Mycotoxins produced by Fusarium proliferatum and F. pseudonygamai on maize, sorghum and pearl millet grains in vitro

Maize (Zea mays), sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) are basic staple foods for many rural or poorer communities. These crops are susceptible to plant diseases caused by multiple species of Fusarium, some of which also produce mycotoxins, including fumonisins and moniliformin that are detrimental to both humans and domesticated animals. Eighteen potentially toxigenic Fusarium strains were isolated from maize (n = 10), sorghum (n = 7) and pearl millet (n = 1) growing in the same field in Nigeria. The 17 strains from maize and sorghum were all F. proliferatum and the one strain from pearl millet was F. pseudonygamai. Under conducive conditions, the 17 F. proliferatum strains produced fumonisins, 11 in relatively large quantities (700-17,000 mg total fumonisins, i.e., FB₁ + FB₂ + FB₃/kg culture material), and six at <45 mg/kg. Ten F. proliferatum strains produced >100 mg of moniliformin per kg culture material with a maximum of 8900 mg/kg culture material. All strains could use all grains for growth and toxin production, regardless of the host from which they were isolated. Isolates varied in the amount of toxin produced on each substrate, with toxin production a property of the strain and not the host from which the strain was recovered. However, the extent to which a toxin-producing phenotype could be altered by the grain on which the fungus was grown is consistent with subtle genetic × environment interactions that require a larger data set than the one presented here to rigorously identify. In conclusion, there is significant variation in the ability of strains of F. proliferatum to produce fumonisins and moniliformin on maize, sorghum and millet. If the amount of toxin produced on the various grains in this study reflects real-world settings, e.g., poor storage, then the consumers of these contaminated grains could be exposed to mycotoxin levels that greatly exceed the tolerable daily intakes.

Relative severity of fumonisin contamination of cereal crops in West Africa

Traditional and improved varieties of maize, pearl millet and sorghum were planted by small-scale farmers under the direction of the International Institute for Tropical Agriculture in two Nigerian agro-ecological zones: the Sudan Savanna and the Northern Guinea Savanna. Samples were collected for the determination of Fusarium infection and fumonisin (B1, B2 and B3) contamination. A previous paper reported Aspergillus infection and aflatoxin contamination of these samples. Fusarium infection levels, measured by per cent kernels infected, were modest with mean levels for the above cereals of 16% ± 11% (SD), 12% ± 7% and 13% ± 16%, respectively. However, the Fusarium species recovered from maize were predominantly the fumonisin producers F. verticillioides and F. proliferatum, together making an infection rate of 15% ± 10%, whereas these species were present to a limited extent only in the other two cereals, 1% ± 1% for pearl millet and 2% ± 6% for sorghum. Fumonisin contamination was variable but reflected the diversity of Fusarium producers in these three cereals. Mean levels were 228 ± 579 µg kg(-1) (range < 5-2860 µg kg(-1)) for maize, 18 ± 7 µg kg(-1) (range = 6-29 µg kg(-1)) for pearl millet and 131 ± 270 µg kg(-1) (range < 5-1340 µg kg(-1)) for sorghum. Together with previous results on aflatoxin, this study confirmed the co-occurrence of aflatoxins and fumonisins in maize as well as in the traditional African cereals, millet and sorghum (89% co-occurrence across all three cereals). The low fumonisin levels may be ascribed to the use of good agricultural practices. Of the Fusarium species present, those in maize consisted mainly of fumonisin producers, the opposite of what was observed in pearl millet and sorghum. It is concluded that replacement of maize by pearl millet and sorghum could improve food safety with regards to aflatoxin B and fumonisin B exposure.

A dimorphic fungus causing disseminated infection in South Africa

BACKGROUND

The genus emmonsia contains three species that are associated with human disease. Emmonsia crescens and Emmonsia parva are the agents that cause adiaspiromycosis, and one human case of Emmonsia pasteuriana infection has been described. We report a fungal pathogen within the genus emmonsia that is most closely related to E. pasteuriana in human immunodeficiency virus (HIV)-infected adults in South Africa.

METHODS

Between July 2008 and July 2011, we conducted enhanced surveillance to identify the cause of systemic, dimorphic fungal infections in patients presenting to Groote Schuur Hospital and other hospitals affiliated with the University of Cape Town, Cape Town, South Africa. DNA sequencing was used to identify pathogenic fungi.

