Gel clot LAL assay in the initial management of peritoneal dialysis patients with peritonitis: a retrospective study.

BACKGROUND: Indiscriminate use of broad-spectrum antibiotic treatment of peritonitis in peritoneal dialysis patients may have either unwanted side-effects or contribute to the development of antibiotic resistance. This may be avoided by improved diagnosis at presentation. The Limulus amoebocyte lysate assay is a convenient test detecting bacterial endotoxins or fungal beta glucans. This study evaluates a qualitative Limulus amoebocyte lysate test as a diagnostic tool used at presentation of a peritoneal dialysis patient with peritonitis. METHODS: One-hundred and eleven episodes of peritonitis in peritoneal dialysis patients have been analysed retrospectively. Limulus amoebocyte lysate results at presentation were compared with culture results. A Limulus amoebocyte lysate assay was performed using a commercial kit by incubating a mixture of dialysate effluent and Limulus amoebocyte lysate reagent at 37 degrees C. The development of a stable solid clot was considered positive. The specificity and sensitivity of the test were calculated. RESULTS: The specificity of the Limulus amoebocyte lysate assay was found to be 98% and the sensitivity 74%. Limulus amoebocyte lysate assay was false-negative in 13 cases of Gram-negative peritonitis (22%). Limulus amoebocyte lysate was positive in three of seven cases of fungal peritonitis. The study included one case each with false-positive Limulus amoebocyte lysate and with culture-negative peritonitis. CONCLUSIONS: The Limulus amoebocyte lysate assay is a convenient and valuable diagnostic tool for excluding Gram-positive peritonitis in peritoneal dialysis patients. This allows more specific antibiotic treatment at presentation and may avoid the development of bacterial resistance. A negative Limulus amoebocyte lysate test is not reliable for the exclusion of Gram-negative peritonitis. In the absence of a positive culture result 48 h after presentation, accompanied by a delayed response to treatment, a positive Limulus amoebocyte lysate assay may indicate the presence of fungus. This justifies early empiric antifungal treatment before definitive culture results are made available. Routine Limulus amoebocyte lysate assay of dialysate effluent from continuous ambulatory peritoneal dialysis patients presenting with peritonitis is recommended.     

An ancient antimicrobial protein co-opted by a fungal plant pathogen for in planta mycobiome manipulation

Microbes typically secrete a plethora of molecules to promote niche colonization. Soil-dwelling microbes are well-known producers of antimicrobials that are exploited to outcompete microbial coinhabitants. Also, plant pathogenic microbes secrete a diversity of molecules into their environment for niche establishment. Upon plant colonization, microbial pathogens secrete so-called effector proteins that promote disease development. While such effectors are typically considered to exclusively act through direct host manipulation, we recently reported that the soil-borne, fungal, xylem-colonizing vascular wilt pathogen Verticillium dahliae exploits effector proteins with antibacterial properties to promote host colonization through the manipulation of beneficial host microbiota. Since fungal evolution preceded land plant evolution, we now speculate that a subset of the pathogen effectors involved in host microbiota manipulation evolved from ancient antimicrobial proteins of terrestrial fungal ancestors that served in microbial competition prior to the evolution of plant pathogenicity. Here, we show that V. dahliae has co-opted an ancient antimicrobial protein as effector, named VdAMP3, for mycobiome manipulation in planta. We show that VdAMP3 is specifically expressed to ward off fungal niche competitors during resting structure formation in senescing mesophyll tissues. Our findings indicate that effector-mediated microbiome manipulation by plant pathogenic microbes extends beyond bacteria and also concerns eukaryotic members of the plant microbiome. Finally, we demonstrate that fungal pathogens can exploit plant microbiome-manipulating effectors in a life stage–specific manner and that a subset of these effectors has evolved from ancient antimicrobial proteins of fungal ancestors that likely originally functioned in manipulation of terrestrial biota.

