In vitro antimalarial activity and cytotoxicity of cochlospermum tinctorium and C. planchonii leaf extracts and essential oils

The antimalarial and toxicological properties of Cochlospermum tinctorium and C. planchonii extracts and essential oils prepared from their leaves were studied. The oil components were extracted by hydrodistillation of the plant leaves and characterized by gas chromatography and mass spectrometry. Crude extracts and oils were tested for in vitro antimalarial activity on Plasmodium falciparum. The IC50 were evaluated after 24 and 72 h contact between the oils and the parasite culture, and ranged from 22 to 500 micrograms/ml. C. planchonii leaf oil yielded the best antimalarial effect (IC50: 22-35 micrograms/ml), while the most potent effect from crude leaf extracts was induced by C. tinctorium. The cytotoxicity of the leaf crude extracts and oils was assessed on the K562 cell line and showed IC50 values ranging between 33 and 2000 micrograms/ml.

Genetic multilocus studies of different strains of Cryptococcus neoformans: taxonomy and genetic structure

The genotypes of 107 strains of Cryptococcus isolated from the environment or from patients from various geographical areas were determined by multilocus enzyme electrophoresis (MLEE). We analyzed the relationships between genotype structure and serotype and between genotype structure and strain origin. Twelve of the 14 enzyme-encoding loci studied were polymorphic, giving rise to 48 electrophoretic types. The genotypes of C. neoformans and C. laurentii were very similar. MLEE could not distinguish between these two pathogenic species. A correlation between the genetic multilocus structure and the origin of the sample (from the environment or patients) existed. A second analysis detected a correlation between genotype distribution and serotype. The second analysis considered three serotype groups (B, C, and A plus D plus A/D), proving that serotypes A, D, and A/D are closely related. MLEE is a useful epidemiological tool for improving our understanding of the biology of this fungus.

In vitro antiplasmodial activity of stem and root extracts of Nauclea latifolia S.M. (Rubiaceae)

Aqueous extracts from Nauclea latifolia S.M. (Rubiaceae), a plant commonly used in Ivory Coast by traditional healers for the treatment of malaria, were tested on two strains of Plasmodium faliparum: FcB1-Colombia (chloroquine-resistant) and a Nigerian strain (chloroquine-sensitive). The extracts were obtained from stems and roots of the plant in two forms, infusion and decoction, both methods used by most traditional healers. The in vitro activity of N. latifolia extracts on P. falciparum was assessed both visually and by a radioactive method. The visual analysis allowed determination of the time of extract action on the erythrocytic cycle, as well as the parasitic stage of most inhibitory effect. Similar results were obtained applying fresh, frozen or lyophilized extracts. The IC50 values determined were within the range already reported for other antimalarial plants such as Azadirachta indica A. Juss (Meliaceae) or Artemisia annua L. (Asteraceae). Aqueous extracts of N. latifolia inhibited P. falciparum (FcB1 strain) mainly at the end of the erythrocytic cycle (32nd to 48th hour).

Oropharyngeal candidiasis in AIDS patients from Abidjan (Ivory Coast): antifungal susceptibilities and multilocus enzyme electrophoresis analysis of Candida albicans isolates

Multilocus enzyme electrophoresis (MEE) and in vitro antifungal susceptibility testing were used to investigate the Candida albicans strain diversity in twenty nine AIDS patients from Abidjan (Ivory Coast). All patients were monitored for a first episode of oropharyngeal candidiasis and were randomly clustered into three groups of therapy: ketoconazole, amphotericin B or nystatin. Oral swabs were collected before every treatment, 14 and 30 days after the initiation of the therapy; a total of 67 isolates were investigated. No resistant or less susceptible isolate to any antifungal agent was found despite the emergence of clinical relapses, mainly for patients treated with nystatin or amphotericin B. The MEE analysis revealed 27 different electrophoretic types (ETs). Genetic distances between ETs were statistically analyzed and represented on a dendrogram. The 27 ETs clustered into three groups; in each group, ETs represented variants of the same strain. A segregation of the C. albicans isolates seemed to be as a function of the serotype.

