临床分离的金黄色葡萄球菌mecA和qacA/B基因检测

目的了解临床分离的金黄色葡萄球菌对常用抗菌药物的耐药性及mecA基因和qacA/B基因携带现状。方法收集临床分离的111株金黄色葡萄球菌,采用K-B药敏纸片法检测其对抗菌药物的耐药性,用聚合酶链反应检测mecA和qacA/B基因。结果 111株金黄色葡萄球菌对青霉素G、氨苄西林、红霉素和苯唑西林的耐药率较高,分别为97.3%、93.4%、86.5%和82.9%,对万古霉素和替考拉宁均敏感;mecA基因和qacA/B基因的检出率分别为63.9%和13.5%;将部分菌株的mecA和qacA/B基因扩增产物进行测序,并将测序结果登录NCBI进行比对。结论临床分离的金黄色葡萄球菌mecA基因检出率较高且呈多药耐药趋势;大部分MRSA和少部分MSSA中携带消毒剂抵抗基因qacA/B;临床应重视由此类金黄色葡萄球菌所引起的感染的诊断、治疗和医院感染的控制,并合理使用消毒剂。     

葡萄球菌属mecA基因检测与药敏结果分析

目的 探讨医院2006年分离的葡萄球菌属mecA基因检测及耐药情况,为医院耐药性监测和临床用药提供指导.方法 采用 Microscan-Autoscan-4微生物分析仪及PC12复合板鉴定葡萄球菌属并测定对药物的敏感性;E-test检测各菌株对苯唑西林的最低抑菌浓度(MIC)值;PCR检测mecA基因.结果 共分离出472株葡萄球菌属,金黄色葡萄球菌196株,其中耐甲氧西林金黄色葡萄球菌(MRSA)133株、甲氧西林敏感金黄色葡萄球菌(MSSA)63株;凝固酶阴性葡萄球菌(CNS)276株,其中耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)233株、甲氧西林敏感凝固酶阴性葡萄球菌(MSCNS)43株;PCR检测出MRSA和MRCNS都具有mecA基因,耐药性高的菌株有阿莫西林(91.3%)、氨苄西林(95.6%)、青霉素(99.2%)和头孢唑林(93.5%),耐药性低的菌株有利福平(22.9%)、庆大霉素(21.7%);未发现耐万古霉素菌株.结论 医院葡萄球菌属耐药性较为严重;PCR检测mecA基因和苯唑西林MIC值具有良好相关性.     

临床分离的葡萄球菌中mecA基因的检测

目的了解临床分离的葡萄球菌中mecA基因的产生情况。方法收集临床分离的葡萄球菌154株,采用聚合酶链反应(PCR)检测mecA基因并进行DNA测序,头孢西丁药敏试验采用Kirby-bauer(KB)法。结果 mecA基因在葡萄球菌中的阳性检出率为67.53%,药敏法MRS的阳性率为58.44%。结论在本院分离的葡萄球菌中mecA基因携带率较高。     

<Emphasis Type="Italic">van</Emphasis>A Gene Harboring Enterococcal and Non-enterococcal Isolates Expressing High Level Vancomycin and Teicoplanin Resistance Reservoired in Surface Waters

Untreated wastewaters and treated effluents even after final disinfection contain antibiotic resistant bacteria and resistance genes before they are released into surface waters. A correlation between resistant bacteria and antibiotics in surface waters has been found, as have antibiotic resistance genes. Of particular interest are vancomycin-resistant enterococci harboring vanA gene that confers high level of resistance to glycopeptide antibiotics including teicoplanin. Therefore, in this study, river water samples were analysed to investigate vancomycin- and teicoplanin-resistant bacterial isolates harboring vanA gene. Out of 290, 15 surface water isolates displayed resistance to both antibiotics. These glycopeptide resistant enterococcal and non-enterococcal isolates, identified by 16S rRNA sequencing, were found to harbor vanA gene with sequence similarities of 50?% to 100?%. The presence of d-alanine-d-lactate ligase encoded by vanA gene was also shown for all vancomycin- and teicoplanin-resistant isolates through western blot analysis. Due to reuse of treated wastewater and release of untreated wastewaters to water bodies, antibiotic resistant bacteria and resistance genes are being introduced into surface waters and present human health risks. Therefore, surface waters are not only hot spots for vanA harboring enterococcal isolates but also non-enterococcal isolates due to gene dissemination and require special scientific consideration.     

