Cryptococcus neoformans isolation from swallow (Hirundo rustica) excreta in Iran

Area of Science:

• Medical Mycology
• Environmental Microbiology
• Infectious Diseases

Background:

• Cryptococcus neoformans causes life-threatening cryptococcosis, primarily in immunocompromised patients.
• The fungus is commonly associated with avian droppings in soil, representing a significant environmental reservoir.
• Understanding environmental sources is crucial for controlling fungal infections.

Purpose of the Study:

• To investigate the presence and isolation of Cryptococcus neoformans in swallow (Hirundo rustica) excreta.
• To assess swallow droppings as a potential environmental source for C. neoformans dissemination.
• To identify other potentially pathogenic yeasts in swallow excreta.

Main Methods:

• Collection of 97 swallow dropping samples from two cities in northern Iran.
• Isolation and identification of yeast-like colonies using standard microbiological techniques.
• Quantification of Cryptococcus neoformans using colony-forming units (CFU) per gram.

Main Results:

• Cryptococcus neoformans was isolated from 5.2% (5/97) of the collected swallow dropping samples.
• The prevalence of Rhodotorula spp. was 62.8%, Candida spp. was 28.5%, and C. neoformans was 8.7% among isolated yeast-like colonies.
• Positive samples yielded 3-10 C. neoformans colonies per gram, with a mean of 4.8 CFU/gram.

Conclusions:

• Swallow excreta can serve as a habitat for potentially pathogenic yeasts, including Cryptococcus neoformans.
• Swallows may contribute to the environmental dissemination of C. neoformans.
• Further research is warranted to understand the epidemiological significance of avian excreta in fungal transmission.