Biomedical subjects
Publications and source records attributed to H F Vismer.
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.
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.
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.
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.
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.
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.
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.
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 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.
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.
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.
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.
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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 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.
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.
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.
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).