Cy5 labeled antimicrobial peptides for enhanced detection of Escherichia coli O157:H7

Fluorescently labeled antimicrobial peptides were evaluated as a potential replacement of labeled antibodies in a sandwich assay for the detection of Escherichia coli O157:H7. Antimicrobial peptides naturally bind to the lipopolysaccharide component of bacterial cell walls as part of their mode of action. Because of their small size relative to antibodies peptides can bind to cell surfaces with greater density, thereby increasing the optical signal and improving sensitivity. This method combines the specificity of a capture antibody with the increased sensitivity provided by using a labeled peptide as a detection molecule. The antimicrobial peptides cecropin P1, SMAP29, and PGQ were labeled with the fluorescent dye Cy5 via maleimide linker chemistry. Preliminary screening using a whole-cell solution binding assay revealed that Cy5 cecropin P1 enhanced the detection of E. coli O157:H7 relative to a Cy5 labeled anti-E. coli O157:H7 antibody 10-fold. Detection sensitivity of antibody and peptide were also compared with a prototype immuno-magnetic bead biosensor. Detection using Cy5 cecropin P1 resulted in a 10-fold improvement in sensitivity. Correlation of peptide antimicrobial activity with detection of E. coli O157:H7 indicated that activity was not predictive of the sensitivity of the fluorescent assay.     

平湖市第一人民医院儿科患者主要病原菌分布及耐药性分析

目的了解和探讨平湖市第一人民医院儿科感染的常见病原菌的分布状况及耐药情况。方法对该院2012年1月至2012年12月儿科患者送检的合格标本进行细菌培养和药敏试验,并统计分析。结果分离出305株病原菌,其中革兰阳性球菌166株,占54. 5%,革兰阴性杆菌134株,占43. 9%,真菌5株,占1. 6%。革兰阳性球菌中前几位依次为金黄色葡萄球菌82株,占49.4%,人葡萄球菌27株,占16. 3%,表皮葡萄球菌27株,占16. 3%,溶血葡萄球菌17株,占10. 2%。革兰阴性杆菌中前几位依次为肺炎克雷伯菌42株,占30. 2%,大肠埃希菌28株,占20. 1%,鲍曼不动杆菌21株,占15. 1%,阴沟肠杆菌15株,占10. 8%,不同病原菌对常用抗菌药物呈现不同程度的耐药,大肠埃希菌的ESBLs阳性率为28. 6%,肺炎克雷伯菌ESBLs阳性率为11.9%。结论该院儿科患者感染的主要病原菌以革兰阳性球菌为主,最常见为金黄色葡萄球菌,不同病原菌对抗生素的耐药性不同,应加强病原菌的检测及耐药性监测,严格执行消毒灭菌操作的各项规定,尽早进行细菌鉴定和药敏试验,临床应根据药敏结果选择用药,合理使用抗菌药物。     

2009年度宁波市妇儿医院主要病原菌的临床分布及耐药性分析

目的了解宁波市妇儿医院主要病原菌的临床分布及耐药性分析。方法血液培养采用法国生物梅里埃公司的BacT/Alert3D,菌株鉴定采用法国生物梅里埃公司的VITEK 60分析仪,药敏试验采用K-B法,纸片扩散确证试验检测ESBLs。结果前10位细菌构成比依次是大肠埃希菌(13.4%)、白色念珠菌(8.7%)、阴道加德纳菌(7.8%)、表皮葡萄球菌(6.9%)、金黄色葡萄球菌(5.6%)、肺炎克雷伯菌(4.9%)、鲍曼复合醋酸钙不动杆菌(3.9%)、粪肠球菌(D群)(3.1%)、铜绿假单胞菌(2.7%)和溶血葡萄球菌(2.0%)。大肠埃希菌539株中产ESBLs阳性率为52.5%,肺炎克雷伯菌195株中产ESBLs阳性率为45.2%。大肠埃希菌主要分离于尿液,其次是脓液/切口。肺炎克雷伯菌在痰及咽拭子中所占比例最高。46株铜绿假单胞菌和11株鲍曼复合醋酸钙不动杆菌对亚胺培南耐药。结论对产ESBLs的肺炎克雷伯菌和大肠埃希菌、耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)、耐亚胺培南的鲍曼复合醋酸钙不动杆菌和铜绿假单胞菌,应加强隔离预防,控制在医院内的扩散,减少耐药菌株产生。     

