[First description of phenotypic profile and in vitro drug susceptibility of Cryptococcus spp yeast isolated from HIV-positive and HIV-negative patients in State of Mato Grosso]

Domestic Birds as Source of Cryptococcus deuterogattii (AFLP6/VGII): Potential Risk for Cryptococcosis

Cryptococcosis is an infection caused by encapsulated basidiomycetous yeasts belonging to the Cryptococcus neoformans/Cryptococcus gattii species complexes. It is acquired through inhalation of infectious propagules, often resulting in meningitis and meningoencephalitis. The ecological niche of these agents is a wide variety of trees species, as well as pigeon, parrot and passerine excreta. The objective of this study was to isolate Cryptococcus yeasts from excreta of commercially traded parrots and passerines. The 237 samples were collected between October 2018 and April 2019 and processed using conventional methodologies. Nineteen colonies with a dark brown phenotype, caused by phenol oxidase activity, were isolated, suggesting the presence of pathogenic Cryptococcus yeasts. All isolates tested positive for urease activity. URA5-RFLP fingerprinting identified 14 isolates (68.4%) as C. neoformans (genotype AFLP1/VNI) and 5 (26.3%) as C. deuterogattii (genotype AFLP6/VGII). Multi-locus sequence typing was applied to investigate the relatedness of the C. deuterogattii isolates with those collected globally, showing that those originating from bird-excreta were genetically indistinguishable from some clinical isolates collected during the past two decades.

Comparative antifungal susceptibility analyses of Cryptococcus neoformans VNI and Cryptococcus gattii VGII from the Brazilian Amazon Region by the Etest, Vitek 2, and the Clinical and Laboratory Standards Institute broth microdilution methods

Early diagnosis, efficient clinical support, and proper antifungal therapy are essential to reduce death and sequels caused by cryptococcosis. The emergence of resistance to the antifungal drugs commonly used for cryptococcosis treatment is an important issue of concern. Thus, the in vitro antifungal susceptibility of clinical strains from northern Brazil, including C. neoformans VNI (n = 62) and C. gattii VGII (n = 37), to amphotericin B (AMB), 5-flucytosine, fluconazole, voriconazole, and itraconazole was evaluated using the Etest and Vitek 2 systems and the standardized broth microdilution (CLSI-BMD) methodology. According to the CLSI-BMD, the most active in vitro azole was voriconazole (C. neoformans VNI modal MIC of 0.06 μg/ml and C. gattii VGII modal MIC of 0.25 μg/ml), and fluconazole was the least active (modal MIC of 4 μg/ml for both fungi). Modal MICs for amphotericin B were 1 μg/ml for both fungi. In general, good essential agreement (EA) values were observed between the methods. However, AMB presented the lowest EA between CLSI-BMD and Etest for C. neoformans VNI and C. gattii VGII (1.6% and 2.56%, respectively, P < .05 for both). Considering the proposed Cryptococcus spp. epidemiological cutoff values, more than 97% of the studied isolates were categorized as wild-type for the azoles. However, the high frequency of C. neoformans VNI isolates in the population described here that displayed non-wild-type susceptibility to AMB is noteworthy. Epidemiological surveillance of the antifungal resistance of cryptococcal strains is relevant due to the potential burden and the high lethality of cryptococcal meningitis in the Amazon region.

Molecular typing of environmental Cryptococcus neoformans/C. gattii species complex isolates from Manaus, Amazonas, Brazil

Cryptococcus neoformans and Cryptococcus gattii are the main causative agents of cryptococcosis, a systemic fungal disease that affects internal organs and skin, and which is acquired by inhalation of spores or encapsulated yeasts. It is currently known that the C. neoformans/C. gattii species complex has a worldwide distribution, however, some molecular types seem to prevail in certain regions. Few environmental studies of Cryptococcus have been conducted in the Brazilian Amazon. This is the first ecological study of the pathogenic fungi C. neoformans/C. gattii species complex in the urban area of Manaus, Amazonas, Brazil. A total of 506 samples from pigeon droppings (n = 191), captive bird droppings (n = 60) and tree hollows (n = 255) were collected from June 2012 to January 2014 at schools and public buildings, squares, pet shops, households, the zoo and the bus station. Samples were plated on niger seed agar (NSA) medium supplemented with chloramphenicol and incubated at 25°C for 5 days. Dark-brown colonies were isolated and tested for thermotolerance at 37°C, cycloheximide resistance and growth on canavanine-glycine-bromothymol blue agar. Molecular typing was done by PCR-RFLP. Susceptibility to the antifungal drugs amphotericin B, fluconazole, itraconazole and ketoconazole was tested using Etest(®) strips. In total, 13 positive samples were obtained: one tree hollow (C. gattiiVGII), nine pigeon droppings (C. neoformansVNI) and three captive bird droppings (C. neoformansVNI). The environmental cryptococcal isolates found in this study were of the same molecular types as those responsible for infections in Manaus.

