scholarly journals Genotype, Antifungal Susceptibility, and Virulence of Clinical South African Cryptococcus neoformans Strains from National Surveillance, 2005–2009

2021 ◽  
Vol 7 (5) ◽  
pp. 338
Author(s):  
Serisha D. Naicker ◽  
Rindidzani E. Magobo ◽  
Tsidiso G. Maphanga ◽  
Carolina Firacative ◽  
Erika van Schalkwyk ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Cryptococcus Neoformans ◽  
South African ◽  
Reference Strain ◽  
Galleria Mellonella ◽  
Antifungal Susceptibility ◽  
National Surveillance ◽  
Molecular Type ◽  
African Patients ◽  
Sequence Types

In South Africa, Cryptococcus neoformans is the most common cause of adult meningitis. We performed multi locus sequence typing and fluconazole susceptibility testing of clinical C. neoformans isolates collected from 251 South African patients with cryptococcosis through national surveillance from 2005 to 2009. We examined the association between clinical characteristics of patients and genotype, and the effect of genotype on in-hospital mortality. We performed whole genome phylogenetic analysis of fifteen C. neoformans isolates with the molecular type VNB and tested their virulence in a Galleria mellonella model. Most isolates had the molecular type VNI (206/251, 82%), followed by VNII (25/251, 10%), VNB (15/251, 6%), and VNIV (5/251, 2%); 67 sequence types were identified. There were no differences in fluconazole minimum inhibitory concentration (MIC) values among molecular types and the majority of strains had low MIC values (MIC50 of 1 µg/mL and MIC90 of 4 µg/mL). Males were almost twice as likely of being infected with a non-VNI genotype (adjusted odds ratio [OR]: 1.65, 95% confidence interval [CI]: 0.25–10.99; p = 0.61). Compared to patients infected with a VNI genotype, those with a non-VNI genotype had a 50% reduced adjusted odds of dying in hospital (95% CI: 0.03–7.57; p = 0.62). However, for both these analyses, our estimates had wide confidence intervals spanning 1 with large p-values. Fifteen VNB strains were not as virulent in a G. mellonella larval model as the H99 reference strain. A majority of these VNB strains belonged to the VNBII clade and were very closely related by phylogenetic analysis.

scholarly journals Cryptococcus neoformans and Cryptococcus gattii Species Complexes in Latin America: A Map of Molecular Types, Genotypic Diversity, and Antifungal Susceptibility as Reported by the Latin American Cryptococcal Study Group

2021 ◽  
Vol 7 (4) ◽  
pp. 282
Author(s):  
Carolina Firacative ◽  
Wieland Meyer ◽  
Elizabeth Castañeda
Keyword(s):  
Latin America ◽  
Cryptococcus Neoformans ◽  
Latin American ◽  
Antifungal Susceptibility ◽  
Genotypic Diversity ◽  
Cryptococcus Gattii ◽  
Study Group ◽  
Molecular Type ◽  
Infected People ◽  
Species Complexes

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.

scholarly journals Multi-locus sequence typing reveals genotypic similarity in Nigerian Cryptococcus neoformans AFLP1/VNI of environmental and clinical origin

2021 ◽  
Vol 70 (10) ◽  
Author(s):  
Paul E. Chidebelu ◽  
Emeka I. Nweze ◽  
Jacques F. Meis ◽  
Massimo Cogliati ◽  
Ferry Hagen
Keyword(s):  
Cryptococcus Neoformans ◽  
Antifungal Susceptibility ◽  
Epidemiological Data ◽  
Clinical Samples ◽  
Molecular Type ◽  
Aids Patients ◽  
Susceptible Population ◽  
South Eastern ◽  
Pigeon Droppings ◽  
Hiv Aids