呼吸道感染临床实验室检查标本的评价

急性呼吸道感染(RTIs)是临床常见多发病,其病原体对抗生素耐药率的增加对诊断微生物学构成了严峻的挑战。临床微生物室对感染病原体的检出率较低,一般只有50%,且不同部位感染所采集的标本,其结果差异很大。本研究将评述呼吸道感染实验室检查标本采集的影响因素和常见病原体肺炎链球菌、流感嗜血杆菌、肺炎支原体、卡他莫拉菌、肺炎衣原体、嗜肺性军团病杆菌、呼吸道病毒、尿抗原试验的临床意义。     

青春双歧杆菌辅助治疗牙周炎的疗效及对常见致病菌和炎性因子水平的影响

目的探讨青春双歧杆菌辅助治疗牙周炎的疗效及对常见致病菌和炎性因子水平的影响。方法选择2017年6月-2018年6月于我院确诊并治疗的慢性牙周炎患者84例,按照随机数字表法将所有患者分为双歧杆菌组(n=43)和对照组(n=41),所有患者均予以一次牙周清洁治疗。双歧杆菌组在此基础上使用双歧杆菌活菌散含服3周,治疗结束后进行为期3个月的随访。观察比较两组患者治疗前后牙周炎相关指标、龈沟液(GCF)内双歧杆菌及常见致病菌水平及炎性因子水平之间的差异,并分析GCF内双歧杆菌与炎性因子水平的相关性。结果双歧杆菌组出血指数(BI)、菌斑指数(PLI)、牙龈指数(GI)及探诊深度(PD)均显著低于对照组(均P<0.05)。双歧杆菌组患者末次随访时GCF内牙龈卟啉单胞菌、福赛斯坦纳菌、中间普雷沃菌及齿垢密螺旋体水平显著低于对照组,双歧杆菌水平显著高于对照组(均P<0.05)。双歧杆菌组患者末次随访时GCF内IL-6、TNF-α、MMP-8及TIMP-2水平显著低于对照组(均P<0.05)。GCF内IL-6、TNF-α、MMP-8及TIMP-2含量均与双歧杆菌水平呈负相关(β=-0.311,-0.309,-0.306,-0.142,均P<0.05)。结论双歧杆菌能有效改善牙周炎患者口腔内微生物环境,降低患处GCF内炎性因子水平,对牙周炎的辅助治疗起到较好的效果。     

乳腺癌术后医院感染患者病原菌分布和危险因素及血清炎症因子水平分析

目的分析乳腺癌术后医院感染患者病原菌分布、危险因素及血清炎症因子水平,并探讨其临床意义。方法收集2016年3月至2018年3月我院诊治的80例乳腺癌术后医院感染患者为观察组。同期选取80例乳腺癌术后未发生感染者为对照组。利用全自动微生物分析仪对感染患者进行病原菌分布检测。对乳腺癌术后医院感染的危险因素进行单因素回归分析,同时检测并比较两组患者血清中白细胞介素-10(IL-10)、干扰素-γ(IFN-γ)及肿瘤坏死因子-α(TNF-α)的水平。结果80例乳腺癌术后医院感染患者共检出病原微生物97株。其中革兰阴性菌55株,以大肠埃希菌及铜绿假单胞菌为主;革兰阳性菌39株,以金黄色葡萄球菌为主(16株);真菌3株。观察组患者血清中IL-10、INF-γ及TNF-α水平均显著高于对照组(均P<0.05)。患者合并疾病情况、引流天数、住院天数及辅助化疗均与乳腺癌术后发生医院感染有密切联系(均P<0.05)。结论乳腺癌术后医院感染病原菌分布较广,以革兰阴性菌为主。患者合并疾病情况、引流天数、住院天数及辅助化疗均为医院感染的危险因素。血清中炎症因子水平可作为乳腺癌术后医院感染的诊断标志物。     

