阴沟肠杆菌产超广谱β-内酰胺酶与AmpC酶基因及其流行病学研究

目的分析医院2008-2010年临床分离阴沟肠杆菌产ESBLs和AmpC酶及其对抗菌药物的耐药性,并了解其耐药基因的传播机制。方法采用改良三维试验筛选AmpC酶,双纸片扩散法检测ESBLs,聚合酶链反应(PCR)检测ESBLs和AmpC酶的基因,采用微量肉汤稀释法分析细菌耐药性,质粒接合试验分析耐药基因的传播特点。结果同时产ESBLs和AmpC酶菌株对三、四代头孢菌素及含酶抑制剂药物的耐药率均>50.0%;45株改良三维试验阳性,14株ESBLs确证试验阳性,ESBLs和AmpC酶的基因阳性者分别为25、38株,分别以TEM-1型、MIR-3型为主,其次为CTX-M-3、DHA-1型,SHV-11型广谱β-内酰胺酶2株,未检测到CIT、MOX、FOX、ACC型AmpC酶的基因,5株接合试验成功。结论阴沟肠杆菌主要携带TEM-1型广谱β-内酰胺酶、CTX-M-3型ESBLs和MIR-3型AmpC酶,耐药现状严重,应采取积极有效的措施预防多药耐药菌株的播散与暴发流行。     

产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌的分布及耐药性分析

目的了解医院产超广谱β-内酰胺酶（ESBLs）大肠埃希菌和肺炎克雷伯菌的分布及耐药性特点。方法对我院2004年7月～2006年7月间各类临床标本分离出的大肠埃希菌307株和肺炎克雷伯菌202株，用CLSI／NCCLS推荐的表型确证法检测其ESBLs，采用K-B纸片琼脂扩散法进行药敏试验，分析产ESBLs菌株的分布及耐药性。结果大肠埃希菌和肺炎克雷伯菌产ESBLS菌株的检出率分别为38．4％（118／307）和31．7％（64／202），主要分布于尿和痰、咽拭子中，病区主要集中于肺科、神经外科、感染科、泌尿外科、ICU室。产ESBLs菌株对亚胺培南和美罗培南呈高度敏感，对哌托西林／三唑巴坦、头孢哌酮／舒巴坦、头孢西丁耐药率较低，对其他抗菌药物均出现较高耐药。结论产ESBLS的大肠埃希菌和肺炎克雷伯菌分布在不同病区的不同标本中，碳青霉烯类抗生素亚胺培南和美罗培南是治疗产ESBLS菌株感染的较佳药物。     

Occurrence of extended spectrum beta-lactamase enzymes in clinical isolates of Klebsiella species from Harar region, eastern Ethiopia

Extended Spectrum beta-Lactamases (ESBLs) producer and multidrug resistant Klebsiella spp. are becoming a major nosocomial pathogen globally. There are no documented reports yet on the occurrence of ESBL enzymes in Klebsiella spp. species from Ethiopia. This study was undertaken to isolate and determine the occurrence of ESBLs and multi-drug resistant Klebsiella spp. in different clinical samples obtained from patients. A cross-sectional survey was conducted in four different hospitals of Harar region (Hiwot Fana, Misrak-Arbegnoch, Police and Army) from December 2003 to February 2004. Three hundred and eighty four clinical specimens (202 sputum, 164 urine and 18 pus) were collected from patients admitted in different wards. Antimicrobial susceptibilities were performed on 57 clinical isolates by standard disk diffusion procedures against eight antimicrobial agents. The ESBLs detection was made by using cefotaxime and ceftazidime alone and in combination with clavulanate. A total of 57 (15%) Klebsiella spp. were isolated from 384 patients. Of the 57 isolates, 33 (58%) were from sputum, 18 (31.5%) from urine and 6 (10.5%) from pus. Of the 57 Klebsiella spp., 54 (94.7%) were identified as K. pneumoniae and 3 (5.3%) as K. oxytoca. Resistance was found against cephalosporins [cefotaxime (39.0%), cefoxitin (39.0%), ceftazidime (40.0%), ceftriaxone (40.0%), cephalothin (42.0%)], chloramphenicol (70.0%), gentamicin (61.0%) and trimethoprim-sulphamethoxazole (65.0%). Analyzed Klebsiella isolates were characterized also by a high degree of multi-resistance (67.0%). In 19/57 (33.3%) of the Klebsiella isolates, ESBL production was detected. Rates of detection of ESBL producers were 42.1, 26.3, 26.3 and 5.3% in Hiwot-Fana, Misrak-Arbegnoch, Police and Army hospitals, respectively. Multi-drug resistant isolates were more prevalent among the ESBLs producers (95.0%) than non-producers (53.0%) (p=0.24). In conclusion, our results show that awareness of ESBL production by Klebsiella spp. is clinically important. In the absence of infection control measures, ESBL producing organisms readily pass horizontally from patient to patient. These strains also transiently colonize the hands of hospital staff members, thereby facilitating patient-to-patient transmission of the organism.     

