Cation conductance and efflux induced by polyene antibiotics in the membrane of skeletal muscle fiber.

Cation conductance and efflux induced by polyene antibiotics amphotericin B (AMB), amphotericin B methyl ester (AME), nystatin, mycoheptin, and levorin on frog isolated skeletal muscle fibers and whole sartorius muscles were investigated. Conductance was measured under current-clamp conditions using a double sucrose-gap technique. Cation efflux was studied using flame emission photometry. Some new data were obtained concerning the effects of levorin and mycoheptin on biological membranes. The power dependence of polyene-induced cation transport on antibiotic concentration in muscle membrane was lower than that in bilayers. The decline in the equilibrium conductance caused by polyene removal (except for levorin) was very fast. There was reverse temperature dependence of AMB- and nystatin-induced conductances. Both induced conductance and efflux values demonstrated a correlation with the order of antifungal activities: levorin > AMB, mycoheptin > AME > nystatin, except for AME, which was more potent on yeastlike cells. These effects were interpreted in terms of possible differences in the kinetics of channel formation in biological and model membranes and in light of the role of nonconducting antibiotic forms in biological membranes.     

Sensitivity of Candida strains to polyenic antibiotics in the treatment of oral candidiasis

Sensitivity of 146 clinical strains of Candida albicans to nystatin, levorin and amphoglucamine was studied on solid media with the replica method. The strains were isolated from 79 patients with candidiasis of the oral mucosa. It was found that sensitivity of the fungi to the polyenic antibiotics was different which should be considered in treatment of candidiasis. On the basis of the mean MICs for the clinical strains and their distribution by the MICs it was shown that the activity level of levorin and amphoglucamine was higher than that of nystatin. During the treatment resistance of the Candida strains to the polyenic antibiotics increased and cross resistance developed which required application of other treatment means.     

Supersensitivity to levorin and amphotericin B in several Saccharomyces cerevisiae mutants resistant to nystatin]

104 mutants resistant to nystatin were isolated after UV-treatment of two haploid marked strains of Saccharomyces cerevisiae. The analysis of resistance to three polyene antibiotics allowed to determine 8 phenotype classes of mutants including those resistant to nystatin but in various combinations showing hypersensitivity to levorin and (or) amphotericin B. The analysis of UV absorption spectra of sterolic extracts prepared from cells of different mutants showed that similar quality changes in sterol composition could be associated both with polyresistant an supersensitive phenotype. New type of mutants resistant to nystatin and supersensitive to levorin and (or) amphotericin B seems to be promising for studies on the mechanisms of action of polyene antibiotics, the bases of resistance to them and also in consideration of the possibility to increase the efficiency of antimycotic antibiotic therapy.     

Study of components of standard samples of polyene macrolide antibiotics by the methods of high performance liquid chromatography and SIEAP mass spectrometry]

The component composition of reference samples of polyenic macrolide antibiotics such as nystatin, mycoheptin, amphotericin B and levorin was studied by HPLC and chromatographic mass spectrometry in comparison to the WHO standards. It was shown that the samples were close by their component composition to the analogous samples of the WHO standards.     

Comparative study of fungicidal and herbicidal activities of salts of polyenic macrolide antibiotics]

The fungicidal and herbicidal activities of water soluble salts of levorin, nystatin, mycoheptin and amphotericin B, polyenic macrolide antibiotics, were studied. The biological tests showed that the antibiotics had fungicidal and low herbicidal activities. They also had a growth regulating action.     

Study of the resistance of Candida guilliermondii to polyene antibiotics

250 Candida guilliermondii strains resistant to the polyene antibiotics nystatin, levorin and amphotericin B were obtained using UV irradiation. When the mutant strains became resistant to one of the polyene antibiotics, their resistance to the other ones changed. Phenotypic analysis showed that the resistance of the strains to polyene antibiotics did not make them susceptible to a rise in osmotic pressure and to a change of the temperature of incubation. Some of the polyene-resistant strains were stained in a medium with methylene blue. Analysis of the sterol composition in the mutants by UV spectroscopy showed that the resistance to polyene antibiotics sometimes involved changes in the sterol composition. Two new UV spectrum types were recorded for the sterols of the mutant strains; they differed from the UV spectrum for the sterols of the parent sensitive strain.     