产ESBLs大肠埃希菌与肺炎克雷伯菌院内垂直传播分析

目的调查产ESBLs大肠埃希菌(ECO)与肺炎克雷伯菌(KPN)院内垂直传播流行状况。方法脉冲场凝胶电泳(PFGE),用Quantity One软件进行PFGE指纹比较分析。结果ICU分离的21株ECO中有10株和7株的相似性系数>90%和100%;KPN有3株相似性系数为100%;神经外科分离的20株ECO中,有9株相似性系数>90%;6株KPN中有4株的相似性系数>90%;干部病房分离的10株ECO中有3株和2株相似性系数>90%和100%;消化科和呼吸科分别在7株和18株ECO中,有2株和2株相似性系数>90%;其他科室也有检出相似性系数>90%的菌株。结论多科室存在垂直传播,尤以ICU病房严重,应采取有力措施加强感染控制管理工作。     

浙江、江西地区MRSA耐mecA、qacA/B基因检测

目的了解浙江、江西地区临床分离的耐甲氧西林金黄色葡萄球菌(meticillin-resistant Staphylococcus aureus, MRSA)中mecA基因及qacA/B基因存在状况. 方法在2004年1～12月间分别从浙江、江西地区住院患者中分离到42株和31株MRSA,采用聚合酶链反应(PCR)及序列分析技术检测mecA基因及qacA/B基因. 结果 73株MRSA中mecA基因均为阳性(100%),qacA/B基因34株(46.6%)阳性,其中浙江地区qacA/B基因阳性率为52.4%,江西地区为38.7%. 结论浙江、江西地区临床分离的MRSA中mecA基因和qacA/B基因携带率很高或较高.     

Ferredoxin Gene Mutation in Iranian Trichomonas vaginalis Isolates

Background

Trichomonas vaginalis causes trichomoniasis and metronidazole is its chosen drug for treatment. Ferredoxin has role in electron transport and carbohydrate metabolism and the conversion of an inactive form of metronidazole (CO) to its active form (CPR). Ferredoxin gene mutations reduce gene expression and increase its resistance to metronidazole. In this study, the frequency of ferredoxin gene mutations in clinical isolates of T.vaginalis in Tehran has been studied.

Methods

Forty six clinical T. vaginalis isolates of vaginal secretions and urine sediment were collected from Tehran Province since 2011 till 2012. DNA was extracted and ferredoxin gene was amplified by PCR technique. The ferredoxin gene PCR products were sequenced to determine gene mutations.

Results

In four isolates (8.69%) point mutation at nucleotide position -239 (the translation start codon) of the ferredoxin gene were detected in which adenosine were converted to thymine.

Conclusion

Mutation at nucleotide -239 ferredoxin gene reduces translational regulatory protein''s binding affinity which concludes reduction of ferredoxin expression. For this reduction, decrease in activity and decrease in metronidazole drug delivery into the cells occur. Mutations in these four isolates may lead to resistance of them to metronidazole.     

Antimicrobial Resistance Among Nosocomial Isolates in a Teaching Hospital in Goa

Background:

Emergence of polyantimicrobial resistant strains of hospital pathogens has presented a challenge in the provision of good quality in-patient care. Inappropriate use of antibiotics in the hospital is largely responsible for this catastrophe. Bacteriological surveillance of the cases of nosocomial infections is crucial for framing an evidence-based antimicrobial policy for a hospital.

Materials and Methods:

A prospective study was undertaken among 498 patients from medicine and surgery wards in a tertiary teaching hospital in Goa. The patients were followed up clinico-bacteriologically for the occurrence of nosocomial infections (NI). Antibiotic susceptibility testing was done using Kirby-Bauer disc diffusion method.

Results:

The overall infection rate was 33.93 ± 4.16 infections per 100 patients. Urinary tract infection was the most common NI (26.63%), followed by surgical site infection (23.67%), wound infection (23%) and nosocomial pneumonia (18.34%). Ninety-seven percent of the isolates were bacterial, while the others were fungal. More than 80% of the NIs were caused by Gram-negative bacteria, predominantly Pseudomonas aeruginosa, Escherichia coli and Aceinetobacter baumanii. Almost 70% of the isolates were resistant to all the antibiotics for which susceptibility was tested; the rest were sensitive to amikacin, cefoperazone-sulbactam and other antibiotics including methicillin, co-trimoxazole, teicoplenin, vancomycin and rifampicin, either singly or in combination. The proportion of MRSA was 71.4%. Resistance to a particular antibiotic was found to be directly proportional to the antibiotic usage in the study setting.

