病原菌群体感应系统的研究进展

群体感应是细菌间依赖细胞密度的一种信息传递方式.细菌通过合成、分泌信号分子感知细菌群体密度,从而控制整个细菌群体行为.目前已在许多革兰阴性菌、革兰阳性菌和真菌中发现群体感应系统,对群体感应系统信号分子结构、信号传导通路进行大量研究后,发现其与细菌生物膜形成、生成分泌毒力因子密切相关.本文就以典型的铜绿假单胞菌、金黄色葡萄球菌、哈氏弧菌、白色念珠菌为例,对群体感应系统相关机制及研究进展予以综述.     

2019至2020年西安儿童医院儿童细菌感染分布和耐药监测分析

目的了解西安儿童医院儿童细菌感染性疾病的病原分布特点和耐药现状,以指导抗菌药物的应用并预防多重耐药菌(MDROs)的产生。方法收集2019年1月至2020年12月西安市儿童医院住院患儿临床分离的菌株,对菌株临床分布特点及耐药性进行分析,并与全国监测数据进行比较。结果共分离出菌株9044株,检出数居前5位依次为凝固酶阴性葡萄球菌(CNS)、大肠埃希菌(Eco)、化脓性链球菌(Spy)、金黄色葡萄球菌(Sau)和嗜麦芽窄食单胞菌(Sma),分别占14.3%(1291/9044)、10.3%(920/9044)、9.6%(870/9044)、9.0%(822/9044)和5.6%(507/9044)。重点耐药菌中耐甲氧西林金黄色葡萄球菌(MRSA)、红霉素耐药肺炎链球菌(ERSP)、碳青霉烯耐药铜绿假单胞菌(CR-Pae)检出率分别为30.1%、92.1%和14.2%,低于全国水平(35.0%、98.8%和23.2%),差异均有统计学意义(χ^(2)=7.89、P=0.01,χ^(2)=75.98、P<0.001,χ^(2)=10.12、P<0.001),而耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)和碳青霉烯耐药鲍曼不动杆菌(CR-Aba)检出率分别为81.8%和68.9%,均高于全国水平(76.4%和54.0%),差异均有统计学意义(χ^(2)=4.78、P=0.03,χ^(2)=11.53、P<0.001)。共检出MDROs 920株,检出率为10.2%(920/9044),最常见的依次为Eco[47.4%(436/920)]、Sau[23.7%(218/920)]和Kpn[13.2%(121/920)];主要分离自脓液[46.1%(424/920)]、呼吸道[28.9%(266/920)]和血液[11.1%(102/920)]。分离细菌对多种抗菌药物呈现不同程度的耐药性,部分菌株耐药率与全国监测数据差异较大,其中Sau和CNS对克林霉素耐药率分别为67.8%(564/832)和65.0%(724/1114),显著高于全国监测数据[30.9%(2645/8561)和25.5%(1409/5524)](χ^(2)=458.8、662.7,P均<0.001);Eco对头孢吡肟、亚胺培南和美罗培南耐药率分别为14.4%(135/935),1.7%(16/935)和1.2%(11/935),显著低于全国水平[22.8%(2181/9567),3.2%(306/9567)和4.2%(402/9567)](χ^(2)=34.62、P<0.001,χ^(2)=6.34、P=0.01,χ^(2)=20.64、P<0.001);Aba对头孢他啶、亚胺培南耐药率分别为65.2%(88/135)和62.5%(84/135),显著高于全国水平[53.4%(1621/3036)和51.9%(1576/3036)](χ^(2)=7.23、P=0.01,χ^(2)=5.51、P=0.02);Pae对哌拉西林、头孢他啶、头孢吡肟、美罗培南耐药率分别为8.6%(20/233),7.7%(18/233),2.7%(6/233)和8.7%(20/233),显著低于监测数据[15.2%(508/3344),14.0%(468/3344),10.2%(341/3344)和20.0%(669/3344)],差异有统计学意义(χ^(2)=7.56、P=0.01,χ^(2)=7.29、P=0.01,χ^(2)=14.45、P<0.001,χ^(2)=18.27、P<0.001)。结论本院儿童感染性疾病常见细菌分布及对多种抗菌药物的耐药率如Sau和CNS对克林霉素,Eco对头孢吡肟、碳青霉烯类抗菌药物,Aba对头孢他啶、亚胺培南以及Pae对β-内酰胺类和碳青霉烯类抗菌药物的耐药性与全国监测水平差异较大,需进一步加强对重点耐药菌如MRCNS、CR-Aba的感染防控,针对本地区细菌感染特点合理应用抗菌药物,对于降低感染率和院内感染播散有重要意义。     

