产碳青霉烯酶产气肠杆菌的ERIC-PCR图谱分析

目的了解医院临床产碳青霉烯酶产气肠杆菌感染流行情况,为医院感染控制提供帮助。方法对医院检验科微生物实验室在2009年6月-2010年3月临床分离出的16株产碳青霉烯酶产气肠杆菌及1株非产碳青霉烯酶产气肠杆菌,用肠杆菌基因间重复一致序列聚合酶链反应(ERIC-PCR)进行基因分型。结果 17株菌株分为两个克隆型,其中16株产碳青霉烯酶产气肠杆菌为同一型,而另1株非产酶菌株为另一型。结论医院存在产碳青霉烯酶产气肠杆菌克隆传播现象,医护人员应予以高度关注,并及时采取有效措施。     

市售国产婴幼儿配方奶粉中阪崎肠杆菌污染情况调查

目的了解成都市市售国产婴幼儿配方奶粉中阪崎肠杆菌污染情况,为制定婴幼儿配方奶粉阪崎肠杆菌的限量标准提供科学依据。方法对2006-09/2007-03采集的80份市售婴幼儿配方奶粉进行菌落总数、大肠菌群及阪崎肠杆菌的检测,并对分离的阪崎肠杆菌进行药敏试验。结果所有检测样品中,有5份样品检出阪崎肠杆菌,阳性率为6.25%,且其中4份样品的菌落总数、大肠菌群均合格。分离的阪崎肠杆菌对常用抗生素普遍敏感。结论市售国产婴幼儿配方奶粉中存在少量阪崎肠杆菌污染,应尽快制定婴幼儿配方奶粉中适宜的阪崎肠杆菌微生物限量标准和相应检验方法。     

肠杆菌科细菌KPC型碳青霉烯酶的研究

目的了解某院临床分离的肠杆菌科细菌产KPC型碳青霉烯酶情况及其基因型别。方法收集该院2009—2010年临床分离的肠杆菌科细菌1 801株,经药敏试验筛选出耐药性高的菌株,采用改良Hodge试验和聚合酶链反应(PCR)扩增检测细菌产KPC型碳青霉烯酶情况,并测序分析其基因型别。结果 1 801株肠杆菌科细菌中,有783株(43.48%)对第三代头孢菌素耐药,其中4株还对碳青霉烯类抗菌药物耐药;改良Hodge试验初筛出2株耐药菌株,经PCR扩增证实为碳青霉烯酶blaKPC-2基因。结论该院已出现产KPC-2型碳青霉烯酶耐药基因的肠杆菌科细菌,临床与实验室应加强监测和控制。     

LAMP法和PCR法快速检测阪崎肠杆菌的比较

[目的]建立阪崎肠杆菌环介导等温扩增(loop-mediated isothermal amplification,LAMP)快速检测技术,并与PCR检测方法进行比较,为阪岐肠杆菌感染的快速诊断提供实验依据。[方法]根据阪崎肠杆菌外膜蛋白OmpA基因,设计特异性引物,建立LAMP和PCR检测技术体系,并对2种方法检测的灵敏度、特异性和实际样品的检测结果进行比较。[结果]建立了优化的LAMP和PCR检测体系,灵敏度检测结果显示,LAMP检测限为101cfu/ml,PCR检测限为102cfu/ml,LAMP检测灵敏度高于PCR;对36株近源菌进行特异性检测,结果显示,LAMP仅8株阪崎肠杆菌得到阳性结果,PCR产物则出现非特异性条带,LAMP特异性比PCR高。应用于46份奶粉样品的检测,LAMP和PCR均有清晰、特异的预期条带和结果产生,并与常规检测结果一致。[结论]LAMP检测技术作为一种快速检测阪崎肠杆菌的方法具有简便、灵敏快速,与PCR方法比较,特异性强、操作简便、检测成本低,耗时短,更有望发展成为快速检测阪岐肠杆菌的有效手段。     

肠杆菌目细菌产耐碳青霉烯酶的基因分型检测方法进展

由耐碳青霉烯类肠杆菌目细菌（carbapenem-resistant Enterobacteriales,CRE）引起的感染,尤其是血流感染,可导致较高的患者死亡率,给临床治疗带来很大挑战。目前只有数种新型抗生素可用于CRE相关感染,如头孢他啶-阿维巴坦。但头孢他啶-阿维巴坦对产金属β内酰胺酶的CRE没有活性,因此快速、准确地检测CRE菌株的碳青霉烯酶种类,对临床合理选择抗生素至关重要。目前检测肠杆菌目细菌耐碳青霉烯类药物的基因分型的实验方法主要包括表型方法、分子生物学检测方法、质谱方法,各有优缺点,本文对此进行总结。     

