念珠菌耐药机制的研究进展

目前,在抗真菌药物非常有限的条件下,耐药念珠菌的出现给临床抗真菌治疗带来很大的困难。念珠菌主要对唑类药物、两性霉素B及5-氟胞嘧啶这三大类药物耐药,本文就念珠菌对这三类药物耐药机制的研究现状作了综述。     

白色念珠菌对唑类药物耐药机制的研究进展

近年来,白色念珠菌导致的感染发病率逐年上升,已严重威胁人们健康。在临床上,最常用的唑类抗真菌药物因长期广泛使用,导致致病真菌耐药性逐年增加。文章综述白色念珠菌对唑类药物耐药机制的研究进展,为合理应用唑类药物和开发新型药物提供理论依据。     

念珠菌耐药机制的研究进展

目前，在抗真菌药物非常有限的条件下，耐药念珠菌的出现给临床抗真菌治疗带来很大的困难。念珠菌主要对唑类药物、两性霉素B及5-氟胞嘧啶这三大类药物耐药，本文就念珠菌对这三类药物耐药机制的研究现状作了综述。     

80株生殖道白念珠菌的药物敏感性研究

目的 为了解生殖道白念珠菌对五种抗真菌药物的敏感性及是否存在交叉耐药性，了解对抗真菌药物的耐药率，使临床医师能选择敏感的药物控制白念珠菌感染。方法 采用NCCLS M27-A推荐方法检测80株临床分离的生殖道白念珠菌对五种抗真菌药物的最低抑菌浓度(MIC80)。结果 80株临床分离生殖道白念珠菌对五种抗真菌药物的敏感率分别从41．3％至87．5％不等，而耐药率从0％至26．2％不等。且10株同时对氟康唑、咪康唑耐药，2株同时对氟康唑、酮康唑耐药，有1株同时对咪康唑、酮康唑耐药。结论 发现白念珠菌对两性霉素B最敏感，而对唑类药物耐药率较高，且唑类药物之间存在交叉耐药性。     

新合成抗结核药物研究进展

目前,世界范围内结核病仍是广泛流行的重要传染病,多重耐药结核分枝杆菌的出现和艾滋病合并结核感染的致死性协同作用使得这种情况雪上加霜。因此,临床渴求新的抗痨药物以满足耐药结核治疗的需求。现主要对喹啉类、硝基咪唑吡喃类、嗯唑烷酮类、吡咯类等新合成的抗结核药物作综述。     

高脂血症合并感染患者细菌检出特征及耐药情况分析

目的 探讨高脂血症合并感染患者细菌检出特征及耐药情况，为临床治疗提供依据。方法 选取2019年1月—2021年12月本院高脂血症合并感染患者315例，收集临床资料，采用WHONET 5.6对细菌标本分布、种类特征、耐药谱特点及多重耐药情况进行统计分析。结果 高脂血症合并感染患者315例，剔除重复菌株后共检出细菌910株，以呼吸道标本为主。革兰阴性菌占79.2%,前3位细菌为肺炎克雷伯菌、铜绿假单胞菌、大肠埃希菌；革兰阳性菌占20.8%,前二位细菌为金黄色葡萄球菌、屎肠球菌。主要的革兰阴性菌对碳青霉烯类或氨基糖苷类药物敏感性尚可，对其余药物有相对较高的耐药率。主要的革兰阳性菌对利奈唑胺、万古霉素等药物较敏感，而对β-内酰胺类、大环内酯类、喹诺酮类药物耐药率较高。在常见的多重耐药菌检出方面，MRSA、CRPAE、CRE检出率高于全国平均水平，尚未发现VRE。结论 高脂血症合并感染患者细菌耐药形势严峻，应根据细菌培养结果合理选择抗生素，降低耐药率。     

