儿童重症监护病房医院感染暴发白色念珠菌血流感染4例分析

摘要 目的：探讨儿童重症监护病房白色念珠菌血流感染暴发的临床表现、危险因素、控制措施等,为预防和控制院内白色念珠菌血流感染暴发提供科学依据。方法：以2018年7月我院儿童重症监护病房发生的4例白色念珠菌血流感染暴发患儿为研究对象,分析患儿临床情况、临床特征、危险因素、暴发原因以及采取的预防控制措施。结果：4例医院感染暴发白色念珠菌血流感染患儿均存在基础疾病、有机械通气史、存在中心静脉或动脉置管、静脉或动脉置管前后均使用碘伏消毒、曾使用广谱抗生素、输血制品,白色念珠菌血流感染后最突出的临床表现均是发热。药敏方面,医院感染暴发的4例白色念珠菌感染患儿对唑类及5-氟胞嘧啶均耐药,但对两性霉素B均敏感。经拔除血管置管、减少或者避免广谱抗菌药的应用,根据药敏使用卡泊芬净及两性霉素B抗真菌等积极治疗,1例患儿放弃治疗后死亡,3例患儿顺利出院。通过Fisher确切概率法分析可知,留置中心静脉或动脉置管是儿童重症监护病房发生医院感染暴发白色念珠菌血流感染的危险因素（P<0.05）。结论：留置中心静脉或动脉置管是儿童重症监护病房发生医院感染暴发白色念珠菌血流感染的危险因素,医院感染暴发白色念珠菌血流感染患儿最突出的临床表现是发热,唑类及5-氟胞嘧啶耐药的患儿使用卡泊芬净及两性霉素B可能获得较好的治疗效果。     

两性霉素B联合氟康唑治疗艾滋病合并新型隐球菌性脑膜脑炎的疗效预测因素分析

目的:探讨两性霉素B联合氟康唑治疗艾滋病合并新型隐球菌性脑膜脑炎(简称"艾滋病合并隐脑")的疗效预测因素。方法:回顾性收集2010年1月1日-2016年12月31日58例在首都医科大学附属北京佑安医院住院治疗且接受两性霉素B联合氟康唑治疗的艾滋病合并隐脑患者的临床资料,分析其疗效预测因素及预测价值。结果:根据预后将患者分为好转组(38例)和死亡组(20例),单因素分析结果显示两组之间CD4+T细胞计数、脑脊液细胞计数比较有统计学差异(P分别为0.032,0.001)。Logistic回归多因素分析结果显示脑脊液细胞计数是两性霉素B联合氟康唑治疗艾滋病合并隐脑的疗效预测因素(P=0.023),Exp(B)=1.01,95%置信区间为1.00-1.03。ROC曲线对脑脊液细胞计数的预测价值进行分析,结果显示曲线下面积为0.889,预测阈值为261个/mm3,对应的敏感性=0.684,特异性=1.0。结论:脑脊液细胞计数是两性霉素B联合氟康唑治疗艾滋病合并新型隐球菌性脑膜脑炎良好的疗效预测参考因素。     

Interference of melanin in the susceptibility profile of Sporothrix species to amphotericin B

BackgroundThe presence of melanin in the fungal cell is a major virulence factor of the genus Sporothrix since it protects the fungal cells against the defense systems.AimsThe present study aimed to investigate the interference of melanin in the susceptibility of Sporothrix brasiliensis and Sporothrix schenckii sensu stricto to amphotericin B and itraconazole, drugs recommended as therapy for disseminated and subcutaneous sporotrichosis, respectively.MethodsYeast cells were cultivated in minimal medium with or without l-DOPA in order to induce the production of melanin. Microdilution and killing assay methods were used to determine the antifungal activity against yeast cells with different amounts of melanin.ResultsThe killing assay showed that melanization protected isolates within the S. schenckii complex from amphotericin B, particularly in the lower concentrations tested.ConclusionsStudies combining amphotericin B and inhibitors of melanin are required in order to avoid this effect.     

