氟哌酸和黄连素对志贺氏菌耐药性质粒消除研究

用氟哌酸和黄连素对２０株携有接合传递耐药性质粒（Ｒ质粒）及１９株携有非接合传递耐药性质粒（ｒ质粒）志贺氏菌进行体外消除研究。结果显示，可被消除的耐药性质粒大多数在２４小时内被消除。氟哌酸对Ｒ质粒及ｒ质粒消除率分别为５％和５２．６％，黄连素对Ｒ质粒及ｒ质粒消除率分别为１０％和５７．９％，两种药物对ｒ质粒消除率明显优于对Ｒ质粒消除率，其原因可能与ｒ质粒分子量小，非传递性及在药物作用下易于丢失有关。氟哌酸和黄连素均为广谱抗菌药物，因此在临床上治疗感染的同时又能消除耐药性质粒，阻止耐性扩散。     

细菌性痢疾流行特点及志贺菌耐药性研究

目的研究近年来肠道门诊细菌性痢疾流行概况及志贺菌耐药特点,为细菌性痢疾临床治疗和预防控制提供依据。方法采用志贺菌及沙门菌琼脂培养基培养,可疑菌株经VITEK-32细菌鉴定仪及血清凝集鉴定到群,K-B法检测抗菌药物的耐药性,纸片确认试验检测产超广谱β-内酰胺酶（ESBLs）,三维试验检测AmpCβ-内酰胺酶（AmpC酶）。结果 279例细菌性痢疾感染患者主要以宋内志贺菌（201株,占72.4%）和福氏志贺菌（76株,占27.2%）感染为主,且患者主要集中在0～11岁年龄段,占总感染率的71.3%（199/279）,高发季节为7-11月。药敏结果显示,志贺菌对氨苄西林、哌拉西林和复方新诺明的耐药率较高,均〉60%;对环丙沙星和左旋氧氟沙星的耐药率较低,均〈40%,未发现耐哌拉西林/他唑巴坦和亚胺培南的志贺菌。151株志贺菌纸片确认试验为产ESBLs阳性菌株,占54.1%（151/279）;未发现AmpC酶阳性者。结论我院肠道门诊细菌性痢疾以感染宋内志贺菌和福氏志贺菌的婴幼儿为主,且宋内志贺菌有增高趋势,2种志贺菌对部分种类的抗菌药物药敏性差别较大,临床医师应根据菌群鉴定及药物敏感试验结果合理选择抗菌药物。     

志贺氏菌感染的研究进展

志贺氏菌感染的研究进展张开瑞志贺氏菌感染是我国夏秋季常见的以腹泻为主的急性肠道传染病。在环境卫生及卫生习惯不良的情况下，易于流行。因此，积极防治本病，对保障人民健康，具有重要意义。现将其研究进展作一扼要介绍。一、志贺氏菌菌群分布与变迁志贺氏菌属菌型较...     

福氏志贺菌对诺氟沙星耐药性及耐药机制的研究

目的研究福氏志贺菌对诺氟沙星的耐药性及耐药机制。方法收集福氏志贺菌３０株,进行抗菌药物敏感试验,４株耐药菌,１株敏感菌和福氏志贺菌标准菌５１５７３的ｇｙｒＡ基因的Ｎ末端编码区进行ＰＣＲ扩增并克隆和测序。结果福氏志贺菌对诺氟沙星的耐药率高达５３．３％,ｇｙｒＡ基因的序列分析结果揭示存在３个导致氨基酸改变的基因点突变：丝氨酸８３→亮氨酸,天冬氨酸８７→天冬酰氨,天冬氨酸８７→甘氨酸。结论福氏志贺菌对诺氟沙星已有较高的耐药性,ｇｙｒＡ基因点突变与福氏志贺菌对诺氟沙星的耐药性有关。     

