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Bertout S, Laroche L, Roger F, Krasteva D, Drakulovski P, Bellet V. Fluconazole Resistance and Virulence in In Vitro Induced-Fluconazole Resistant Strains and in Clinical Fluconazole Resistant Strain of Cryptococcus deuterogattii. Pathogens 2023; 12:758. [PMID: 37375448 DOI: 10.3390/pathogens12060758] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Neuromeningeal cryptococcosis is a life-threatening infection of the central nervous system, caused by encapsulated yeast belonging to the Cryptococcus neoformans and Cryptococcus gattii species complexes. Recent data showed that virulence and antifungal resistance are variable for yeasts belonging to the C. gattii species complex. There is an increase in resistance to fluconazole for yeasts of the C. gattii species complex and the virulence is variable according to the genotype. In the present study, (i) we explored and compared the mechanisms of resistance to fluconazole between C. deuterogattii clinically resistant strains and induced fluconazole-resistant strains by exposure to fluconazole in vitro, and (ii) we studied their virulence in the Galleria mellonella study model. We demonstrated that the fluconazole resistance mechanisms involved were different between clinically resistant strains and induced resistant strains. We also demonstrated that fluconazole-induced resistant strains are less virulent when compared to the original susceptible strains. On the contrary, the clinically resistant strain tested maintains its virulence compared to fluconazole-susceptible strains of the same sequence type.
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Affiliation(s)
- Sébastien Bertout
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Laetitia Laroche
- Laboratoire de Biologie Médicale, Hôpital Lozère, 48000 Mende, France
| | - Frédéric Roger
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Donika Krasteva
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Pascal Drakulovski
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Virginie Bellet
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
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Firacative C, Zuluaga-Puerto N, Guevara J. Cryptococcus neoformans Causing Meningoencephalitis in Adults and a Child from Lima, Peru: Genotypic Diversity and Antifungal Susceptibility. J Fungi (Basel) 2022; 8:jof8121306. [PMID: 36547639 PMCID: PMC9781953 DOI: 10.3390/jof8121306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Cryptococcosis, caused predominantly by Cryptococcus neoformans, is a potentially fatal, opportunistic infection that commonly affects the central nervous system of immunocompromised patients. Globally, this mycosis is responsible for almost 20% of AIDS-related deaths, and in countries like Peru, its incidence remains high, mostly due to the annual increase in new cases of HIV infection. This study aimed to establish the genotypic diversity and antifungal susceptibility of C. neoformans isolates causing meningoencephalitis in 25 adults and a 9-year-old girl with HIV and other risk factors from Lima, Peru. To identify the genotype of the isolates, multilocus sequence typing was applied, and to establish the susceptibility of the isolates to six antifungals, a YeastOne® broth microdilution was used. From the isolates, 19 were identified as molecular type VNI, and seven as VNII, grouped in eight and three sequence types, respectively, which shows that the studied population was highly diverse. Most isolates were susceptible to all antifungals tested. However, VNI isolates were less susceptible to fluconazole, itraconazole and voriconazole than VNII isolates (p < 0.05). This study contributes data on the molecular epidemiology and the antifungal susceptibility profile of the most common etiological agent of cryptococcosis, highlighting a pediatric case, something which is rare among cryptococcal infection.
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Affiliation(s)
- Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad de Rosario, Bogota 111221, Colombia
- Correspondence:
| | | | - José Guevara
- Facultad de Medicina “San Fernando”, Universidad Nacional Mayor de San Marcos, Lima 15081, Peru
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Vélez N, Vega-Vela N, Muñoz M, Gómez P, Escandón P, Ramírez JD, Zaragoza O, Monteoliva Diaz L, Parra-Giraldo CM. Deciphering the Association among Pathogenicity, Production and Polymorphisms of Capsule/Melanin in Clinical Isolates of Cryptococcus neoformans var. grubii VNI. J Fungi (Basel) 2022; 8:245. [PMID: 35330247 PMCID: PMC8950468 DOI: 10.3390/jof8030245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Cryptococcus neoformans is an opportunistic fungal pathogen that can cause meningitis in immunocompromised individuals. The objective of this work was to study the relationship between the phenotypes and genotypes of isolates of clinical origin from different cities in Colombia. METHODS Genome classification of 29 clinical isolates of C. neoformans var. grubii was performed using multilocus sequence typing (MLST), and genomic sequencing was used to genotype protein-coding genes. Pathogenicity was assessed in a larval model, and melanin production and capsule size were evaluated in vitro and in vivo. RESULTS Eleven MLST sequence types (STs) were found, the most frequent being ST69 (n = 9), ST2, ST93, and ST377 (each with n = 4). In the 29 isolates, different levels of pigmentation, capsule size and pathogenicity were observed. Isolates classified as highly pathogenic showed a tendency to exhibit larger increases in capsule size. In the analysis of polymorphisms, 48 non-synonymous variants located in the predicted functional domains of 39 genes were found to be associated with capsule size change, melanin, or pathogenicity. CONCLUSIONS No clear patterns were found in the analysis of the phenotype and genotype of Cryptococcus. However, the data suggest that the increase in capsule size is a key variable for the differentiation of pathogenic isolates, regardless of the method used for its induction.
