Isolation of Cryptococcus neoformans from pigeon droppings in Ahwaz, Iran

Aim: Cryptococcus neoformans is an opportunistic human pathogen that causes cryptococcosis, a life-threatening infection that is usually manifested as menigeoencephalitis mainly in immunocompromised patients. The objective of this study was to evaluate the presence of Cryptococcus neoformans in Ahwaz, Iran.Materials and methods: Sixty-five samples of pigeon droppings were collected from 10 different regions in Ahwaz. Each sample was suspended 1:10 in saline solution and then cultured in Sabouraud s dextrose agar medium including chloramphenicol. Identification of C. neoformans was performed on the basis of melanin synthesis on bird seed agar,presence of a capsule on India ink preparation, urease production on urea agar medium, and ability to grow at 37 °C. An assimilation test was also used to confirm C. neoformans. Results: Of the 65 samples, 22 (34%) were positive for C. neoformans. The highest frequency was observed in droppings from site 7 (86%). The lowest frequency was obtained on samples from sites 2, 3, and 4 (17%).Conclusion: Our study showed the presence of C. neoformans in urban environmental sources at places with a large population in Ahwaz.