Introduction Pigeon droppings are among the major environmental sources of Cryptococcus neoformans AFLP1/VNI, from where the organism infects susceptible humans and animals resulting in cryptococcosis. Until now, C. neoformans AFLP1B/VNII was the only molecular type reported in Nigeria. Effective clinical treatment of this infection has occasionally been stymied by the emergence of antifungal non-susceptible, and resistant strains of C. neoformans AFLP1/VNI. Hypothesis/Gap Statement Pigeon droppings harbour C. neoformans and HIV/AIDS patients are among the susceptible population to develop cryptococcal infection. Epidemiological data on cryptococcal prevalence is limited in Nigeria. Aim To investigate the environmental prevalence of C. neoformans in South-eastern Nigeria and compare the isolates with other lineages by using molecular and microbiological tools. Methodology A total of 500 pigeon droppings and 300 blood samples of HIV/AIDS patients were collected, respectively, from five market squares and three tertiary healthcare centres within the Nsukka area of South-eastern Nigeria. The antifungal susceptibility of the C. neoformans isolates to amphotericin B, fluconazole, 5-fluorocytosine, itraconazole, voriconazole, posaconazole, and isavuconazole was investigated based on the CLSI M27-A3 protocol. Yeasts were identified by MALDI-TOF MS, thereafter Cryptococcus MLST was performed according to the International Society for Human and Animal Mycology (ISHAM) consensus scheme. Results C. neoformans was recovered from 6 (1.2 %) pigeon droppings and 6 (2 %) blood cultures of HIV/AIDS patients. Molecular analyses indicated that all cryptococcal isolates belong to serotype A and the AFLP1/VNI molecular type with sequence type (ST)32. Infection with C. neoformans was independent of sex and age of the patients investigated. All C. neoformans isolates were susceptible to the seven antifungal agents. Conclusion This is the first report on the prevalence of C. neoformans AFLP1/VNI (ST32) in environmental and clinical samples from Nigeria. The antifungal susceptibility indicates that antifungal resistance by C. neoformans is yet a rare occurrence in Nigeria.

scholarly journals Kpi, a chaperone-usher pili system associated with the worldwide-disseminated high-risk cloneKlebsiella pneumoniaeST-15

2020 ◽  
Vol 117 (29) ◽  
pp. 17249-17259
Author(s):  
Eva Gato ◽  
Juan Carlos Vázquez-Ucha ◽  
Soraya Rumbo-Feal ◽  
Laura Álvarez-Fraga ◽  
Juan A. Vallejo ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
High Risk ◽  
Antimicrobial Resistance ◽  
Galleria Mellonella ◽  
Carbapenem Resistant ◽  
Defective Mutant ◽  
Gastrointestinal Colonization ◽  
Sequence Types ◽  
Host Tissues

Control of infections caused by carbapenem-resistantKlebsiella pneumoniaecontinues to be challenging. The success of this pathogen is favored by its ability to acquire antimicrobial resistance and to spread and persist in both the environment and in humans. The emergence of clinically important clones, such as sequence types 11, 15, 101, and 258, has been reported worldwide. However, the mechanisms promoting the dissemination of such high-risk clones are unknown. Unraveling the factors that play a role in the pathobiology and epidemicity ofK. pneumoniaeis therefore important for managing infections. To address this issue, we studied a carbapenem-resistant ST-15K. pneumoniaeisolate (Kp3380) that displayed a remarkable adherent phenotype with abundant pilus-like structures. Genome sequencing enabled us to identify a chaperone-usher pili system (Kpi) in Kp3380. Analysis of a largeK. pneumoniaepopulation from 32 European countries showed that the Kpi system is associated with the ST-15 clone. Phylogenetic analysis of the operon revealed that Kpi belongs to the little-characterized γ2-fimbrial clade. We demonstrate that Kpi contributes positively to the ability ofK. pneumoniaeto form biofilms and adhere to different host tissues. Moreover, the in vivo intestinal colonizing capacity of the Kpi-defective mutant was significantly reduced, as was its ability to infectGalleria mellonella. The findings provide information about the pathobiology and epidemicity of Kpi+K. pneumoniaeand indicate that the presence of Kpi may explain the success of the ST-15 clone. Disrupting bacterial adherence to the intestinal surface could potentially target gastrointestinal colonization.

scholarly journals Evaluation of Genetic Variability of Cryptococcus neoformans VNB Isolates

2021 ◽  
Vol 10 (9) ◽  
pp. 284-290
Author(s):  
Luísa Silva Nangi dos Santos OseiYaw Nyarko ◽  
Leonardo Euripedes de Andrade e Silva
Keyword(s):  
Phylogenetic Analysis ◽  
Genetic Variability ◽  
Cryptococcus Neoformans ◽  
Nucleotide Diversity ◽  
Haplotype Diversity ◽  
Antifungal Resistance ◽  
High Genetic Variability ◽  
Potential Impact ◽  
Sequence Types ◽  
Cluster 2

Phylogenetic analysis of pathogenic microorganisms contributes to better understanding the distribution of genotypes that may be specific of certain regions and maybe associated with an increased virulence or antifungal resistance. This study performed phylogenetic analysis of 105 Sequence Types (ST) described for the VNB genotype of Cryptococcus neoformans available on the MLST database in order to better understand this population structure. We found three main clusters, being Cluster 1 the largest with 83 STs and Cluster 2 the smallest with three STs. In general, the isolates presented high genetic variability with haplotype diversity (HD) of 0.998 and nucleotide diversity (π)of 0.00372.Results also demonstrated recombination events, although PHY test showed no significance (p=5.5511). These findings are important since they illustrate that a genotype previously restricted to Africa and now distributed worldwide presents high genetic variability, with potential impact in the development of increased virulence, antifungal resistance, among other factors.

