Antifungal susceptibility of clinical Cryptococcus gattii isolates from Colombia varies among molecular types.
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ABSTRACT: Lay summary
Cryptococcosis gattii affects immunocompetent people. For a correct treatment, antifungal susceptibility testing is essential. This study shows differences in the susceptibility to commonly used antimycotics among genotypes of Colombian clinical C. gattii isolates, some of which are non-wild-type.
SUBMITTER: Firacative C
PROVIDER: S-EPMC8757315 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Introduction. Limited data regarding the epidemiology and susceptibility profiles of cryptococcosis are available in the Middle East.Aim. Our study aimed to evaluate the molecular diversity, mating types and antifungal susceptibility pattern of Cryptococcus species (n=14) isolated from 320 suspected patients with cryptococcosis.Methodology. The URA5 gene was subjected to restriction fragment length polymorphism and sequence analysis. In addition, in vitro antifungal susceptibility testing was performed by Clinical and Laboratory Standards Institute (CLSI) M27-A4 and M59 guidelines.Results. Overall, 14 (4.4 %) patients were confirmed as cryptococcosis. Based on molecular type, 85.7 and 14.3 % of the isolates were C. neoformans VN I and VN II, respectively. Phylogenetic analysis of URA5 gene sequences revealed clustering of VN I and VN II isolates into two distinct clades with a substantial difference within each molecular type. Voriconazole and 5-fluorocytosine, respectively, had the lowest (0.031 μg ml-1) and highest (8 µg ml-1) MICs. The epidemiological cutoff values (ECVs) for amphotericin B, fluconazole, voriconazole and 5-fluorocytosine encompassed ≥97 % of all 14 C. neoformans VN I species. However, according to the CLSI document M59, ECVs for itraconazole (7; 50 % of the isolates) and for posaconazole (1; 7.1 % of the isolate), were one log2 dilution higher than the wild type range. Combinations of amphotericin B with 5-fluorocytosine, amphotericin B with fluconazole and fluconazole with 5-fluorocytosine exhibited synergistic effects against 37, 31 and 12.5 % of the isolates, respectively.Conclusion. Our findings may significantly contribute to the development of management strategies for patients at a higher risk of cryptococcosis, particularly HIV-positive individuals.
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Project description:As is the case globally, Cryptococcus gattii is a less frequent cause of cryptococcosis than Cryptococcus neoformans in South Africa. We performed multilocus sequence typing (MLST) and fluconazole susceptibility testing of 146 isolates randomly selected from 750 South African patients with C. gattii disease identified through enhanced laboratory surveillance, 2005 to 2013. The dominant molecular type was VGIV (101/146, 70%), followed by VGI (40/146, 27%), VGII (3/146, 2%) and VGIII (2/146, 1%). Among the 146 C. gattii isolates, 99 different sequence types (STs) were identified, with ST294 (14/146, 10%) and ST155 (10/146, 7%) being most commonly observed. The fluconazole MIC50 and MIC90 values of 105 (of 146) randomly selected C. gattii isolates were 4 μg/ml and 16 μg/ml, respectively. VGIV isolates had a lower MIC50 value compared to non-VGIV isolates, but these values were within one double-dilution of each other. HIV-seropositive patients had a ten-fold increased adjusted odds of a VGIV infection compared to HIV-seronegative patients, though with small numbers (99/136; 73% vs. 2/10; 20%), the confidence interval (CI) was wide (95% CI: 1.93-55.31, p = 0.006). Whole genome phylogeny of 98 isolates of South Africa's most prevalent molecular type, VGIV, identified that this molecular type is highly diverse, with two interesting clusters of ten and six closely related isolates being identified, respectively. One of these clusters consisted only of patients from the Mpumalanga Province in South Africa, suggesting a similar environmental source. This study contributed new insights into the global population structure of this important human pathogen.
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Project description:The genus Cryptococcus comprises more than 80 species, including C. neoformans and C. gattii, which are pathogenic to humans, mainly affecting the central nervous system. The two species differ in geographic distribution and environmental niche. C. neoformans has a worldwide distribution and is often isolated from bird droppings. On the contrary, C. gattii is reported in tropical and subtropical regions and is associated with Eucalyptus species. This review aims to describe the distribution of environmental isolates of the Cryptococcus neoformans species complex and the Cryptococcus gattii species complex in Colombia. A systematic investigation was carried out using different databases, excluding studies of clinical isolates reported in the country. The complex of the species of C. gattii is recovered mainly from trees of the genus Eucalyptus spp., while the complex of the species of C. neoformans is recovered mainly from avian excrement, primarily Columba livia (pigeons) excrement. In addition, greater positivity was found at high levels of relative humidity. Likewise, an association was observed between the presence of the fungus in places with little insolation and cold or temperate temperatures compared to regions with high temperatures.