Action of polyene antibiotics on actinomycetes with a varying lipid makeup]

The effect of polyenic antibiotics, such as nystatin, levorin, amphotericin B and mycoheptin on 93 representatives of various species of the ray fungi was studied. It was shown that resistance of the actinomycetes to the polyens was connected with the absence or insufficient content of sterols (0.001--0.008 per cent in the dry mycelium). On addition of cholesterol to the nutrient media (100 microgram/ml) it was included into the membranes of some cultures and their sensitivity increased 2--60 times. Resistance of Actinomyces sp. LIA 0775 grown on the media with fats differing in their composition decreased 2--4 times. In these cases the culture lipids were characterized by lower content of phospholipids (35--45 per cent from the total lipids as compared to 70--80 per cent when grown on the control medium without fats) and significantly increased content of unsaturated fatty acids (3--4 times).     

Effect of gamma-irradiation on some biological and physico-chemical properties of polyene antibiotics]

Deep effect of gamma-rays on polyenic antibiotics was studied. It was shown that gamma-radiation induced radiation-chemical oxidation of the substances. The chromatographic analysis showed that the levorin degradation products were identical to the polyenic products of the antibiotic oxidative destruction. As for mycoheptin and amphotericin B, destruction of their molecules to non-polyenic products was observed. It was found that toxicity of the levorin aromatic heptaen did not practically change after gamma-irradiation in high doses. The toxicity of mycoheptin and amphotericin B, non-aromatic heptaens increased after exposure to high doses of gamma-rays.     

Lethal and mutagenic action of N-nitroso-N-methylbiuret on the producers of levorin, amphotericin and mycoheptin]

The lethal and mutagenic effect of N-nitrozo-N-methylbiuret (NMB) on the organisms producing levorin, amphotericin B and mycoheptin was studied. The mutagen effect depended on the dose, culture and physiological state of the spores. NMB had a low mutagenic effect on the levorin-producing organism characterized by high activity and genetic homogenicity with respect to the colony morphology and antibiotic production. As for the organisms producing amphotericin B and mycoheptin characterized by high genetic heterogenicity, significant variation of all the features studied was observed on their exposure to the mutagen. Inspite of diverse reaction of the organisms producing levorin, amphotericin B and mycoheptin to the effect of NMB mutants with increased antibiotic production were obtained from the three cultures. The lethal and mutagenic effect of NMB on the mycoheptin-producing organism depended on the process of the spore DNA replication. The spores during the DNA replication period were least sensitive to the lethal effect of the mutagen and most mutable with the respect to the colony morphology. For selection of highly active and stable strains exposure to NMB of the spores of the mycoheptin-producing organism during replication of DNA proved to be more effective than that of the spores during the lag-phase.     

In vitro resistance to fluconazole and itraconazole in clinical isolates of Candida spp and Cryptococcus neoformans

An in vitro susceptibility testing of 181 strains of six species of Candida and 21 strains of Cryptococcus neoformans was carried out in order to investigate the resistance to new antifungal drugs. We have studied clinical isolates from 200 different patients of Hospital del Mar (Barcelona) and Hospital La Inmaculada (Almería). An agar diffusion method (NeoSensitabs, Rosco, Taastrup, Denmark), was employed with fluconazole, itraconazole, and reference drugs amphotericin B, flucytosine, tioconazole and ketoconazole. A high level of susceptibility was found for amphotericin B in C. neoformans strains while 19% of them were resistant to flucytosine. All the strains of C. neoformans and Candida guilliermondii were susceptible to the new azoles derivatives and also Candida parapsilosis and Candida albicans had a great susceptibility to this antifungals. A greater level of resistance was found for Candida krusei, Candida tropicalis and Candida glabrata to fluconazole, itraconazole and ketoconazole, but resistance to fluconazole and itraconazole is not always linked because ten resistant strains for fluconazole were susceptible to itraconazole, and two other resistant to itraconazole were susceptible to fluconazole.     

地塞米松影响念珠菌对抗真菌药物敏感性的实验研究

目的 探讨地塞米松在体外试验中是否影响念珠菌对抗真菌药物的敏感性,以了解糖皮质激素与抗真菌药物直接作用于念珠菌时是否存在相互作用。方法 用微量液体培养基稀释法分别测定26株白念珠菌与地塞米松（0．2mg／ml）共同孵育前、孵育24～48h及7d时氟康唑、伊曲康唑、两性霉素B的最低抑菌浓度（MIC）值,并作对照。结果 白念珠菌与地塞米松孵育24～48h后、孵育后第7d氟康唑和伊曲康唑的MIC值升高,分别与孵育前的MIC值存在统计学差异,但孵育24～48h后的MIC与孵育后第7d的MIC无统计学差异;白念珠菌与地塞米松共同孵育24～48h后两性霉素B的MIC值也较孵育前升高,但第7d的MIC值与孵育前无差异。结论 地塞米松可增加三种抗真菌药物对于白念珠菌的MIC,但三种抗真菌药物间存在差异,表明地塞米松对于氟康唑和伊曲康唑体外抗白念珠菌的活性有拮抗作用,但没有时间依赖性,地塞米松对于两性霉素B的影响较氟康唑和伊曲康唑小,且影响时间较短。     