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Affiliation(s)
- Nórida Vélez
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá 110231, Colombia
| | - Nelson Vega-Vela
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá 110231, Colombia
| | - Marina Muñoz
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá 111221, Colombia
| | - Paola Gómez
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá 110231, Colombia
| | - Patricia Escandón
- Grupo de Microbiología, Instituto Nacional de Salud, Bogotá 111321, Colombia
| | - Juan David Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá 111221, Colombia
- Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Oscar Zaragoza
- Mycology Reference Laboratory National Centre for Microbiology, Instituto de Salud Carlos III, 28222 Madrid, Spain
| | - Lucía Monteoliva Diaz
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Claudia-Marcela Parra-Giraldo
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá 110231, Colombia
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Bellet V, Roger F, Krasteva D, Gouveia T, Drakulovski P, Pottier C, Bertout S. Multilocus sequence typing of strains from the Cryptococcus gattii species complex from different continents. Mycoses 2021; 65:88-96. [PMID: 34726802 DOI: 10.1111/myc.13389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 01/27/2023]
Abstract
BACKGROUND Cryptococcus neoformans and Cryptococcus gattii species complexes are pathogens causing cryptococcal meningitis, a fungal infection that leads to death unless treated. Worldwide, it is estimated to kill over 180,000 individuals annually. OBJECTIVES We aim to investigate the molecular diversity of C. gattii isolates from strains isolated from 1995 to the present day from different continents. METHOD In this study, we analysed the molecular diversity by MLST and antifungal susceptibility by using the broth microdilution method according to the CLSI M27-A4 protocol of a total of 26 strains from Cryptococcus gattii species complex from both clinical and environmental sources. RESULTS Genotyping showed that most of the strains (17/26; 65.4%) belonged to serotype B and were distributed between three genotypes: VGI (13/17; 76.5%), VGII (3/17; 17.6%) and VGVI (1/17; 5.9%). The serotype C strains (9/26; 34.6%) were distributed between the VGIII (1/9; 11.1%) and VGIV (8/9; 88.9%) genotypes. The 26 strains belonged to 17 different MLST subtypes, and we highlight four new MLST genotypes (ST553, 554, 555 and 556). The two environmental strains were identified as serotype B and genotype VGI, but were of ST 51 and 154. All isolates have wild-type MIC of fluconazole and flucytosine. Regarding amphotericin B, five VGI strains showed MICs to AMB equal to 1 µg/ml, and according to the ECV for these genotypes, they were considered non-wild-type strains. CONCLUSIONS The current study reveals the genetic diversity and new sequence types among strains from the C. gattii complex species.
