细菌性角膜炎致病菌属的分布及其耐药性分析

目的:分析细菌性角膜炎致病菌属的分布情况及其耐药情况,提高临床用药合理性。方法:选取680例细菌性角膜炎患者的细菌培养标本,分析其致病菌属的分布情况及耐药性。结果:本次研究680份样本,细菌培养阳性228株,阳性率33.53%,其中,革兰氏阳性球菌、革兰氏阴性杆菌占86.40%,明显高于其他菌属;0~18岁(n=17)、19~60岁(n=148)、61~80岁(n=63)不同年龄段患者感染率最高的均是表皮葡萄球菌,分别是23.53%、30.41%、19.05%;另外,60岁以上患者肺炎链球菌的感染率最高,0~18岁和19~60岁患者铜绿假单胞菌感染率最高;革兰氏阳性球菌对青霉素G耐药性最高,革兰氏阴性杆菌对氨苄西林的耐药性最高。结论:葡萄球菌属、假单胞菌属是引起细菌性角膜炎最主要的致病菌,不同年龄段人群病菌属分布存在一定差异,且不同抗生素的耐药性差异较大,应根据药敏试验结果合理给药。

甲真菌病临床特点及致病菌谱的研究

目的探讨甲真菌病流行病学特点如发病年龄、临床形态学分型、易感因素,以及致病菌谱状况。方法对2010年12月—2011年12月我院328例甲真菌病的病甲进行拍照和真菌检查(包括直接镜检、真菌培养),并对所有真菌检查阳性患者进行临床形态学分型,其中113例填写调查问卷调查易感因素。结果 328例甲真菌病统计结果显示,男性发病率高于女性,男女比例为1.45∶1,最主要的发病年龄为20～29岁(35.7%)。370例指甲及趾甲的临床形态学分型中最常见的是远端侧缘甲下型(51.4%),其次为全甲毁损型(24.3%),白色浅表型(18.6%),近端甲下型(5.7%)。196例甲标本培养阳性结果中皮肤癣菌最常见(82.7%),其次为念珠菌属(11.2%)和非皮肤癣菌的霉菌(6.1%)如曲霉属、青霉属、镰刀菌属等。皮肤癣菌中最常见的是红色毛癣菌,其次须癣毛癣菌。念珠菌属中最常见的是白念珠菌。113例经调查显示易感因素为家族性感染(11.5%),慢性肾病(4.4%)及肾移植(0.9%),糖尿病(1.8%),甲外伤(1.8%),白血病(0.9%)和特发性血小板较少性紫癜(0.9%)。结论临床通过对甲真菌病患者的流行病学特点及菌种分布等情况进行了解,可指导临床治疗及采取相应的预防措施。

Study of signal transduction factors involved in mycoparasitic response of Trichoderma atroviride

Numerous Trichoderma spp. are mycoparasites and commercially applied as biological control agents against a large number of plant pathogenic fungi. The mycoparasitic interaction is host-specific and several research strategies have been applied to identify the main genes and compounds involved in the antagonist-plant-pathogen three-way interaction. During mycoparasitism, signals from the host fungus are recognised by Trichoderma, stimulating antifungal activities that are accompanied by morphological changes and the secretion of hydrolytic enzymes and antibiotics. Interestingly some morphological changes appeared highly conserved in the strategy of pathogenicity within the fungal world, i.e. the formation of appressoria as well as the secretion of hydrolytic enzymes seem to be general mechanisms of attack both for plant pathogens and mycoparasitic antagonists. This knowledge is being used to identify receptors and key components of signalling pathways involved in fungus-fungus interaction. For this purpose we have cloned the first genes (tmk1, tga1, tga3) from T. atroviride showing a high similarity to MAP kinase and G protein subunits (see abstract by Zeilinger et al.), which have been found to have an important role in pathogenicity by Magnaporthe grisea. To identify the function and involvement of these factors in mycoparasitism by T. atroviride, tmk1, tga1, tga3 disruptant strains were produced. The knock-out mutants were tested by in vivo biocontrol assays for their ability to inhibit soil and foliar plant pathogens such as Rhizoctonia solani, Pythium ultimum and Botrytis cinerea . Disruption of these genes corresponded to a complete loss of biocontrol ability, suggesting a significant role in mycoparasitism. In particular, it has been suggested that tga3 regulates the expression of chitinase-encoding genes, the secretion of the corresponding enzymes and the process of conidiation. Comparative proteome analysis of wild type and disruptants supported this hypothesis, and indicated many changes in the protein profiles of T. atroviride in different interaction conditions with plants and pathogenic hosts.

