In vitro activity of fluconazole, a novel bistriazole antifungal agent

Fluconazole is a novel triazole antifungal agent with excellent activities against a broad range of medically important fungi. The in vitro antifungal activities of fluconazole especially against Candida albicans were examined and the results summarized as follows: 1. Fluconazole was proved to exhibit the highest antifungal activity in synthetic amino-acid medium, fungal (SAAMF), well buffered in a physiologically neutral range. 2. In a exposed time-killing test performed using SAAMF (pH 7.4), the growth inhibition by fluconazole was enhanced in proportion to an increase of fluconazole concentration and 99% inhibition was observed at a concentration of 1 microgram/ml though further increases of concentration up to 80 micrograms/ml failed to demonstrate complete inhibition. 3. Activities of fluconazole against medically important various yeasts were determined by a broth dilution method in SAAMF using the viable counts technique. Among 9 species tested, C. albicans and Candida kefyr were the most sensitive to fluconazole with a IC99 range from 0.20 microgram/ml to 0.39 microgram/ml. On the contrary, Candida glabrata, Cryptococcus neoformans and Trichosporon cutaneum were the least sensitive with a IC99 range from 3.13 micrograms/ml to 12.5 micrograms/ml. 4. Growth inhibition activities of fluconazole against 4 species of Aspergillus were measured on the basis of mycelial protein content. IC50 and IC90 of fluconazole against Aspergillus fumigatus were distributed in the range of 23.9-43.5 micrograms/ml and 50- greater than 100 micrograms/ml, respectively. 5. The anti-Candida activity of fluconazole was little affected by serum concentrations. Fluconazole at a concentration of 0.20 microgram/ml inhibited significantly the mycelial-phase growth and germ tube elongation of C. albicans in a medium supplemented with serum. 6. The germ tube formation and elongation of C. albicans cells engulfed by murine peritoneal exudative cells were significantly affected in a medium containing 1 microgram fluconazole per ml.     

In vitro antifungal activity of amorolfine, a new morpholine antimycotic agent

In vitro antifungal activities of amorolfine (MT-861), a newly developed morpholine antimycotic agent, against a wide range of pathogenic fungal strains were investigated using an agar-dilution method with an imidazole antifungal agent, clotrimazole (CTZ), as the reference drug. The results showed that MT-861 had a broad antifungal spectrum, and was active against all of the pathogenic fungi tested except nonpigmented filamentous fungi such as aspergilli and penicillia. Dermatophytes and Malassezia furfur was the most highly susceptible to MT-861. Antifungal activities of MT-861 against most strains of these fungi as well as those against most strains of dimorphic fungi were higher than those of CTZ. By contrast, MT-861 showed lower activities against pathogenic yeasts such as Candida albicans than CTZ. Several assay conditions, such as inoculum size of fungi, incubation time, media pH and compositions including serum supplementation, affected MT-861 activities against C. albicans and, to lesser extents, those against Trichophyton mentagrophytes. MIC values of MT-861 against C. albicans and other Candida spp., were the lowest on casitone agar. MT-861 exerted fungicidal actions toward susceptible fungi such as T. mentagrophytes and Sporothrix schenckii at relatively low concentrations, and these activities were increased when the time of incubation was extended beyond 24 hours after inoculation of testing organisms. Susceptibilities of any strains of C. albicans and C. glabrata to MT-861 were not reduced by as many as 15 successive transfers in MT-861 containing media.     

微量液基稀释法测定化合物特苄康唑的体外抗真菌活性

参照美国国家临床试验标准化委员会提出的标准,以氟康唑,酮康唑和布替萘芬为对照,用微量液基稀释药敏试验方法,测定特苄康唑对１２种临床常见真菌的最低抑菌浓度。结果除烟曲霉外,特苄康唑对其他１１和睦具菌的ＭＩＣ８０均４ｍｇ／Ｌ以下,其体外抗直菌活性明显于氟康唑,尤其对酵母的抗菌活性是氟康唑的８－２５６倍,与酮康唑作用相当。     

In vitro antifungal activity of a novel lipopeptide antifungal agent, FK463, against various fungal pathogens