阴沟肠杆菌质粒介导耐喹诺酮类药物的机制研究

目的了解深圳地区阴沟肠杆菌中qnrA基因的流行情况、基因定位及其介导喹诺酮耐药性产生的机制。方法收集临床分离的阴沟肠杆菌45株,采用PCR法结合测序的技术筛查qnrA基因,大质粒提取技术、Southern杂交和接合传递试验进行质粒定位,琼脂对倍稀释法进行药物敏感性检测。结果45株阴沟肠杆菌中,7株PCR法及测序证实为qnrA基因。7株菌中6株菌所携质粒被成功提取并进行Southern杂交,qnrA基因定位于80~200kb大小的低拷贝数天然质粒上。4株菌成功进行接合传递试验,使接合子对环丙沙星的MIC值提高了32~64倍。结论质粒介导的喹诺酮耐药基因qnrA在深圳地区阴沟肠杆菌中具有较高的流行率,可能是导致阴沟肠杆菌对喹诺酮类抗菌药获得性耐药的重要原因。     

产气肠杆菌EAM-Z1荚膜的去除对胞内pyNPase活力和菌体生长量的影响

研究产气肠杆菌(EAM-Z1)荚膜去除或变薄对于胞内嘧啶核苷磷酸化酶(PyNPase)活力的菌体生长量和影响。在培养基中增加碳源以去除荚膜或使荚膜变薄,研究其对菌体生长的影响,并通过转化合成5-氟尿苷的方法研究其对PyNPase活力的影响。结果:在培养基中增加4%的D-甘露糖,1%的甲醇,2%的甘油或2%的丙酮都能使产气肠杆菌的荚膜变薄;其中增加2%丙酮时,菌体量增加43.92%,在工业生产中有重要意义,转化率为57.5%,提高2.8%,PyNPase比活力提高4.8%,转化合成5-氟尿苷的最佳反应时间为45 min,缩短了1/4。     

阪崎肠杆菌环介导等温扩增检测方法建立

目的 针对当前国内外传统检测方法缺点,建立阪崎肠杆菌快速检测法.方法 根据阪崎肠杆菌外膜蛋白(OmpA)基因,设计4条特异性引物(内、外引物各2条),建立并优化环介导等温扩增(loop-mediated isotherm alamp lification,LAMP)检测体系及反应条件,并进行LAMP反应的灵敏度、特异性实验及实际样品检测.结果 LAMP检测阪崎肠杆菌,优化后的条件选择为:Mg²⁺浓度6 mmol/L,dNTP浓度0.6 mmol/L,甜菜碱浓度0.8 mol/L,外引物与内引物的浓度比1:4,扩增温度58℃60min;细菌纯培养检测灵敏度为101cfu/mL;对11种细菌共26株菌进行LAMP扩增,仅8株阪崎肠杆菌得到阳性扩增结果,证明引物具有很高的特异性;对实际样品进行增菌检测,采用试剂盒提取DNA,从样品处理到报告结果,耗时26 h;并采用传统检测方法验证,正确性为100%.结论 该方法检测阪岐肠杆菌特异性强、灵敏度高,并且操作简便、检测成本低、耗时短,有望成为快速检测阪岐肠杆菌的有效方法.     

Microbiological findings and clinical treatment procedures in endodontic cases selected for microbiological investigation

The relationship between bacteriological findings and clinical treatment procedures was investigated in root canal treatment cases that were selected for bacteriological investigation by general dental practitioners in Finland. The cultures were sent to the Oral Microbiological Service Laboratory at the Institute of Dentistry in Helsinki. Two groups of teeth were selected based on the type of infection present in the root canal system. The 'enteric bacteria' group consisted of 40 sequential cases where Enterococcus faecalis and/or other facultative enteric bacteria or Pseudomonas sp. were found in the samples in pure culture (35%) or together with other types of bacteria. The group 'non-enteric bacteria' consisted of 40 sequential cases where only non-enteric bacteria were found. The dentists who had sent the bacteriological samples received a questionnaire where they were asked about the treatment protocol and procedures. A total of 70 out of 80 questionnaires were returned. If the root canals had been unsealed at some point during the treatment, enteric bacteria were found more frequently than in canals with an adequate seal between the appointments. Of cases with enteric bacteria 55% had been open during the treatment, while in the group where only non-enteric bacteria were found 30% had been open. Enteric bacteria were also more frequently isolated in cases with a high number of appointments before sampling. In the enteric bacteria group 35% of the samples were taken at the 10th visit or later, while the corresponding percentage in the non-enteric group was 3%. In addition, the number of retreatment cases was significantly higher, 12 out of 34, in the enteric bacteria group than in non-enteric bacteria group, which was five out of 36. Other clinical parameters showed no differences between the two groups. The results emphasize the importance of controlled asepsis throughout the root canal treatment.