Comparative efficacy of amphotericin B,clotrimazole and itraconazole againstAspergillus spp.

The susceptibilities of two isolates ofAspergillus flavus, one from a human case of recalcitrant mycotic keratitis, and an environmental isolate ofA. fumigatus, to itraconazole, clotrimazole and amphotericin B were measured. Observations of macroscopic growth and microscopic evaluations of conidia germination both indicated that the two isolates ofA. flavus were markedly more resistant to amphotericin B than to itraconazole and clotrimazole. Itraconazole was more effective than clotrimazole for all isolates. Ourin vitro susceptibility results suggest the use of itraconazole should be a primary consideration in the treatment ofAspergillus keratitis.     

Interaction between Candida agglutinins and antifungal agents

Antifungal agents alter the function and morphology of Candida cell membranes and cell walls. We observed that brief (30 minute) exposure to either amphotericin B or clotrimazole inhibited the agglutination of Candida blastoconidia by murine bronchoalveolar lavage fluid. This inhibition required continuous drug presence. Neither amphotericin nor clotrimazole inhibited Candida agglutination by concanavalin A or pooled human serum. These results demonstrate that antifungal drugs can produce rapid changes in the surface characteristics of some fungi.     

Systemic Candida infection in University Hospital 1997–1999: the distribution of Candida biotypes and antifungal susceptibility patterns

A total of 102 Candida species were isolated from blood cultures from January 1997 to October 1999. Using assimilation of carbohydrate test, 52 (51.0%) of the Candida sp. were identified as C. parapsilosis, 25.5% (26) were C. tropicalis. C. albicans made up 11.8% (12), 6.9% (7) were C. rugosa, 3.8% (4) C. glabrata and 1% (1) C. guilliermondii. No C. dubliniensis was found in the study. In vitro antifungal susceptibility tests showed that all Candida species were sensitive to nystatin, amphotericin B and ketoconazole. Although all isolates remained sensitive to fluconazole, intermediate susceptibility was found in 3 C. rugosa isolates. Antifungal agents with high frequency of resistance were econazole, clotrimazole, miconazole and 5-fluorocytosine. Candida species found to have resistance to these antifungal agents were non-C. albicans. This revised version was published online in June 2006 with corrections to the Cover Date.     

Paronychia and black discoloration of a thumb nail caused by Curvularia lunata

Chronic paronychia associated with black discoloration of the left thumb nail in a 51 year old female caused by Curvularia lunata is reported for the first time. The keratolytic activity of the fungus in the nail and its complete clearance by topical clotrimazole are reported.     

Efficacy of 6-amino-2-n-pentylthiobenzothiazole onTrichophyton in vitro and in vivo

In vitro and in vivo antifungal activities of synthetically parepared 6-animo-2-n-pentylthiobenzothiazole (APB) againstTrichophyton strains were studied. APB inhibited the growth of 3Trichophyton strains at 65 µg/ml. 2-Mercaptobenzothiazole was not effective at 125 µg/ml and ketoconazole inhibited the growth at 20–30 µg/ml. Treatment of experimental dermatophytosis in guinea pigs using 2.5% APB cream was studied in comparison to Canesten cream (1% clotrimazole). Dermatophytosis was considerably reduced after both APB and Canesten therapies.     

Relationship between <Emphasis Type="Italic">Psoroptes cuniculi</Emphasis> and the Internal Bacterium <Emphasis Type="Italic">Serratia marcescens</Emphasis>

The bacterium Serratia marcescens isolated from surface-sterilised Psoroptes cuniculi was found sensitive to the antibiotic Amikacin. Mites placed in this antibiotic for 48–72 h and then washed by centrifugation were found to be alive and S. marcescens-free. Two experimental infestations were undertaken in order to verify the ability of the S. marcescens-free mites to infect and to give ear skin lesions in healthy rabbits and to evaluate the differential ability of the S. marcescens-free and S. marcescens-infected mites to give ear skin lesions. All rabbits were found to be infested, but only rabbits infested with S. marcescens-free mites presented crusts in their ears, whereas mites and/or eggs were only detected in the ear cerumen of all rabbits infested with S. marcescens-infected mites. S. marcescens was isolated only from P. cuniculi mites taken from these latter rabbits. Results indicate that P. cuniculi mites do not need S. marcescens to live and to be able to infest a healthy rabbit. In addition, S. marcescens was not isolated from eggs and newly born larvae of S. marcescens-infected P. cuniculi, demonstrating that in a population of P. cuniculi this bacterium is not transmitted transovarially.     