Pathogens and antibiotic residues in animal manures and hygienic and ecological risks related to subsequent land application

The practice of spreading of livestock wastes onto land used for the production of food or animal feeds is widely regarded as the least environmentally damaging disposal method, however, the practice is still fraught with pitfalls such as N pollution of air and water and significant microbiological risks. Therefore this paper focuses on some of the latest developments that provide new insights into the microbiological safety of animal manures, the related treatment options and the spreading the products onto land. In conclusion the paper stresses the need to fully address issues concerning environmental contamination and transmission of antimicrobial-resistant bacteria through livestock manure, improve current environmental regulations regarding manure management practice and coordination of research activities and dissemination of technical information.     

Hollow-fiber ultrafiltration for simultaneous recovery of viruses, bacteria and parasites from reclaimed water

Hollow-fiber ultrafiltration (UF) is a technique that has been reported to be effective for recovering a diverse array of microbes from water, and may also be potentially useful for microbial monitoring of effluent from water reclamation facilities. However, few data are available to indicate the potential limitations and efficacy of the UF technique for treated wastewater. In this study, recovery efficiencies were determined for various options available for performing the tangential-flow UF technique, including hollow-fiber ultrafilter (i.e., dialyzer) type, ultrafilter pre-treatment (i.e., blocking), and elution. MS2 and ΦX174 bacteriophages, Clostridium perfringens spores, Escherichia coli, and Cryptosporidium parvum oocysts were seeded into 10-L reclaimed water samples to evaluate UF options. Then a single UF protocol was established and studied using seeded and non-seeded 100-L samples from two water reclamation facilities in Georgia, USA. Baxter Exeltra Plus 210 and Fresenius F200NR dialyzers were found to provide significantly higher microbial recovery than Minntech HPH 1400 hemoconcentrators. The selected final UF method incorporated use of a non-blocked ultrafilter for UF followed by elution using a surfactant-based solution. For 10-L samples, this method achieved recovery efficiencies of greater than 50% recovery of seeded viruses, bacteria, and parasites. There was no significant difference in overall microbial recovery efficiency when the method was applied to 10- and 100-L samples. In addition, detection levels for pathogens in seeded 100-L reclaimed water samples were 1000 PFU HAV, 10,000 GI norovirus particles, < 500 Salmonella and < 200 Cryptosporidium oocysts. These data demonstrate that UF can be an effective technique for recovering diverse microbes in reclaimed water to monitor and improve effluent water quality in wastewater treatment plants.     

益生菌和致病菌对肠道的黏附及其相互作用研究进展

探讨益生菌及致病菌对肠道上皮细胞的黏附机制,比较其黏附后的生物学效应差异,重点对二者之间的竞争性黏附作用进行了概述.在上述基础上对益生菌抑制致病菌的研究前景和发展趋势进行了展望.     

CD4+CD25+ suppressor T cells regulate pathogen induced inflammation and disease

A key suppressor role has recently been ascribed to the natural CD4+CD25+ regulatory T cells (Treg), the removal of which leads to the development of autoimmune disease and aggravated pathogen-induced inflammation in otherwise normal hosts. The repertoire of antigen specificities of Treg is as broad as that of naive T cells, recognizing both self and non-self antigens, enabling Treg to control a broad range of immune responses. Although widely acknowledged to play a role in the maintenance of self-tolerance, recent studies indicate that Treg can be activated and expanded against bacterial, viral and parasite antigens in vivo. Such pathogen-specific Treg can prevent infection-induced immunopathology but may also increase the load of infection and prolong pathogen persistence by suppressing protective immune responses. This review discusses the role of Treg in the prevention of exaggerated inflammation favoring chronicity in bacterial or fungal infections and latency in viral infections. Special attention is given to the role of Treg in the modulation of gastric inflammation induced by Helicobacter pylori infection. Findings in both experimentally infected mice and humans with natural infection indicate that Treg are important in protecting the H. pylori-infected host against excessive gastric inflammation and disease symptoms but on the negative side promote bacterial colonization at the gastric and duodenal mucosa which may increase the risk in H. pylori-infected individuals to develop duodenal ulcers.