Conclusion:

Surveillance of nosocomial infections with emphasis on the microbiologic surveillance and frequent antimicrobial audit are critical towards curbing the evil of polyantimicrobial resistant nosocomial infections in a hospital.     

Fate of Triclosan and Triclosan-Methyl in Sewage TreatmentPlants and Surface Waters

The fate of triclosan in diverse stages of two sewage treatment processes has been determined. The elimination process differed considerably depending on the technology applied in the respective sewage treatment plant (STP). The plant operating with a two-stage biologic (activated sludge) process removed triclosan more efficiently than the STP with a combination of physical and activated sludge process. The treatment in the aeration basin was the dominant elimination mechanism, whereas the final biologic filter was not very effective. The elimination rates for triclosan were 87% and 95%, respectively. These data were compared with emissions of a multitude of STPs in the river Ruhr catchment area as well as triclosan and its known transformation product, triclosan-methyl, in the river. The concentrations of both compounds were between <3 and 10 ng/L in true surface-water samples for triclosan and between 0.3 and 10 ng/L for triclosan-methyl. The STP effluents held higher concentrations (10 to 600 ng/L triclosan). The ratio of triclosan to triclosan-methyl did not change significantly within the longitudinal profile of the river, but diverse STPs discharging to the river exhibited individual triclosan–to–triclosan-methyl ratios. From the riverine concentration data, in-river elimination rates and half-life were estimated.     

耐甲氧西林金黄色葡萄球菌SCCmec基因分型及PVL基因研究

目的了解耐甲氧西林金黄色葡萄球菌(MRSA)SCCmec基因型的分布特征并检测杀白细胞毒素(PVL)基因。方法收集2007年10月-2008年5月临床标本中,分离的非重复金黄色葡萄球菌110株,用头孢西丁纸片扩散法对MRSA进行初筛;用多重聚合酶链反应(PCR)对MRSA进行SCCmec基因分型及PVL基因检测;用琼脂稀释法对MRSA菌株进行抗菌药物最低抑菌浓度(MIC)检测。结果 64株MRSA中,63株医院获得性(HA)-MRSA,1株社区获得性(CA)-MRSA,其中SCCmecⅢ型57株(89.0%),Ⅱ型1株(1.6%),SCCmecⅣ型1株(1.6%),未分型5株(7.8%);未发现SCCmecⅠ、Ⅴ型菌株;SCCm ecⅡ型、SCCm ecⅢ型的菌株均为多药耐药株,SCCmecⅣ型的菌株除对β-内酰胺类抗菌药物耐药外,对其他类抗菌药物较敏感。结论 HA-MRSA主要以SCCmecⅢ型为主,CA-MRSA菌株为SCCmecⅣ型,携带PVL毒力基因,HA-MRSA对抗菌药物呈多药耐药性,CA-MRSA菌株耐药谱比HA-MRSA菌株耐药谱窄,加强对MRSA的监测,对指导临床合理使用抗菌药物具有重要意义。     

Occurrence of Glyphosate in Surface Waters of Southern Ontario

Glyphosate in surface waters of southern Ontario (Canada) was studied over a 2-year period. A small percentage of samples exhibited glyphosate concentrations greater than the analytical limit of quantitation (17 microg a.e./L), and the maximum concentration of glyphosate measured was 40.8 microg/L. No samples of roughly 500 analyzed exceeded the Canadian Water Quality Guideline of 65 microg a.e./L considered protective of aquatic life. Typical concentrations of glyphosate in amphibian habitats were well below a range of toxicity thresholds for aquatic organisms, and were thus judged to be unlikely to pose a substantial risk to either sensitive amphibian larvae or other aquatic biota.     