Multilocus enzyme electrophoresis analysis of Candida albicans isolates from three intensive care units. An epidemiological study

To evaluate the mechanism and risk factor associated with the nosocomial acquisition of Candida albicans, a 3-month prospective study was conducted on non-neutropenic patients in three distinct intensive care units in distinct hospitals. A total of 43 samples from 19 patients has been typed by multilocus enzyme electrophoresis (MEE). Samples (24) from the deep pharynx of hospital staff members were also cultured and typed. Thirteen of the 19 enzyme loci studied were polymorphic. The 52 electrophoretic types were assigned to 67 isolates, each type was represented by one to five isolates; this proved the great diversity of the isolates. It appeared that most patients were colonized or infected with different C. albicans strains. This study pointed out a possible cross-infection between patients and hospital staff and between healthy members of the hospital staff, and also showed the successive stages of infection by different electrophoretic types. Intubation and respiratory equipment as surgery intervention were possible sources of observed infections.

In vitro antimalarial activity of penduline, a bisbenzylisoquinoline from Isopyrum thalictroides

Two bisbenzylisoquinolines, tetrandrine and penduline, were purified from Isopyrum thalictroides. When tested for antimalarial activity in vitro, penduline was efficient at concentrations fivefold lower than those of tetrandrine. In highly synchronized parasite cultures, penduline mostly interfered between the 8th and the 32nd hours of the parasite cycle.

Murine macrophage elastolytic activity induced by Aspergillus fumigatusstrains in vitro: evidence of the expression of two macrophage-induced protease genes

The interaction between Aspergillus fumigatus conidia and murine macrophages of various origins was investigated. Cocultures were carried out between A. fumigatus strains and freshly isolated murine pulmonary alveolar macrophages or two murine macrophage cell-lines: murine alveolar cell-line MALU and murine astrocytoma cell-line J774. By measuring the variation of elastolytic activity in the coculture supernatants with two elastin substrates, we demonstrated that either viable or fixed A. fumigatus or C. albicans yeasts or nonspecific particles induced significant macrophage elastolytic activity. The effect of A. fumigatus supernatant or the purified A. fumigatus galactomannan suggested also the possible involvement of this polysaccharide in macrophage-protease gene expression, release, and activity in invasive aspergillosis. The effect of inhibitory compounds demonstrated the potential implication of a macrophagic metalloprotease and a macrophagic cysteine protease. RNA analysis allowed us to demonstrate the induction of expression of two macrophagic protease genes in stimulated macrophages. Two distinctive mechanisms appeared to be implicated in macrophage protease induction: nonspecific phagocytosis in the earliest times of the coculture and (or) specific galactomannan recognition after its gradual release by the mycelium.

Atypical strains of Candida albicans recovered from AIDS patients

By using multilocus enzyme electrophoresis (MLEE) we have analyzed the genetic diversity encountered among chlamydospore-positive Candida albicans strains. While the type II strains of the former C. stellatoidea were genetically indistinguishable from those of C. albicans, type I strains constituted a distinct subgroup compared with C. albicans strains. Nevertheless, all these strains remained genetically very closely related compared with other species of Candida (e.g. C. tropicalis, C. krusei and C. glabrata). These results corroborate the synonymy between C. stellatoidea and C. albicans. Chlamydospore-positive C. albicans strains with atypical sugar assimilation patterns displayed a great genetic divergence from the cluster constituted by C. albicans and the strains of the former C. stellatoidea. However, these atypical strains were more closely related to C. albicans than they were to C. tropicalis, C. krusei or C. glabrata. These strains represent a genetically entity distinct from the typical C. albicans strains used in this study. The data also support the view that the atypical strains described here belong to the same genetic group as atypical C. albicans strains previously described by others.