RESULTS

A total of 24 cases of dimorphic fungal infection were diagnosed, 13 of which were caused by an emmonsia species. All 13 patients were HIV-infected, with a median CD4+ T-cell count of 16 cells per cubic millimeter (interquartile range, 10 to 44), and all had evidence of disseminated fungal disease. Three patients died soon after presentation, but the others had a good response to a variety of antifungal agents and antiretroviral therapy. Phylogenetic analysis of five genes (LSU, ITS1-2, and the genes encoding actin, β-tubulin, and intein PRP8) revealed that this fungus belongs in the genus emmonsia and is most closely related to E. pasteuriana.

CONCLUSIONS

The findings suggest that these isolates of an emmonsia species represent a new species of dimorphic fungus that is pathogenic to humans. The species appears to be an important cause of infections in Cape Town.

Preliminary Identification and Typing of Pathogenic and Toxigenic Fusarium Species Using Restriction Digestion of ITS1-5.8S rDNA-ITS2 Region

BACKGROUND

Fusarium species are capable of causing a wide range of crop plants infections as well as uncommon human infections. Many species of the genus produce mycotoxins, which are responsible for acute or chronic diseases in animals and humans. Identification of Fusaria to the species level is necessary for biological, epidemiological, pathological, and toxicological purposes. In this study, we undertook a computer-based analysis of ITS1-5.8SrDNA-ITS2 in 192 GenBank sequences from 36 Fusarium species to achieve data for establishing a molecular method for specie-specific identification.

METHODS

Sequence data and 610 restriction enzymes were analyzed for choosing RFLP profiles, and subsequently designed and validated a PCR-restriction enzyme system for identification and typing of species. DNA extracted from 32 reference strains of 16 species were amplified using ITS1 and ITS4 universal primers followed by sequencing and restriction enzyme digestion of PCR products.

RESULTS

The following 3 restriction enzymes TasI, ItaI and CfoI provide the best discriminatory power. Using ITS1 and ITS4 primers a product of approximately 550bp was observed for all Fusarium strains, as expected regarding the sequence analyses. After RFLP of the PCR products, some species were definitely identified by the method and some strains had different patterns in same species.

CONCLUSION

Our profile has potential not only for identification of species, but also for genotyping of strains. On the other hand, some Fusarium species were 100% identical in their ITS-5.8SrDNA-ITS2 sequences, therefore differentiation of these species is impossible regarding this target alone. ITS-PCR-RFLP method might be useful for preliminary differentiation and typing of most common Fusarium species.

Antifungal activity of four weedy plant extracts against selected mycotoxigenic fungi

AIMS

To investigate the antifungal activity of aqueous and organic extracts of four weedy plant species viz. Tagetes minuta, Lippia javanica, Amaranthus spinosus and Vigna unguiculata against isolates of four agriculturally important fungi, i.e. Fusarium verticillioides, F. proliferatum, Aspergillus flavus and A. parasiticus.

METHODS AND RESULTS

Dried powdered aerial parts of the plants were extracted sequentially with hexane, dichloromethane, methanol and water and tested for activity using a serial microdilution assay. Results were read every day over 120 h. All extracts except for the water extracts showed growth inhibitory activity against most isolates of the Fusarium spp. The most active were the methanol and hexane extracts of V. unguiculata and A. spinosus with minimum inhibitory concentration (MIC) values of <0.5 mg ml(-1) after 48 h against Fusarium spp. No inhibition of the Aspergillus spp. tested was observed, but conidium formation was stimulated on plates treated with plant extracts when visually compared to the growth controls.

CONCLUSIONS

The results obtained from this study indicated that chemical constituents from these plant species may be developed as potential agrochemical fungicides. SIGNIFICANCE AND IMPACT OF THE RESEARCH: Food and feed are subject to infection by a variety of micro-organisms that can induce spoilage and/or produce metabolites that are toxic to humans and animals. Extracts of V. unguiculata and A. spinosus were most active and maybe developed into environmentally friendly fungicides, which are affordable to rural farmers in developing countries.