Complexes of Amphotericin B and Cholesteryl Sulfate

Abstract

To improve the clinical utility of amphotericin B, we have developed a novel formulation of amphotericin B, Amphocil® (also known as Amphotericin B Colloidal Dispersion, or ABCD). Amphocil is a uniform disc-shaped complex of amphotericin B and sodium cholesteryl sulfate in a molar ratio of 1:1. The complex has a mean hydrodynamic diameter of approximately 115 nm and is thermodynamically stable. In an extensive series of pharmacodynamic, pharmacokinetic and toxicology studies, Amphocil was found to be less toxic than conventional amphotericin B (Fungizone®), providing a four- to five-fold improvement in safety, while remaining effective in treating a variety of fungal infections. Plasma pharmacokinetics and tissue disposition of amphotericin B differ in several respects after administration of Amphocil and conventional amphotericin B, due to a rapid uptake of Amphocil by liver. Animals receiving Amphocil demonstrated reduced peak levels in plasma, prolonged residence time and lowered levels of amphotericin B in most tissues including the kidney, the major target organ for toxicity, compared with animals receiving conventional amphotericin B.

In healthy male subjects receiving a single dose of Amphocil, ranging from 0.25-1.5 mg/kg, mild to moderate dose-dependent acute side effects typically seen with conventional amphotericin B were observed but there was no sign of renal or hepatic toxicities. In two dose-escalating studies, multiple daily doses of Amphocil up to 4.5 mg/kg were well tolerated in patients who had previously failed to tolerate or respond to conventional amphotericin B. In addition, complete clearance of fungal infection was observed with the Amphocil therapy. Thus, Amphocil is a safe and effective agent for treating systemic mycoses. Toleration and efficacy of higher doses of Amphocil in patients with life-threatening mycoses is currently being evaluated.     

Unilamellar-Vesicle Systems as Model for Studying Membrane Permeabilization by Polyene Antibiotics

Abstract

Permeabilization of phospholipid/sterol unilamellar vesicles by polyene antibiotics (amphotericin B and lucensomycin) was studied by measuring proton leakage with a pH-stat method. The percentage of proton release was directly related to the antibiotic concentration. Using ergosterol-containing vesicles, a relevant proton efflux was induced by micromolar concentrations of amphotericin B, whereas lucensomycin caused membrane permeabilization at higher concentrations (0.1 mM). Cholesterol-containing vesicles were less sensible to the lytic action of polyenes. When amphotericin B was carried in cholesterol-containing liposomes, the selectivity towards ergosterol-containing vesicles was enhanced. An increase in drug selectivity was also observed by dissolving amphotericin B in fresh human plasma. At concentrations one order of magnitude lower than those necessary to induce a detectable proton efflux, lucensomycin seemed to protect the vesicles from the subsequent permeabilizing action of amphotericin B.     

Molecular Modeling Studies on Amphotericin B and its Complex with Phospholipid

Abstract

Molecular dynamics simulation studies on polyene antifungal antibiotic amphotericin B, its head-to-tail dimeric structure and lipid - amphotericin B complex demonstrate interesting features of the flexibilities within the molecule and define the optimal interactions for the formation of a stable dimeric structure and complex with phospholipid.     

Infección múltiple fúngica en un paciente diabético

BackgroundMixed fungal infections although undervalued, are more common than mentioned in the scientific literature. These infections have a poor prognosis for the patient.ObjectivesWe present an unusual case of a 61-year-old diabetic male who had a rhino-orbito-sinusal zygomycosis in 2001. After surgical debridement of the infected parts, along with antifungal therapy with liposomal amphotericin B, the patient started improving. Several years later the patient was hospitalized due to a similar problem and was diagnosed of rhino-orbito-cerebral zygomycosis.MethodsIn both episodes, a histopathological examination and cultures were performed on the sinus lesions. Tissue sections were stained with haematoxylin and eosin, Giemsa, periodic acid-Schiff (PAS) and Grocott's methenamine silver, and cultures specific for fungi were performed.ResultsThe histopathology studies revealed the presence of bacteria, actinomyces and a mixed infection by at least four different fungi, all of them well differentiated by their morphology. Despite the rapid diagnosis the patient died due to spreading to the central nervous system.ConclusionsMixed infections by fungi are rare, but due to the high incidence of immunodeficiencies they could occur more often than reported. We would like to alert on the possibility of acquired mixed infection by fungi which have shown to be high aggressive and have a worse prognostic in patients with underlying diseases.     