scholarly journals Prevalence, Genetic Structure, and Antifungal Susceptibility of the Cryptococcus neoformans/C. gattii Species Complex Strains Collected from the Arboreal Niche in Poland

Pathogens ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Magdalena Florek ◽  
Agnieszka Korzeniowska-Kowal ◽  
Anna Wzorek ◽  
Katarzyna Włodarczyk ◽  
Maja Marynowska ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Cryptococcus Neoformans ◽  
Species Complex ◽  
Central And Eastern Europe ◽  
Antifungal Susceptibility ◽  
Environmental Study ◽  
Wild Type ◽  
Molecular Type ◽  
Pathogen Population ◽  
Etiological Agents

Fungi belonging to the Cryptococcus neoformans/C. gattii species complex (CNGSC) are etiological agents of serious and not infrequently fatal infections in both humans and animals. Trees are the main ecological niche and source of potential exposition concerning these pathogens. With regard to epidemiology of cryptococcosis, various surveys were performed worldwide, enabling the establishment of a map of distribution and genetic structure of the arboreal population of the CNGSC. However, there are regions, among them Central and Eastern Europe, in which the data are lacking. The present study shows the results of such an environmental study performed in Wrocław, Poland. The CNGSC strains were detected in 2.2% of the tested trees belonging to four genera. The obtained pathogen population consisted exclusively of C. neoformans, represented by both the major molecular type VNI and VNIV. Within the tested group of isolates, resistance to commonly used antimycotics was not found, except for 5-fluorocytosine, in which about 5% of the strains were classified as a non-wild type.

Molecular types of Cryptococcus neoformans and Cryptococcus gattii in Western Australia and correlation with antifungal susceptibility

2019 ◽  
Vol 57 (8) ◽  
pp. 1004-1010 ◽  
Author(s):  
Gar-hing Andrew Lee ◽  
Ian Arthur ◽  
Adam Merritt ◽  
Michael Leung
Keyword(s):  
Cryptococcus Neoformans ◽  
Antifungal Agents ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Cryptococcus Gattii ◽  
Molecular Type ◽  
Australian Population ◽  
Worldwide Distribution ◽  
Species Complexes ◽  
Western Australian

AbstractCryptococcus neoformans and Cryptococcus gattii species complexes have a worldwide distribution; however, there is geographical variation in the prevalence of different molecular types. Additionally, antifungal susceptibility differences between molecular types have been demonstrated. This study investigates the distribution of cryptococcal molecular types among human clinical isolates over a 10-year period from a Western Australian population. Molecular type was determined based on polymorphisms in the phospholipase gene locus identified through amplification and sequencing. Minimum inhibitory concentrations (MICs) were identified for fluconazole, 5-fluorocytosine, posaconazole, itraconazole, voriconazole, and amphotericin B. Most isolates were C. neoformans complex (42) of which over half were molecular type VNI (22) followed by VNII (20). Among the remaining C. gattii complex (13) the majority were VGI (11) with VGII (2) uncommonly found. All isolates demonstrated low MICs to antifungal agents including fluconazole. Geometric mean MIC values against 5-fluorocytosine for VNI (1.741 mg/l) were significantly higher than those for VGI (0.47 mg/l, P = .002). Similarly fluconazole geometric mean MICs against fluconazole for VNI (2.3 mg/l) were significantly higher than VNII (0.87 mg/l, P = .036). These data reveal the presence of four molecular types (VNI, VNII, VGI and VGII) within clinical Western Australian cryptococcal isolates and, while elevated antifungal MICs were not encountered, significant molecular type dependent differences in susceptibility were found.

scholarly journals Characterization of Cryptococcus Neoformans Strains From Cases of Cryptococcal Meningitis in India

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Harish C Gugnani ◽  
Thomas G. Mitchell ◽  
Anubha Paliwal-Joshi ◽  
Ashok Rattan
Keyword(s):  
Cryptococcus Neoformans ◽  
Mating Type ◽  
Antifungal Susceptibility ◽  
In Vitro Assays ◽  
Molecular Type ◽  
Minimal Inhibitory Concentrations ◽  
Susceptibility Tests ◽  
In Vitro Antifungal Susceptibility

