies were focused on peptide characterization and the mechanism pathways of different AMPs from a variety of insect Orders. Most studied insect Orders are as follows: Hymenoptera (50%), Diptera (17%), Coleoptera (13%), Lepidoptera (10%), Hemiptera (5%), Blattodea (3%) and Odonata (2%). Dozens of new AMPs have been extracted from insects recently. However, more studies in vivo and in vitro are necessary to fully understand their effect and the mechanisms of antimicrobial action to utilize their promising potential in cosmetic and pharmaceutical industries.     

Mutagenicity of ptaquiloside, the carcinogen in bracken, and its related illudane-type sesquiterpenes. I. Mutagenicity in Salmonella typhimurium

Ptaquiloside, a potent carcinogen of an illudane-type sesquiterpene glycoside isolated from Pteridium aquilium, and its related compounds, hypolosides having the same nucleus isolated from the Pteridaceae, exhited marked mutagenicity in the modified Ames test with Salmonella typhimurian TA98 and A100 using a preincubation at pH 8.5 Illudins M and S, sesquiterpenes of the same illudane type from basidiomycetes, also exhibited mutagenicity. The structural requirements for mutagenicity are discussed.     

鸡白痢沙门菌ipaJ基因的克隆与鉴定

摘要：【目的】从鸡白痢沙门菌C79-13中克隆ipaJ基因,体外表达该蛋白后进行免疫原性分析。【方法】鸡白痢沙门菌C79-13与肠炎沙门菌50041进行抑制差减杂交后获得的片段PEA2、PE31和PE44与猪霍乱沙门菌C500疫苗株pSFD10质粒上ipaJ基因高度同源,拼接后获得了鸡白痢沙门菌完整的ipaJ基因序列。从鸡白痢沙门菌中克隆出ipaJ基因并将其构建到原核表达载体pET-30a(+)上,Western-blot检测体外表达蛋白的免疫原性,同时检测了该基因在鸡白痢沙门菌分离株中的分布。【结果】从鸡白痢沙门菌中克隆了大小为840 bp的ipaJ基因序列,并获得了体外原核表达的大小为37 kDa融合蛋白。该蛋白可与鸡白痢沙门菌阳性血清反应。PCR结果显示该基因广泛存在于鸡白痢沙门菌菌株中。 【结论】本文首次报道和克隆了鸡白痢沙门菌ipaJ基因,并证明了IpaJ蛋白具有免疫原性。