Changes in growth patterns and intracellular calcium concentrations in Aspergillus awamori treated with amphotericin B

Growth patterns and intracellular Ca²⁺ concentrations in the mutant strain Aspergillus awamori 66A containing a recombinant aequorin gene were studied in the presence of a permeabilizing fungicidal agent amphotericin B. The cell response, i.e., changes in the growth and development of the fungus (initiation of spore germination, mycelial growth, and intensity of sporulation) was dose-dependent. Low concentrations of amphotericin B (2.5 μM) stimulated spore germination: the number of germinating spores was 2–3 times higher than in the control (without the fungicide). At higher amphotericin concentrations (20 μM) spore germination was inhibited. Amphotericin B had a dose-dependent effect on mycelial growth and sporulation intensity on solid Vogel medium. Intracellular Ca²⁺ concentrations in the presence of amphotericin B were investigated using the luminescence of the photoprotein aequorin. High concentrations of amphotericin B (10 and 20 μM) were shown to cause an instantaneous increase in Ca²⁺ concentrations compared to the control and lower amphotericin concentration (2.5 μM). Ca²⁺ concentrations remained elevated throughout the experiment and correlated with the inhibition of mycelial growth and development.     

Development,Characterization, Efficacy and Mode of Action of Ambisome,A Unilamellar Liposomal Formulation of Amphotericin B

Abstract

AmBisome is a lyophilized formulation of amphotericin B incorporated into small unilamellar liposomes composed of hydrogenated soy phosphatidylcholine, distearoyl phosphatidylglycerol, and cholesterol. In aqueous solution AmBisome is quite stable; less than 5% of the drug dissociates from the liposomes during a 72 hour incubation period in human plasma. This stability to loss of drug is a key factor, accounting for the ability of AmBisome to markedly reduce the well known acute and chronic toxicities associated with administration of amphotericin B. Numerous animal and clinical studies have documented therapeutic efficacy of AmBisome for a wide range of fungal infections. Mechanism of action studies indicate that AmBisome liposomes specifically bind to the fungal cell surface, dam the cell membrane, and kill the fungus. In some cases, AmBisome had a slightly lower potency than amphotericin B itself, but much higher doses of AmBisome could be administered safely resulting in an improved therapeutic profile.     

Antifungal Activity of Antifungal Drugs,as Well as Drug Combinations Against <Emphasis Type="Italic">Exophiala dermatitidis</Emphasis>

To evaluate the in vitro efficacy of common antifungal drugs, as well as the interactions of caspofungin with voriconazole, amphotericin B, or itraconazole against the pathogenic black yeast Exophiala dermatitidis from China, the minimal inhibitory concentrations (MICs) of terbinafine, voriconazole, itraconazole, amphotericin B, fluconazole, and caspofungin against 16 strains of E. dermatitidis were determined by using CLSI broth microdilution method (M38-A2). The minimal fungicidal concentrations (MFCs) were also determined. Additionally, the interactions of caspofungin with voriconazole, amphotericin B, itraconazole or fluconazole, that of terbinafine with itraconazole, or that of fluconazole with amphotericin B were assessed by using the checkerboard technique. The fractional inhibitory concentration index (FICI) was used to categorize drug interactions as following, synergy, FICI ≤ 0.5; indifference, FICI > 0.5 and ≤4.0; or antagonism, FICI > 4.0. The MIC ranges of terbinafine, voriconazole, itraconazole, amphotericin B, fluconazole, and caspofungin against E. dermatitidis were 0.06–0.125 mg/l, 0.25–1.0 mg/l, 1.0–2.0 mg/l, 1.0–2.0 mg/l, 16–64 mg/l, and 32–64 mg/l, respectively. The in vitro interactions of caspofungin with voriconazole, amphotericin B, and itraconazole showed synergic effect against 10/16(62.5%), 15/16(93.75%), and 16/16(100%) isolates, while that of caspofungin with fluconazole showed indifference. Besides, the interaction of terbinafine with itraconazole as well as that of fluconazole with amphotericin B showed indifference. Terbinafine, voriconazole, itraconazole, and amphotericin B have good activity against E. dermatitidis. The combinations of caspofungin with voriconazole, amphotericin B or itraconazole present synergic activity against E. dermatitidis. These results provide the basis for novel options in treating various E. dermatitidis infections.     