A preliminary survey of mycological and fumonisin and aflatoxin contamination of African traditional herbal medicines sold in South Africa

Traditional medicine is an important aspect of healthcare delivery in South Africa and is used by at least 70% of the country's population. The trade in medicinal plants is a multi-million rand business which is a major driver for rural economies. However, the conditions in which these plant products are transported and stored make them prone to fungal contamination which results in economic losses to the traders and pose potential health hazards to consumers. Of major concern is the possible presence of toxigenic fungi and mycotoxins. This study assessed fungal and mycotoxin contamination of African herbal products sold in Cape Town and Tshwane (formerly Pretoria) in South Africa. Of the 16 samples analyzed, 15 were contaminated with at least one of these three fungal genera: Aspergillus, Fusarium, and Penicillium. Fumonisin B(1) was present in 13 of the samples in quantities ranging from 14 to 139 microg/kg (detection limit 5 microg/kg). None of the samples was contaminated with aflatoxigenic fungi or aflatoxin (detection limit 0.5 microg/kg). This is the first study to report on mycological and mycotoxin contamination of commercial traditional African medicines in South Africa. There is a need to expand the study to other urban centers to gain enough insight into this problem and then to intervene with measures that can protect the public from potential harm.

Corneal ulcer due toNeocosmospora vasinfectain an immunocompetent patient

We report a case of Neocosmospora vasinfecta keratitis in a 55-year-old man. While the patient did not recall any specific trauma or eye injury, he might have sustained a trivial wound during the course of his duties as a farmer. Direct examination of corneal scrapings revealed fungus filaments. As topical treatment with natamycin and econazole and subsequent systemic ketoconazole therapy failed, a full thickness therapeutic keratoplasty was performed. Post-operative treatment with amphotericin B and clotrimazole combined with cyclosporine resulted in a complete cure. The residual corneal infiltration in the recipient cornea became clear in a week. The fungal isolate was initially identified as a Fusarium species, but later reidentified through the use of morphological characteristics and sequence analysis of the internal transcribed spacer region as N. vasinfecta. The latters is a Hypocrealean fungus not hitherto reported as a causative agent of keratomycosis.

Incidence of Fusarium verticillioides and levels of fumonisins in corn from main production areas in Iran

A total of 52 corn samples collected in 2000 from four main corn production provinces of Iran (Fars, Kermanshah, Khuzestan, and Mazandaran) were analyzed for contamination with Fusarium verticillioides and fumonisins (FB(1), FB(2), FB(3), and 3-epi-FB(3)). The mean incidence of F. verticillioides (percent of kernels infected) for these four areas was 26.7, 21.4, 24.9, and 59.0%, respectively. The incidence in Mazandaran was significantly (p < 0.05) above that of the other areas. All samples from Mazandaran were contaminated with fumonisins with a mean level of total fumonisins of 10674 microg/kg. In contrast, the incidence of fumonisin contamination above 10 microg/kg was 53 (8/15), 42 (5/12), and 57% (8/14) in the samples from Fars, Kermanshah, and Khuzestan, respectively, and the corresponding mean total fumonisin levels were 215, 71, and 174 microg/kg, respectively. No statistical differences (p > 0.05) were observed in the fumonisin levels of the corn samples from these three provinces, which were significantly (p < 0.05) lower than the fumonisin contamination in samples from Mazandaran.

Rhino-orbitocerebral entomophthoramycosis

Conidiobolus coronatus is recognized as a human pathogen causing subcutaneous fungal infection of the face in immunocompetent patients. The disease process is usually benign. We report, what we believe to be the first case of intracranial extension of C. coronatus producing rhino-orbitocerebral syndrome, and subsequent dissemination of C. coronatus in an immunocompetent patient.

Production of fumonisin B and C analogues by several fusarium species

Six strains of Fusarium verticillioides, two of F. oxysporum, one strain of F. proliferatum, and a strain of an unidentified species were cultured on maize patties and rice and evaluated for their ability to simultaneously produce fumonisin B (FB) and C (FC) series analogues. Fumonisins were quantified by LC-MS-MS using positive ion electrospray ionization. FC1 provided characteristic fragment ions at m/z 690, 672, 654, 532, 514, and 338 corresponding to sequential loss of H2O and tricarboxylic acid moieties from the alkyl backbone, while FC3 and FC4 provided equivalent product ions 16 and 32 amu lower than the corresponding FC1 fragments, respectively. All isolates cultured on maize produced FC4. All isolates except for that of F. proliferatum also produced FC1, and three of the six strains of F. verticillioides produced FC3. All isolates except those of F. oxysporum produced detectable amounts of FB1, FB2, and FB3. Isolates that produced fumonisin B analogues produced at least 10 fold more of the B series analogues than they did of the C series analogues. The results confirm that at least some strains of F. oxysporum produce FC, but not FB, fumonisin analogues and also suggest that the genetics and physiological regulation of fumonisin production may be more complicated than previously envisaged since some strains of F. verticillioides and F. proliferatum as well as the strain of the unidentified species can simultaneously produce both FB and FC analogues.