养鸡场空气微生物污染及工人呼吸暴露风险

动物养殖场是空气环境微生物污染的重要来源,然而目前关于养殖场空气中微生物污染特征的时间规律少有报道.针对以上情况,以蛋鸡场为例,采用16S r RNA基因扩增子测序分别对养殖场空气和粪便环境中细菌分布特点及呼吸暴露展开为期80余周的研究.结果表明,空气和粪便样本中16S r RNA含量范围分别在6.08×10^(5)~4.90×10^(6)copies·m^(-3)和4.27×10^(8)~1.15×10^(10)copies·g^(-1)之间.空气中细菌浓度的平均值在冬季显著高于夏季,而生物多样性则呈现相反趋势.蛋鸡场空气与粪便中的优势细菌门均为厚壁菌门(Firmicutes).在所调查时间内,空气中前3个优势菌属的种类较为稳定,依次为乳杆菌属(Lactobacillus)、拟杆菌属(Bacteroides)和栖粪杆菌属(Faecalibacterium),而粪便中优势菌属则随养殖时间的增加波动较大.空气和动物粪便中细菌和致病菌群落结构的相关性均不显著,但不同介质中两种目标微生物的含量均显著相关.粪便中细菌的气溶胶化指数随养殖时间的增加而呈上升趋势,而致病菌趋势相反.其中,瘤胃菌科torques属([Ruminococcus]_torques_group)、拟杆菌属(Bacteroides)和栖粪杆菌属(Faecalibacterium)为最易发生气溶胶化的前3个致病菌属.养鸡场工人的细菌呼吸暴露具有季节性差异,其中细菌和致病菌摄入量的平均值分别为2.54×10^(7)copies·d^(-1)和2.87×10^(5)copies·d^(-1).研究结果将为系统评估养殖场空气微生物的污染特征和潜在健康风险,对以及制定相应的职业暴露行业标准和防控措施提供科学依据.

脓毒症患者肠道菌群紊乱的临床研究

目的分析ICU内脓毒症及非脓毒症患者肠道菌群紊乱特征。方法采用前瞻性观察性研究方法,纳入2017年2月至2017年6月收住宁夏医科大学总医院重症医学科(ICU)的脓毒症患者10例(脓毒症组)、同期入住宁夏医科大学总医院ICU内未并发脓毒症的患者10例(非脓毒症组)以及健康人10例(对照组)。采集脓毒症、非脓毒症组患者入住ICU后2 d内的粪便标本,健康对照组为随机粪便样本,运用高通量16S rRNA基因测序技术进行肠道菌群检测。记录脓毒症组及非脓毒症组患者入ICU第1天急性生理学与慢性健康状况评分Ⅱ(APACHE Ⅱ)、序贯器官衰竭(SOFA)评分。结果与健康对照组比较,非脓毒症组、脓毒症组患者肠道菌群α多样性呈下降趋势,β多样性显示菌群结构均存在差异,且个体差异性更加明显。在菌门水平,非脓毒症组和脓毒症组患者肠道厚壁菌门+拟杆菌门比例均明显下降(P=0.013、0.028)、变形菌门比例升高(P=0.017、0.026),而梭杆菌门仅在非脓毒症组比例升高(P<0.01)。在菌属水平,非脓毒症、脓毒症患者均可见有益共生菌属比例均下降,如瘤胃球菌属(P=0.045、0.026)、假丁酸弧菌属(P=0.009、<0.01)、厌氧棒状菌属(P=0.011、0.003)、粪球菌属(P=0.045、0.011)、考拉杆菌属(P=0.008、0.022)、罕见小球菌属(P=0.006、0.026)。而乳酸杆菌属、多尔菌属、粪杆菌属、罗斯菌属、布劳特菌属在非脓毒症组、脓毒症组均呈下降趋势,但乳酸杆菌属仅在非脓毒症组下降具有统计学意义(P=0.005),而多尔菌属、粪杆菌属、罗斯菌属、布劳特菌属仅在脓毒症组下降具有统计学意义(P分别为0.037、0.038、0.002和0.017)。非脓毒症组患者肠道菌群中的梭杆菌属、放线菌属、消化链球菌属、链球菌属等条件致病菌比例升高(P分别为0.001、0.019、0.011和0.014),而致病葡萄球菌属(P=0.035、0.006)、肠球菌属(P=0.001、0.001)、厌氧球菌属(P=0.006、0.006)、芽孢杆菌属(均P<0.01))在非脓毒症、脓毒症组比例均升高。结论ICU内脓毒症和非脓毒症患者均发生了肠道菌群紊乱,表现为多样性下降、菌群结构改变、专性厌氧菌减少而兼性厌氧菌增多、有益共生菌减少而机会致病菌增多,且致病菌属可成为主要菌属。