Differential immunomodulatory properties of Bifidobacterium logum strains: relevance to probiotic selection and clinical applications

Modulation of host immunity is one of the proposed benefits of the consumption of probiotics. Nonetheless, comparative studies on the immunological properties that support the selection of strains of the same species for specific health benefits are limited. In this study, the ability of different strains of Bifidobacterium longum to induce cytokine production by peripheral blood mononuclear cells (PBMCs) has been evaluated. Live cells of all B. longum strains greatly stimulated regulatory cytokine interleukin (IL)-10 and proinflammatory cytokine tumour necrosis factor (TNF)-alpha production. Strains of the same species also induced specific cytokine patterns, suggesting that they could drive immune responses in different directions. The probiotic strain B. longum W11 stimulated strongly the production of T helper 1 (Th1) cytokines while B. longum NCIMB 8809 and BIF53 induced low levels of Th1 cytokines and high levels of IL-10. The effects of cell-surface components obtained by sonication of B. longum strains overall confirm the effects detected by stimulation of PBMCs with live cells, indicating that these components are important determinants of the immunomodulatory activity of B. longum. Genomic DNA of some strains stimulated the production of the Th1 and pro-inflammatory cytokines, interferon (IFN)-gamma and TNF-alpha, but not that of IL-10. None of the cell-free culture supernatants of the studied strains was able to induce TNF-alpha production, suggesting that the proinflammatory component of these strains is associated mainly with structural cell molecules. The results suggest that despite sharing certain features, some strains can perform a better functional role than others and their careful selection for therapeutic use is desirable.     

氧驱动雾化吸入器消毒方法的临床研究

目的调查临床使用雾化吸入器沾染的细菌种类和3种不同处理方法的灭菌效果。方法通过细菌培养法鉴定雾化吸入器的细菌污染情况,分别采用清水冲洗、酒精擦洗和健之素浸泡的方法进行处理后再次进行细菌培养。结果临床使用的雾化吸入器上含有致病细菌,清水冲洗酒精擦洗和健之素浸泡能清除雾化器表面的多数细菌,细菌清除率为73.80%、81.59%和93.42%,只有健之素组符合国家标准。结论健之素浸泡是临床消毒雾化吸入器的简便有效方法。     

166例支气管哮喘急性发作期患儿呼吸道病原学分析

目的：了解东莞市儿童支气管哮喘急性发作期的病原学分布特征,指导临床治疗。方法：选择东莞市太平人民医院2012年6月至2013年6月收治住院的支气管哮喘急性发作患儿共166例,根据年龄分为〈3岁婴幼儿组和≥3岁儿童组,分别检测病毒、支原体（MP）、衣原体（CP）及细菌等病原体分布情况。结果：166例患儿检出病毒、MP、CP、细菌感染任何一项阳性者共132例,占79.5%,其中检出病毒69例（41.6%）、CP 16例（9.6%）、MP 39例（23.5%）,细菌培养阳性39例（23.5%）。结论：东莞市儿童哮喘急性发作与感染密切相关,病毒感染最多见,MP、细菌感染亦较常见。     

Nanocarriers for antibiotics: A promising solution to treat intracellular bacterial infections