Fumonisin production by Fusarium species isolated from freshly harvested corn in Iran

Fifty-one strains of Fusarium verticillioides and F. proliferatum isolated from corn collected from four different geographic areas in Iran, namely Fars, Khuzestan, Kermanshah and Mazandaran (an endemic oesophageal cancer (OC) area) were evaluated for their ability to produce fumonisins B1 (FB1), B2 (FB2) and B3 (FB3) in corn culture. Fumonisin levels were determined by high-performance liquid chromatography. All tested strains of F. verticillioides and F. proliferatumproduced fumonisins within a wide range of concentrations, 197-9661 microg/g, 18-1974 microg/g, and 21-1725 microg/g for FB1, FB2, and FB3, respectively. The highest mean concentrations of FB1, FB2, and FB3 were 3897, 806 and 827 microg/g, respectively. Overall, 61% of the F. verticillioides and F. proliferatum strains produced higher levels of FB3 than FB2. The mean ratios of FB1:FB2, FB1:FB3 and FB1:total fumonisins were 8, 7 and 0.7 for F. verticillioides and 5.7, 10.7 and 0.7 for F. proliferatum, respectively. Significant differences in some of the meteorological data (rainfall, relative humidity and minimum temperature) from the four provinces were observed. Fumonisin levels produced by F. verticillioides strains isolated from Khuzestan province (tropical zone) were significantly (P < 0.01) higher than the other three provinces. This is the first report of the fumonisin-producing ability of F.verticillioides and F. proliferatum strains isolated from corn harvested from different geographic areas in Iran.

Fumonisin contamination and fusarium incidence in corn from Santa Catarina, Brazil

In Brazil, the southern region has the highest incidence of esophageal cancer and also the highest production and consumption of corn (Zea mays) products. Corn samples intended for human consumption from the western, northern, and southern regions of the state of Santa Catarina, southern Brazil, had mean total fumonisin B (B(1), B(2), and B(3)) levels of 3.2, 3.4, and 1.7 mg/kg, respectively. Fusarium verticillioides, the predominant fungus in the corn samples, had mean incidences (percent of kernels infected) of 14, 11, and 18% for the three regions, respectively. Additional corn samples intended for animal feed from the southern region had a mean total fumonisin level of 1.5 mg/kg and a mean F. verticillioides incidence of 10%. The fumonisin levels in corn from the state of Santa Catarina, Brazil, were similar to the high levels determined in other high esophageal cancer incidence regions of the world.

Phylogeny of the Ophiostoma stenoceras-Sporothrix schenckii complex

Ophiostoma stenoceras is a well-known sapwood-colonizing fungus occurring on some coniferous and hardwood hosts in the Northern Hemisphere. In the Southern Hemisphere, the fungus has been reported only from New Zealand. The human pathogen, Sporothrix schenckii, has been suggested to be the anamorph of O. stenoceras. The aim of this study was to gain a better understanding of the phylogenetic relationship between these two species. The study also provided the opportunity to confirm the identity of some Sporothrix and O. stenoceras-like isolates recently collected from wood and soil around the world. For this purpose, the DNA sequence of internal transcribed spacer (ITS) regions of the ribosomal RNA operon was determined. Isolates of O. nigrocarpum, O. albidum, O. abietinum, O. narcissi and O. ponderosae, all morphologically similar to O. stenoceras, were included in the study. From phylogenetic analyses of the sequence data, four main clades were observed. These represented O. stenoceras, O. nigrocarpum and two separate groups containing isolates of S. schenckii. Our results confirm earlier suggestions that S. schenckii should be classified within the teleomorph genus Ophiostoma but support studies separating O. stenoceras and S. schenckii. Ophiostoma albidum and O. ponderosae should be considered synonyms of O. stenoceras. The status of O. narcissi and O. abietinum needs further clarification. The two groups within S. schenckii might represent two species, but this needs to be confirmed. This study represents the first reports of O. stenoceras from Colombia, Kenya, Uruguay and South Africa.