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Project description:Cryptococcosis, a potentially fatal mycosis, is caused by members of the Cryptococcus neoformans and Cryptococcus gattii species complexes. In Latin America, cryptococcal meningitis is still an important health threat with a significant clinical burden. Analysis of publicly available molecular data from 5686 clinical, environmental, and veterinary cryptococcal isolates from member countries of the Latin American Cryptococcal Study Group showed that, as worldwide, C. neoformans molecular type VNI is the most common cause of cryptococcosis (76.01%) in HIV-infected people, followed by C. gattii molecular type VGII (12.37%), affecting mostly otherwise healthy hosts. These two molecular types also predominate in the environment (68.60% for VNI and 20.70% for VGII). Among the scarce number of veterinary cases, VGII is the predominant molecular type (73.68%). Multilocus sequence typing analysis showed that, in Latin America, the C. neoformans population is less diverse than the C. gattii population (D of 0.7104 vs. 0.9755). Analysis of antifungal susceptibility data showed the presence of non-wild-type VNI, VGI, VGII, and VGIII isolates in the region. Overall, the data presented herein summarize the progress that has been made towards the molecular epidemiology of cryptococcal isolates in Latin America, contributing to the characterization of the genetic diversity and antifungal susceptibility of these globally spreading pathogenic yeasts.
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Project description:Cryptococcus-macrophage interaction is crucial in the development of cryptococcocal diseases. C. neoformans and C. gattii are major pathogenic species that occupy different niches and cause different clinical manifestations. However, the differences of macrophage interaction among these species in affecting different disease outcomes and immune responses have not been clearly addressed. Here, we examined the macrophage uptake rates, intracellular loads and intracellular proliferation rates of C. neoformans and C. gattii clinical isolates from Thailand and analyzed the effect of those interactions on fungal burdens and host immune responses. C. neoformans isolates showed a higher phagocytosis rate but lower intracellular proliferation rate than C. gattii. Indeed, the high intracellular proliferation rate of C. gattii isolates did not influence the fungal burdens in lungs and brains of infected mice, whereas infection with high-uptake C. neoformans isolates resulted in significantly higher brain burdens that associated with reduced survival rate. Interestingly, alveolar macrophages of mice infected with high-uptake C. neoformans isolates showed distinct patterns of alternatively activated macrophage (M2) gene expressions with higher Arg1, Fizz1, Il13 and lower Nos2, Ifng, Il6, Tnfa, Mcp1, csf2 and Ip10 transcripts. Corresponding to this finding, infection with high-uptake C. neoformans resulted in enhanced arginase enzyme activity, elevated IL-4 and IL-13 and lowered IL-17 in the bronchoalveolar lavage. Thus, our data suggest that the macrophage interaction with C. neoformans and C. gattii may affect different disease outcomes and the high phagocytosis rates of C. neoformans influence the induction of type-2 immune responses that support fungal dissemination and disease progression. Abbreviation: Arg1: Arginase 1; BAL: Bronchoalveolar lavage; CCL17: Chemokine (C-C motif) ligand 17; CNS: Central nervous system; CSF: Cerebrospinal fluid; Csf2: Colony-stimulating factor 2; Fizz1: Found in inflammatory zone 1; HIV: Human immunodeficiency virus; ICL: Intracellular cryptococcal load; Ifng: Interferon gamma; Ip10: IFN-g-inducible protein 10; IPR: Intracellular proliferation rate; Mcp1: Monocyte chemoattractant protein 1; Nos2: Nitric oxide synthase 2; PBS: Phosphate-Buffered Saline; Th: T helper cell; Tnfa: Tumor necrosis factor alpha.
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Project description:The environmental isolation of Cryptococcus spp. is typically a difficult undertaking. Collecting samples in the field is costly in terms of travel, personnel time and materials. Furthermore, the recovery rate of Cryptococcus spp. may be very low, thereby requiring a large number of samples to be taken without any guarantee of success. Ecological niche modeling is a tool that has traditionally been used to forecast the distribution of plant and animal of species for biodiversity and conservation purposes. Here, we use it in a public health application to produce risk area maps for cryptococcal disease in Colombia. The Genetic Algorithm for Ruleset Production (GARP) was used to create models for Cryptococcus neoformans (C. neoformans) and Cryptococcus gattii (C. gattii), based on environmental sampling and clinical records data recorded since 1987. These maps could be used to focus public health messaging related to cryptococcal disease, and it enables us to characterize the ecological niche for Cryptococcus in Colombia. We found that the OPEN ACCESS J. Fungi 2015, 1 333 ecological niche for C. gattii in Colombia is quite diverse, establishing itself in sub-tropical and temperate ecoregions within the country. This suggests that C. gattii is highly adaptive to different ecological conditions in Colombia and different regions of the world.
