Gene characteristics,immune and stress responses of PmPrx1 in black tiger shrimp (Penaeus monodon): Insights from exposure to pathogenic bacteria and toxic environmental stressors

Peroxiredoxins (Prxs) are ubiquitous, multifunctional and evolutionarily conserved enzymes that can protect cells from oxidative damage caused by ROS and play a vital role in immune responses. Here, a full-length Prx1 cDNA sequence (PmPrx1) was isolated from Penaeus monodon. The PmPrx1 cDNA was 951 base pairs (bp), encoding 198 amino acid polypeptides. The results of qRT-PCR showed that the PmPrx1 mRNA was ubiquitously expressed in all tissues tested and had a comparatively high expression level in immune-associated tissues (gill, hepatopancreas). To explore the immune and anti-stress roles of PmPrx1, the gills and hepatopancreas were chosen as target tissues in Penaeus monodon and were challenged with bacteria (Vibrio harveyi and Streptococcus agalactiae) and toxic environmental stresses. To further clarify the immune function of PmPrx1 after bacterial challenge, the recombinant PmPrx1 protein was acquired using a prokaryotic expression method. The antioxidant activity of the recombinant PmPrx1 was assessed by the catalyzing hydrogen peroxide assay method, and the results showed obvious antioxidant activity in a dose-dependent and temperature-dependent manner. The antimicrobial activity of purified PmPrx1 protein was evaluated and further studied in vitro relying on a bacterial growth inhibition test which was conducted in both liquid and solid cultures. Furthermore, E. coli transferred with pRSET-PmPrx1 was dramatically protected in response to metal toxicity and H₂O₂ oxidative stress. In summary, this study provides useful information about the role of the Prx1 gene in defense against a variety of toxic factors in shrimps that help to further clarify the functional mechanism of Prx.     

老年机械通气患者呼吸机气路管道更换周期探讨

目的探讨老年机械通气患者呼吸机气路管道的最佳更换时间,评价气路管道污染与下呼吸道感染的关系。方法将我院干部医疗科76例老年机械通气患者分为A、B、C三组,分别在48、72、96小时更换呼吸机气路管道,对三组更换的呼吸机气路管道及部分患者口咽部或下呼吸道分泌物进行采样,进行细菌培养及半定量分析。结果气路管道污染率与换管时间同步增长,并与下呼吸道细菌培养结果具有高度的一致性。结论老年机械通气患者下呼吸道感染与气路管道污染的细菌具有高度一致性,应在48～96小时依据呼吸机气路管道的污染情况及时更换循环管路。     

泌尿系统感染细菌病原学临床监测分析

目的了解近4年泌尿系统感染(UTI)细菌构成比与耐药性变化。方法采用多平板不同条件接种UTI患者尿标本进行细菌培养,采用BioMerieux VITEK2型全自动微生物仪与ID卡进行菌种鉴定,采用双纸片表型确证扩散法进行产超广谱β-内酰胺酶大肠埃希菌检测,采用Kirby-Bauer琼脂扩散法进行抗菌药物敏感试验,采用WHONET5.3软件进行数据统计分析。结果检出细菌768株,分布为G+菌/G-菌=26.4%/73.6%,大肠埃希菌占比49.2%。其他优势菌Sa、Se、ET、Kp、Ec及Pa占比分别为7.6%、6.8%、5.2%、6.5%、5.7%及4.9%,耐药率增高/持平/降低的品种分别为9/4/3、7/7/2、8/4/4、11/4/3、12/5/1及12/4/2个。134个药敏试验组合中82个(61.2%)为耐药率增高。结论 UTI细菌构成比例与耐药性在不断变化中,主要菌种对常用抗菌药的耐药率超6成在增高。提高标本送检率,加强临床监测,对减缓细菌抗药性蔓延与恶化有积极意义。     

老年泌尿感染病原菌分布及耐药性分析

目的：讨论研究老年泌尿感染病的病原菌分布情况及其耐药性。方法整群选取3043例次清洁中段的尿标本送检,采用VITEK-60微生物鉴定系统进行药敏实验和鉴定菌株。结果样本结果分析显示,其培养阳性率为39.9%,分离真菌<占28.7%,其中革兰阳性菌占19.4%,主要包括屎肠球菌、粪肠球菌、金黄色葡萄球菌;革兰阴性菌占52.0%,主要包括大肠埃希菌、肺炎克雷伯菌、肠杆菌科;分离株耐药程度也较高。结论对引发疾病的病原菌及相关药物的特点进行分析有助于临床更好的选择针对性药物抑制病原菌繁殖,控制病情进一步发展并改善预后具有重要意义。     