Cancer patterns in four districts of the Transkei region--1991-1995

BACKGROUND

Oesophageal cancer (OC) is an important public health problem among the Xhosa-speaking people of the Transkei region in the Eastern Cape Province, South Africa, with incidence rates for males among the highest in the world.

OBJECTIVES

To record the occurrence of cancer among men and women of all ages in four districts in the Transkei during the period 1991-1995, to identify common cancers and to compare the variations in cancer incidences in this region with incidences in Africa and the rest of the world.

DESIGN

Cancer registration of cases reported from all clinics and hospitals was conducted in the four selected districts.

SETTING

The districts included Centane (Kentani), Butterworth, Bizana and Lusikisiki in the Transkei region.

METHODS

Active and passive methods were used to collect data, which were analysed using the Statistical Analyses Systems (SAS) package.

RESULTS

The mean annual number of all cancer cases reported was 310, with age-standardised incidence rates (ASIRs, world standard) of 98.2/100,000 and 74.3/100,000 for males and females, respectively. The most frequently reported cancer was OC, with mean annual ASIRs of 76.6/100,000 and 36.5/100,000 for males and females, respectively, with a male/female ratio of 2:1.

CONCLUSION

The present data confirm previous reports that OC rates in Centane have consistently remained very high, whereas time-dependent changes in the incidence of OC have occurred in Butterworth, Bizana and Lusikisiki suggesting changes in the risk determinants in these districts.

Fusarium dimerum as a cause of human eye infections

Fusarium dimerum, typically a soil fungus, was isolated from an adult male suffering from a corneal ulcer following an injury to the eye. This fungus has not been described to cause human infections in South Africa and has not been recorded from soil, plant or organic material in this country. The macro- and microscopic characteristics of the isolate were found to be indistinguishable from described strains. Its authenticity was confirmed by comparing it to other human isolates from the eye obtained in the USA, thus rendering this the first report of F. dimerum from an eye infection in a human in South Africa.

Prevalence, epidemiology and geographical distribution of Sporothrix schenckii infections in Gauteng, South Africa

Sporotrichosis is a subcutaneous fungal infection caused by the traumatic implantation of the dimorphic, pathogenic fungus, Sporothrix schenkii. It constitutes the most common subcutaneous fungal infection in the general population in South Africa. Sporotrichosis in South Africa dates back to 1914, when the disease was first diagnosed in the gold mines. Occupational and recreational circumstances of infection are well established, and the environmental requirements for contracting the disease are better understood. Sporotrichosis cases were recorded from 42 suburbs in the greater Pretoria area as well as from 23 towns outside the Pretoria municipal boundary. It occurred in 154 patients with ages ranging from less than 1 year to 90 years old, with males predominating. Females in the area seemed to be at lesser risk, mainly becoming infected through gardening injuries, insect bites or other minor injuries due to outdoor activities. Exposure to possible sources of the fungus, either from recreational or occupational activities in males, was the main determining factor in acquiring the disease. The lymphocutaneous and localized forms of the disease were most often recorded. Our study indicates that, while there is no pronounced seasonal variation, the onset of the disease seemed to be mainly in the cooler and dryer months of the year.

The influence of deck storage and initial processing on patulin levels in apple juice

Patulin, a secondary metabolite produced by Penicillium expansum and some other fungal species, is a common contaminant of ripened apples used for the production of apple juice concentrates. The limited availability of suitable storage facilities may result in fruit being subjected to storage in the open ('deck storage') for extended periods of time, prior to processing. A study was conducted to determine the influence that deck storage and subsequent initial processing practices had on patulin levels in freshly pressed juice. Over the study period, triplicate samples were collected at four strategic processing points from individual consignments of Granny Smith apples deck-stored for 7, 15 and 33 days, respectively. Over the study period, mean patulin levels in non-processed fruit increased from 90 to 2445 ng/g, respectively, but decreased to between 75 and 695 ng/g, respectively, following a water wash step. Subsequent removal of rotten/damaged fruit decreased patulin levels further (to between 55 and 405 ng/g, respectively), although the numerical decreases between sampling points were not shown to be statistically significant (P > 0.05). However, patulin levels were significantly higher (P < 0.05) in the rejected rotten/damaged fruit (mean levels ranged from 1120 to 6235 ng/g, respectively). P. expansum was the major patulin-producing fungus isolated from the juice samples. The mycological analyses tended to support the chemical data, in that removal of the rotten/damaged fractions significantly reduced total fungal counts in the juice samples.