Sensibilidad de aislamientos de Candida albicans de hemocultivos a 3 fármacos: estudio retrospectivo en Rio Grande do Sul,Brasil, 1999 a 2009

BackgroundCandidiasis is one of the most important among recurrent invasive yeast infections in patients, thus antifungal treatment becomes a challenge.AimsThe aim of this study was to evaluate the in vitro activity of clinical Candida albicans isolates from blood cultures to fluconazole, amphotericin B and anidulafungin, in a hospital from Rio Grande do Sul, Brazil.MethodsThe susceptibility of 153 isolates to the 3 drugs mentioned was tested according to Clinical and Laboratory Standars Institute. Minimal inhibitory and fungicidal concentrations (MIC, MFC, respectively) of each drug were determined, as well as the epidemiological cutoff value (ECV).ResultsAll of the isolates were susceptible to anidulafungin, MIC and MFC ≤ 1 μg/ml; however, when compared with ECV, 3% of the isolates exhibited higher values against fluconazole, 96% were susceptible, 3% susceptible dose-dependent, and 1% resistant. Also, it was observed that 21% of the isolates exhibited higher values than ECV. One isolate was resistant to amphotericin B; the other ones, susceptible, based on the MFC; furthermore, 1.5% of the isolates exhibited higher values.ConclusionsC. albicans isolates exhibited more susceptibility to anidulafungin, and 90% of them (MIC₉₀) exhibited the lowest values against amphotericin B. Based on ECV and Pfaller classification, isolates could be resistant to fluconazole, demonstrating the importance of the combination of these parameters.     

Aspergilosis pulmonar en un paciente crítico no inmunodeprimido

BackgroundIn non-immunocompromised patients admitted to intensive care departments or units (ICU), it is difficult to establish a definitive diagnosis of pulmonary aspergillosis because the signs and symptoms of this infectious disease are non-specific, and serological techniques are not very specific as well. For this reason, a diagnosis of possible pulmonary aspergillosis is initially established, and the starting of the treatment is controversial.Case reportAn immunocompetent subject had a work-related accident after a fall, which resulted in multiple injuries (head, thorax, lower extremities). The patient required mechanical ventilation since admission. On the second week of ICU admission, he showed a clinical presentation of respiratory infection with fever, purulent secretions, bilateral pulmonary infiltrates and repeated isolation of Mucor and Aspergillus fumigatus in bronchial secretions and pharyngeal swabs. The patient was treated with amphotericin B lipid complex and voriconazole with an excellent clinical and radiological outcome.ConclusionsCombined treatment of antifungal agents, in this case amphotericin B lipid complex and voriconazole, is a therapeutic possibility to be considered in patients who failed to respond to initial antifungal monotherapy.     

Leishmania-HIV Co-infection: Clinical Presentation and Outcomes in an Urban Area in Brazil

BackgroundVisceral leishmaniasis (VL) is an emerging condition affecting HIV-infected patients living in Latin America, particularly in Brazil. Leishmania-HIV coinfection represents a challenging diagnosis because the clinical picture of VL is similar to that of other disseminated opportunistic diseases. Additionally, coinfection is related to treatment failure, relapse and high mortality.ObjectiveTo assess the clinical-laboratory profile and outcomes of VL-HIV-coinfected patients using a group of non HIV-infected patients diagnosed with VL during the same period as a comparator.MethodsThe study was conducted at a reference center for infectious diseases in Brazil. All patients with suspected VL were evaluated in an ongoing cohort study. Confirmed cases were divided into two groups: with and without HIV coinfection. Patients were treated according to the current guidelines of the Ministry of Health of Brazil, which considers antimony as the first-choice therapy for non HIV-infected patients and recommends amphotericin B for HIV-infected patients. After treatment, all patients with CD4 counts below 350 cells/mm³ received secondary prophylaxis with amphotericin B.ResultsBetween 2011 and 2013, 168 patients with suspected VL were evaluated, of whom 90 were confirmed to have VL. In total, 51% were HIV coinfected patients (46 patients). HIV-infected patients had a lower rate of fever and splenomegaly compared with immunocompetent patients. The VL relapse rate in 6 months was 37% among HIV-infected patients, despite receiving secondary prophylaxis. The overall case-fatality rate was 6.6% (4 deaths in the HIV-infected group versus 2 deaths in the non HIV-infected group). The main risk factors for a poor outcome at 6 months after the end of treatment were HIV infection, bleeding and a previous VL episode.ConclusionAlthough VL mortality rates among HIV-infected individuals are close to those observed among immunocompetent patients treated with amphotericin B, HIV coinfection is related to a low clinical response and high relapse rates within 6 months.     