2013年北京市儿童A组链球菌药敏结果分析

目的观察北京市儿童A组链球菌(GAS)对目前常用抗菌药物的敏感性,为临床用药提供依据。方法 2013年的5月-7月,在北京市36家医院收集儿童A组链球菌153株,全部菌株来自咽拭子标本。采用VITEK-2全自动微生物分析系统及GPS-67药敏卡进行药敏试验,依据CLSI 2012年M100-S22判定标准判断其对相关抗菌药物的敏感性。结果 153株GAS对青霉素、氨苄西林、左氧氟沙星、替加环素、万古霉素、链阳霉素、利奈唑胺敏感率均为100.0%(153/153);对克林霉素、红霉素耐药率均为99.3%(152/153);对四环素耐药率为88.2%(135/153);在不同地区、不同年龄和临床诊断病例间菌株对红霉素、克林霉素和四环素耐药率的分布差异无统计学意义(P0.05)。结论 2013年北京市儿童A组链球菌的病原菌GAS对青霉素等β-内酰胺类和左氧氟沙星等喹诺酮类药物具有高度敏感性,对红霉素等大环内酯类抗菌药物和克林霉素耐药率高,提示临床谨慎选择该类药物。青霉素类仍然是治疗猩红热的首选药物。     

鲍氏不动杆菌耐药性分析

目的分析医院鲍氏不动杆菌(ABA)的耐药性及其变迁,以指导临床合理用药。方法回顾性总结医院2006~2008年分离的428株鲍氏不动杆菌药物敏感性试验资料。结果鲍氏不动杆菌体外药敏试验最敏感药物为亚胺培南,耐药率在11.3%~34.0%;阿米卡星的耐药率在29.8%~49.5%;对青霉素类的耐药率在57.7%~91.0%;对含酶抑制剂青霉素类药物的耐药率较高,为54.0%~74.5%;对氨苄西林、头孢唑林、头孢泊肟、头孢西丁高度耐受,耐药率均91.0%,且呈多药耐药。结论亚胺培南、美罗培南及多黏菌素B是治疗鲍氏不动杆菌感染最有效的抗菌药物。     

肉桂醛联合两性霉素B对烟曲霉菌的体外抗菌活性研究

目的评价肉桂醛联合两性霉素B(AMB)应用对烟曲霉菌的体外抗真菌效果,以进一步探讨联合应用这两种药物能否抑制AMB耐药烟曲霉菌。方法采用微量液基稀释法对临床分离的30株烟曲霉菌进行体外药敏试验,用棋盘法测部分抑菌浓度指数(FIC),评定两种药物联合的抗真菌效果。结果 30株烟曲霉菌中有8株MIC>1μg/ml为AMB耐药菌株,耐药率为26.7%;肉桂醛与AMB对30株烟曲霉菌单用时的MIC50、MIC90及MIC均数(MICG)比联用时高,差异有统计学意义(P<0.01);同一药物的相同浓度下,联合应用时的累计抑菌百分率比单用时高;肉桂醛与AMB联合时主要表现为协同、相加作用,部分表现出无关作用,未出现拮抗作用。结论肉桂醛与AMB联合应用,对AMB耐药的烟曲霉菌株主要表现为协同作用;对AMB敏感的烟曲霉菌株主要表现为相加作用。     

2008-2011年产气肠杆菌的临床分布及耐药性分析

目的 分析产气肠杆菌临床分布特点及对常用抗菌药物的耐药性变化,以更好地指导临床的合理使用抗菌药物.方法 采用WHONET5软件统计分析2008年1月-2011年12月临床分离的产气肠杆菌临床分布和耐药率.结果 4年内共分离到产气肠杆菌459株,其中2008-2011年分别检出108、101、130、120株；病原菌主要来源于住院患者的痰液213株占46.4％、胆汁70株占15.3％、血液51株占11.1％、尿液50株占10.9％;4年耐药监测显示,亚胺培南和美罗培南的耐药率在2.0％～7.9％,呈明显的逐年上升趋势；头孢类抗菌药物除头孢唑林耐药率较高约90.0％外,其他如头孢替坦、头孢曲松、头孢他啶、头孢吡肟等耐药率由最高的55.5％下降至最低28.5％,氨苄西林/舒巴坦、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦等复合制剂耐药率也由最高70.2％下降至最低21.1％,同时阿米卡星、庆大霉素等氨基糖苷类等药物的耐药率亦呈下降趋势,最高30.4％,最低为0,对喹诺酮类的耐药率约30.0％,保持相对稳定.结论 4年产气肠杆菌对头孢菌类、氨基糖苷类、复合制剂等药物的耐药率有所降低,而碳青霉烯类药物的耐药率呈上升趋势,说明细菌耐药性存在动态的变化,及时对细菌耐药性进行分析,依据药敏结果合理选用抗菌药物,严格掌握适应证,可减少或延缓耐药菌株的播散.     