The antifungal activities of FK463 against various pathogenic fungi were tested by standard broth microdilution methods, and compared with the activities of five currently available antifungal agents; viz., fluconazole (FLCZ), itraconazole, miconazole, amphotericin B and flucytosine. Fourteen clinical isolates of Candida albicans categorized as FLCZ susceptible, FLCZ susceptible-dose dependent and FLCZ resistant were similarly susceptible to FK463 with geometric (GM) MIC values of 0.010, 0.011 and 0.015 microg/ml, respectively. All of 17 clinical isolates of Aspergillus fumigatus were inhibited by FK463 at 0.0078 microg/ml or lower concentrations. The antifungal activity of FK463 against a wider range of medically important yeasts and filamentous fungi were studied using stock fungal strains. While Cryptococcus, Trichosporon, Fusarium, Pseudallescheria and Alternaria species or zygomycetes were scarcely or not inhibited by 16 microg/ml of FK463, two Candida species (C. albicans, C. glabrata), as well as all species of Aspergillus, Paecilomyces and Penicillium, were highly susceptible with GM-MICs of < or = 0.008 microg/ml. The other fungal species including several non-albicans Candida were less susceptible with GM-MICs ranging between 0.016 and 2 microg/ml. MICs of the reference drugs were within the range thus previously reported. These results suggest that FK463 be of use in the treatment of serious fungal infections.     

In vitro activity of novel imidazole antifungal agent NND-502 against Malassezia species

The in vitro activity of NND-502, a novel antifungal imidazole compound, was tested against the three major Malassezia species by an agar dilution method with modified Dixon medium and compared with the activities of three reference antifungal drugs of topical use, lanoconazole (LCZ), bifonazole (BFZ) and terbinafine (TBF). The geometric mean (GM)-MICs of NND-502 for 25 strains of M. furfur, 15 strains of M. sympodialis and ten strains of M. slooffiae were approximately 1.4, 0.1 and 1.0 mg/l, respectively, showing the greatest activity against M. sympodialis and the least against M. slooffiae. These values were similar to that of LCZ, but four to 69 times lower than that of BFZ and two to three times lower than that of TBF. The results suggest that NND-502 might be beneficial in the treatment of Malassezia-associated skin diseases.     

In vitro antifungal activity of itraconazole, a new triazole antifungal agent, against clinical isolates from patients with dermatomycoses]

In vitro antifungal activities of itraconazole (ITZ), a triazole antifungal agent, against clinical isolates obtained from patients with superficial and subcutaneous mycoses were examined using the agar dilution method on casitone agar. The clinical isolates tested were 7 species and 263 isolates including Trichophyton mentagrophytes (104 isolates), Trichophyton rubrum (103 isolates), Microsporum canis (3 isolates), Epidermophyton floccosum (2 isolates), Candida albicans (32 isolates), Malassezia furfur (7 isolates) and Sporothrix schenckii (12 isolates). The results are summarized as follows: 1. MIC values of ITZ for the isolates of dermatophytes and M. furfur distributed in a range of less than 0.0012-5 micrograms/ml indicating that ITZ had greater in vitro activities. These in vitro activities of ITZ were greater than those of clotrimazole or bifonazole. 2. C. albicans isolates were divided into 2 groups in terms of ITZ-susceptibilities, a high susceptibility group and low-susceptibility group with MIC values of 0.02-0.08 micrograms/ml and greater than 10 micrograms/ml, respectively. 3. The in vitro activities of ITZ against S. schenckii isolates with a geometric mean MIC of 0.119 micrograms/ml were greater than those of ketoconazole, miconazole or amphotericin B used as reference drugs.     

In vitro antifungal activity of itraconazole, a new triazole antifungal agent, against clinical isolates from patients with systemic mycoses]

The in vitro antifungal activity of itraconazole (ITZ), a new oral triazole antifungal agent, against clinical isolates from patients with systemic mycoses were compared with those of existing systemic antifungals, viz. ketoconazole (KCZ), miconazole or amphotericin B. The studies were performed with 65 isolates of pathogenic yeasts and 13 isolates of Aspergillus spp. using the agar dilution method on casitone agar. ITZ showed the most potent antifungal activities against isolates of pathogenic yeasts including several Candida spp. (Candida parapsilosis, Candida krusei, Candida guilliermondii), Cryptococcus neoformans, Trichosporon cutaneum (MIC less than or equal to 0.08 micrograms/ml) and Aspergillus spp. including Aspergillus fumigatus (MIC less than or equal to 5 micrograms/ml). On the other hand, activities of ITZ against isolates of other Candida spp. such as Candida albicans and Candida glabrata were lower than those of KCZ and other reference drugs. Some isolates of C. albicans and C. tropicalis were not completely inhibited by ITZ even at concentrations above 10 micrograms/ml on casitone agar. However, in the micro-broth dilution method using synthetic amino acid medium, fungal as the test medium, ITZ completely inhibited the growth of all these isolates at drug concentrations of less than or equal to 0.20 micrograms/ml.     