宋内志贺菌流行新趋势和耐药新特点

志贺菌是感染性腹泻的主要病原.其中宋内志贺菌的流行出现新趋势,不但在发达国家是优势流行株,在发展中国家的流行率也逐渐增加,已取代福氏志贺菌成为主要流行菌群.宋内志贺菌对临床常用抗生素(包括头孢菌素)的耐药性升高并快速增长,产生了超广谱β-内酰胺酶及AmpC酶,产生率为0.12％～12.74％,引起广泛关注,但实际的耐药状况更加严峻.目前报道的耐药基因型包括SHV-11、CTX-M-2、CTX-M-3、CTX-M-14、CTX-M-15、CTX-M-27、CTX-M-39、CTX-M-64、CTX-M-65、CTX-M-79、TEM-15、TEM-17、TEM-19、TEM-20、TEM-52和CMY-2等,提示须要加强耐药机制的研究,提高警惕并加强监测.     

临床分离志贺菌质粒介导喹诺酮类耐药基因的检测

目的 了解临床分离志贺菌质粒介导喹诺酮类耐药基因的种类、分布以及对抗菌药物的耐药性。方法 PCR法检测137株志贺菌的qnr、aac(6′)- Ib-cr和qepA基因,对阳性扩增产物进行测序分析并对阳性菌株做接合试验,采用琼脂倍比稀释法测定志贺菌、受体菌和接合子对喹诺酮类及其他抗菌药物的最低抑菌浓度(MIC)。PCR...     

天津地区福氏志贺菌整合子携带及耐药性研究

目的了解天津地区不同年份福氏志贺菌血清型分布,整合子携带情况,耐药性及其变化趋势。方法采用血清学方法对天津地区不同年份分离的56株福氏志贺菌进行分型;PCR扩增整合子整合酶及可变区,并测序;采用K-B法测定其对16种抗菌药物的敏感性。结果 1981~1983年分离株福氏志贺菌1类整合酶阳性率为87.50%(28/32),其中27株可变区含氨基糖苷类药物耐药基因aadA;2009~2011年分离株福氏志贺菌1类整合酶阳性率为91.67%(22/24),可变区及3’末端扩增均阴性。1981~1983年分离株福氏志贺菌2类整合酶均阴性;2009~2011年分离株福氏志贺菌2类整合酶阳性率79.17%(19/24),可变区含dfrA1、sat1、aadA1,介导对甲氧苄啶、链丝菌素和链霉素耐药。有17株福氏志贺菌1、2类整合酶均阳性。1981~1983年分离株福氏志贺菌对四环素、链霉素、氯霉素及甲氧苄啶/磺胺甲噁唑耐药率高,多重耐药率为65.63%;2009~2011年分离株福氏志贺菌对氨苄西林、链霉素、甲氧苄啶/磺胺甲噁唑、哌拉西林和四环素耐药率高,多重耐药率为83.33%。结论 1、2类整合子广泛存在于天津地区福氏志贺菌中,其中1类整合子3’保守末端可能缺失或存在变异。2009~2011年分离株福氏志贺菌对抗菌药物耐药性较1981~1983年分离株增强,多重耐药率增高。福氏志贺菌优势血清型发生转变,血清型分布呈现多样化。     

老年福氏志贺菌感染141例临床特点及耐药性分析

福氏志贺菌感染引起的细菌性痢疾是我国常见的传染病.近年来此病的发病率明显下降,但由于老年人口增加,老年人患细菌性痢疾的比例有升高趋势.本文分析我院近年来老年细菌性痢疾的临床特点及细菌耐药性变迁.     

志贺菌属整合子系统研究进展

志贺菌属(Shigella)是感染性腹泻的主要病原,对公共健康造成严重威胁,也给国家带来巨大的疾病负担。随着临床治疗上抗生素的不合理应用,志贺菌耐药问题越来越凸显,其中整合子-基因盒系统在其多重耐药性传播发展过程中起重要作用。以往单一针对志贺菌属整合子-基因盒系统的传播规律和流行特点的研究较少。本文拟对志贺菌属整合子系统及其耐药调控机制和耐药性的传播特点进行综述。     