In vitro susceptibility testing of amphotericin B for Cryptococcus neoformans variety grubii AFLP1/VNI and Cryptococcus gattii AFLP6/VGII by CLSI and flow cytometry

Cryptococcus neoformans var. grubii AFLP1/VNI is the main causative agent of cryptococcosis associated with AIDS in the world. Cryptococcus gattii AFLP6/VGII causes mainly endemic primary infection in immunocompetent hosts. To determine the minimum inhibitory concentrations (MICs) of C. neoformans var. grubii AFLP1/VNI and C. gattii AFLP6/VGII against amphotericin B (AMB) in a short period of time, flow cytometry (FCM) with FUN-1 fluorochrome was used to compare with broth microdilution method (CLSI M27-A3). The minimum incubation period was evaluated by minimum fungicidal concentration procedure. Seventeen clinical isolates of C. neoformans var. grubii AFLP1/VNI and 18 of C. gattii AFLP6/VGII were analysed. The time for the determination of MICs by FCM was 2 h against 72 h by CLSI M27-A3 and the comparison of MIC showed a positive significant correlation (P = 0.048). It is important to highlight the role of the FCM as an alternative method to determine the MICs for AMB in within a day, with positive cost-benefit.

Determination of the minimum inhibitory concentration of Cryptococcus neoformans and Cryptococcus gattii against fluconazole by flow cytometry

Recent studies have used flow cytometry (FCM) as an important alternative method to determine the antifungal susceptibility of yeasts compared to the broth microdilution Clinical and Laboratory Standards Institute (CLSI) reference procedure. We present a comparative study of the broth microdilution method and flow cytometry to assess the in vitro antifungal susceptibility of Cryptococcus neoformans (n = 16) and C. gattii (n = 24) to fluconazole. The minimum inhibitory concentration (MIC) assays by flow cytometry were defined as the lowest drug concentration that showed ∼50% of the count of acridine orange negative cells compared to that of the growth control. Categorical classification showed all C. neoformans isolates were susceptible to fluconazole. Three isolates of C. gattii were susceptible dose-dependent and the remaining 21 isolates were classified as susceptible. MICs comparison of both methodologies demonstrated 100% categorical agreement of the results obtained for C. neoformans and C. gattii. The MICs obtained with the CLSI-approved method and flow cytometry were compared by the Spearman correlation test and a significant Pv = 0.001. The flow cytometric method has the advantage of analyzing a large and constant number of cells in less time, i.e., 9 h incubation for fluconazole using acridine orange versus 72 h for broth microdilution method. In conclusion, the two methods were comparable and flow cytometry method can expedite and improve the results of in vitro susceptibility tests of C. neoformans and C. gattii against fluconazole and also allows comparative studies in vitro/in vivo more rapidly, which along with clinical data, could assist in selecting the most appropriate treatment choice.

Retrospective study of the epidemiology and clinical manifestations of Cryptococcus gattii infections in Colombia from 1997-2011

BACKGROUND

Cryptococcosis due to Cryptococcus gattii is endemic in various parts of the world, affecting mostly immunocompetent patients. A national surveillance study of cryptococcosis, including demographical, clinical and microbiological data, has been ongoing since 1997 in Colombia, to provide insights into the epidemiology of this mycosis.