Microbes are found in a wide diversity of niches on our planet. To facilitate establishment within microbial communities, microbes secrete a multitude of molecules to manipulate each other. Many of these molecules exert antimicrobial activities and are exploited to directly suppress microbial coinhabitants in order to outcompete them for the limitedly available nutrients and space of a niche. Microbially secreted antimicrobials encompass diverse molecules including peptides and lytic enzymes but also nonproteinaceous molecules such as secondary metabolites. Soils are among the most biologically diverse and microbially competitive environments on earth. Microbial proliferation in the soil environment is generally limited by the availability of organic carbon (1), for which soil microbes continuously compete. Consequently, numerous saprophytic soil-dwelling microbes secrete potent antimicrobials that promote niche protection or colonization. Notably, these microbes are the primary source of our clinically used antibiotics (2, 3).Like free-living microbes, microbial plant pathogens also secrete a multitude of molecules into their environment to mediate niche colonization (4, 5). The study of molecules secreted by microbial plant pathogens has been largely confined to the context of binary interactions between pathogens and hosts. To establish disease, plant pathogenic microbes secrete a plethora of so-called effectors, molecules of various kinds that promote host colonization and that are typically thought to mainly deregulate host immune responses (4, 6, 7). Upon host colonization, plant pathogens encounter a plethora of plant-associated microbes that collectively form the plant microbiota, which represent a key factor for plant health. Beneficial plant-associated microbes are found in and on all organs of the plant and help to mitigate (a)biotic stresses (8–13). Plants shape their microbiota and specifically attract beneficial microbes to suppress pathogens (14–16). Hence, the plant microbiome can be considered an inherent, exogenous layer that complements the plant’s endogenous innate immune system. We previously hypothesized that plant pathogens not only utilize effectors to target components of host immunity as well as other aspects of host physiology to support host colonization but also to target the host microbiota in order to establish niche colonization (4, 5). We recently provided experimental evidence for this hypothesis by showing that the ubiquitously expressed effector VdAve1 that is secreted by the soil-borne fungal plant pathogen Verticillium dahliae acts as a bactericidal protein that promotes host colonization through the selective manipulation of host microbiomes by suppressing microbial antagonists (17, 18). Additionally, we demonstrated that VdAve1 and a further antibacterial effector named VdAMP2 are exploited by V. dahliae for microbial competition in soil and promote virulence of V. dahliae in an indirect manner (18). Collectively, these observations demonstrate that V. dahliae dedicates part of its effector catalog toward microbiota manipulation. Likely, the V. dahliae genome encodes further effectors that act in microbiome manipulation.Evidently, bacterial and fungal evolution on land preceded land plant evolution. As a consequence, fungal pathogen effectors involved in the manipulation of (host-associated) microbial communities may have evolved from ancestors that served in microbial competition in terrestrial niches hundreds of millions of years ago prior to land plant evolution. However, evidence for this hypothesis is presently lacking.V. dahliae is an asexual xylem-dwelling fungus that causes vascular wilt disease on hundreds of plant species (19). The fungus survives in the soil in the form of multicellular melanized resting structures, called microsclerotia, that offer protection against (a)biotic stresses and can persist in the soil for many years (20). Microsclerotia represent the major inoculum source of V. dahliae in nature, and their germination is triggered by carbon- and nitrogen-rich exudates from plant roots (21). Following microsclerotia germination, fungal hyphae grow through the soil and rhizosphere toward the roots of host plants. Next, V. dahliae colonizes the root cortex and crosses the endodermis, from which it invades xylem vessels. Once the fungus enters those vessels, it forms conidiospores that are transported with the water flow until they get trapped, for instance, by vessel end walls. This triggers germination of the conidiospores followed by penetration of cell walls, hyphal growth, and renewed sporulation, leading to systematic colonization of the plant (22). Once tissue necrosis commences and plant senescence occurs, host immune responses fade and V. dahliae enters a saprophytic phase in which it emerges from the xylem vessels to invade adjacent host tissues, which is accompanied by the production of microsclerotia. Upon littering and decomposition of plant tissues, these microsclerotia are released into the soil (23).     

HPLC法测定蛹虫草中腺苷和虫草素的含量

目的建立HPLC法测定蛹虫草中腺苷和虫草素的含量。方法采用SinochromODS Cl8柱,以磷酸盐缓冲液-甲醇(85:15)为流动相;流速为1.0 mL·min-1;检测波长为260 nm。结果腺苷在8.92~44.6μg·mL-1范围内线性关系良好,r=0.999 9;虫草素在6.23~31.15μg?mL-1范围内线性关系良好,r=0.999 9;腺苷平均加样回收率为97.80%,RSD为1.1%(n=5)。虫草素平均加样回收率为97.46%,RSD为1.5%(n=5)。结论本法专属性强,准确度高,重现性好,可作为蛹虫草质量控制的方法。     

药用真菌竹黄化学成分的研究

目的研究药用真菌竹黄Shiraia bambusicola的化学成分。方法利用硅胶柱色谱及高效制备液相色谱等分离纯化手段,并通过1H-NMR、13C-NMR、MS等波谱学技术进行结构鉴定。结果共分离得到9个化合物,分别鉴定为3,6,8-三羟基-1-甲基酮(1)、3,8-二羟基-6-甲氧基-1-甲基酮(2)、2,3,6,8-四羟基-1-甲基酮(3)、3,4,6,8-四羟基-1-甲基酮(4)、Δ5,10-3β,17α,20β-孕甾三醇(5)、macrosphelide A(6)、(+)-griseofulvin(7)、griseophe-none A(8)和抗肿瘤活性成分11,11′-dideoxyverticillin A(9)。结论化合物1~9均为首次从该真菌中分离得到。     