2008-2010年住院患者不发酵糖菌分布及耐药性分析

目的 了解福建医科大学附属第一医院2008年1月1日至2010年12月31日临床分离不发酵糖菌分布及其对所测抗菌药物的耐药性,以引起临床医师和医院感染管理部门的关注,指导临床合理用药.方法 收集2008年1月1日至2010年12月31日我院住院患者临床分离的不发酵糖菌,采用法国生物梅里埃公司VITEK 2全自动细菌鉴定仪器检测,采用纸片扩散法(Kirby-Bauer法)进行抗菌药物的药敏试验,并对数据进行统计分析.结果 3年临床分离的不发酵糖菌共2 651株,其中铜绿假单胞菌1 268株,不动杆菌属1119株,嗜麦芽窄食单胞菌264株.铜绿假单胞菌对碳青霉烯类抗生素的耐药率在上升,达到19.5％～28.8％.不动杆菌耐药性更强,目前仅有米诺环素、头孢哌酮/舒巴坦、阿米卡星的耐药率＜30％,碳青霉烯类、喹诺酮类及氨苄西林/舒巴坦等抗菌药物的耐药率已经超过50％.嗜麦芽窄食单胞菌耐药率变化不大,对哌拉西林/他唑巴坦、复方新诺明、米诺环素等敏感率超过90％.结论 3年来我院住院患者临床分离不发酵糖菌占总的临床分离菌的比例波动于36.9％～40.6％,铜绿假单胞菌、不动杆菌属始终占据临床分离菌的前两位,不动杆菌耐药性逐年上升,铜绿假单胞菌对碳青霉烯类抗生素敏感性在下降,值得临床医师高度重视,定期开展细菌分布及耐药性监测,了解其动态变化,对合理应用抗菌药物有重要指导意义,同时院感部门应加强消毒隔离工作,防止耐药菌医院内传播.     

Increased copy number couples the evolution of plasmid horizontal transmission and plasmid-encoded antibiotic resistance

Conjugative plasmids are mobile elements that spread horizontally between bacterial hosts and often confer adaptive phenotypes, including antimicrobial resistance (AMR). Theory suggests that opportunities for horizontal transmission favor plasmids with higher transfer rates, whereas selection for plasmid carriage favors less-mobile plasmids. However, little is known about the mechanisms leading to variation in transmission rates in natural plasmids or the resultant effects on their bacterial host. We investigated the evolution of AMR plasmids confronted with different immigration rates of susceptible hosts. Plasmid RP4 did not evolve in response to the manipulations, but plasmid R1 rapidly evolved up to 1,000-fold increased transfer rates in the presence of susceptible hosts. Most evolved plasmids also conferred on their hosts the ability to grow at high concentrations of antibiotics. This was because plasmids evolved greater copy numbers as a function of mutations in the copA gene controlling plasmid replication, causing both higher transfer rates and AMR. Reciprocally, plasmids with increased conjugation rates also evolved when selecting for high levels of AMR, despite the absence of susceptible hosts. Such correlated selection between plasmid transfer and AMR could increase the spread of AMR within populations and communities.

Conjugative plasmids are mobile genetic elements that transmit horizontally within and between species of bacteria (1). Plasmids often confer adaptive traits such as new metabolic abilities, virulence, and antimicrobial resistance (AMR); therefore, an understanding of variation in plasmid transmission rate (transfer) (2) is critical (3, 4). While greater transfer is expected to directly increase the frequency of plasmids in a population, it might also affect the phenotypes conferred by plasmids in other ways. Greater transfer may confer a cost to the host (5) (limiting growth and reducing the frequency of plasmid-carried traits), directly or indirectly modifying the expression of other plasmid-encoded traits (6) or promoting loss of accessory genes (7). Finally, plasmids that are at high frequencies within communities may rapidly adapt to ameliorate their costs (8), further increasing their frequency (9–11). Here, we experimentally investigate the consequences of selection for increased plasmid transfer rates on plasmid-encoded AMR.Increased plasmid transfer (or parasite transmission in general) is predicted to be favored only when susceptible hosts are present in abundance (12). This is because the cost to host bacteria limits plasmid vertical transmission, leading to a trade-off between horizontal and vertical transmission (5). Indeed, evolution experiments in conditions with low opportunity for transfer observe decreased transfer rates and carriage costs (10, 13–15), but horizontal transmission can increase when susceptible hosts are available (5, 16–18). Here, we evolved conjugative plasmids under variable host availability and followed the evolution of transfer rates and AMR. We used two plasmids, R1 and RP4, which have variable transfer rates in closely related host strains (19), suggesting the potential for rapid evolution. R1 and RP4 are both conjugative multidrug-resistant plasmids, but differ in replication mechanisms, host range, and transfer regulation (20, 21).     