55株结核分枝杆菌临床分离株rpoB基因突变研究

[目的]了解福建省耐多药结核分枝杆菌临床分离株rpoB基因的突变特征。[方法]PCR扩增了55株结核分枝杆菌临床分离株，对包括81个碱基利福平耐药决定区（RRDR）在内的rpoB基因片段进行序列测定。[结果]10株敏感菌株rpoB基因未检测到突变。45株耐多药分离株中有40株rpoB基因存在21种不同类型突变，其中17个点突变，2个插入突变，2个缺失。[结论]88．9％的耐多药菌株检测到rpoB基因的突变，最常见的突变部位分别是531、526和516位密码子，突变率分别是47．1％、19．6％和7．8％。     

耐甲氧西林金黄色葡萄球菌和溶血葡萄球菌耐药基因的检测

目的 对医院临床标本中分离的36株耐甲氧西林金黄色葡萄球菌(MRSA)和24株耐甲氧西林溶血葡萄球菌(MRSH)进行常见耐药基因的检测,探讨MRSH与MRSA临床分离株耐药基因检出率之间的差异.方法 用MicroScan auto SCAN4仪进行细菌鉴定和药敏试验;用聚合酶链反应(PCR)法检测耐消毒剂qacA/B基因、耐氨基糖苷类药物的aac(6')/aph(2")、aph(3')-Ⅲ、ant(4',4")基因、产β-内酰胺酶基因TEM、编码PBP2a的mecA基因、耐红霉素erm、耐四环素tetM、耐万古霉素vanA等基因;用肉汤稀释法对携带了耐消毒剂qacA/B基因的葡萄球菌属进行消毒剂苯扎溴铵最低抑菌浓度(MIC)、最小杀菌浓度(MBC)测定.结果 24株MRSH耐消毒剂qacA/B基因的阳性率为37.5%;氨基糖苷类药物耐药基因aac(6')/aph(2")、aph(3')-Ⅲ和ant(4',4")阳性率分别分别为87.5%、33.3%和29.2%,TEM基因、erm基因和tetM基因的阳性率为95.8%、62.5%和20.8%;36株MRSA耐消毒剂qacA/B基因阳性率为30.6%;氨基糖苷类药物耐药基因aac(6')/aph(2")、aph(3')-Ⅲ和ant(4'、4")阳性率分别为91.7%、72.2%和8.3%;TEM基因、erm基因和tetM阳性率分别为100.0%、94.4%和91.7%;MRSH和MRSA临床株的苯扎溴铵MIC值均为32～128 mg/L,MBC值MRSH为256～512 mg/L,MRSA为512～1024 mg/L,标准菌株ATCC25923的苯扎溴铵MIC值为16 mg/L,MBC值为32 mg/L.结论 MRSA与MRSH临床分离株携带多种耐药基因且检出率非常高.     

Dissolved Organochlorine and PAH Pollution Profiles in Lithuanian and Swedish Surface Waters

In recent decades, knowledge and concern regarding persistent organic pollutants and the environmental hazards they may pose have increased considerably, leading to international agreements such as the United Nations environment program Stockholm convention on persistent organic pollutants (POPs), to minimize further release of POPs into the environment (UNECE Protocol, 1979; UNEP Stockholm convention, 2001; UNECE Convention, 1998). National POP monitoring programs should be designed to identify, characterize and address the release of the POPs listed in the Stockholm convention. However, analyses of grab samples only provide crude snapshots of total concentrations at single points in space and time, which may be highly unrepresentative of average concentrations, and fail to account for differences in the POPs’ bioavailability and various other relevant factors. To obtain a better understanding of the fate and availability of pollutants in the environment it is necessary to obtain data regarding their site-specific and regional exposure levels. Exposure levels expressed in terms of total chemical concentrations do not reflect the actual exposure of organisms, and thus may not accurately reflect the true risks posed. Therefore, environmental monitoring programs would be improved by using reliable, integrative sampling methods that would not only allow time-weighted average concentrations of pollutants in the environment to be determined, but also facilitate assessments of the risks these chemicals pose to the environment.     