Sensitivity of fungi of the genus Candida to antifungal drugs

Seventy two Candida strains isolated from patients with candidiosis of the oral mucosa were studied with respect to their sensitivity to nystatin, levorin, decamine, ethonium, sanguiritrin and clotrimazole. At concentrations of 0.5 to 5 micrograms/ml all the Candida species i.e. C. albicans, C. tropicalis, C. krusei and C. quilliermondii were highly sensitive to clotrimazole. Fungistatic action of levorin, nystatin and sanguiritrin was observed in 91, 67 and 38 per cent of the strains respectively. The Candida strains were resistant to decamine and ethonium used in the above concentrations.     

重症监护病房白念珠菌耐药性8年变化趋势

目的调查上海长征医院重症监护室(ICU)近8 a中临床分离白念珠菌的耐药性变化,为临床治疗提供参考。方法上海长征医院ICU 2002～2009年从414例患者中首次分离出414株白念珠菌,对其中277株进行药敏试验。采用Cox-Stuart趋势检验回顾性分析临床分离真菌中白念珠菌所占比例变化趋势和白念珠菌对常用抗真菌药物耐药率的变化趋势。结果 2002～2009年间,上海长征医院ICU白念珠菌分离株数从2002年的34株增加至2009年的92株,但白念珠菌占总真菌分离株数的百分比维持在34.6%～55.7%,P=0.03。白念珠菌对于5-氟胞嘧啶和两性霉素B平均耐药率分别为4.0%和0.7%,对其他常用抗真菌药的耐药率依次为咪康唑47.0%、酮康唑10.8%、伊曲康唑19.9%、特比萘芬42.6%、氟康唑14.6%及伏立康唑13.0%。白念珠菌对5-氟胞嘧啶和两性霉素B和伊曲康唑耐药率的8年变化无统计学差异。结论上海长征医院ICU近8 a来白念珠菌仍然为临床较为常见的真菌分离株,但白念珠菌占总分离株数的百分比有逐渐减少的趋势。白念珠菌对常用抗真菌药物耐药性均无明显变化趋势。     

Properties of a Candida albicans strain possessing an increased sensitivity to polyene antibiotics]

Characteristics of a mutant of the yeast-like fungus Candida albicans with increased sensitivity to amphotericin B, levorin and nystatin is presented. Increased sensitivity to the polyens in the isolate must be associated with changes in the cell wall and/or with decreased total viability of the strain. The following factors were in favour of this: presence of significant amounts of pseudomycelial cells with thinner cell walls as compared to the yeast cells in the population of the mutant strain; a higher rate of potassium liberation from the cells of the mutant strain in the presence of amphotericin B; a lower growth rate of the mutant strain on solid and liquid media; an increased death rate of the cells in the intact culture of the mutant strain as compared to the initial strain; absence of changes in the absorption spectrum of sterols isolated from the cells of the mutant strain as compared to the initial culture.     

In vitro antifungal resistance in Candida albicans from HIV-infected patients with and without oral candidosis.

The main purpose of this study has been to determine the in vitro antifungal susceptibility of clinical isolates from HIV-infected or AIDS patients, depending on the presence of oral candidosis. The oral cavity of 307 HIV-infected or AIDS patients was examined and an oral swab was cultured on Sabouraud glucose agar and studied by conventional mycological methods. In vitro antifungal susceptibility to amphotericin B, nystatin, fluconazole, itraconazole and ketoconazole was tested by disk diffusion with Neo-Sensitabs tablets (Rosco Diagnostica, Dinamarca). One hundred and thirty five Candida albicans isolates (91 serotype A, 38 serotype B, three C. albicans variety stellatoidea and three untyped isolates), three Candida krusei and two Candida glabrata were obtained. All the isolates were susceptible to nystatin and amphotericin B. However, 7.9% isolates were resistant to fluconazole and 2.9% isolates were resistant to ketoconazole or itraconazole. Nearly all C. krusei and C. glabrata isolates, 31% patients with candidosis and 20% Candida-colonized patients showed decreased susceptibility to azoles. This study shows that polyenes had a great in vitro efficacy against clinical isolates from HIV-infected patients and that in vitro resistance to azoles is not as high as observed in other countries.     