两年间临床分离念珠菌耐药情况分析

目的 了解我院住院患者临床分离的念珠菌分布及耐药现状.方法 收集近两年我院临床分离的念珠菌,测定常用抗真菌药物的敏感性.结果 两年内分别分离出念珠菌585株和1030株,分离率分别为11.76%和16.21%.白色念珠菌是最常见的分离菌,但热带念珠菌分离率上升.受检药物均有较高的抗菌活性,仅克柔念珠菌对氟康唑的耐药率分别为66.7%和77.1%,剂量依赖性敏感的比例分别为16.7%和20.0%.结论 白色念珠菌仍是分离出最常见的念珠菌,其次为热带念珠菌,建议白色念珠菌和热带念珠菌感染时使用氟康唑,克柔念珠菌感染者应用伊曲康唑.     

Primary and secondary antibiotic resistance of Helicobacter pylori strains isolated in central Italy during the years 1998–2002

BACKGROUND: Antibiotic resistance of Helicobacter pylori is the most common reason for failure in its eradication. AIM: To determine the incidence of primary and secondary resistance to tinidazole, clarithromycin and amoxycillin in Helicobacter pylori isolates from dyspeptic patients in central Italy and to evaluate the modifications of resistance over the period from 1998 to 2002. METHODS: H. pylori strains were isolated from antral biopsies taken during upper endoscopy in 406 dyspeptic patients with no previous therapy against H. pylori, and in 96 patients who had already undergone one or more triple therapies. Antibiotic susceptibility test was performed using the screening agar method and agar dilution method. RESULTS: Overall primary resistance to tinidazole, clarithromycin and amoxycillin was 36.7, 23.4 and 0.2%, respectively. Secondary resistance rates were: tinidazole 69.8%, clarithromycin 82.3% and amoxycillin 1%. Resistance to clarithromycin was often associated with tinidazole resistance and was significantly higher in female patients (p<0.05). Primary and secondary antibiotic resistance did not change during the 4 years of observation. CONCLUSIONS: The dyspeptic population with H. pylori infection in central Italy shows high levels of antibiotic resistance. Primary resistance to clarithromycin is most frequent in female patients. In patients with secondary resistance, dual resistance to clarithromycin and tinidazole is found in the majority of cases.     

木香、黄精提取液抑制R质粒接合传递的体外实验研究

目的体外观察中药木香、黄精提取液抑制痢疾杆菌氯霉素耐药株(S.flexneRiD15 R-plasmid CmR)和大肠埃希菌氯霉素敏感株(E.coli1485 RifR)间的R质粒接合传递作用。方法木香、黄精提取液分别与S.flexneRiD15 R-plasmid CmR和E.coli1485 RifR共同培养24 h和48 h后接种于麦康凯琼脂平板,37℃培养24 h,计算木香、黄精及不加药对照组的R质粒转移率和R质粒转移抑制率。结果24 h R质粒转移率木香组为(4.60±0.14)%,黄精组为(4.15±0.78)%,未加药对照组为(47.3±0.53)%,差异有统计学意义(P0.01);48 h R质粒转移率木香组为(3.65±0.07)%,黄精组为(2.8±0.71)%,未加药对照组为(68.90±1.01)%,差异有统计学意义(P0.01)。24 h的R质粒转移抑制率木香组为(90.30±8.33)%,黄精组为(91.22±7.76)%;48 h的R质粒转移抑制率木香组为(94.70±9.68)%,黄精组为(95.90±10.23)%。结论木香、黄精均具有体外抑制S.flexneRiD15 R-plasmid CmR和E.coli1485 RifR间R质粒接合传递的作用。     