Occurrence and Distribution of Hexavalent Chromium in Ground and Surface Waters in Cyprus

The origin and distribution of hexavalent chromium, Cr (VI) over four seasonal cycles was investigated through a conceptual model that included three aquifer systems in Cyprus. An extensive water sampling grid covered two sea water intruded coastal aquifers, namely the Kokkinochoria (A1) and Kiti-Pervolia (A2) aquifers and the Troodos massif (A3). Analytical results give a first insight to the presence of Cr (VI) in Cyprus ground and surface waters. The highest Cr (VI) value of 26 μg L⁻¹ is observed in the Troodos area (A3) where Cr(VI) is detected in all sampled water systems (surface and ground/spring). Nonetheless, the highest median values of 4.6 and 4.5 μg L⁻¹ are observed in the Kokkinochoria (A1) and Kiti-Pervolia (A2) study areas respectively, where the local aquifers are under increased pressure from agriculture, urbanization and seawater intrusion. Stable isotopes were used to discern the effect of return irrigation and seawater intrusion. Stable isotope analyses from Troodos samples show two distinct groups of meteoric and near meteoric waters whereas isotopically enriched water is shown to correspond to the Kiti and Kokkinochoria area.

     

耐唑类白色假丝酵母菌临床株CYP51基因的研究

目的 探讨白色假丝酵母菌临床株CYP51基因突变与对唑类抗真菌药物耐药的关系,从分子水平了解白色假丝酵母菌的耐药机制.方法 纸片扩散法初步筛选呼吸道感染对耐唑类白色假丝酵母菌,按NCCLS公布的M-27方案测定初筛耐药株对氟康唑和伊曲康唑的MIC,设计3对引物,对分离的2株耐唑类白色假丝酵母菌(2007H株,2007T株)进行PCR,扩增CYP51基因;扩增产物纯化后,进行测序并与GenBank序列(X13296)相比较分析.结果 PCR扩增产物大小与预期结果一致;测序分析表明.成功扩增到白色假丝酵母菌CYP51基因,与X13296序列相比较,两个耐药株都存在有义突变和无义突变,两株白色假丝酵母菌共有22个碱基突变;突变发生氨基酸替换的有F105L、K128T、Y132H、T199I、R267H、G464S和G467K,其中,两株菌都有Y132H和G467K突变,F71L、W244R、T311N和T352I为新发现的突变,同时,也发现了9个未发生氨基酸替换的突变.结论 白色假丝酵母菌对唑类抗真菌药物的耐药与CYP51基因突变有关,且为多位点突变,研究发现了新的突变点,它在耐药机制中的作用需进一步研究.     

2006-2010年秦皇岛地区临床分离肺炎克雷伯菌耐药性分析

目的 分析2006-2010年秦皇岛地区肺炎克雷伯菌耐药性的变化,探究产生超广谱β-内酰胺酶(ESBLs)和碳青霉烯酶的趋势.方法 肺炎克雷伯菌菌株的鉴定、药敏试验采用黑马半自动细菌分析系统,用微量肉汤法确认肺炎克雷伯菌产生ESBLs情况,用改良Hodge试验确认肺炎克雷伯菌产碳青霉烯酶的情况;感染分布统计采用WHONET 5.3软件.结果 2006-2010年秦皇岛地区临床各类标本中分离出肺炎克雷伯菌605株,前4位分别是:呼吸道标本分离371株,中段尿分离85株,脓、伤口及其他分泌物中分离78株,血中分离32株;肺炎克雷伯菌对亚胺培南、美罗培南耐药率很低(2006年0.0％,2010年6.1％),对头孢吡肟的耐药率低于23.6％,抗菌药物耐药率大于90％(2006年90.6％,2010年93.2％)为氨苄西林,对其他抗菌药物耐药率均小于70％;但整体上肺炎克雷伯菌对各种抗生素的耐药率呈逐年上升的趋势.5年平均ESBLs分离率为37.5％;共检出2株肺炎克雷伯菌为改良Hodge试验阳性.结论 2006-2010年秦皇岛地区肺炎克雷伯菌对各种抗生素的耐药率呈逐年上升的趋势,碳青霉烯类对肺炎克雷伯菌高度敏感,是最有效的一类抗菌药物.     

Seasonal Dynamics of Dissolved Metals in Surface Coastal Waters of Southwest India

Spatial and temporal variations in concentration of dissolved metals viz. Copper (Cu), Lead (Pb), Chromium (Cr), Nickel (Ni), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) in surface waters of southwest coast of India were studied. Concentrations of metals showed an aberration both temporally and spatially. Seasonal average concentrations of the analyzed metals followed the order Zn > Ni > Cu > Pb > Cd > Cr > Hg. The degree of contamination due to metal was determined by comparison with coastal water quality criteria. It established enrichment of Cu, Zn, Ni and Hg due to anthropogenic influence along southwest coast of India.