La recherche des levures du genre Cryptococcus dans les fientes de pigeons

Abstract

Introduction : Cryptococcus is an opportunistic yeast that causes life-threatening infections such as meningoencephalitis mainly in immunocompromised hosts, usually associated with AIDS. Several species make up this genus, the vast majority of which are non-pathogenic. Only the neoformans and gattii species are capable of causing infection in humans. The main environmental source of this fungus is droppings, especially of pigeons. This study was proposed to investigate the species of Cryptococcus from pigeon droppings in the wilayas of Constantine and Oum El Bouaghi (exactly in the daïra of Ain M'lila which is close to Constantine). Material and methods : An environmental survey of pigeon droppings was carried out in the laboratory of parasitology and mycology at the CHU of Constantine. The collection of samples, 18 in total, was done between 27/04/2021 and 06/05/2021. These samples of pigeon droppings were subjected to mycological diagnostic steps (a culture according to the protocol of F. Mariat, a macroscopic examination of the culture, a microscopic examination with India ink from the culture and a biochemical identification) and a study of the sensitivity profile to antifungal agents. Results : Our study allowed us to isolate and identify 11 species. The genus Cryptococcus was found in 22.22%, divided into 2 C. terreus (11.11%), 1 C. albidus (5.55%) and 1 C. laurenti (5.55%). It should be noted that no species of Cryptococcus neoformans or Cryptococcus gattii was identified in our samples. Conclusion : The presence of pigeons in the vicinity of certain places such as hospitals and health care facilities should be considered as a risk factor for this vulnerable population. This study should be continued and complemented by other environmental surveys, with the objective of applying effective preventive measures to decrease the progression of the disease in the homes at risk. Cryptococcus is an opportunistic yeast that causes life-threatening infections such as meningoencephalitis mainly in immunocompromised hosts, usually associated with AIDS. Several species make up this genus, the vast majority of which are non-pathogenic. Only the neoformans and gattii species are capable of causing infection in humans. The main environmental source of this fungus is droppings, especially of pigeons. This study was proposed to investigate the species of Cryptococcus from pigeon droppings in the wilayas of Constantine and Oum El Bouaghi (exactly in the daïra of Ain M'lila which is close to Constantine). Material and methods : An environmental survey of pigeon droppings was carried out in the laboratory of parasitology and mycology at the CHU of Constantine. The collection of samples, 18 in total, was done between 27/04/2021 and 06/05/2021. These samples of pigeon droppings were subjected to mycological diagnostic steps (a culture according to the protocol of F. Mariat, a macroscopic examination of the culture, a microscopic examination with India ink from the culture and a biochemical identification) and a study of the sensitivity profile to antifungal agents. Results : Our study allowed us to isolate and identify 11 species. The genus Cryptococcus was found in 22.22%, divided into 2 C. terreus (11.11%), 1 C. albidus (5.55%) and 1 C. laurenti (5.55%). It should be noted that no species of Cryptococcus neoformans or Cryptococcus gattii was identified in our samples. Conclusion : The presence of pigeons in the vicinity of certain places such as hospitals and health care facilities should be considered as a risk factor for this vulnerable population. This study should be continued and complemented by other environmental surveys, with the objective of applying effective preventive measures to decrease the progression of the disease in the homes at risk.