Diagnostic, Epidemiological and Pathological Aspects of Opportunistic Mycoses

Shankland, Gillian Sheana (1987) Diagnostic, Epidemiological and Pathological Aspects of Opportunistic Mycoses. PhD thesis, University of Glasgow.

Abstract

Laboratory tests can help to confirm or establish the diagnosis of a fungal infection. They can provide an assessment of the response to therapy and monitor the resolution of infection. Histopathological recognition of fungal elements in biopsy or post-mortem material provides the definitive diagnosis of fungal infection. To improve the performance and specificity of histopathological procedures, a peroxidase anti-peroxidase (PAP) staining method for the specific recognition of Aspergillus, Candida and Rhizopus was developed. To verify the specificity of the primary fungal antisera employed in this method, they were tested for cross-reactivity by CIE, double diffusion and ELISA. The antisera were also tested for their cross-reactivity in PAP staining using sections cut from agar blocks inoculated with fungi. This novel technique was developed to simulate fungi growing in three dimensions through tissue. The sera could be tested against a wide range of fungi for which no control material was available. The agar block method conferred the additional advantage of having no background staining to complicate the results. The PAP technique was shown to be extremely sensitive and able to detect fungi in tissue sections. It was able to distinguish fungi by genus and showed little cross-reactivity among the genera tested. However, none of the antisera were completely specific and cross-reactivity was evident among species within the same genus. The various manifestations of Candida infection present a range of diagnostic problems. One presentation of candidosis is Candida endophthalmitis. The epidemiology of this disease, in a cluster of heroin addicts from the Castlemilk area of Glasgow, was studied. Heroin samples, diluent, injection paraphernalia and clinical samples were cultured. Isolates of Candida albicans from these samples were further differentiated by a biotyping system. It was found that there was a preponderance of one biotype. The source of the Candida was unlikely to be the street drug as diamorphine hydrochloride was shown to have antifungal properties. The "Jif" lemon juice used by the addicts as a diluent proved to be the probable source of infection. The SO2 content of lemons purchased in the Castlemilk area or from new "Jif" lemons heated to drive off the preservative, was lower than the recommended standard. Juice from lemons with reduced levels of SO2 was shown to be able to support the growth of C. albicans. An experimental murine model of haematogenous C. albicans endophthalmitis was investigated to study the pathology of the disease. The model demonstrated the presence of yeast in murine retinae five minutes after infection. Over several days the yeasts were seen to multiply and produce pseudomycelium. Local areas of inflammation developed around the yeasts and these resulted in protrusions of the retinae. The presence of infection was confirmed by culture of the eyes and by tests for the detection of Candida antigenaemia.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Medicine, Epidemiology
• Date of Award: 1987
• Depositing User: Enlighten Team
• Unique ID: glathesis:1987-77505
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jan 2020 11:53
• Last Modified: 14 Jan 2020 11:53
• URI: https://theses.gla.ac.uk/id/eprint/77505