In vitro antifungal activity of naphthoquinone derivatives

In vitro antifungal activities of naphtoquinone-derivatives, which are constituents of Shikon, roots of Lithospermum erythrorhizon, were investigated against several fungal pathogens. When the biological activity of these compounds was tested against fungi, a wide range of sensitivity was recorded. Shikonin was found to have a stronger than fluconazole against yeast-like fungi: four-fold against Candida krusei (minimal inhibitory concentration (MIC); 4 microg/ml) and two-fold (MIC; 4 microg/ml) against Saccharomyces cerevisiae, though it showed the same potency as fluconazole against C. glabrata. Deoxyshikonin also exhibited four-fold stronger activity against C. krusei (MIC; 4 microg/mi) and three-fold (MIC; 2 microg/ml) stronger against S. cerevisiae. Acetylshikonin and beta-hydroxyisovaleryl shikonin showed lower activities against all fungal pathogens except for C. krusei compared with the standard. Against the filamentous fungus, Trichosporon cutaneum, all naphthoquinones were found to have a range of activity with lower potency than standard. This result provides a rational basis for the clinical use of shikon and shows the possibility of its use in medicinal treatment as an anti-inflammatory agent with antifungal activity.     

In vitro antifungal activity of amorolfine against Malassezia species

In vitro antifungal activities of a new morpholine agent, amorolfine (MT-861) were investigated, against 39 strains of Malassezia furfur (11 stock cultures and 28 clinical isolates) and 8 strains (stock cultures) of Malassezia pachydermatis, in comparison with those of 2 reference drugs, clotrimazole (CTZ) and bifonazole (BFZ). Of the 3 antifungal agents, MT-861 exhibited strongest antifungal activities against the stock cultures of M. furfur and M. pachydermatis with average MIC values of 0.428 and 0.174 micrograms/ml, respectively; and the average BFZ activity was less than 1/10, and the average CTZ activity was 1/100, of the average MT-861 activity. All of the clinical isolates of M. furfur also showed high susceptibilities, though they were more susceptible to BFZ and CTZ.     

In vivo and in vitro antifungal activity of fluconazole

We examined in vivo efficacy and in vitro activity of fluconazole, a novel triazole antifungal agent, and obtained results which are summarized as follows: 1. Fluconazole showed a higher serum concentration than ketoconazole after oral administration to mice. The 50% effective dose of fluconazole administered orally to mice was similar to that of fluconazole injected to mice intraperitoneally in a systemic candidiasis model. 2. Prophylactic effects of fluconazole were excellent against systemic candidiasis, cryptococcosis and aspergillosis in mice in comparison with those of ketoconazole and miconazole. 3. The multiple administration of fluconazole effectively decreased the number of viable cells of Candida albicans colonized in kidneys of mice when the serum level of fluconazole was kept to exceed its IC99 values against the inoculated pathogen. Thus, a good correlation between the in vitro activity of fluconazole and its in vivo efficacy was confirmed. In vivo efficacies of ketoconazole and miconazole, however, failed to reflect their marked in vitro activities. 4. C. albicans No. 32 developed no drug-resistance to fluconazole during transfers in medium containing fluonazole at a concentration of 1 micrograms/ml.     

In vitro and in vivo antimycobacterial activity of an antihypertensive agent methyl-L-DOPA

Methyl-L-DOPA, an antihypertensive agent, has significant in vitro activity against a variety of atypical mycobacteria such as the Mycobacterium avium complex, M. scrofulaceum, M. xenopi and M. marinum, and rare pathogens like M. fortuitum. In the present investigation, the screening of the in vitro activity was further extended by testing the in vitro activity against a total of 53 different strains of mycobacteria, including 34 clinical isolates of both drug-sensitive and drug-resistant Mycobacterium tuberculosis. Most of the strains were inhibited at 10-25 microg/mL concentrations of the drug. When methyl-L-DOPA was injected into male mice at a concentration of 10 microg/g body weight (20 g each), methyl-L-DOPA significantly protected them when challenged with a 50 median lethal dose of M. tuberculosis H37Rv102. According to the chi2 test, the in vivo data were highly significant (p<0.01).     