Azole resistant Aspergillus fumigatus: An emerging problem

Azole resistance has appeared recently in Aspergillus fumigatus and increased dangerously in the last decade. The main resistance mechanism is a point mutation of CYP51A, the gene encoding 14α-sterol demethylase, the target enzyme of azole antifungal drugs. This mutation can induce resistance to itraconazole alone or multi-azole resistance. CYP51A mutation can occur in two cases. The first usually concerns patients receiving long-term azole therapy, most of the time for chronic aspergillosis, and involves a wide range of mutations. The second is due to the use of azole fungicides in agriculture. The latter favors a single mutagenesis event: a substitution of leucine for histidine at codon 98 and the tandem repeat of a 34-base pair tandem sequence in the CYP51A gene promoter region. This confers cross-resistance to all azole antifungal drugs. This emerging and environmentally linked issue is of growing concern for the management of antifungal therapy. This mechanism of resistance was first described in the Netherlands and is now reported worldwide. It may have become the leading mechanism of azole resistance in A. fumigatus. Azoles are major agents for the treatment of aspergillosis, and the only oral antifungals. Infection with antifungal-resistant strains is correlated with treatment failure. This emerging phenomenon stresses the urgent need for new preventive strategies (controlled use of antifungals and azole prophylaxis), new diagnostic strategies (early detection of resistance), and new therapeutic strategies in the management of A. fumigatus infections.     

Azole-resistant Aspergillus fumigatus: A global phenomenon originating in the environment?

Aspergillus fumigatus is the predominant etiological agent of invasive aspergillosis (IA), a difficult-to-manage fungal disease associated with a high case fatality rate. Azole antifungals, particularly voriconazole, have significantly improved the survival rate of patients with IA. However, the clinical advances made possible through the use of medical azoles could be threatened by the emergence of azole-resistant strains which has been reported in an ever-increasing number of countries over the last 10 years. The major resistance mechanism, that combines point mutation(s) in the coding sequence of cyp51A gene and an insertion of a tandem repeat in the promoter region of this gene which leads to its overexpression (TR₃₄/L98H and TR₄₆/Y121F/T289A), is presumed to be of environmental origin. However, the emergence of clinical and environmental azole-resistant strains without the cyp51A gene mutation suggests that other mechanisms could also be responsible for azole resistance (for example, overexpression of efflux pumps). The development of resistance may be linked to either long-term use of azole antifungals in patients with chronic aspergillosis (patient-acquired route) or selection pressure of the fungicides in the environment (environmental route). The fungicide-driven route could be responsible for resistance in azole-naive patients with IA. This literature review aims to summarize recent findings, focusing on the current situation of azole-resistance in A. fumigatus, and provides better understanding of the importance of the environmental route in resistance acquisition.     

Passive Surveillance for Azole-Resistant Aspergillus fumigatus,United States, 2011–2013

Emergence of Aspergillus fumigatus strains containing mutations that lead to azole resistance has become a serious public health threat in many countries. Nucleotide polymorphisms leading to amino acid substitutions in the lanosterol demethylase gene (cyp51A) are associated with reduced susceptibility to azole drugs. The most widely recognized mutation is a lysine to histidine substitution at aa 98 (L98H) and a duplication of the untranscribed promoter region, together known as TR₃₄/L98H. This mechanism of resistance has been reported in Europe, Asia, and the Middle East, and is associated with resistance to all azole drugs and subsequent treatment failures. To determine whether isolates with this mutation are spreading into the United States, we conducted a passive surveillance–based study of 1,026 clinical isolates of A. fumigatus from 22 US states during 2011–2013. No isolates harboring the TR₃₄/L98H mutation were detected, and MICs of itraconazole were generally low.     