木香、黄精提取液在小鼠体内抑制R质粒接合传递的实验研究

目的观察中药木香、黄精提取液在小鼠体内抑制S.flexneriD15 R-plasmid CmR和E.coli1485 RifR之间R质粒的接合传递作用。方法木香、黄精提取液分别与S.flexneriD15 R-plasmid CmR和E.coli1485 RifR混合后注入昆明小鼠腹腔;取作用24和48 h的腹腔液接种含氯霉素和不含氯霉素麦康凯琼脂平板,37℃培养。实验设溴化乙锭组和未加药对照组。根据培养24 h后的菌落数计算各组的R质粒转移率及R质粒转移抑制率。结果木香组、黄精组及未加药对照组24 h R质粒转移率分别为(4.17±0.59)%、(11.83±2.37)%和(58.67±5.80)%,差异有统计学意义(P0.01);48 h R质粒转移率分别为(1.94±0.62)%、(15.61±0.12)%和(57.61±3.32)%,差异有统计学意义(P0.01)。木香组和黄精组24 h的R质粒转移抑制率分别为(92.9±7.81)%和(79.82±6.94)%;48 h的R质粒转移抑制率分别为(96.63±8.52)%和(72.91±7.42)%。结论木香、黄精提取液在体内能有效抑制S.flexneriD15 R-plas-mid CmR和E.coli1485 RifR之间R质粒的接合传递。     

鼠疫菌质粒缺陷株的建立及66Mdal质粒的功能

本文报道了应用吖啶黄诱变鼠疫菌获得了53株缺失66Mdal 质粒的鼠疫菌突变株。经反相间接血凝试验证实66Mdal 质粒决定 F1和 F2抗原(鼠毒素)的产生。     

急诊重症监护病房金黄色葡萄球菌耐药性分析

目的:研究急诊重症监护病房(ICU)2009—2010年临床分离的金黄色葡萄球菌(金葡菌)对各类抗菌药物的耐药性分析。方法:按统一的材料、方法和判断标准[美国临床实验室标准化协会(CLSI)2009年版]对急诊ICU2009年1月至2010年12月分离的117株金葡菌行耐药性监测,并对下呼吸道感染者的临床资料行回顾性分析。结果:117株金葡菌中耐甲氧西林金葡菌(MRSA)占85.5%,甲氧西林敏感金葡菌(MSSA)为14.5%;随着年龄的增加,MRSA感染者增多;MRSA对喹诺酮、红霉素、四环素的耐药率较高,对万古霉素、替考拉宁、利奈唑胺和达福普汀-奎奴普丁的敏感率仍保持100%;未发现万古霉素中介株(VISA)和耐药株(VRSA);急性生理学及慢性健康状况评分Ⅱ(APACHⅡ)评分、高龄(>70岁)、住院天数>20 d、清蛋白水平、慢性肺病、机械通气、意识障碍、长期住护理院是下呼吸道感染MRSA的危险因素,清蛋白、高龄和住护理院是其独立危险因素。结论:MRSA的耐药性高,应加强其耐药性监测,并根据分离株的耐药特点规范抗菌药物的应用。     

桑茶治疗感染性腹泻的临床与实验研究

目的　探讨桑茶治疗感染性腹泻的疗效及其抑菌作用。方法　采用桑茶治疗感染性腹泻患者 12 3例 ,同时用氟哌酸治疗作对照观察。并对鼠伤寒沙门菌 ,金葡菌及大肠杆菌作抑菌试验。结果　桑茶的总有效率为89 4% ,对照组为 6 8 3%。两组疗效有显著差异 (P <0 0 1)。桑茶对鼠伤寒沙门菌及金葡菌有抑菌作用 ,不抑制大肠杆菌生长。结论　桑茶有治疗感染性腹泻的效果 ,其疗效部分与抑菌作用有关