降钙素原在小儿重症感染细菌感染性疾病预后中指导意义研究

目的：探析降钙素原在小儿重症感染细菌感染性疾病中的应用及在疾病预后指导中的价值。方法以该院2010年6月—2013年10月期间所收治的108例重症感染细菌感染性疾病患儿作为研究对象,分为观察组和对照组。分别测定两组降钙素原水平与C反应蛋白水平,对照组结合C反应蛋白水平测定结果进行治疗,观察组结合降钙素原测定结果治疗,比较两种检测方法敏感性与特异性、住院时间及病死率。结果两组降钙素原、C反应蛋白测定结果的比较均差异无统计学意义（P＞0.05）,观察组住院时间为（8.2±2.1）d,病死率为0%,明显比对照组的（13.4±3.0）d和5.7%（3/53）更小,组间对比差异有统计学意义（P＜0.05）。两组降钙素原测定的敏感性、特异性与两组C反应蛋白所测定相比均更高,差异有统计学意义（P＜0.05）。结论在重症感染细菌感染性疾病患儿的临床治疗中动态监测其血清降钙素原变化情况可有效反映患儿感染情况进而为临床治疗提供指导,对于改善疾病预后具有重要意义。     

新生儿败血症病原学特征分析

目的 探讨本院新生儿败血症病原菌的分布及耐药情况,指导临床合理使用抗生素,促进医院感染的有效防控.方法 对2006年1月至2011年5月我院新生儿科收治的败血症患儿进行回顾性分析,按照发病时间分为早发型败血症及晚发型败血症,并根据发生感染的地点分为社区获得性感染及医院感染.结果 研究期间共收治新生儿败血症121例.早发型败血症50例(41.3％),病原菌以革兰阴性杆菌为主,共40例(80％),其中含产超广谱β内酰胺酶(ESBLS)株5例(10％),革兰阳性凝固酶阴性葡萄球菌10例(20％).晚发型败血症71例(58.6％),其中社区感染56例(78.9％),病原菌以革兰阳性球菌为主,共30例(42.2％),革兰阴性杆菌26例(36.6％);医院感染15例(21.1％),革兰阴性杆菌7例(9.9％),其中产ESBLs株4例(5.6％),革兰阳性凝固酶阴性葡萄球菌4例(5.6％),真菌4例(5.6％),均为白色念珠菌.结论 早发型败血症及晚发型败血症、社区获得性败血症及医院感染败血症病原谱不同,均有多重耐药菌产生.     

细菌感染与支气管哮喘关系及其机制的研究进展

支气管哮喘的发病机制尚不明确,目前认为感染在哮喘的发病中有着重要作用,已证实病毒、支原体、衣原体感染可诱发或加重哮喘发作.目前,细菌感染与哮喘的关系尚不明确.有学者研究发现细菌感染可以降低哮喘的发病率、减轻症状,而有研究则报道细菌感染导致哮喘发病及病情的加重.为进一步探讨细菌与哮喘的关系,该文对细菌感染与支气管哮喘关系及其可能机制进行初步探讨,以期为了解哮喘的发病及早期防治提供思路.     

Early IFN type I response: Learning from microbial evasion strategies

Type I interferon (IFN) comprises a class of cytokines first discovered more than 50 years ago and initially characterized for their ability to interfere with viral replication and restrict locally viral propagation. As such, their induction downstream of germ-line encoded pattern recognition receptors (PRRs) upon recognition of pathogen-associated molecular patterns (PAMPs) is a hallmark of the host antiviral response. The acknowledgment that several PAMPs, not just of viral origin, may induce IFN, pinpoints at these molecules as a first line of host defense against a number of invading pathogens. Acting in both autocrine and paracrine manner, IFN interferes with viral replication by inducing hundreds of different IFN-stimulated genes with both direct anti-pathogenic as well as immunomodulatory activities, therefore functioning as a bridge between innate and adaptive immunity. On the other hand an inverse interference to escape the IFN system is largely exploited by pathogens through a number of tactics and tricks aimed at evading, inhibiting or manipulating the IFN pathway, that result in progression of infection or establishment of chronic disease.In this review we discuss the interplay between the IFN system and some selected clinically important and challenging viruses and bacteria, highlighting the wide array of pathogen-triggered molecular mechanisms involved in evasion strategies.