In the field of antibiotherapy, intracellular infections remain difficult to eradicate mainly due to the poor intracellular penetration of most of the commonly used antibiotics. Bacteria have quickly understood that their intracellular localisation allows them to be protected from the host immune system, but also from the action of antimicrobial agents. In addition, in most cases pathogens nestle in professional phagocytic cells, and can even use them as a ‘Trojan horse’ to induce a secondary site of infection thereby causing persistent or recurrent infections. Thus, new strategies had to be considered in order to counteract these problems. Amongst them, nanocarriers loaded with antibiotics represent a promising approach. Nowadays, it is possible to encapsulate, incorporate or even conjugate biologically active molecules into different families of nanocarriers such as liposomes or nanoparticles in order to deliver antibiotics intracellularly and hence to treat infections. This review gives an overview of the variety of nanocarriers developed to deliver antibiotics directly into infected cells.     

Improper positioning of the elevator lever of duodenoscopes may lead to sequestered bacteria that survive disinfection by automated endoscope reprocessors

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近3年我院重症医学科细菌检出及抗菌药物耐药率分析

摘 要 目的：对我院重症医学科近3年细菌检出结果和耐药率进行统计分析,为临床抗感染治疗提供参考。方法：收集2015~2017年粤北人民医院重症医学科所有检出细菌分离的菌株及药敏结果,统计分析该区域细菌流行趋势及耐药率变迁。结果：近3年共检出1 399株细菌,其中革兰阴性菌株1 021株（72.98%）,革兰阳性菌378株（27.02%）,多重耐药菌448株（32.02%）。鲍曼不动杆菌是检出率最高的细菌（25.16%）,对碳青霉烯耐药严峻（＞73.31%）;肺炎克雷伯菌属（17.30%）近3年检出率呈上升趋势,对酶抑制药复合制剂和碳青霉烯类药物耐药率逐年增高;铜绿假单胞菌检出率排第3,检出率呈下降趋势;凝固酶阴性葡萄球菌、金黄色葡萄球菌和肺炎链球菌是检出率最高的革兰阳性菌,其中肺炎链球菌近3年检出趋势逐渐升高,3种细菌对青霉素耐药严重（＞90%）,暂未发现万古霉素、替考拉宁和利奈唑胺耐药菌。结论：我院重症医学科检出细菌以革兰阴性菌为主,抗菌药物耐药情况严峻,应结合本区域细菌流行趋势和耐药情况合理选用抗菌药物。     

Microbiota,infecciones gastrointestinales,inflamación de bajo grado y antibioticoterapia en el síndrome de intestino irritable. Una revisión basada en evidencias

BackgroundPost-infectious irritable bowel syndrome (PI-IBS) prevalence, small intestinal bacterial overgrowth (SIBO), altered microbiota, low-grade inflammation, and antibiotic therapy in IBS are all controversial issues.AimsTo conduct an evidence-based review of these factors.MethodsA review of the literature was carried out up to July 2012, with the inclusion of additional articles as far as August 2013, all of which were analyzed through the Oxford Centre for Evidence-Based Medicine (OCEBM) system.Results1. There is greater SIBO probability in IBS when breath tests are performed, but prevalence varies widely (2-84%). 2. The gut microbiota in individuals with IBS is different from that in healthy subjects, but a common characteristic present in all the patients has not been established. 3. The incidence and prevalence of PI-IBS varies from 9-10% and 3-17%, respectively, and the latter decreases over time. Bacterial etiology is the most frequent but post-viral and parasitic cases have been reported. 4. A sub-group of patients has increased enterochromaffin cells, intraepithelial lymphocytes, and mast cells in the intestinal mucosa, but no differences between PI-IBS and non-PI-IBS have been determined. 5. Methanogenic microbiota has been associated with IBS with constipation. 6. Rifaximin at doses of 400 mg TID/10 days or 550 mg TID/14 days is effective treatment for the majority of overall symptoms and abdominal bloating in IBS. Retreatment effectiveness appears to be similar to that of the first cycle.ConclusionsFurther studies are required to determine the nature of the gut microbiota in IBS and the differences in low-grade inflammation between PI-IBS and non-PI-IBS. Rifaximin has shown itself to be effective treatment for IBS, regardless of prior factors.