METHODOLOGY/PRINCIPAL FINDINGS

From 1,209 surveys analyzed between 1997-2011, 45 cases caused by C. gattii were reported (prevalence 3.7%; annual incidence 0.07 cases/million inhabitants/year). Norte de Santander had the highest incidence (0.81 cases/million/year), representing 33.3% of all cases. The male: female ratio was 3.3∶1. Mean age at diagnosis was 41±16 years. No specific risk factors were identified in 91.1% of patients. HIV infection was reported in 6.7% of patients, autoimmune disease and steroids use in 2.2%. Clinical features included headache (80.5%), nausea/vomiting (56.1%) and neurological derangements (48.8%). Chest radiographs were taken in 21 (46.7%) cases, with abnormal findings in 7 (33.3%). Cranial CT scans were obtained in 15 (33.3%) cases, with abnormalities detected in 10 (66.7%). Treatment was well documented in 30 cases, with most receiving amphotericin B. Direct sample examination was positive in 97.7% cases. Antigen detection was positive for all CSF specimens and for 75% of serum samples. C. gattii was recovered from CSF (93.3%) and respiratory specimens (6.6%). Serotype was determined in 42 isolates; 36 isolates were serotype B (85.7%), while 6 were C (14.3%). The breakdowns of molecular types were VGII (55.6%), VGIII (31.1%) and VGI (13.3%). Among 44 strains, 16 MLST sequence types (ST) were identified, 11 of them newly reported.

CONCLUSIONS/SIGNIFICANCE

The results of this passive surveillance study demonstrate that cryptococcosis caused by C. gattii has a low prevalence in Colombia, with the exception of Norte de Santander. The predominance of molecular type VGII is of concern considering its association with high virulence and the potential to evolve into outbreaks.

First report on Cryptococcus neoformans in pigeon excreta from public and residential locations in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil

Cryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformans was evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5), churches (n = 4), educational institutions (n = 3), health units (n = 8), open areas covered with asbestos (n = 4), residences (n = 23), factory (n = 1) and a prison (n = 1). Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA). Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6%) samples corresponding to six (12.2%) locations. Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

Microbiological characteristics of clinical isolates of Cryptococcus spp. in Bahia, Brazil: molecular types and antifungal susceptibilities

To determine the profiles of susceptibility to antifungal and the genotypes of clinical isolates of Cryptococcus in Bahia, Brazil, 62 isolates were collected from cases of meningitis in the period from 2006 to 2010. Their susceptibilities to fluconazole, itraconazole, amphotericin B and 5-flucytosine were determined by the broth microdilution technique described by the Clinical and Laboratory Standards Institute and genotyping of the URA5 gene was accomplished by restriction fragment length polymorphism. C. neoformans accounted for 79% of the identified yeast and C. gattii represented the remaining 21%. Evaluation of the genotypes determined that 100% of the C. gattii isolates belong to the VGII genotype, and 98% of the C. neoformans isolates belong to the VNI genotype. Determination of susceptibility revealed isolates resistant to fluconazole (4.8%), 5-flucytosine (1.6%) and amphotericin B (3.2%); the stratification of sensitivity results for each species showed significant differences in susceptibility to azoles. This study is the first to describe the susceptibility profiles of molecular and clinical isolates of Cryptococcus in Bahia, Brazil. The high percentage of C. gattii isolates belonging to the VGII genotype and its lower susceptibility to antifungal agents highlight the importance of knowing which species are involved in cryptococcal infections in northeastern Brazil.

Cryptococcus spp isolated from dust microhabitat in Brazilian libraries

BACKGROUND

The Cryptococcus spp is currently composed of encapsulated yeasts of cosmopolitan distribution, including the etiological agents of cryptococcosis. The fungus are found mainly in substrates of animal and plant origin. Human infection occurs through inhalation of spores present in the environment.

METHODS

Eighty-four swab collections were performed on dust found on books in three libraries in the city of Cuiabá, state of Mato Grosso, Brazil. The material was seeded in Sabouraud agar and then observed for characteristics compatible with colonies with a creamy to mucous aspect; the material was then isolated in birdseed (Niger) agar and cultivated at a temperature of 37°C for 5 to 7 days. Identification of isolated colonies was performed by microscopic observation in fresh preparations dyed with India ink, additional tests performed on CGB (L-canavanine glycine bromothymol blue), urea broth, and carbohydrate assimilation tests (auxanogram).

RESULTS

Of the 84 samples collected from book dust, 18 (21.4%) were positive for Cryptococcus spp totalizing 41 UFC's. The most frequently isolated species was C. gattii 15 (36.6%); followed by C. terreus, 12 (29.3%); C. luteolus 4 (9.8%); C. neoformans, and C. uniguttulatus 3 (7.3%), and C. albidus and C. humiculus with 2 (4.6%) of the isolates.

CONCLUSION

The high biodiversity of the yeasts of the Cryptococcus genus, isolated from different environmental sources in urban areas of Brazil suggests the possibility of individuals whose immune systems have been compromised or even healthy individuals coming into sources of fungal propagules on a daily bases throughout their lives. This study demonstrates the acquisition possible of cryptococcosis infection from dust in libraries.