Natural occurrence and growth reaction on canavanine–glycine–bromothymol blue agar of non‐neoformans Cryptococcus spp. in Malaysia

Abstract

Cryptococcus albidus and C. laurentii were the predominant non-neoformans cryptococci isolated during an environmental sampling study for C. gattii at Klang Valley, Malaysia. Cryptococcus gattii was not isolated from any of the environmental samples. Cryptococcus albidus and C. laurentii were isolated mainly from vegetative samples of Eucalyptus trees and bird droppings. Upon testing on canavanine-glycine-bromothymol blue (CGB) agar, all the C. albidus isolates remained unchanged. Interestingly, a total of 29 (76.3%) C. laurentii isolates formed blue colours on the CGB agar. Sequence analysis of ITS1-5.8rDNA-ITS2 gene sequences (468 bp) of four CGB-blue C. laurentii isolates demonstrated the closest match (99%) with that of C. laurentii CBS 7140. This study demonstrated the diverse environmental niche of C. albidus and C. laurentii in Malaysia.

Molecular characterization and evaluation of virulence factors of Cryptococcus laurentii and Cryptococcus neoformans strains isolated from external hospital areas

“…The positive findings of C. laurentii in bird droppings in the present study is concordant with the results from other authors such as Pedroso et al (2009), Bernardo et al (2001 and Tay et al (2008), who reported positive findings of 12.9 %, 40.0 % and 4.6 %, respectively. C. laurentii was isolated concomitantly with C. neoformans in 10.9 % of the samples, which exceeds the results described recently (2.3 %) in another region of Brazil (Pedroso et al 2009).…”

“…Data from other studies have demonstrated positive findings of C. laurentii in tree detritus at rates ranging from 12.7 % to 77.0 % (Montenegro & Paula 2000;Bernardo et al 2001;Tay et al 2008). The results from the present study resemble those obtained by Montenegro & Paula (2000), who reported a positive rate of 58.3 %, for samples from detritus of trees of the genus Eucalyptus, in public parks in the city of Sã o Paulo.…”

Genotyping of Cryptococcus neoformans isolated from captive birds in Uberaba, Minas Gerais, Brazil

“…In the present study, 5.26% of C. laurentii isolates is in line with data from Malaysia, with 5.5% (38/694), and from Brazil, with 3.79% (11/290) and 8.9% (7/79), although these isolates had been obtained from pigeon droppings alone 34,40,41 . Both, C. neoformans and C. laurentii were simultaneously isolated in 2.26% of the cases in this study, which is in accordance with the 3.79% already reported from another area in Brazil 42 …”

“…Recently, one report from Malaysia described 29 (76.3%) C. laurentii isolates with a positive CGB test 41 . Because of this, the seven C. laurentii isolates here described were tested in this medium and six (85.7%) showed positive results.…”

Phylogenetic Analysis of Phenotypically Characterized Cryptococcus laurentii Isolates Reveals High Frequency of Cryptic Species

“…Unlike C. neoformans and C. gattii , few studies have applied DNA sequencing to describe the molecular phylogeny of C. laurentii [11], [16], [17]. Thus, considering the potential pathogenicity of this species, this study aimed to evaluate the molecular phylogeny of clinical and environmental C. laurentii isolates through the sequencing of multiple ribosomal DNA regions.…”