马尔尼菲蓝状菌病致溶骨性损害合并Sweet样皮疹1例

本文报道广西医科大学第一附属医院皮肤性病科收治的马尔尼菲蓝状菌病致溶骨性损害合并Sweet样皮疹1例。免疫力正常人群较少患马尔尼菲蓝状菌病。本例患者既往体健,起初合并融骨性损害,在两性霉素B、伊曲康唑治疗过程中逐渐出现Sweet样皮疹。患者经两性霉素B、伊曲康唑、激素等治疗后,病情逐渐好转。     

Amphotericin B: How Much Is Enough?

The total curative dose of amphotericin B for any given fungal infection or specific patient is not precisely known. Prior to the availability of lipid formulations of amphotericin B (LFAB), dosing of amphotericin B was dictated by its associated toxicity. The unique pharmacokinetic features of each LFAB have led to differences in their recommended doses. Most published data have evaluated doses of 3–5 mg/kg/day, although niches exist for both higher and lower doses. Low-dose LFAB allows for intravenous broad-spectrum antifungal coverage without drug-drug interactions and with reduced toxicity. High-dose LFAB demonstrates increased fungal clearance in animal models, although this has not translated to improved clinical outcomes for most invasive fungal infections. Although available data do not demonstrate significant benefit associated with high-dose therapy, for liposomal amphotericin B, the data also demonstrate no significant harm. As such, the use of high-dose liposomal amphotericin B for salvage therapy may be a consideration.     

Designing a highly immunogenic multi epitope based subunit vaccine against Bacillus cereus

ObjectiveSerious non-gastrointestinal-tract infections and food poisoning are caused by Bacillus cereus. Vaccination against B. cereus is very important. The aim of this study was to identify and analyze B and T cell epitopes for chromate transporter protein of the bacteria.MethodsMultiple sequence alignment with the Clustal Omega method was used to identify conserved regions and Geneious Prime was used to produce a consensus sequence. T and B cell epitopes were predicted by various computational tools from the NetCTL and Immune Epitope Database (IEDB), respectively.ResultsAltogether, 6 HTL cells and 11 CTL epitopes were predicted. This vaccine's molecular docking is done with Patch Dock and LigPlot to verify interactions. The immune server (C-IMMSIM) was used to develop In silico immune response in order to assess the multi-epitope vaccine's immunogenic profile.ConclusionWe designed universal vaccine against B. cereus responsible for food poisoning. The disease may be avoided with the aid of the proposed epitope-based vaccine.     

Exophiala dermatitidis as a cause of central line associated bloodstream infection in an infant: Case report and literature review

BackgroundExophiala dermatitidis is a dematiaceous fungus known to cause superficial, subcutaneous, cutaneous and deep seated infections, and rarely central line associated bloodstream infection (CLABSI). A case of CLABSI due to E. dermatitidis in an infant is described.Case reportClinical and laboratory data were extracted from patient's chart and laboratory records. The isolate was identified as E. dermatitidis by phenotypic characterization and sequencing of the ITS and LSU regions of the ribosomal DNA. Medline search was done to review all cases of CLABSI due to E. dermatitidis. Among the azoles tested, posaconazole (0.06 mg/l), voriconazole (0.03 mg/l) and itraconazole (0.03 mg/l) showed very low MICs when compared to fluconazole (4 mg/l)ConclusionsAs we did not found in the literature any case of CLABSI due to E. dermatitidis in an infant, we report the first one. Sequencing is a mandatory method for accurately identifying this species. Prompt removal of the central line, followed by a treatment with amphotericin B or an azole, seems to be the most effective treatment.     