产超广谱β-内酰胺酶大肠埃希菌检出率及耐药性分析

目的了解2007～2009年产超广谱β-内酰胺酶(ESBLs)大肠埃希菌的检出率及对抗菌药物的耐药情况。方法细菌培养分离采用常规方法,细菌鉴定应用VTECK-2全自动细菌鉴定分析仪。ESBLs菌株采用双纸片确认法检测,药敏试验采用纸片扩散(K-B)法,按美国临床实验室标准化协会(CLSI)规定标准进行。结果 3年内从临床感染标本中共分离获得1510株大肠埃希菌,产ESBLs百分率为57.5%;各年度产ESBLs检出率分别为54.4%、55.5%和63.0%。产酶菌对头孢呋辛、头孢曲松、头孢他啶几乎全部耐药,对氨苄西林/舒巴坦、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦耐药率分别为40.0%、10.0%和1.0%左右,对环丙沙星和阿米卡星耐药率分别为70.0%以上和20.0%左右,对亚胺培南和美罗培南全部敏感。结论 2007～2009年产ESBLs大肠埃希菌检出率呈上升趋势,产酶菌对含酶抑制剂复合抗菌药物的耐药性也呈上升趋势,这与近几年来头孢类抗菌药物在临床广泛、大量应用有关,应引起临床医生高度重视。对产酶菌引起的重度感染应首选碳青霉烯类抗菌药物治疗。     

痰热清注射液对产ESBLs肺炎克雷伯菌的体外抑制作用

目的观察产ESBLs肺炎克雷伯菌在体外对中药痰热清注射液以及其与特治星（哌拉西林/他唑巴坦）联合应用的效果,为耐药菌株的治疗提供新的思路。方法采用临床和实验室标准化协会（CLSI）推荐的肉汤稀释法,中药及中西药联合应用对产ESBLs肺炎克雷伯菌进行抑菌试验。结果痰热清注射液对产ESBLs的肺炎克雷伯菌的最小抑菌浓度（MIC）值为750μL/mL;特治星对产ESBLs的肺炎克雷伯菌的MIC值为28.125μg/mL,当痰热清注射液与特治星同时作用于产ESBLs的肺炎克雷伯菌,痰热清注射液浓度为0.001~1.758μL/mL时,可以使特治星的用量比单用时减少1~2倍。结论中西药联合应用具有明显的抑菌效果,可以显著的减少抗菌药物的用量,这对于耐药菌的临床治疗以及减少耐药菌株的产生具有一定的意义。     

痰标本中铜绿假单胞菌AmpC酶的检测及其耐药性研究

目的　调查痰标本中铜绿假单胞菌AmpC酶的表达情况 ,比较产酶菌和非产酶菌的耐药性。 方法　收集来源痰标本中的铜绿假单胞菌 114株 ,首先采用K -B法检测铜绿假单胞菌的AmpC酶以及 3种不同表型的AmpC酶产生情况 ,然后使用微量肉汤稀释法分析产酶菌株与不产酶菌株耐药性。结果　在 114株铜绿假单胞菌中检出产AmpC酶菌 79株 ( 69.5 % )。产AmpC酶的菌株表现为 3种表型 ,高产高表达型 61株 ( 5 3 .5 % )、低产高表达型 3 3株( 2 7.5 % )、低产低表达型 43株 ( 3 7.7% )。高产高表达AmpC酶菌株明显多于低产高表达型和低产低表达型。 3种不同AmpC酶表型的菌株 ,低产低表达型对哌拉西林 /他唑巴坦 (P/T)、哌拉西林 (PI)、氨曲南 (ATM )、头孢他啶 (CAZ)、头孢吡肟 (FEP)、亚胺培南 (IMP)的敏感率均明显高于低产高表达型和高产高表达型。结论　痰标本中铜绿假单胞菌AmpC酶产生率高 ,可能是对 β -内酰胺类抗生素耐药的主要机制。     