Molecular typing of Aspergillus fumigatus strains by sequence-specific DNA primer (SSDP) analysis

A PCR typing method has been developed and tested to investigate the polymorphism of clinical strains of Aspergillus fumigatus. Firstly, the DNA fragments from random amplified polymorphic DNA (RAPD) patterns of nine epidemiologically and geographically non-related monosporal strains of A. fumigatus were cloned and sequenced. The pairs of five sequence-specific DNA primers (SSDP), characteristic of the 5' and 3' extremities of the RAPD products, were then used in high stringency PCR to type 43 clinical strains of A. fumigatus from 13 patients, according to the presence or absence of a single amplified band. This original approach, which uses the advantages of PCR, has made it possible to overcome the difficulties resulting from the low stringency amplification. The SSDP analysis of 51 A. fumigatus strains (9 unrelated monosporal strains and 43 clinical strains from 13 patients) can be classed into 22 different types with a high reproducibility and a high level of discrimination (D = 0.96). The results suggest that seven lung transplant patients with necrotizing aspergillosis, bronchitis aspergillosis and bronchial colonization were infected by multiple strain genotypes, whereas three patients with invasive aspergillosis seem to have been infected by a single strain.

Specific antibody detection in human aspergillosis: a GEMO* multicentre evaluation of a rapid immunoelectrophoresis method (Paragon). Group d'Etude des Mycoses Opportunistes

A new immunoelectrophoresis system, the Paragon system, was evaluated in three different hospital centres with the aim of improving standardization of the serodiagnosis of human aspergillosis. To select the most efficient antigen, various commercial and home-made antigens were first tested on 19 sera from 19 patients with highly probable aspergillosis. The value measured using the Paragon anti-Aspergillus antibody detection system was then compared with the results obtained by conventional serological diagnostic methods (conventional immunoelectrophoresis, enzyme linked-immunosorbent assay, indirect immunofluorescence): this step was performed using the first 19 sera as well as 16 other sera from 13 patients with suspected aspergillosis. Concordant results were obtained in 28 cases. The discrepancies observed with seven sera were probably related to differences in the nature of the antigens. Paragon immunoelectrophoresis proved to be a practicable technique requiring only a small amount of serum and giving results within a shorter time than competitive methods (24-48 h). Its major drawbacks compared with conventional immunoelectrophoresis are some difficulties in reading, fewer precipitin lines and the relatively high cost of routine analysis.

[Mycological monitoring of Candida albicans infections in various hospital care units. Molecular typing of isolated strains and epidemiological survey]

To evaluate risk factors associated with the nosocomial infection of Candida albicans, a prospective study is conducted twice for three months in three intensive care units. Samples from patients HIV negatives, non neutropenic and non immunodepressive are collected as they came in the unit, on several anatomic sites. Every C. albicans carriers are included in a mycological monitoring. Samples from environmental surfaces, hands and deep pharynx from hospital personnel were also cultured. Strains genetic profile are defined by isoenzyme electrophoresis technique. Thirteen polymorphic loci allowed samples classement into 52 electrophoretic types (ET). If only one crossed contamination is described, strains regroupment into some ET incites us to extend this study. C. albicans strains from patients closed environment have never been isolated.

Simultaneous carriage of Candida albicans strains from HIV-infected patients with oral candidiasis: multilocus enzyme electrophoresis analysis

Genetic diversity of 160 Candida albicans isolates from the oral cavity of 16 HIV-infected adults prior to antifungal treatment was assessed using multilocus enzyme electrophoresis (10 C. albicans colonies were randomly chosen from each specimen culture). 20 electrophoretic types were distinguished from the analysis of 21 enzyme loci (10 were polymorphic). Five patients (31%) were found to be colonized by 2 or 3 genetically distinct strains. Nevertheless, in these five cases, one strain predominated (from 7 to 9 of the 10 colonies). Some HIV + patients with oral candidiasis appear to be simultaneously infected with several genetically different C. albicans strains before antifungal treatment.