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Project description:Cryptococcus gattii (C. gattii) is a fungal pathogen that once caused an outbreak of cryptococcosis on Vancouver Island, and had spread worldwide, while few data were available in China. In this study, seven clinical isolates of C. gattii VGII were collected from 19 hospitals, Multi-locus Sequence Typing (MLST) analysis and whole-genome sequencing (WGS) was performed, combined with published data for phylogenetic analysis. In addition, in vitro antifungal susceptibility testing, phenotypic analysis, and in vivo virulence studies were performed, subsequently, histopathological analysis of lung tissue was performed. C.gattii VGII infected patients were mainly immunocompetent male, and most of them had symptoms of central nervous system (CNS) involvement. MLST results showed that isolates from China exhibited high genetic diversity, and sequence type (ST) 7 was the major ST among the isolates. Some clinical isolates showed a close phylogenetic relationship with strains from Australia and South America. All clinical isolates did not show resistance to antifungal drugs. In addition, there was no correlation between virulence factors (temperature, melanin production, and capsule size) and virulence while in vivo experiments showed significant differences in virulence among strains. Lung fungal burden and damage to lung tissue correlated with virulence, and degree of damage to lung tissue in mice may highlight differences in virulence. Our work seeks to provide useful data for molecular epidemiology, antifungal susceptibility, and virulence differences of C. gattii VGII in China.
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2009-08-07 | GSE17052 | GEO
Project description:The pathogenic species of Cryptococcus are a major cause of mortality owing to severe infections in immunocompromised as well as immunocompetent individuals. Although antifungal treatment is usually effective, many patients relapse after treatment, and in such cases, comparative analyses of the genomes of incident and relapse isolates may reveal evidence of determinative, microevolutionary changes within the host. Here, we analyzed serial isolates cultured from cerebrospinal fluid specimens of 18 South African patients with recurrent cryptococcal meningitis. The time between collection of the incident isolates and collection of the relapse isolates ranged from 124 days to 290 days, and the analyses revealed that, during this period within the patients, the isolates underwent several genetic and phenotypic changes. Considering the vast genetic diversity of cryptococcal isolates in sub-Saharan Africa, it was not surprising to find that the relapse isolates had acquired different genetic and correlative phenotypic changes. They exhibited various mechanisms for enhancing virulence, such as growth at 39°C, adaptation to stress, and capsule production; a remarkable amplification of ERG11 at the native and unlinked locus may provide stable resistance to fluconazole. Our data provide a deeper understanding of the microevolution of Cryptococcus species under pressure from antifungal chemotherapy and host immune responses. This investigation clearly suggests a promising strategy to identify novel targets for improved diagnosis, therapy, and prognosis.IMPORTANCE Opportunistic infections caused by species of the pathogenic yeast Cryptococcus lead to chronic meningoencephalitis and continue to ravage thousands of patients with HIV/AIDS. Despite receiving antifungal treatment, over 10% of patients develop recurrent disease. In this study, we collected isolates of Cryptococcus from cerebrospinal fluid specimens of 18 patients at the time of their diagnosis and when they relapsed several months later. We then sequenced and compared the genomic DNAs of each pair of initial and relapse isolates. We also tested the isolates for several key properties related to cryptococcal virulence as well as for their susceptibility to the antifungal drug fluconazole. These analyses revealed that the relapsing isolates manifested multiple genetic and chromosomal changes that affected a variety of genes implicated in the pathogenicity of Cryptococcus or resistance to fluconazole. This application of comparative genomics to serial clinical isolates provides a blueprint for identifying the mechanisms whereby pathogenic microbes adapt within patients to prolong disease.
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Project description:Cryptococcus gattii is a primary pathogenic yeast that causes disease in both animals and humans. It is closely related to Cryptococcus neoformans and diverged from a common ancestor approximately 40 million years ago. While C. gattii has a characterized sexual cycle dependent upon a dimorphic region of the genome known as the MAT locus, mating has rarely been observed in this species. In this study, we identify for the first time clinical (both human and veterinary) and environmental isolates from Australia that retain sexual fecundity. A collection of 120 isolates from a variety of geographic locations was analyzed for molecular type, mating type, and the ability to develop mating structures when cocultured with fertile tester strains. Nine isolates produced dikaryotic filaments with paired nuclei, fused clamp connections, and basidiospores. DNA sequence analysis of three genes (URA5, the MATalpha-specific SXI1alpha gene, and the MATa-specific SXI2a gene) revealed little or no variability in URA5 and SXI2a, respectively. However across the 108 MATalpha strains sequenced, the SXI1alpha gene was found to exist as 11 different alleles. Phylogenetic analysis found most variation to occur in the more fertile genotypes. Although some lineages of Australian C. gattii have retained the ability to mate, the majority of isolates were sterile, suggesting that asexuality is the dominant mode of propagation in these populations.
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