Frequency and Evolution of Azole Resistance in Aspergillus fumigatus Associated with Treatment Failure

Azoles are the mainstay of oral therapy for aspergillosis. Azole resistance in Aspergillus has been reported infrequently. The first resistant isolate was detected in 1999 in Manchester, UK. In a clinical collection of 519 A. fumigatus isolates, the frequency of itraconazole resistance was 5%, a significant increase since 2004 (p<0.001). Of the 34 itraconazole-resistant isolates we studied, 65% (22) were cross-resistant to voriconazole and 74% (25) were cross-resistant to posaconazole. Thirteen of 14 evaluable patients in our study had prior azole exposure; 8 infections failed therapy (progressed), and 5 failed to improve (remained stable). Eighteen amino acid alterations were found in the target enzyme, Cyp51A, 4 of which were novel. A population genetic analysis of microsatellites showed the existence of resistant mutants that evolved from originally susceptible strains, different cyp51A mutations in the same strain, and microalterations in microsatellite repeat number. Azole resistance in A. fumigatus is an emerging problem and may develop during azole therapy.     

Prospective Multicenter International Surveillance of Azole Resistance in Aspergillus fumigatus

To investigate azole resistance in clinical Aspergillus isolates, we conducted prospective multicenter international surveillance. A total of 3,788 Aspergillus isolates were screened in 22 centers from 19 countries. Azole-resistant A. fumigatus was more frequently found (3.2% prevalence) than previously acknowledged, causing resistant invasive and noninvasive aspergillosis and severely compromising clinical use of azoles.     

Recombinant Aspergillus fumigatus antigens Asp f 3 and Asp f 9 in liposomal vaccine protect mice against invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis caused by the ubiquitous mold Aspergillus fumigatus is a major threat to immunocompromised patients, causing unacceptably high mortality despite standard of care treatment, and costing an estimated $1.2 billion annually. Treatment for this disease has been complicated by the emergence of azole resistant strains of A. fumigatus, rendering first-line antifungal therapy ineffective. The difficulties in treating infected patients using currently available drugs make immunotherapeutic vaccination an attractive option. Here, we demonstrate the efficacy of VesiVax® adjuvant liposomes, consisting of a combination of two individual liposome preparations, to which two recombinant A. fumigatus surface antigens, Asp f 3 and Asp f 9 (VesiVax® Af3/9), have been chemically conjugated. Using a murine model, we demonstrate that VesiVax® Af3/9 is protective against infection by azole resistant strains of A. fumigatus in both steroid-suppressed and neutropenic mice as quantified by improved survival and reduced fungal burden in the lungs. This protection correlates with upregulation of IL-4 produced by splenocytes, and the presence of Asp f 3 and Asp f 9 specific IgG2a antibodies in the serum of mice given VesiVax® Af3/9. Furthermore, mice given VesiVax® Af3/9 with a subsequent course of liposomal amphotericin B (AmBisome®) had improved survival over those given either treatment alone, indicating a benefit to VesiVax® Af3/9 vaccination even in the case of infections that require follow-up antifungal treatment. These data demonstrate that prophylactic vaccination with VesiVax® Af3/9 is a promising method of protection against invasive pulmonary aspergillosis even as the changing face of the disease renders current therapies ineffective.     

Studies on the epidemiology of Aspergillus fumigatus infections in a university hospital

The impact of the airborne opportunistic fungus pathogen, Aspergillus fumigatus in patients hospitalized at the university hospital of Parma, Italy, and its outpatients was investigated during a period of six months. Sputum and bronchial washings were collected from 986 patients. The 2,437 specimens were culturally examined for the presence of A. fumigatus regardless of the patient's clinical diagnosis. This fungus was isolated from 32 patients (3.2%). Subsequently, immunological tests for aspergillosis were performed on 22 of these culture-positive patients. Eight of these patients (36.4%) were serologically proven to be affected by aspergillosis. The 32 A. fumigatus isolates were epidemiologically investigated by the killer system to determine the mode of spread of these infections. Among the patients, fifteen different biotypes were differentiated, and their value in studying the epidemiology of aspergillosis in the hospital environment was investigated.Corresponding author.     

