Contribuição para a história natural da criptococose: analisando espécimes vegetais e ar atmosférico de parques da cidade de São Paulo

Abstract

The main role of plant specimens in the life cycle of fungi is to provide organic matter to their proliferation. So,  many species that cause human infection have been described in this habitat. It is important to know the natural  niches of agents with pathogenic potential, allowing measures aiming prevention and prophylaxis to reduce the  risk of human exposure. Among the opportunistic species, members of the genus Cryptococcus spp. are relevant,  since they can cause cryptococcosis, one of the most lethal systemic mycoses nowadays. The objective of this study  was to investigate the presence of Cryptococcus members in environmental niches of parks located in São Paulo  city, in particular, hollow trunks of plant specimens and adjacent atmospheric air. In addition, we evaluated a new  culture medium for the isolation of such agents. The study was performed with 45 trees, comprising 25 different  plant species, located in five regions 5 parks located in the city. The collection of organic material removed from  each hollow, and air adjacent to the specimen plant, was performed every three months during the period of one  year. Two culture media were used for isolation of colonies of Cryptococcus spp.: the classic Guizzotia abssynica  (niger agar) medium and a new medium, called modified Dicloran Rose Bengal (DRBCm) which showed better  performance for detection of these agents. One hundred and twenty-three isolates of Cryptococcus spp. were  obtained from tree hollows (111; 90.2%) and air (12; 9.8%) samples. Twenty (44.5%, 20/45) trees belonging to 19  species were positive for Cryptococcus spp. The following Cryptococcus species were found in hollow samples:  C. neoformans (61.2%, 68/111), C. laurentii (30.6%, 34/111), C. albidus (2.7%, 3/111), and C. terrestris (1.8%,  2/111). Sixty-eight isolates of C. neoformans were obtained from samples of Hymenaea courbaril. Molecular  identification by PCR / RFLP indicated the molecular type was VNI. One of the positive samples for C. neoformans  isolates showed concomitant presence of an C. albidus isolate. In 3.6% (4/111) of isolates of hollow species  identification of Cryptococcus couldn’t determine by the methods employed in the study. The results of the study  indicated the occurrence of atmospheric: C. laurentii (66.8% 8/12), C. albidus (8.3%, 1/12), C. humicola (8.3%,  1/12), and C. flavescens (8.3%, 1/12). In 1 (8.3%, 1/12) isolated the species can not be identified by the methods  employed. Comparing the Cryptococcus species, found in the hollow and the adjacent air, it was found that in five  (50%, 5/10) occasions they were equivalent. The species C. laurentii was observed in all these 5 ocasions, which  were envolved the following tree species: G. japonica, M. nictitans, E. speciosa, T. granulosa and L. japonicum. It  was reported, for the first time, the occurrence of Cryptococcus species in the following plant specimens: Vochysia  tucanorum; Cedrela fissilis; Astronium flaxinifolium; Rapanea umbellata; Gryobotria japonica; Machoenium  nictitans; Spathodea campanulata; Plumeria rubr; Casuarina cunninghamiana and Astronium flaxinifolium,  highlighting the range of environmental niches of such agents. It is concluded that contamination by Cryptococcus  spp. is extensive in plant specimens located in parks in São Paulo city. The possibility of aerial dispersion of these  agents were suggested. The finding of C. neoformans VNI molecular type of organic matter from Hymenaea  courbaril (Jatoba) is pioneer, indicating one more potential source of infection for the most frequent agent of  cryptococcosis. The finding of C. albidus along C. neoformans suggests the possibility of an epidemiological  marker for the main agent of cryptococcosis. The results of this study allow us to recommend a new culture  medium (DRBCm) for isolation of Cryptococcus spp. from plants. Data from this study, along with those from  future research may complement the monitoring of the occurrence of agents of cryptococcosis in recreational areas  of the urban population of São Paulo, and constitute subsidies for health monitoring measures to reduce the risk of  public exposure to these agents opportunistic.