Antifungal drug resistance pattern of Candida. spp isolated from vaginitis in Ilam-Iran during 2013-2014

Vaginal Candidiasis is the most common and important opportunistic fungal infection in women. By increasing use of antifungal drugs in recent years, it has caused drug resistance. This study aims to evaluate antifungal drugs susceptibility of Candida. spp isolated of women with vaginitis from Ilam-Iran during 2013-2014. samples were collected and cultured from 385 women with vaginitis, then Candida.spp was diagnosed by standard method. Antifungal drug susceptibility test for nystatin 100 unit/disk, fluconazole 10µg/disk, itraconazole 10µg/disk, ketoconazole 10µg/disk, amphotericinB 20µg/disk, clotrimazole 10µg/disk, posaconazole 5µg/disk, and voriconazole 1µg/disk were carried out by M44-A method(CLSI). From all culture positive samples, 150 isolates were Candida albicans and 89 isolates were non-albicans. The resistance to fluconazole, itraconazole, ketoconazole, clotrimazole, voriconazole, posaconazole, nystatin and amphotericin B was 76%, 62%, 72%, 55%, 6%, 7%, 1% and 0%. The highest resistance was seen for fluconazole , itraconazole, and the highest susceptible was seen for nystatin and amphotericin B. These results indicate nystatin and amphotericin B can be used as the first line for empirical therapy of vaginal candidiasis in the district.     

临床酵母样真菌的感染特点及耐药性研究

目的了解临床酵母样真菌的感染类型、分布以及耐药情况,为临床诊断治疗提供合理的用药依据.方法采用常规方法进行真菌培养,用科玛嘉显色培养基联合法国生物梅里埃API 20C AUX鉴定条进行鉴定,药敏试验采用微量稀释法.结果864株酵母样真菌中,白色念珠菌619株（71.6%）,其次为热带念珠菌116株（13.4%）和克柔念珠菌47株（5.4%）,非白色念珠菌感染的比例逐年上升（21.5%）.其中,呼吸道标本酵母样真菌检出率最高,达79.7%,其次是消化道为8.8%,泌尿道为4.7%.科室分布依次为干部科、呼吸科、急诊内科、血液科等;白色念珠菌对两性霉素B、5-氟胞嘧啶高度敏感,达90%以上,对氟康唑和伊曲康唑的敏感性有所降低.结论酵母样真菌的检出率与患者基础疾病密切相关;对氟康唑等药物的敏感性有下降的趋势,未发现对4种药物同时耐药的菌株,提示在治疗中,药敏监测是非常必要的.     

浅部真菌病病原酵母菌构成调查及药敏研究

目的了解本地区浅部真菌病病原酵母菌感染菌种的构成及其耐药性特点,为临床提供病原学诊断和合理使用抗真菌药物的依据。方法采用改良沙氏培养基对1354份临床标本进行酵母菌培养和菌株分离,用科玛嘉念珠菌显色培养基和YBC鉴定卡对所分离的酵母菌进行鉴定,用ROSCO纸片扩散法检测分离菌株对6种常见抗真菌药物的耐药性。结果共分离出10种219株酵母菌,甲真菌病检出率最高(43.80%),其次是股癣(16.70%)、体癣(13.00%)、足癣(11.11%),手癣最低(9.40%)。其中白念珠菌为63.47%;近平滑念珠菌为17.81%;热带念珠菌为6.85%;季也蒙念珠菌为5.94%;无名念珠菌为2.28%,其他酵母菌为3.65%。219株酵母菌对特比萘芬(TBE)、伊曲康唑(ITC)、氟康唑(FLC)、制霉菌素(NYS)、咪康唑(MIC)和酮康唑(KTC)的敏感性分别为53.42%、87.21%、97.26%、100%、80.35%和100%,耐药性分别为20.55%、11.11%、2.28%、0.0、12.72%和0.0。结论本地区浅部真菌病酵母菌感染菌谱以白念珠菌为主,其次是近平滑念珠菌和热带念珠菌,体外药敏显示对制霉菌素、酮康唑和氟康唑有很好的敏感性,对特比萘芬、伊曲康唑和咪康唑产生了较高的耐药性。     

Effect of terrilytin on antifungal antibiotic activity]

The antifungal activity of terrilitine, an enzymatic preparation of microbial origin and its effect on the activity of antifungal polyenic antibiotics and griseofulvine were studied in vitro. It was found with the method of serial dilutions in Sabourand's liquid medium that terrilitine was active against C. albicans and certain dermatophytes. In combination with amphotericin B, amphoglucamine, mycoheptine, levorin, nystatin or griseofulvin it increased the activity of these antibiotics 2-16 times.     

Possible use of a single test culture in determining the biological activity of polyene antibiotics

A possibility using a common test-culture in estimation of biological activity of levorin, amphotericin B, mycoheptin and nistatin was studied. It was found that C. guillier mondii, strain 40, may be used as a common test-culture. It provided satisfactory microbial growth, clear and rather large inhibition growth zones with respect to all the drugs tested.