Epidemiología de las fungemias en un hospital pediátrico de alta complejidad

BackgroundA retrospective study on the epidemiology of fungaemia due to yeasts of medical importance at the Hospital Nacional de Pediatría Prof. Dr. J. Garrahan, Buenos Aires was conducted between September 2001 and September 2003.ObjectivesTo learn the distribution of yeast species and to evaluate their in vitro antifungal susceptibility profile.MethodsThe minimum inhibitory concentration (MIC) was determined according to the CLSI M27-A2 procedure, and time kill curves against amphotericin B were also performed.Results-ConclusionsThe species isolated were Candida parapsilosis (32.6% of isolates); Candida albicans (26.5%), Candida tropicalis (24.5%), and other yeasts (16.4%). Candida isolates were susceptible to the antifungals evaluated, but amphotericin B-tolerant isolates were detected using time kill curves.     

Utilidad clínica de la micafungina en el tratamiento de las candidiasis invasoras en el paciente oncohematológico

BackgroundInvasive candidiasis is a severe infection among onco-hematological patients, with an attributable mortality around 40%. Micafungin has shown efficacy in antifungal prophylaxis among hematopoietic stem cell transplant recipients and in the treatment of esophageal candidiasis.AimsTo assess the role of micafungin in the treatment of invasive candidiasis among onco-hematological patients.MethodsLiterature review.ResultsIn a study on 126 patients with candidemia treated with micafungin, an overall response rate of 83% was reported. A double-blind study of 531 patients with invasive candidiasis comparing micafungin (100 mg/day) versus liposomal amphotericin B (3 mg/kg/day) reported success in 90% of patients in both arms, with a more favorable safety profile with micafungin. Other double blind randomized, phase III study compared two doses of micafungin (100 mg/day and 150 mg/day) with standard doses of caspofungin (70 mg loading dose, then 50 mg/day) in adults with invasive candidiasis. Overall success rate was 74% for micafungin 100 mg/day, 70% for micafungin 150 mg/day, and 71% for caspofungin. A double blind randomized study compared micafungin (2 mg/kg/day) to liposomal amphotericin B (3 mg/kg/day) in the treatment of invasive candidiasis in children with a predominance of infections with non-albicans Candida spp. Overall success rate was similar (73% for micafungin and 76% for liposomal amphotericin B).ConclusionsComparative phase III studies have demonstrated non-inferiority of micafungin compared to standard antifungal agents for invasive candidiasis. Micafungin is safe and effective in the treatment of children and adults with invasive candidiasis. Effectivity in invasive infections caused by non-albicans Candida spp is especially relevant in onco-hematological patients receiving fluconazole prophylaxis.     

Análisis de la utilización de anfotericina B liposomal

BackgroundThe increase in immunosuppressed patients and in the use of cytotoxic and immunosuppressive agents in the last few years has led to a rise in the incidence of invasive fungal infections.AimsThe objective of this study is to evaluate the use of liposomal amphotericin B according to its indication, dosage, effectiveness and nephrotoxicity.MethodsThis is a retrospective study over a 8 year-period. Indications and dosage described in the Summary of Product Characteristics were taken as reference. Effectiveness was measured in terms of resolution of infection, no recurrence or emergence, survival at 7th day, no discontinuation and no addition of another antifungal. Effectiveness was also analysed in relation to indication, dosage, treatment duration, cumulative dose and comorbidity. Nephrotoxicity was defined as a doubled serum creatinine when compared with basal values.ResultsA total of 47 episodes were analysed, with 91.5% of treatments being adequate for the indications. Effectiveness was achieved in 44.7% of cases: 33% in neutropenic patients, 50% of aspergillosis, 60% of candidiasis, and 100% of the leishmaniasis. Response rates in patients treated for 15 days or less and those for more than 15 days were 25 and 56.5% (P = .039), respectively. The main causes of failure were death (23%) and lack of effectiveness (17%), with 9% of patients suffering from nephrotoxicity.ConclusionsThe effectiveness and nephrotoxicity data agree with those obtained in other studies. Liposomal amphotericin B is a safe drug with a moderate effectiveness that is associated with the duration of the treatment.