Medically important fungi found in hallux nails of university students from Cali, Colombia

The presence of medically important fungi was studied in hallux nails scrapings obtained from 504 students (204 males, 300 females) of three universities in Cali. Specimens were examined by direct microscopic examination and fungal culture. Medically important fungi were found in 49 (9.7%) students, 24 (4.8%) had onychomycosis while the rest did not have nail lesions. Trichophyton rubrum was the most commonly isolated fungi in students with lesions, where as T. mentagrophytes predominated in healthy nails. Most of the students with fungi were males. The prevalence of fungi was higher in individuals between 26 and 35 years. No association was observed between fungi and practicing sports or undergoing pedicures. These results suggest that dermatophytes can be found in healthy hallux nails, which can be reservoirs of pathogenic fungi.     

Differential cytotoxicity and mycotoxin content among isolates of Fusarium moniliforme

Curvularia lunata was found causing (disseminated phaeohyphomycosis among a group of Nezara viridula (Insecta:Heteroptera) parasitizing vegetable crop Vigna unguiculata. Dark lesions were seen on pronotum and abdominal sterna. Experimental lesions were produced by applying 0.1 ml of 6.2 × 10⁸cfu/ml^–1 on abdominal sterna. Histopathology revealed that almost all internal organs and tissues showed extensive damage. It is interesting to note that C. lunata exhibited predeliction for chitinous tissues and elicited cellular immune response by granulocytes (phagocytosis). This is the first report of phaeohyphomycosis of an insect, extending the disease to invertebrates.A promising research career of one of the authors (Mrs. Vinita Dubey) was cut short by untimely death. This paper is dedicated to her memory.     

Fungispecificity of fluconazole against Candida albicans

Candida albicans is an opportunistic pathogen of human mucosal surfaces. Colonization of oral and vaginal mucosa by this yeast is antagonized by the resident normal bacterial population. However, antibacterial therapy can alter the normal flora to allow fungal cells to attach, grow and invade host tissues. We studied the antimicrobic activity of fluconazole against clinical isolates of oral and vaginal bacteria and Candida albicans in vitro and in vivo by scanning and transmission electron microscopy; we also compared the bactericidal activity of fluconazole with clotrimazole in vitro by microbiologie assay. Fluconazole lysed fungi but did not change the ultrastructure of bacteria. Clotrimazole, but not fluconazole, was bactericidal against lactobacillus and streptococcus, the principal species of the oral and vaginal cavities. We conclude that Candida albicans, but not oral and vaginal bacteria, is susceptible to fluconazole. These observations help explain the antimycotic specificity of fluconazole and its efficacy against candidiasis in humans.     

Two translesion synthesis DNA polymerase genes, AtPOLH and AtREV1, are involved in development and UV light resistance in Arabidopsis

Plants are continually exposed to external and internal DNA-damaging agents. Although lesions can be removed by different repair processes, damages often remain in the DNA during replication. Synthesis of template damages requires the replacement of replicative enzymes by translesion synthesis polymerases, which are able to perform DNA synthesis opposite specific lesions. These proteins, in contrast to replicative polymerases, operate at low processivity and fidelity. DNA polymerase η and Rev 1 are two proteins found in eukaryotes that are involved in translesion DNA synthesis. In Arabidopsis, DNA polymerase η and Rev 1 are encoded by AtPOLH and AtREV1 genes, respectively. Transgenic plants over-expressing AtPOLH showed increased resistance to ultraviolet light. Only plants with moderate AtREV1 over-expression were obtained, indicating that this enzyme could be toxic at high levels. Transgenic plants that over-expressed or disrupted AtREV1 showed reduced germination percentage, but the former exhibited a higher stem growth rate than the wild type during development.     

Isolation of Malassezia globosa and M. sympodialis from patients with pityriasis versicolor in Spain

Pityriasis versicolor is a superficial infection of the stratum corneum by several yeast species formerly collectively named Malassezia furfur. The genus Malassezia has been recently enlarged with new species. With the exception of M. pachydermatis, the remaining six species have an absolute requirement in vitro for supplementation of long-chain fatty acids in media. These lipophilic yeasts comprise six species: M. furfur, M. globosa, M. obtusa, M. restricta, M. slooffiae and M. sympodialis. The aim of this study was to establish whether there was any association between the various species of Malassezia and pityriasis versicolor lesions. Thus, we studied the isolates from 79 patients with pityriasis versicolor, both from lesions and from apparently healthy skin close to the visible lesions. In pityriasis versicolor lesions, the species most frequently isolated was M. globosa (90%), followed by M. sympodialis (41%). Almost all isolates (99%) belonged to one of these two species. The most frequent pattern was M. globosa as the sole species (58% of cases), although the association with M. sympodialis was also frequent (30%). These results confirmed M. globosa as the main agent of pityriasis versicolor and M. sympodialis as the second agent in importance. Malassezia globosa was found to be a species with high levels of esterase and lipase enzymes of probable importance in their pathogenicity. This revised version was published online in June 2006 with corrections to the Cover Date.     