In vitro susceptibility of 115 isolates of Candida to amphotericin B, fluconazole and itraconazole

Opportunistic fungal infections are an increasingly important cause of morbidity and mortality particularly due to Candida species (1). There is also an increase of candidosis especially ascribed to acquired or induced immunodeficiency syndromes or in the event of long-term antibiotic, immuno-suppressor or cytotoxic therapies. Consequently there has been an increase in the use of systemic antifungal agents responsible for the emergence of new opportunistic fungi (2) and resistant species (3, 4). Oropharyngeal candidiasis caused by various species of Candida is one of the most common opportunistic infections in AIDS. In recent years there has been an increasing number of yeast isolates resistant to fluconazole (4, 5) or to amphotericin B (6). The aim of the present study was to examine the susceptibility in vitro of itraconazole, a newly introduced antifungal agent in the local or systemic therapy of oropharyngeal candidiosis, vs well-known agents such as amphotericin B and fluconazole, against various Candida clinical isolates. The present results, in agreement with other studies, show strong in vitro activity of itraconazole against Candida spp. and particularly against less susceptible species C. glabrata, C. tropicalis or C. krusei.

Evaluation of the susceptibility of dermatophytes to antifungal drugs: a new technique

The evaluation of the minimal inhibitory concentration (MIC) for pathogenic fungi is still a technically difficult assay. Insufficient standardization of the technique is often the basis of problems which appear. Culture characteristic of dermatophytes do not favour techniques usually used in bacteriology (Steers agar dilution method). A study was undertaken to compare the Steers agar dilution method and a new culture method to evaluate the minimal inhibitory concentration of antifungal compounds on several species of dermatophytes. The new method involves dilution of the antifungal drug in solid medium in a Petri dish. Standardized agar cylinders are cut from the plates and filled with inocula of the same size cut from plates of dermatophyte cultures. Such inocula facilitate analysis of the fungus in its natural growth conditions in vitro without being submitted to a disruptive preparative technique. The MIC values were similar for the two methods of evaluation in spite of important differences between the inocula. The new technique is reliable, quick, and highly reproducible. It is more efficient than the Steers agar dilution method because it enables assays to be run on several strains simultaneously and avoids labour-intensive procedures for the preparation of the inocula.

Fluconazole- and itraconazole-resistant Candida albicans strains from AIDS patients: multilocus enzyme electrophoresis analysis and antifungal susceptibilities

Multilocus enzyme electrophoresis and in vitro susceptibility testing with a broth microdilution method were used to analyze Candida albicans strain diversity in four AIDS patients with recurrent oropharyngeal candidiasis who successively developed clinical resistance to fluconazole (FCZ) and itraconazole (ITZ). One to ten colonies per sample were randomly chosen from oral washings collected before the initial FCZ treatment and just before every other antifungal treatment; a total of 98 isolates were analyzed. Multilocus enzyme electrophoresis analysis revealed 14 different electrophoretic types (ETs). Statistical analysis of genetic distances showed that C. albicans isolates clustered into five subpopulations (I to V). In each subpopulation, isolates are closely related, and genetic distances between subpopulations I to IV are short. In contrast, subpopulation V, which contained isolates typed as ET8 and ET14, is strongly divergent from the others; these isolates may represent atypical C. albicans isolates. Only one patient was infected with a single strain during the course of azole therapy; for the three remaining patients, variants of the same strain and different strains were concurrently isolated. Clinical FCZ resistance was clearly correlated with in vitro data for three patients. Moreover, MICs of ITZ increased during FCZ therapy, and MICs of ITZ which were > or = 1.56 micrograms/ml were found when clinical ITZ resistance occurred; isolates from subpopulation V showed the highest MICs of ITZ. Because of the emergence of clinical ITZ resistance after clinical FCZ resistance, the feasibility of long-term azole therapy for mucosal candidiasis in AIDS patients is questioned.