L-671,329, a new antifungal agent. III. In vitro activity, toxicity and efficacy in comparison to aculeacin

L-671,329 is a novel, echinocandin-like natural product that possesses potent anti-Candida activity, including activity against Candida parapsilosis. The in vitro MICs of L-671,329 were comparable to aculeacin against 18 yeasts and three filamentous fungi in an agar dilution assay. L-671,329 lysed mouse red blood cells (RBCs) at a concentration of 400 micrograms/ml, but not at 50 or 12.5 micrograms/ml. Aculeacin lysed RBCs at 400 and 50 micrograms/ml. L-671,329 significantly prolonged survival of mice infected with Candida albicans (ED50 3.38 mg/kg) following twice-daily intraperitoneal dosing for five consecutive days. The prolongation observed was greater than that seen with aculeacin therapy (ED50 6.44 mg/kg). No acute or chronic toxicities of L-671,329 or aculeacin (as measured by mortality) were detected at a concentration of 100 mg/kg following intraperitoneal administration (TD50 greater than 100 mg/kg). Both L-671,329 and aculeacin eradicated cells of C. albicans from the kidneys of infected mice. L-671,329 eradicated the yeast at therapeutic concentrations of 12.5 to 100 mg/kg. Aculeacin eradicated yeast cells at therapy concentrations of 25 to 100 mg/kg. L-671,329 has potential as an anti-Candida compound.     

In vitro and in vivo activities of HQQ-3, a new triazole antifungal agent

The activity of HQQ-3, a new triazole antifungal agent, was evaluated and compared with those of fluconazole, ketoconazole and terbinafine in vitro and with fluconazole in vivo. HQQ-3 exhibited potent in vitro activity against clinically important fungi. The activity of HQQ-3 against Candida spp. was superior to those of fluconazole and terbinafine and comparable or superior to that of ketoconazole. HQQ-3 retained potent activity against Candida albicans strains with low levels of susceptibility to fluconazole (fluconazole MIC80s range, 4 to >64 microg/ml). Against Cryptococcus neoformans and filamentous fungi, the activity of HQQ-3 was superior to that of fluconazole. HQQ-3 also exhibited potent in vivo activity against murine systemic infections caused by C. albicns and C. krusei. The 50% effective doses against these infections were 0.12 to 1.9 mg/kg of body weight. These result suggest that HQQ-3 may be useful in the treatment of candidiasis.     

Mulundocandin, an echinocandin-like lipopeptide antifungal agent: biological activities in vitro.

Mulundocandin (MCN) is an antifungal lipopeptide which belongs to the echinocandin class of antimycotic agents. MCN exhibited good in vitro activity against Candida albicans and C. glabrata isolates with MIC ranges of 0.5-4.0 microg/ml and 2.0-4.0 microg/ml, respectively. MCN also exhibited some activity against C. tropicalis isolates (MIC range 1.0-8.0 microg/ml). However, MCN was poorly active against other non-albicans isolates and was inactive against Cryptococcus neoformans, Aspergillus species and Trichophyton. MCN appeared to exert its antifungal activity through preferential inhibition of germ tube formation (MIC-HY 0.015-0.03 microg/ml) and was typically less active on the yeast form (MIC 0.5-4.0 microg/ml). In kill-curve experiments 99.9% reductions in cell viability were observed following 8 hours exposure to MCN at 4 x MIC and 8 x MIC and after 5 hours exposure to 16 x MIC.     

In vitro antifungal activity of posaconazole against various pathogenic fungi

The antifungal activity of posaconazole (SCH56592), a new triazole antifungal, against stock cultures and fresh clinical isolates of a wide range of pathogenic fungi was compared with that of itraconazole, fluconazole and amphotericin B. Posaconazole inhibited growth of all the fungal species tested except Fusarium spp. at 1 mg/l or lower concentrations, showing a broad-spectrum antifungal activity. The activities of posaconazole for all the fungal species far surpassed those of fluconazole and were even superior to those of itraconazole for Aspergillus spp. as well as for many other fungal species.     

In vitro antifungal activity of N,N-phenyl-1,2,3,4-thiatriazole-5-yl-2,4-beta-resorcylcarbothioamide