Histopathology of experimental Aspergillus fumigatus keratitis

Histopathological studies in rabbit's eyes, 7 and 14 days after intracorneal inoculation with 1×10⁵ Aspergillus fumigatus conidia have been performed.Similar lesions were found in both periods with fungal hyphae in the anterior third of corneal stroma, round cell infiltration from the sclero-corneal edge and in the anterior chamber and, neovascularization.No lesions were found in the Descemet's membrane.Gomori silver-methenamine stain with hematoxiline-eosine counter-stain was found to be the most reliable stain to detect fungal presence in corneal stroma, and Masson's trichromic stain in the study of pathological changes in ocular elements.     

Clotrimazole as a pharmaceutical: past,present and future.

Clotrimazole is a broad‐spectrum antimycotic drug mainly used for the treatment of Candida albicans and other fungal infections. A synthetic, azole antimycotic, clotrimazole is widely used as a topical treatment for tinea pedis (athlete's foot), as well as vulvovaginal and oropharyngeal candidiasis. It displays fungistatic antimycotic activity by targeting the biosynthesis of ergosterol, thereby inhibiting fungal growth. As well as its antimycotic activity, clotrimazole has become a drug of interest against several other diseases such as sickle cell disease, malaria and some cancers. It has also been combined with other molecules, such as the metals, to produce clotrimazole complexes that show improved pharmacological efficacy. Moreover, several new, modified‐release pharmaceutical formulations are also undergoing development. Clotrimazole is a very well‐tolerated product with few side effects, although there is some drug resistance appearing among immunocompromised patients. Here, we review the pharmaceutical chemistry, application and pharmacology of clotrimazole and discuss future prospects for its further development as a chemotherapeutic agent.     

Inducible expression of bacterio-opsin in transgenic tobacco and tomato plants

The development of new strategies to enhance resistance of plants to pathogens is instrumental in preventing agricultural losses. Lesion mimic, the spontaneous formation of lesions resembling hypersensitive response lesions in the absence of a pathogen, is a dramatic phenotype occasionally induced upon expression of certain transgenes in plants. These transgenes simulate the presence of a pathogen and, therefore, activate the plant anti-pathogen defense mechanisms and induce a state of systemic resistance. Lesion mimic genes have been successfully used to enhance the resistance of a number of different plants to pathogen attack. However, constitutive expression of these genes in plants is associated with the spontaneous formation of lesions on leaves and stems, reduced growth, and lower yield. We tested the possibility of using a wound-inducible promoter to control the expression of bacterio-opsin (bO), a transgene that confers a lesion mimic phenotype in tobacco and tomato plants when constitutively expressed. We found that plants with inducible expression of bO did not develop spontaneous lesions. Nevertheless, under controlled laboratory conditions, they were found to be resistant to infection by pathogens. The activation of defense mechanisms by the bO gene was not constitutive, and occurred in response to wounding or pathogen infection. Furthermore, wounding of transgenic tobacco plants resulted in the induction of systemic resistance to pathogen attack within 48 h. Our findings provide a promising initial assessment for the use of wound-inducible promoters as a new strategy to enhance pathogen resistance in transgenic crops by means of lesion mimic genes.     

Connection of Gnomonia intermedia to Discula betulina and its relationship to other taxa in Gnomoniaceae

Discula betulina is a foliar pathogen on birch (Betula) and Gnomonia intermedia is found on overwintered birch leaves. Perithecia of G. intermedia developed in vitro on colonies of D. betulina isolated from birch tissues in late summer, and single ascospores of G. intermedia consistently developed into colonies similar to D. betulina, producing typical D. betulina conidia. Isolates of D. betulina could be grouped into two mating types, which produced fertile perithecia of G. intermedia when mated with each other. Mycelia from single-ascospore and single-conidial isolates were inoculated onto shoots of downy birch, causing lesions and die-back from which D. betulina was consistently isolated. ITS region ribosomal DNA sequence analysis confirmed the results of the morphological and mating studies, and found that the closest known relatives of G. intermedia/D. betulina are Gnomoniella nana and Sirococcus clavigignenti-juglandacearum. The conclusion from these studies is that D. betulina is the anamorph of G. intermedia.     