Antimalarial activity in vitro of Cochlospermum tinctorium tubercle extracts

Resistance of Plasmodium falciparum to current antimalarial compounds has drastically increased during the last few years and is now a major public health problem. We have studied plants traditionally used in Africa against malaria. Extracts of the tubercles of Cochlospermum tinctorium A. Rich, commonly used in Burkina Faso, were tested in vitro on 2 strains of P. falciparum, one (FcB1-Colombia) chloroquine resistant and the other (F32-Tanzania) chloroquine sensitive. Extracts were obtained by infusion and decoction. The 50% inhibitory concentrations (IC50) were determined by measuring [3H]hypoxanthine incorporation and also by microscopical examination which permitted the determination of parasite stages. We obtained similar results with fresh extracts, frozen extracts, and lyophilized extracts of C. tinctorum. IC50 values were of the order of 1-2 micrograms/mL, about one-tenth of those reported for extracts of neem leaves (Azadirachta indica) and about half the values reported for Artemisia annua extracts.

Relationship between fluconazole sensitivity of Candida albicans isolates from HIV positive patients and serotype, adherence and CD4+ lymphocyte count

The sensitivity of fluconazole, serotype and adherence to buccal epithelial cells of 46 Candida albicans isolates was studied in vitro. Strains were isolated from 18 HIV-positive patients with variable CD4+ lymphocyte counts who were receiving long-term fluconazole therapy. Results showed that sensitivity to fluconazole correlated with serotype. Of the sensitive isolates 81.5% were serotype A and 18.5% serotype B, whereas of the resistant isolates 37.5% were serotype A and 62.5% serotype B. Sensitivity to fluconazole also correlated with adherence capacity, resistant isolates showing slightly less adherence to buccal epithelial cells than sensitive isolates. Weakly adherent isolates represented 87% of resistant isolates and only 63% of sensitive isolates. Resistant strains were isolated in highly immunocompromised patients. All strains isolated in patients with CD4+ lymphocyte counts above 200 lymphocytes/microliters were sensitive, whereas intermediate and resistant strains were isolated in patients with counts below 200 lymphocytes/microliters. Statistical analyses showed no correlation between adherence of isolates to buccal epithelial cells and CD4+ lymphocyte counts.

[Adherence of isolated Candida albicans strains from HIV+ infected patients to buccal epithelial cells: correlation with serotype, sensitivity to fluconazole and virulence]

During infection by human immunodeficiency virus (HIV), oral pseudomembranous candidiasis frequency is high. Adherence of Candida albicans to epithelial cells constitutes one of the first step in the setting up of candidiasis. Adherence ability of Candida albicans to buccal epithelial cells (BEC) is estimated for 83 isolates. The yeasts are isolated from buccal swabs from HIV+ patients with clinical oropharyngeal candidiasis. Results show that Candida albicans ability to adhere to BEC is variable within isolates; it appears that most of the isolates are weakly adherent. In addition, adherence is not correlated with the serotype A or B of yeasts. We do not either observe any correlation between adherence capacity and sensibility of yeasts to fluconazole. Moreover, no correlation is observed between a group of 13 genetically identical isolates (analysed on 21 loci with isoenzymes method) and their adherence to BEC. Finally, Candida albicans virulence, which is studied in vivo on intravenously infected mouse model, does not seem to be correlated with capacity of each yeast to adhere on BEC in vitro.

Control of Candida albicans vaginitis in mice by short-duration butoconazole treatment in situ

A short-duration treatment for candidal vaginitis applying butoconazole in situ was tested in an experimental mouse model. One week after artificial induction of an oestrus state (by oestradiol benzoate injection), mice were inoculated intravaginally with 1.5 x 10(7) blastospores of Candida albicans (strain ATCC 44858). Treatment consisted of butoconazole solutions (1%, 2.5% and 5%) administered intravaginally. The development of the infection was monitored daily for 12 days and then three times a week by local samples plated on BiGGY agar. In parallel, twice a week, the vaginas of three mice in each group (control and treated groups) were isolated in order to estimate organ invasion by C. albicans. This was assessed by anatomopathological studies on a fixed and stained part of the organ and by serial dilutions of a homogenate of the remaining part plated on Sabouraud glucose chloramphenicol agar. After a 48-h incubation period the number of colony forming units per gram of tissue was counted. For each treatment, a remission of 10-15 days was observed, but was followed by a recurrence for the lower dose of butoconazole; only the higher butoconazole concentrations tested (2.5% and 5%) gave an apparent full cure for most of the mice tested. The use of the mouse model of candidal vaginitis confirms that short-duration treatment is possible when elevated doses of butoconazole are used.