Tinea corporis/cruris: new treatment options

We undertook a prospective, multicentre, double-blind, placebo controlled, randomised, parallel-group study to evaluate the efficacy and safety of the topical 1% emulsion gel formulation of Lamisil in the treatment of tinea corporis/cruris. Eighty-three patients with clinically and mycologically confirmed tinea corporis/cruris were enrolled from 6 dermatology practices. Of the 62 patients in the intent-to-treat population, 29 were randomised to 1% Lamisil emulsion gel (23 male, 6 female; mean age 42 years, range 19-79 years) and 33 to placebo (25 male, 8 female; mean age 36 years, range 16-73 years). The gels were applied once daily for 1 week. Mycological cure (negative microscopy and culture results) and effectiveness of treatment (mycological cure plus no or minimal signs and symptoms) were measured on day 7, weeks 2, 4 and 8, and at the end of the study. At the study end, rates mycological cure were 83% for Lamisil 1% emulsion gel and 27% for placebo gel (p < 0.001), with respective rates for effective treatment of 83 and 21% (p < 0.001). Complete cure was recorded for 59% of patients receiving Lamisil 1% emulsion gel and 13% of patient receiving placebo gel (p < 0.001). We conclude that a 1-week course of Lamisil 1% emulsion gel is significantly more effective in the treatment of tinea corporis/cruris than placebo gel in respect of complete cure, mycological cure and effective treatment.

Microsporum canis scalp ringworm: its primary or secondary ectothrix character

This study supports the view that, in cases of tinea capitis due to a Microsporum canis infection, ectothrix arthroconidium formation is extrapilary and arises from intrapilary hyphae. The hyphae of M. canis perforate and digest the hair cuticle to alter its appearance from a normally identifiable structure of imbricated cells with a distal free border, to a grossly altered and pathological layer. Conidium production mainly takes place outside the hair shaft and forms thick clusters between the cuticular tiles. Finally, a shaft of conidia is formed around the hair. The cuticular covering of such a conidium sheath belongs to the root sheath of the hair follicle, and not to the hair structure proper.

Mycotic keratitis caused by Curvularia brachyspora (Boedjin). A report of the first case

Curvularia brachyspora has been identified for the first time as a cause of mycotic keratitis. Mycotic infections of the eye have assumed increasing importance in ophthalmology, resulting in a need for fungal identification and early specific treatment for the successful management of cases. A case of mycotic keratitis caused by C. brachyspora is described against the background of other Curvularia species causing mycoses.

Treatment of cutaneous sporotrichosis with terbinafine

Terbinafine, an allylamine antifungal agent, has been shown to have excellent in-vitro activity against dermatophytes. Several other fungi of importance also show in-vitro sensitivity. Because terbinafine is fungicidal rather than fungistatic in action, its efficacy in treating such fungal infections requires evaluation. Five patients with cutaneous sporotrichosis were treated with 250 mg of terbinafine twice daily. All of the patients were cured. Overall, the clinical response was rapid. In three patients, negative culture was achieved within 8 weeks; in the other two, negative culture was obtained at 12 and 32 weeks, respectively. Terbinafine was well tolerated, although one patient developed erectile dysfunction while receiving treatment. This was completely resolved on stopping the treatment. The treatment of sporotrichosis is also reviewed in this article.

Botryomycosis. Some African cases

Botryomycosis is a rare and chronic but readily treatable form of mycetoma. It is caused by a persistent bacterial infection and is distinguished by the formation of grains and multiple sinuses in the skin. The most usual cause is caused by Staphylococcus aureus. The authors' experience with four Transvaal cases is reported. In one case there was destruction of the skull and penetration of the cranial cavity by the botryomycotic process. Treatment with a range of common antistaphylococcal antibiotics led to astonishingly rapid recovery. Among the drugs used, cotrimoxazole was, perhaps, the most practical.

Superficial fungal infections in the Transvaal. A contemporary analysis of dermatophytoses in this region

An 8-year survey of patients from hospital clinics and private practices in Pretoria seeking specialist dermatological advice for dermatophytoses revealed almost 500 cases, which were confirmed by mycological study. Correlation of the data with other localities was made to illustrate the epidemiology for several common dermatophytes in the Transvaal. Trichophyton rubrum (27%) proved to be the most prominent dermatophyte, followed by T. mentagrophytes (23%), Microsporum canis (19%), T. violaceum (18%) and Epidermophyton floccosum (12%), while M. gypseum occurred in only 1% of the cases. Mapped lists of the published dermatophyte species isolated in southern Africa over the past three decades are presented.