Antigen-specific cytolysis of infected cells in murine candidiasis

Immune L3T4+ and Lyt-2+ lymphocytes play an important role in the acquired resistance of mice to challenge with virulent Candida albicans, and release macrophage-activating cytokines in response to yeast cells in vitro. To determine whether antigen (Ag)-specific cytotoxic T lymphocytes are generated during fungal infection, purified L3T4+ and Lyt-2+ lymphocytes from immunized mice were cultured in the presence of syngeneic accessory cells, Candida Ag, and IL-2. Yeast-infected bone marrow macrophages and peritoneal exudate neutrophils were used as target cells in a standard ⁵¹Cr release assay. Ag-specific, MHC-unrestricted lysis of infected macrophages was evident with immune Lyt-2+ cells after 5–10 days in culture. Under the same experimental conditions, the cytotoxic activity of L3T4+ cells was negligible, but its expression could be induced by the addition of anti-CD3 antibody.Culturing immune Lyt-2+ cells for shorter periods of time (1–2 days) resulted in preferential lysis of infected neutrophils. In addition, at limiting effector cell numbers, Ag-specific MHC-restricted lymphocytes with cytotoxic activity to infected macrophages could be identified. We suggest that C. albicans infection stimulates multiple cytotoxic T-cell precursors with varying recognition stringency, wich may have an important role in antifungal resistance in vivo.     

Spatial variations in airborne microorganism and endotoxin concentrations at green waste composting facilities

The emission and dispersal of bioaerosols from open-air commercial composting facilities continues to be contentious. A meta-dataset enumerating cultivable microorganism emission and downwind concentrations is not yet available. A dataset derived from repeated and replicated field studies over a period of two years at two commercial composting facilities is presented. The data characterises patterns in Aspergillus fumigatus, actinomycetes, Gram-negative bacteria and endotoxin emission and downwind concentrations. For all bioaerosols, compost agitation activities had a significant impact on concentrations; levels were variable up to 600 m downwind from site. Bioaerosols declined rapidly from source and exhibited a secondary peak 100–150 m from site boundary. All bioaerosols were found downwind from site in elevated concentrations. Compared to those found 100 m upwind, levels were significantly higher at 180 m downwind for A. fumigatus; at 300–400 m for actinomycetes and Gram negative bacteria, and at 100 m for endotoxins. Periodically, elevated concentrations could be found for all bioaerosols at distances further downwind. The evidence provided by this data set provides operators and regulators of facilities with reliable data to inform the location, risk assessment and bioaerosol sampling strategies of commercial composting facilities.     

Respiratory Mycotic Affection: Sputum Examination of Workers in a Flax Plant in Egypt

The flax industry is very old in Egypt. A very primitive plantused in the industry has been chosen for this study. The sputumof 150 individuals exposed to flax dust were collected on threesuccessive days and inoculated on both Sabourand's dextroseagar and brain heart infusion agar to test for fungal growth.Skin tests were performed for the positive culture of Aspergillusspecies. Of the 150 workers, 74 showed fungal growth on 3 successivedays' samples. The following strains were discovered in orderof frequency. A. mucor; A. niger, A. fumigatus; A Jlavus; Candidaalbicans; yeast; Trichithisum; and Penicillium. This is the first time A. fumigatus has been recorded in Egypt. A. fumigatus has not been discovered in this study among thecontrol subjects in the same plant not exposed to flax dust. The prevalence of particular fungi in the sputum of workersexposed to flax fibres has to be further studied for their probablerole in initiating the occurrence of byssinosis. Differentiationmust be made also between truly byssinotic subjects and thosehaving extrinsic allergic alveolitis. Accepted        1 June 1981