The yeast Candida albicans has a clonal mode of reproduction in a population of infected human immunodeficiency virus-positive patients

To ascertain the population structure of Candida albicans, we have carried out a multilocus enzyme electrophoresis study based on the analysis of 21 gene loci. We have thus characterized 55 strains isolated one each from 55 human immunodeficiency virus-positive patients. There is considerable polymorphism among the strains. A population-genetic analysis indicates that the two fundamental consequences of sexual reproduction (i.e., segregation and recombination) are apparently absent in this population of C. albicans. The population structure of C. albicans appears to be clonal, a state of affairs that has important medical and biological consequences.

Antifungal activity of allylamines on Epidermophyton floccosum: scanning electron microscopy study

The action of allylamine antifungal agents on Epidermophyton floccosum was studied using scanning electron microscopy. After 7 days of culture on Sabouraud dextrose agar, Epidermophyton floccosum samples were brought in contact with concentrations of 0.2 and 2 micrograms ml-1 and 0.01 and 0.1 micrograms ml-1 of naftifine and terbinafine, respectively. Lesions observed after 24 h, 3 and 7 days of contact were mainly on the structure and rigidity of the mycelial and macroconidial wall. They were characterized by hyphal ballooning and twisting and by apical bulbous bulges. Deterioration of macroconidia was characterized by wall exfoliation. The intensity of the deterioration depended on the dose and only slightly on the length of time that the sample and the antifungal drug were in contact.

Low voltage scanning electron microscopy study of naftifine activity on Microsporum canis

Scanning electron microscopy (SEM) is at present considered a good way to observe the morphological alterations induced by an antifungal on pathogenic fungi. Owing to its high precision, low voltage scanning electron microscopy (LVSEM) improves the quality of observations. The Microsporum canis morphology alterations induced by naftifine at a concentration of 0.9 microgram ml-1 (10 times the minimum inhibitory concentration (MIC) for 7 days were studied in LVSEM. The young lateral ramifications and the aborted buds take on a granulous aspect. These granulations can be localized as brassard shapes around hyphae. The mycelial filaments often appear irregularly swollen with bulbous tips. Macroconidia are selectively covered with a microfibrillar network. In addition, LVSEM on control samples reveals pavimentous angular structures on the macroconidial surface and fine granulations on the filament surface of M. canis unknown until now. A cytological study with transmission electron microscopy (TEM) of filaments altered by naftifine permitted us to observe the disorganization of cell wall fibrillar structure, an excessive plasma membrane undulation and an intracytoplasmic accumulation of large vesicles with probably lipidic contents.

[Treatment and secondary prophylaxis with fluconazole for oropharyngeal candidiasis in HIV-positive patients. A mycological analysis of failures]

This prospective study evaluated the in vitro susceptibility of Candida albicans isolates recovered from the oral cavity of AIDS/ARC patients before and during long-term therapy with fluconazole. Thirty adults (15 with ARC and 15 with AIDS) with a first episode of thrush candidiasis were given oral fluconazole (Triflucan 50 mg; one capsule daily) for at least three months. Fungal susceptibility testing was performed before treatment, after one month, and at last follow-up (range 3.5-12 months; mean 5.7 months). MICs were determined using the agar dilution method with casitone (Difco 259-01) as the test medium at pH 7.2-7.4. There were two initial clinical failures (one with high MICs before and under treatment and one with an intermediate MIC initially and a rise in MIC under fluconazole). Four patients developed a clinical relapse with no change in MICs (which were low or intermediate). In six patients, clinical symptoms resolved but carriage of C. albicans persisted (low MICs). In 18 patients, clinical resolution with eradication of C. albicans was achieved. These data suggest that (1) clinical failures may be associated with in vitro resistance; (2) relapses under fluconazole maintenance therapy may develop in patients with advanced HIV disease despite the lack of change in the susceptibility of strains.