The septal ontogeny, germination and electron microscopy of Microsporum gypseum macroaleurioconidia

Microsporum gypseum strains obtained from human and animal cases of dermatophytosis were used to study the septal ontogeny, the germination, and the electron microscopy of the macroaleurioconidia, which are produced so abundantly by this organism. It was found that the number of septa in a macroaleurioconidium depends upon the stage of development, and that their order of formation remains relatively constant. The macroaleurioconidial cell wall proved to be impressive on electron microscopy. The use of a wetting agent (Tween 80) and negative pressure proved necessary for adequate fixation. Poor penetration of the fixing agent is attributable to the electron-dense encrustations over the entire surface of the macroaleurioconidium.

Studies in sporotrichosis: fungal morphogenesis and pathogenicity in differing environments

Sporothrix schenckii exhibits different morphology and pathogenic properties according to the source and circumstances of its growth. The present study considers the morphology and experimental pathogenicity in relation to - the 'wild' strains; the possible circumstances enhancing pathogenicity in strains recovered from the soil; the rate and nature of the transformational steps in morphology, in human and experimental infections by established pathogenic strains; the elimination of pathogenic strains to the surface of clinical lesions, enabling a simplified diagnostic proof of infection; the rate and nature of the reversion of pathogenic forms to the 'wild' type when the constraints of the host are lessened; the plasticity of conidium-pigmentation as a sign of pathogenicity; the morphological conversions on moist wattle-wood as occur in the Gold Mines; and a note on the therapeutic value of itraconazole. Host resistance is seen to play a larger part in morphology of the pathogenic phase, and exhaustion of natural food resources as the generator of potentially pathogenic forms.

Studies on sporotrichosis. Pathogenicity and morphogenesis in the Transvaal strains of Sporothrix schenckii

In the Transvaal, two epidemiologic patterns of Sporothrix infection occur in man. Evidence gathered from nature, the clinic and the laboratory suggests that these patterns are not the result of either a fixed strain specificity or a random mutation. The differences represent a developmental trend, determined by environmental factors, which gradually transform the wild strains of Sporothrix schenckii into variants resembling the earlier descriptions of Sporothrix beurmannii. This change, moreover, is regular and predictable.

Subcutaneous phycomycosis caused by Basidiobolus haptaosporus (Drechsler, 1947)

Subcutaneous phycomycosis in a Black child is reported, together with clinical, histological and mycological studies. This is the first case, to our knowledge, to be identified mycologically in South Africa. Oral potassium iodide gave an excellent therapeutic result.

Spore ultrastructure in Sporothrix schenckii

Pathogenic strains of Sporothrix schenkii may show triangular spores, whose angular shape is maintained by a tie-beam effect in the inner cell wall structure. This difference in wall structure lies adjacent to a folded and possibly more active part of the spore cytoplasm. The supposed generation of asci in old cultures was simulated by the death of hyphae which are reinvaded by intrahyphal growth with intrahyphal spore production, while true asci were not seen.

Black grain mycetoma: the ultrastructure of Madurella mycetomi

Madurella mycetomi, the fungus pathogen of black grain mycetoma, shows an elaborate development of mesosomes as its most striking ultrastructural feature. These occur in addition to mitochondria and endoplasmic reticulum. Condensations of hyphal cytoplasm and recurring intrahyphal growth of new hyphal cells are features of the pigment-producing and pathogenic phases of the organism. The abundant pigment which histochemically resembled melanin was not traceable to any ultrastructural granule, nor was it built from a tyrosine precursor. The ultrastructural changes occurring in collagen through a sclerotizing action by the fungus are briefly noted.

Black grain mycetoma. Atomic absorption and spark source mass spectrophotometry of the tissue grain in Madurella mycetomi infection

The tissue grain of Madurella mycetomi infection shows a spread of mineral constituents which is somewhat higher than the known values for the dermis, but differs little in relative concentrations. The unique physical resistance of the grain cannot be related to departures in concentration of calcium or of trace elements. Our earlier hypothesis of a tanned protein structure for the grain therefore still holds (Findlay & Vismer, 1974).