The aim of this study was the determination of the antifungal activity of N,N-phenyl-1,2,3,4-thiatriazol-5-yl-2,4-beta-resorcylcarbothioamide (PTR) against Candida albicans, non-albicans Candida species, dermatophytes and moulds and of its influence on the enzymatic activity of C. albicans strains. The reference strains C. albicans ATCC 10231, 200 of C. albicans strains, 7 of non-albicans C. species, 12 dermatophyte strains and 20 mould strains were isolated from different patients. The mean minimum inhibitory concentration (MIC) of PTR against C. albicans strains isolated from patients was 19.6 mg/l, for reference C. albicans ATCC 10,231 it was 12.5 mg/l on Sabouraud's medium (SB). The mean MIC of isolates from patients was 16.9 mg/l, and reference strains 6.25 mg/l on YNB medium, respectively. The MIC of PTR against 7 non-albicans C. species was 27.7 mg/l on SB and 15.6 mg/l on YNB, respectively. The mean MIC of PTR against C. albicans strains isolated from patients was 14.9 mg/l, C. albicans ATCC 10,231 6.25 mg/l and non-Candida species strains 14 mg/l on RPMI medium. The MICs of PTR against dermatophytes ranged from 3 to 25 mg/l. The MICs of PTR against moulds were 25 mg/l and 100 mg/l, respectively. PTR inhibited the enzymatic activity of selected hydrolases of C. albicans and non-Candida species strains. PTR exerts a potent antifungal activity against the yeast-like fungi strains, moulds and dermatophytes. This new compound inhibited the enzymatic activity of selected hydrolases.     

ε-聚赖氨酸对白念珠菌抑菌活性及机制研究

目的 研究ε-多聚赖氨酸(ε-poly-L-lysine, ε-PL)对白念珠菌(Candida albicans)的抑菌活性及抑菌机制。方法 以白念珠菌的标准菌株ATCC64548(氟康唑敏感株)、ATCC64550(氟康唑耐药株)以及临床收集的50株菌为实验菌株,按照CLISI- M27文件中的微量稀释法测定ε-多聚赖氨酸的MIC、MFC和SMIC50值;绘制48h内的浮游菌株时间-生长曲线和生物膜抑制-时间曲线;连续观测并记录4h内的芽管形成率和芽管长度;测定药物处理前后白念珠菌的丙二醛和活性氧(ROS)含量。结果 ε-PL对白念珠的最低抑菌浓度(MIC)为512μg/mL,最低杀菌浓度(MFC)为1024μg/mL,SMIC50为512μg/mL,ε-PL对白念珠菌浮游菌及生物膜的抑菌作用随着浓度的升高作用愈明显。抑菌-时间曲线结果表明ε-PL对白念珠菌的浮游菌和生物膜在12h左右即产生明显抑制作用。芽管实验的结果表明高浓度的ε-PL对白念珠菌的芽管形成率及芽管长度具有明显抑制作用。ε-PL作用于白念珠菌后MDA和ROS含量呈现上升趋势,并且与药物浓度大小成正相关。结论 ε-PL对白念珠菌浮游菌株及生物膜均有良好的抑制作用,高浓度ε-PL对白念珠菌主要毒力菌丝有明显抑制作用,ε-PL作用导致白念珠菌内产生大量的活性氧(ROS)以及产生一定程度的脂质氧化,提示ε-PL可能通过氧化作用发挥抑菌效果。     

In vitro antifungal activity of itraconazole: a comparative study with ketoconazole]

In vitro antifungal activities of itraconazole (ITZ), a new oral triazole antifungal agent, were studied against a wide range of medically important fungi including 16 genera, 37 species and 51 strains stocked in this center. The test was carried out using the agar dilution method on Sabouraud dextrose agar. ITZ showed equal or superior antifungal activities to ketoconazole against most strains of pathogenic yeasts, dimorphic fungi, non-pigmented hypomycetes, dermatophytes and dematiacious fungi. Although some strains of Candida albicans and Candida tropicalis were not completely inhibited by ITZ at concentrations up to 80 micrograms/ml, partial growth inhibitions were observed even at drug concentrations as low as 0.04 microgram/ml. The antifungal activity of ITZ against C. albicans was markedly influenced by medium composition, medium pH, inoculum size and incubation time.     

Cefodizime, an aminothiazolylcephalosporin. I. In vitro activity

Cefodizime possesses a broad antibacterial spectrum including staphylococci, streptococci and Enterobacteriaceae. Neisseria gonorrhoeae and Haemophilus influenzae are also highly susceptible to cefodizime. Because of its beta-lactamase stability cefodizime is active against bacterial strains producing especially plasmid-coded enzymes. The MICs of cefodizime are slightly higher than those of cefotaxime, but with most Gram-negative bacteria they are lower than those of cefazolin, cefotiam and piperacillin. The in vitro activity of cefodizime is not dependent on inoculum size, or on the pH and composition of the test medium. Cefodizime did not induce in vitro resistance of Staphylococcus aureus or Escherichia coli. Because of its binding properties to PBPs 1A/B and 3, cefodizime leads to filamentation of Gram-negative rods and, at only slightly higher concentrations, to bacteriolysis.