PCR-based detection and characterization of the fungal pathogens Colletotrichum gloeosporioides and Colletotrichum capsici causing anthracnose in papaya (Carica papaya l.) in the Yucatan peninsula

Colletotrichum gloeosporioides is the common causal agent of anthracnose in papaya (Carica papaya L.) fruits, and infection by this fungal pathogen results in severe post-harvest losses. In the Yucatán peninsula (Mexico) a different Colletotrichum species was isolated from papaya fruits with atypical anthracnose lesions. The DNAs from a variety of Colletotrichum isolates producing typical and atypical lesions, respectively, were amplified by PCR with C.gloeosporioides-specific primers. All isolates from typical anthracnose lesions yielded a 450 bp PCR product, but DNAs from isolates with atypical lesions failed to produce an amplification product. For further characterization, the rDNA 5.8S-ITS region was amplified by PCR and processed for sequencing and RFLP analysis, respectively, to verify the identity of the papaya anthracnose pathogens. The results revealed unequivocally the existence of two Colletotrichum species causing anthracnose lesions on papaya fruits: C. gloeosporioides and C. capsici. PCR-RFLP using the restriction endonuclease MspI reliably reproduced restriction patterns specific for C. capsici or C. gloeosporioides. The generation of RFLP patterns by MspI (or AluI or RsaI) is a rapid, accurate, and unequivocal method for the detection and differentiation of these two Colletotrichum species.     

<Emphasis Type="Italic">Colletotrichum gloeosporioides</Emphasis> can Overgrow <Emphasis Type="Italic">Colletotrichum kahawae</Emphasis> on Green Coffee Berries First Inoculated with <Emphasis Type="Italic">C. kahawae</Emphasis>

Colletotrichum gloeosporioides is a weak pathogen of coffee that infects ripe berries at dark red stage causing necrotic lesions, but only penetrates up to the second superficial layers of the pericarp at the rose and pink stages. C. kahawae, the causal agent of coffee berry disease (CBD) and responsible for 70–80% of crop loss, infects berries at any stage of development. When green berries are first inoculated with C. kahawae and then at 2, 72 or 96 h later with C. gloeosporioides, the necrotic lesions were significantly larger than in the controls, and were much more evident when the berries were incubated at the optimum growth temperature of 28 °C for C. gloeosporioides. Isolations from the lesions induced by the first inoculations with C. kahawae followed by inoculation with C. gloeosporioides revealed that all or most of the time the recovered isolates of the latter. Thus, C. gloeosporioides can overwhelm C. kahawae under conditions of higher environmental temperature and humidity and may enhance the CBD infection process under field conditions.     

Onychomycosis caused by Chaetomium globosum Kunze

In this paper we report a case of onychomycosis caused by Chaetomium globosum. The patient had lesions of the fingernails of the left hand. The direct microscopical examination of the nails showed light-brown hyphae with thick-walled cells. The histopathological examination revealed thick aggregated hyphal element in the nail plate. Amongst the antimycotics tested oxiconazole with MIC values of 0.3 g/ml^–1 was found to be most effective in vitro against Chaetomium globosum.     

Sequential development of pathogens in the maize tarspot disease complex

The tarspot complex is caused by the interaction of Phyllachora maydis and Monographella maydis. Coniothyrium phyllachorae, possibly a mycoparasite, is found in older ascostromata of P. maydis, which always appears first causing tarspot. M. maydis follows and is responsible for the damaging fisheye symptom. The fisheye symptom is always associated with a tarspot in the center of the lesion, whereas 12 to 20% of the Phyllachora ascostromata remained free of M. maydis. Inoculations of maize leaves with the Microdochium anamorph of the Monographella (usually produced in lesions) failed to produce infections. Some infections with M. maydis were, however, obtained under unusual conditions in the field. Inoculations onto tarspots in the laboratory were unsuccessful, but in field experiments inoculations with conidia of M. maydis enhanced severity of the tarspot complex. Fisheye symptoms of the complex naturally appear 2 to 7 days after the manifestation of P. maydis. This is followed a week later by the appearance of M. maydis which became predominant in the lesions and is associated with empty perithecia of P. maydis. In the early stages of the tarspots pycnidia of the anamorph of P. maydis, Linochora sp., could occasionally be observed. Ascomata of M. maydis were rare in the field. Of the 36 genetic materials of CIMMYT tested, 30 developed the fisheye symptom, 4 tarspots only and 2 remained free of symptoms     

Stromatinia cryptomeriae sp. nov., the teleomorph ofGloeosporidina cryptomeriae causing twig blight of Japanese cedar

A new species,Stromatinia cryptomeriae, is described based on a specimen collected in Iwate Prefecture, Japan. It was found on fallen dead branches and twigs of Japanese cedar,Cryptomeria japonica. The morphology of isolates on potato-dextrose agar (PDA), which were obtained from single ascospores ofS. cryptomeriae, was identical withGloeosporidina cryptomeriae, the causal fungus of Japanese cedar twig blight. In an inoculation test using single ascospore isolates, many minute black spots (sclerotioid bodies; sclerotules) and acervuli ofG. cryptomeriae were formed on the necrotic lesions, which developed into typical symptoms of Japanese cedar twig blight. These results show thatStromatinia cryptomeriae is the teleomorph ofG. cryptomeriae. On PDA, the fungus grew over a range of about 1 to 25°C, with the optimum growth at about 15–20°C.