E.S. Mahgoub

The host tissue reaction to Madurella mycetomatis: new classification

In this prospective study, three types of tissue reaction to mycetoma grains are described. Type I reaction is characterized by the adherence of neutrophils to the surface of the grain leading to its disintegration. In Type II reaction, the fragmented grain and the dead neutrophils are cleared by macrophages and multinucleated giant cells, while in Type III reaction there is a discrete well developed epithelioid granuloma with Langhanss giant cells. The three types of reaction are usually seen in different combinations in the same lesion.

New Species of Madurella, Causative Agents of Black-Grain Mycetoma

ABSTRACT A new species of nonsporulating fungus, isolated in a case of black-grain mycetoma in Sudan, is described as Madurella fahalii. The species is characterized by phenotypic and molecular criteria. Multigene phylogenies based on the ribosomal DNA (rDNA) internal transcribed spacer (ITS), the partial β-tubulin gene (BT2), and the RNA polymerase II subunit 2 gene (RPB2) indicate that M. fahalii is closely related to Madurella mycetomatis and M. pseudomycetomatis; the latter name is validated according to the rules of botanical nomenclature. Madurella ikedae was found to be synonymous with M. mycetomatis. An isolate from Indonesia was found to be different from all known species based on multilocus analysis and is described as Madurella tropicana. Madurella is nested within the order Sordariales, with Chaetomium as its nearest neighbor. Madurella fahalii has a relatively low optimum growth temperature (30°C) and is less susceptible to the azoles than other Madurella species, with voriconazole and posaconazole MICs of 1 μg/ml, a ketoconazole MIC of 2 μg/ml, and an itraconazole MIC of >16 μg/ml. Since eumycetoma is still treated only with azoles, correct species identification is important for the optimal choice of antifungal therapy.

Counterimmunoelectrophoresis in the diagnosis of mycetoma and its sensitivity as compared to immunodiffusion

Counterimmunoelectrophoresis used for the diagnosis of mycetoma was found superior to immunodiffusion (ID) especially when using neat serum and 1:2 dilution (P=less than 0.0001 with neat serum; and less than 0.01 with 1:2 dilution). It is recommended for routine use in mycology laboratories for following up patients on treatment and for confirming the diagnosis of sera that are weakly positive by ID.

Post-operative responses of paranasal Aspergillus granuloma to itraconazole

Paranasal Aspergillus granuloma is an invasive infection, seen mainly in tropical countries, involving the paranasal sinuses, orbit and brain. Previously surgical excision has been followed by a high relapse rate, 80% in some series, and mortality. This study involved the use of post-operative therapy with oral itraconazole in doses of 200-300 mg daily. Twenty-two patients were treated for a mean period of 19.7 weeks. Of 19 patients for whom follow-up data were available, 12 (62%) were rated as being in complete remission in a mean period of 17.2 months after the end of therapy. Only one patient developed progressive disease during itraconazole therapy. No serious adverse effect was seen. Use of itraconazole shows promise as a means of preventing relapse after surgery in this progressive infection.

Ultrastructural and immunogenic changes in the formation of mycetoma grains.

The differences in the fine structure and antigenic determinants of mycetoma fungi in the mycelial phase in vitro and in grains in vivo facilitate an interpretation of grain formation. Aggregates of hyphal elements with multiple and thickened walls was a feature of the fungi in vivo. Associated with hyphal wall material, numerous polysaccharide microfibrils were detected in grains of Madurella mycetomatis. These were not seen associated with hyphal elements in vitro and it is suggested that these structures may be concerned with the aggregation of fungal elements in the formation of grains. Antibodies directed against the fungi in vitro were shown, by indirect immunogold labelling, to bind at identical sites in fungal material grown in vitro as in mycetoma grains. However the grain matrix was not labelled, suggesting that part of the structure formed in vivo is composed of modified antigen or is host derived.

Pulmonary aspergillosis caused by Aspergillus flavus

Bronchopulmonary aspergillosis is usually caused by Aspergillus fumigatus. The six cases from the Sudan reported here were due to Aspergillus flavus. Three of the patients had primary invasive disease, one had Aspergillus mycetoma in a pre-existing lung cavity, and two had allergic aspergillosis. A special feature of the invasive disease was the clinical and radiographic simulation of malignancy, particularly in one patient who had multiple disseminated nodules of fungal granulomata in the skin of the lower abdomen.

Internal fistula formation: an unusual complication of mycetoma

This paper reports 2 hitherto undescribed complications of mycetoma, urinary extravasation and expectoration of mycetoma grains due to cutaneo-urethral and cutaneo-pleuro-bronchial fistulae, respectively. The first patient had an infection with Actinomadura madurae which started in the foot and had spread progressively to involve the whole limb, anterior abdominal wall, perineum and urethra. The second patient had Madurella mycetomatis infection of the hand and, in spite of extensive treatment, the infection had spread to the axilla, chest wall, lung and bronchial tree. Both patients died of the sequelae of these complications. The pathogenesis of these unusual complications is discussed.

In vitro studies of antibiotic sensitivities of Streptomyces somaliensis ― a cause of human actinomycetoma

Ten Streptomyces somaliensis strains isolated from mycetoma patients were tested in vitro against 13 antibacterial agents. Rifampicin was the most effective antibiotic in terms of low minimum inhibitory concentration (MIC) followed by erythromycin, tobramycin, fusidic acid and streptomycin sulphate. The S. somaliensis strains were all resistant to trimethoprim, even though the combination of sulphamethoxazole and trimethoprim is commonly used as treatment.

Abdominal wall Mycetoma: an Unusual Presentation

Abstract Three cases of abdominal wall mycetoma in Sudan, caused by Streptomyces somaliensis, presenting as renal and retroperitoneal masses and a desmoid tumour, respectively, are reported.

Gastroenteritis due to Campylobacter jejuni in Riyadh, Saudi Arabia

During one year, 1452 specimens of faeces from patients with diarrhoea were investigated for Campylobacter jejuni. This organism was isolated from nine specimens only (0.6%). None was isolated from 160 control subjects who did not have diarrhoea. Though the number of isolates is small, diarrhoea due to C. jejuni was found to be more common in males; the ratio of males to females was 7:2. Out of the nine patients, only four were Saudis. This indicates that Campylobacter gastroenteritis exists in this part of the world. Its incidence was, however, much lower than gastroenteritis due to other bacterial pathogens which constituted 7%. The source of infection was possibly chickens, both live and dressed. Most of the latter are imported.