2型糖尿病合并感染患者的肺炎克雷伯菌分布及耐药特征分析

目的分析2型糖尿病(T2DM)合并感染患者的肺炎克雷伯菌分布及耐药特征。方法从126例T2DM合并感染患者的痰液、尿液等标本分离肺炎克雷伯菌,全自动微生物分析仪鉴定细菌及药敏试验,测定菌株产超广谱β-内酰胺酶(ESBL)情况。结果126株来自T2DM合并感染患者的肺炎克雷伯菌,在痰液、尿液、血液、脓液及其他标本的构成比分别为45.2%、19.1%、12.7%、9.5%和13.5%;痰液的肺炎克雷伯菌对头孢哌酮/舒巴坦耐药率(31.7%)高于非痰液标本(22.2%)(P<0.01),痰液的肺炎克雷伯菌对庆大霉素耐药率(23.0%)高于非痰液标本(15.9%)(P<0.05);双重耐药、3种及以上药物耐药菌株检出率均高于单一耐药菌株检出率(P<0.01);痰液的产ESBL酶肺炎克雷伯菌检出率(17.5%)高于非痰液标本(6.3%)(P<0.01)。结论T2DM合并感染患者的肺炎克雷伯菌主要分布在痰液和尿液中,菌株交叉耐药现象较严重,产ESBL肺炎克雷伯菌趋于增多。     

耐碳青霉烯类弗劳地枸橼酸杆菌耐药机制及治疗策略研究

目的 探索耐碳青霉烯类弗劳地枸橼酸杆菌耐药机制及治疗对策.方法 收集来自该院的17株耐碳青霉烯类弗劳地枸橼酸杆菌临床资料,采用PCR方法扩增碳青霉烯类耐药基因;采用琼脂稀释法和肉汤稀释棋盘法测磷霉素单药及联合用药最低抑菌浓度(MIC)值,计算部分抑菌浓度指数(ΣFICI).结果 8株菌产blaNDM-1,9株菌产blaIMP,blaKPC、blaoxA-48、blasPM均未检出;磷霉素联合亚胺培南协同作用和相加作用占75.oo％,其中协同作用高达56.25％,磷霉素联合头孢哌酮/舒巴坦钠协同作用和相加作用占50.oo％.结论 磷霉素联合亚胺培南或头孢哌酮/舒巴坦钠体外有较好的抗菌活性,亚胺培南联合磷霉素效果可能更好.     

CuO Bionanocomposite with Enhanced Stability and Antibacterial Activity against Extended-Spectrum Beta-Lactamase Strains

Worldwide, bacterial resistance to beta-lactam antibiotics is the greatest challenge in public health care. To overcome the issue, metal-based nanoparticles were extensively used as an alternative to traditional antibiotics. However, their unstable nature limits their use. In the present study a very simple, environmentally friendly, one-pot synthesis method that avoids the use of organic solvents has been proposed to design stable, novel nanocomposites. Formulation was done by mixing biogenic copper oxide (CuO) nanomaterial with glycerol and phospholipids isolated from egg yolk in an appropriate ratio at optimum conditions. Characterization was done using dynamic light scattering DLS, Zeta potential, high performance liquid chromatography (HPLC), and transmission electron microscopy (TEM). Further, its antibacterial activity was evaluated against the extended-spectrum beta-lactamase strains based on zone of inhibition and minimal inhibitory concentration (MIC) indices. Results from this study have demonstrated the formulation of stable nanocomposites with a zeta potential of 34.9 mV. TEM results indicated clear dispersed particles with an average of 59.3 ± 5 nm size. Furthermore, HPLC analysis of the egg yolk extract exhibits the presence of phospholipids in the sample and has significance in terms of stability. The newly formed nanocomposite has momentous antibacterial activity with MIC 62.5 μg/mL. The results suggest that it could be a good candidate for drug delivery in terms of bactericidal therapeutic applications.     

肿瘤医院产超广谱β-内酰胺酶大肠埃希菌分布及基因型研究

目的了解医院感染的产超广谱β-内酰胺酶(ESBLs)大肠埃希菌医院感染的临床分布及其基因型特征。方法用表型确证试验确定临床标本中产ESBLs大肠埃希菌80株,应用PCR方法分别扩增产酶菌株的TEM、SHV和CTX-M 3种β-内酰胺酶基因,并对PCR扩增结果及ESBLs株临床分布进行分析。结果 PCR扩增结果显示,CTX-M、TEM和SHV基因的阳性率分别为79.5%、12.8%和18.2%;42.3%的菌株同时携带多个基因;产ESBLs大肠埃希菌广泛分布于各个临床科室,其中普外科占32.5%,肝胆外科和重症监护病房均占23.8%;标本分布较为集中,41.3%来自腹腔引流液,23.8%来自呼吸道标本,12.5%来自尿液。结论医院感染中,产ESBLs大肠埃希菌的主要基因型是CTX-M,腹腔引流液、呼吸道标本、尿液是其主要标本来源,CTX-M型产ESBLs菌分布广泛,应特别加强对它的监测,预防医院感染暴发流行。