Online Registry of COVID-19–Associated Mucormycosis Cases,India, 2021

We established an online registry of coronavirus disease–associated mucormycosis cases in India. We analyzed data from 65 cases diagnosed during April–June 2021, when the Delta variant predominated, and found that patients frequently received antibacterial drugs and zinc supplementation. Online registries rapidly provide relevant data for emerging infections.     

儿童脓癣83例临床分析

本文报告儿童脓癣83例(男44例,女39例),全部惠儿均来自农村,平均患病天数61．7％。90％以上惠儿家中养有猫狗动物,患病后100％的患儿均不同程度的使用过皮质类固醇软膏及癣药水。真菌培养出真菌6种,77株,几乎全为亲动物性致病真菌。其中石膏样毛癣菌占一半以上(55．4％46株)。全部患儿均按头癣治疗的“五字决”经验(即：剪、洗、搽、服、消)治愈。文中特别指出被误诊的12例而行切开排脓致永久性疤痕及脱发,给患儿带来了不必要的心理、生理创伤,说明提高农村医务人员医疗技术水平及对脓癣的认识是当务之急,应引起卫生主管部门的高度重视!     

酮康唑治疗真菌性角膜溃疡的疗效观察

目的探讨酮康唑治疗真菌性角膜溃疡的效果.方法酮康唑口服0.2 g每日2次,酮康唑0.2加入生理盐水5 ml中点眼,0.5 h一次,治疗22例真菌性角膜溃疡病人.结果治愈19例,治愈率86.4%;有效1例,占4.5%;失败2例,占9.1%.病情轻重及治疗早晚与愈后关系密切.结论酮康唑治疗真菌性角膜溃疡疗效明显,给药途径方便,值得推广.     

一株藏红花内生真菌多糖的提取及抗氧化活性研究

目的首次由藏红花分离得到内生真菌,研究热水浸提法和超声波法提取真菌#CSL-8多糖的最佳工艺及多糖的抗氧化活性。方法通过正交实验探讨真菌多糖提取的最佳工艺,并采用DPPH法对多糖的抗氧化活性进行评价。结果 热水浸提法提取的最佳工艺参数为:提取温度95℃,料液比1∶30,提取时间4 h,粗多糖得率为9.47%,多糖含量为26.35%;超声波法提取的最佳工艺参数为:超声功率400 W,料液比1∶40,提取时间40 min,粗多糖得率为9.12%,多糖含量为57.65%。两种方法提取的多糖对DPPH自由基的`清除率IC50分别为0.15和0.11 mg/m。l结论与热水浸提法相比,超声波法提取得到的多糖含量较高,提取效果较好。抗氧化实验中,两种方法提取的多糖对DPPH自由基均有较强的清除能力,且有明显的量-效相关性。     

359株临床分离真菌的分布及药敏分析

目的探讨本院检出真菌的分布特征及药敏结果,为预防和减少院内真菌感染及临床合理使用抗真菌药物提供依据。方法利用沙保氏培养基和显色培养基进行分离培养及初步鉴定,利用ATBFUNGUS3试条进行药敏分析,将真菌鉴定和药敏结果输入WHONET5．4软件数据库,然后利用该软件进行数据分析。结果本院2008—2010年从临床分离的359株真菌,白色念珠菌占68．2％,热带念珠菌14．8％,光滑念珠菌8．6％,近平滑念珠菌6．1％,克柔念珠菌1,1％,其他真菌1．1％;对5种临床常用抗真菌药物两性霉素B、5-氟胞嘧啶、伊曲康唑、伏立康唑、氟康唑的敏感性均较高,最高为两性霉素99．6％,最低为伊曲康唑93．9％。结论临床真菌分离率呈逐年升高趋势,但没发现明显的耐药趋势,临床应加强对抗菌药物的合理使用,减少真菌感染的发生。     

A fatal case with disseminated Myceliophthora thermophila infection in a lymphoma patient

We report a lethal Myceliophthora thermophila infection in an immunocompromised patient. Based upon the clinical and mycological presentation, an initial diagnosis of invasive aspergillosis was made, possibly delaying optimal management in the patient. Melanized fungi are emerging pathogens that require early identification to improve their unfavorable prognosis.