Molecular characterization of Cryptococcus neoformans isolated from the environment in Beijing, China

Dou, Hongtao; Wang, Huizhu; Xie, Shaowei; Chen, Xinxin; Xu, Zhaochun; Xu, Yingchun

doi:10.1093/mmy/myx026

Cited by 32 publications

(30 citation statements)

References 34 publications

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“…A recent environmental study in China revealed that ST5 prevalence in nature was low (6.2%); thereby, one must be highly susceptible to the causal microorganism to be infected. In contrast, ST31 was commonly found in China (66.7%) 27 , but rarely caused any diseases (only 1.3% among cryptococcosis in East Asian countries, data not shown). However, it is still unclear whether this high susceptibility is due to genetic background or other factors.…”

Section: Discussionmentioning

confidence: 85%

An Association of Cryptococcus Neoformans/C. gattii Genotype and HIV Status in Asia: A Systematic Review

Ngamskulrungroj

Kammarnjassadakul

Khayhan

et al. 2019

Smj

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Objective: It has been known that VNI molecular type of Cryptococcus neoformans/C. gattii is strongly associated with HIV patients. However, this paradigm has recently been challenged because of the high prevalence of VNI molecular type among non-HIV patients with cryptococcosis in East Asia. The purpose of this study was to answer the question: "Among cryptococcosis in Asia, is there an association between the genotype and the patient's HIV status?" Methods: Using a systematic review and meta-analysis study design, we included all relevant published data, which were any type of study designs, mainly studied clinical Cryptococcus neoformans/C. gattii strains isolated in Asia and had available molecular typing data. The primary study variables were Cryptococcus neoformans molecular type (VNI/non-VNI or ST5/non-ST5) and the HIV status of the patients at the time of diagnosis. We used a randomeffects meta-analysis model to estimate the prevalence of HIV infection. Results: Sixteen retrospective descriptive studies during 2005-2018 (1,584 isolates) were included. Most of the cryptococcosis cases in East Asian countries were in non-HIV patients (72.4-81.8%), which differed from non-East Asian countries (2.6-28.3% associated with non-HIV patients). In East Asia, the HIV prevalence among VNI and ST5 infected patients ranged from 7.5%-46.7% with the pooled prevalence of 19.8% (95% CI, 12.2%-30.4%) and 5.3%-52.4% with the pooled prevalence of 19.9% (95% CI, 6.9%-45.3%), respectively. In non-East Asia, the HIV prevalence among VNI and ST5 infected patients ranged from 48.3%-98.8% with the pooled prevalence of 81.9% (95% CI, 73.3%-88.2%) and 52.3%-88.0% with the pooled prevalence of 74.9% (95% CI, 40.7%-92.8%), respectively. Statistical heterogeneity was high in both analyses with the I 2 of 79-89% in all analyses. Conclusion: Our results confirmed the low prevalence of HIV prevalence among VNI and ST5 strains in East Asian countries. The emergence of high virulence genotype causing disease in non-HIV patient is highly unlikely, because the VNI and ST5 were associated with HIV patients in other Asian countries. It can be hypothesized that the low HIV prevalence among VNI and ST5 strains in East Asian is due to the high susceptibility to cryptococcosis of people living in this region. This requires further investigation.

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Section: Discussionmentioning

confidence: 85%

An Association of Cryptococcus Neoformans/C. gattii Genotype and HIV Status in Asia: A Systematic Review

Ngamskulrungroj

Kammarnjassadakul

Khayhan

et al. 2019

Smj

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“…17,18 Multilocus sequence typing (MLST) epidemiological studies from East Asia have shown limited genetic diversity among the majority of environmental and clinical isolates. 13,19,20 Different geographical areas have distinct population structures, particularly in relation to the predominant sequence types. 17 Previous studies suggested that though in relatively close geographical proximity, the population structure of C. neoformans var.…”

Section: Introductionmentioning

confidence: 99%

Multilocus sequence typing of Cryptococcus neoformans var. grubii from Laos in a regional and global context

et al. 2018

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Cryptococcosis causes approximately 180 000 deaths each year in patients with human immunodeficiency virus (HIV). Patients with other forms of immunosuppression are also at risk, and disease is increasingly recognized in apparently immunocompetent individuals. Cryptococcus neoformans var. grubii , responsible for the majority of cases, is distributed globally. We used the consensus ISHAM Multilocus sequence typing (MLST) scheme to define the population structure of clinical C. neoformans var. grubii isolates from Laos ( n = 81), which we placed into the global context using published MLST data from other countries (total N = 1047), including a reanalysis of 136 Vietnamese isolates previously reported. We observed a phylogeographical relationship in which the Laotian population was similar to its neighbor Thailand, being dominated (83%) by Sequence Types (ST) 4 and 6. This phylogeographical structure changed moving eastwards, with Vietnam's population consisting of an admixture of isolates dominated by the ST4/ST6 (35%) and ST5 (48%) lineages. The ST5 lineage is the predominant ST reported from China and East Asia, where it accounts for >90% of isolates. Analysis of genetic distance ( Fst ) between different populations of C. neoformans var. grubii supports this intermediate structure of the Vietnamese population. The pathogen and host diversity reported from Vietnam provide the strongest epidemiological evidence of the association between ST5 and HIV-uninfected patients. Regional anthropological genetic distances suggest diversity in the C. neoformans var. grubii population across Southeast Asia is driven by ecological rather than human host factors. Where the ST5 lineage is present, disease in HIV-uninfected patients is to be expected.

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“…It is unlikely that the high prevalence of ST5 infection observed in HIV-uninfected patients is explained by a significantly greater prevalence of the lineage in the environment since it causes only 35% of cases in HIV-infected patients within the same geographical area 9 . Furthermore, data from China suggest that ST5 strains are significantly less prevalent in the environment, making up only 5% of isolates recovered in a recent study 29 . We investigated the first hypothesis by comparing previously identified in vitro virulence-associated phenotypes, along with murine in vivo virulence and immune responses, between lineages.…”

Section: Discussionmentioning

confidence: 95%

Assessing the virulence ofCryptococcus neoformanscausing meningitis in HIV infected and uninfected patients in Vietnam

Lam

Toffaletti

Tenor

et al. 2017

Preprint

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Molecular characterization of Cryptococcus neoformans isolated from the environment in Beijing, China

Cited by 32 publications

References 34 publications

An Association of Cryptococcus Neoformans/C. gattii Genotype and HIV Status in Asia: A Systematic Review

An Association of Cryptococcus Neoformans/C. gattii Genotype and HIV Status in Asia: A Systematic Review

Multilocus sequence typing of Cryptococcus neoformans var. grubii from Laos in a regional and global context

Assessing the virulence ofCryptococcus neoformanscausing meningitis in HIV infected and uninfected patients in Vietnam

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