L. Ebiogbe

Cryptococcus neoformans is a capsular fungal pathogen that causes life-threatening opportunistic infections, particularly in immunocompromised individuals. This research involved isolating, screening, and growing C. neoformans from samples collected from pigeon droppings in Uselu, Egor, and New Benin markets, Benin City, Edo State. One gram of pigeon droppings was added to Yeast Peptone Dextrose Broth (YPD) for preliminary culturing and incubated at 25°C for 24 hours. The mixture was then plated onto Yeast Peptone Dextrose Agar (YPDA) plates, incubated for five days, and sub-cultured to obtain contamination-free single colonies. Identification of the organism involved a urease test followed by a Niger seed agar test. The Niger seed agar test detected melanin-producing strains through pigmentation, while the urease test confirmed its presence through a yellow-to-pink color change. Out of 75 samples, 63 tested positive for C. neoformans, signifying its environmental prevalence, 21 from this 63 tested positive for melanin production. Growth pattern analysis showed optimum growth at 37°C, aligning with its pathogenicity in humans, and normal growth at 25°C. Under starvation conditions, colony formation was visibly inhibited, indicating its dependence on environmental nutrients for establishment. Susceptibility tests with fluconazole showed inhibited growth, confirming its efficacy as an antifungal agent. This study provides information on the environmental distribution, melanin production, and adaptability of C. neoformans in variable growth environments. The results suggest the organism's ecological ubiquity, the role of melanin as a virulence factor, and its ability to thrive in environments with high nutrient availability and favorable temperatures. These findings are significant in understanding fungal survival and the management of cryptococcal infections.

immunocompromised patients. Cryptococcus neoformans var. neoformans is found mainly in temperate climates and is often isolated from pigeon droppings. It is the causative agent of Cryptococcosis and is believed to arise after inhalation of yeast cells or basidiospores from environmental sources. For the purpose of this research, two strains of Cryptococcus neoformans; one clinical FBC and one environmental NBM5 were selected and confirmed using urease medium, based on their melanin production on Niger seed agar and ability to grow at 37oC. An antifungal susceptibility test was carried out on the clinical and the environmental isolates using Fluconazole as the antibiotic agent. Fluconazole is an antifungal therapeutic agent used in the treatment of Cryptococcosis. Responses of both isolates to Fluconazole showed similar results. Both isolates were also subjected to environmental stressors using sodium nitrate (NaNO2) to induce nitrosative stress and hydrogen peroxide (H2O2) to induce oxidative stress. The response of both isolates to this environmental stressors were similar. The selected isolates; clinical isolates FBC and environmental isolates NBM5 were determined to be of the same mating types based on their responses to antifungal susceptibility test and environmental tressors. DNA was isolated from both strains for detailed genetic analysis in the near future. This study provides new insights into how the mating type can greatly influence responses of Cryptococcus neoformans to genetic and environmental factors. Thus, serve as a possible instrument for further study of the genetics of C. neoformans.