Reports of clinical isolates of Cryptococcus neoformans often lack information on their mating types, molecular types, and in vitro antimycotic susceptibilities. This study compares these and other related characteristics of fifteen strains of C. neoformans obtained from cases of meningitis in different regions of India. PCR was used to determine the mating type and serotype of each strain, and Amplified Fragment Length Polymorphism was used for molecular typing of the strains. In vitro assays compared the proteinase and phospholipase activities of the strains, and the Clinical and Laboratory Standards Institute (CLSI) protocol was used to determine their minimal inhibitory concentrations (MICs) to amphotericin B (AMB), itraconazole, and fluconazole. All strains were identified as C. neoformans var. grubii (serotype A), possessed the alpha mating type, and belonged to molecular type VNII. Ten of the strains demonstrated strong proteolytic activity, and the remaining five were weakly proteolytic. Nine of the strains were positive for phospholipase. In vitro antifungal susceptibility tests, determined the MIC (µg/ml) values for AMB, itraconazole, and fluconazole to be 0.03-0.5, 0.002-03, and 2-4 µg/ml, respectively. Remarkedly, all 15 strains belonged to the relatively rare molecular type, VNII. This report is one of few studies to characterize clinical strains of C. neoformans from India.

scholarly journals An analysis of the population of Cryptococcus neoformans strains isolated from animals in Poland, in the years 2015–2019

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Magdalena Florek ◽  
Urszula Nawrot ◽  
Agnieszka Korzeniowska-Kowal ◽  
Katarzyna Włodarczyk ◽  
Anna Wzorek ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Species Level ◽  
Molecular Type ◽  
Animal Group ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Severe Infections ◽  
Resistant Strains ◽  
World Distribution ◽  
Tof Ms

AbstractFungi belonging to the Cryptococcus neoformans/C. gattii species complex (CNGSC) are pathogens causing severe infections in humans and animals, that for humans may result in a mortality rate ranging up to 70%. The CNGSC is divided into eight major molecular types, that may differ in their virulence and susceptibility. In order to fully understand the epidemiology of cryptococcosis, it is important to study the world distribution and population structure of these pathogens. The present study is the first presenting a population of strains isolated in Poland and one of the few using a multi-species animal group as a source of the specimen. The pathogen was present in 2.375% of the tested animals. The URA5-RFLP and MALDI-TOF MS analyses have revealed that the population consisted exclusively of C. neoformans strains, with a predominance of major molecular type VNIV (C. neoformans var. neoformans). The MALDI-TOF MS was used to perform the CNGSC strains identification on both the species and sub-species level. Despite the fact that the animals providing the specimens were not treated with 5-fluorocytosine, around 10% of the tested population presented MIC values exceeding 64 mg/L, indicating the existence of the 5-fluorocytosine-resistant strains in the environment.

scholarly journals First Report of blaNDM-1 Bearing IncX3 Plasmid in Clinically Isolated ST11 Klebsiella pneumoniae from Pakistan

2021 ◽  
Vol 9 (5) ◽  
pp. 951
Author(s):  
Hazrat Bilal ◽  
Gaojian Zhang ◽  
Tayyab Rehman ◽  
Jianxion Han ◽  
Sabir Khan ◽  
...  
Keyword(s):  
Sequence Type ◽  
The Other ◽  
High Rate ◽  
Antibiotics Resistance ◽  
New Delhi ◽  
Molecular Type ◽  
Plasmid Analysis ◽  
First Time ◽  
Encoding Genes ◽  
Sequence Types

The New Delhi Metallo-β-lactamase (NDM) is among the most threatening forms of carbapenemases produced by K. pneumoniae, well-known to cause severe worldwide infections. The molecular epidemiology of blaNDM-1-harboring K. pneumoniae is not well elucidated in Pakistan. Herein, we aim to determine the antibiotics-resistance profile, genes type, molecular type, and plasmid analysis of 125 clinically isolated K. pneumoniae strains from urine samples during July 2018 to January 2019 in Pakistan. A total of 34 (27.2%) K. pneumoniae isolates were carbapenemases producers, and 23 (18.4%) harbored the blaNDM-1 gene. The other carbapenemases encoding genes, i.e., blaIMP-1 (7.2%), blaVIM-1 (3.2%), and blaOXA-48 (2.4%) were also detected. The Multi Locus Sequence Typing (MLST) results revealed that all blaNDM-1-harboring isolates were ST11. The other sequence types detected were ST1, ST37, and ST105. The cluster analysis of Xbal Pulsed Field Gel Electrophoresis (PFGE) revealed variation amongst the clusters of the identical sequence type isolates. The blaNDM-1 gene in all of the isolates was located on a 45-kb IncX3 plasmid, successfully transconjugated. For the first time, blaNDM-1-bearing IncX3 plasmids were identified from Pakistan, and this might be a new primary vehicle for disseminating blaNDM-1 in Enterobacteriaceae as it has a high rate of transferability.

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