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Affiliation(s)
- Virginie Bellet
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
| | - Frédéric Roger
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
| | - Donika Krasteva
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
| | - Tiphany Gouveia
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
| | - Pascal Drakulovski
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
| | - Cyril Pottier
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
| | - Sébastien Bertout
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France
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Firacative C, Meyer W, Castañeda E. 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. J Fungi (Basel) 2021; 7:jof7040282. [PMID: 33918572 PMCID: PMC8069395 DOI: 10.3390/jof7040282] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/20/2021] [Accepted: 04/01/2021] [Indexed: 02/07/2023] Open
Abstract
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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Affiliation(s)
- Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogota 111221, Colombia
- Correspondence: ; Tel.: +57-1-297-0200 (ext. 3404)
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Research and Education Network Westmead Hospital, Faculty of Medicine and Health, Sydney Medical School-Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, Westmead Institute for Medical Research, The University of Sydney, Sydney 2145, Australia;
| | - Elizabeth Castañeda
- Grupo de Microbiología, Instituto Nacional de Salud, Bogota 111321, Colombia;
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Predominance of Cryptococcus neoformans Var. grubii in Ahvaz, Molecular Identification and Evaluation of Virulence Factors. Jundishapur J Microbiol 2021. [DOI: 10.5812/jjm.112408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background: Cryptococcus neoformans is an encapsulated yeast pathogen with worldwide distribution, and the highest incidence of cryptococcosis was attributed to C. neoformans (var. grubii. The pathogenicity of Cryptococcus species is associated with several factors, including capsule and melanin production, growth at 37 ºC, and secretion of extracellular enzymes. Objectives: The present study aimed to isolate and identify Cryptococcus species from pigeon guano in Ahvaz, Iran and investigate important virulence factors in the isolates. Methods: Seventy-three isolates of C. neoformans var. grubii were identified based on classical and molecular microbiology methods. Capsule size was measured by the grow yeasts in the presence of 5% CO2. Specific media demonstrated the activity of extracellular enzymes (phospholipase, hemolysin, proteinase, esterase, urease, catalase, and gelatinase). Besides, melanin production was evaluated by the niger seed agar medium. Results: Two hundred and seventeen samples were examined for the presence of Cryptococcus over 165 days in Ahvaz. All tested isolates were contained capsules with variable sizes under 5% CO2 concentration. Moreover, 100% of isolates were produced extracellular enzymes (urease, hemolysin, and catalase), whereas no proteinase and gelatinase activities were observed among isolates. Furthermore, most isolates had phospholipase (93.1%) and esterase activities (86.3%). Also, melanin was produced by all of the isolates. Conclusions: Although two methods were used for recovery of Cryptococcus, only Cryptococcus was isolated from pigeon guano, and swabs from the cage walls were negative. Cryptococcus neoformans var. grubii was the only species from pigeon droppings from Ahvaz with more pathogenic factors. Owing to the high pathogenicity of the isolates, the frequency of the disease is expected to be higher.
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Population diversity and virulence characteristics of Cryptococcus neoformans/C. gattii species complexes isolated during the pre-HIV-pandemic era. PLoS Negl Trop Dis 2020; 14:e0008651. [PMID: 33017391 PMCID: PMC7535028 DOI: 10.1371/journal.pntd.0008651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/27/2020] [Indexed: 11/19/2022] Open
Abstract
Cryptococcosis has become a major global health problem since the advent of the HIV pandemic in 1980s. Although its molecular epidemiology is well-defined, using isolates recovered since then, no pre-HIV-pandemic era epidemiological data exist. We conducted a molecular epidemiological study using 228 isolates of the C. neoformans/C. gattii species complexes isolated before 1975. Genotypes were determined by URA5 restriction fragment length polymorphism analysis and multi-locus sequence typing. Population genetics were defined by nucleotide diversity measurements, neutrality tests, and recombination analysis. Growth at 37°C, melanin synthesis, capsule production, and urease activity as virulence factors were quantified. The pre-HIV-pandemic isolates consisted of 186 (81.5%) clinical, 35 (15.4%) environmental, and 7 (3.1%) veterinary isolates. Of those, 204 (89.5%) belonged to C. neoformans VNI (64.0%), VNII (14.9%) and VNIV (10.5%) while 24 (10.5%) belonged to C. gattii VGIII (7.5%), VGI (2.6%) and VGII (0.5%). Among the 47 sequence types (STs) identified, one of VNII and 8 of VNIV were novel. ST5/VNI (23.0%) in C. neoformans and ST75/VGIII (25.0%) in C. gattii were the most common STs in both species complexes. Among C. neoformans, VNIV had the highest genetic diversity (Hd = 0.926) and the minimum recombination events (Rm = 10), and clinical isolates had less genetic diversity (Hd = 0.866) than environmental (Hd = 0.889) and veterinary isolates (Hd = 0.900). Among C. gattii, VGI had a higher nucleotide diversity (π = 0.01436) than in VGIII (π = 0.00328). The high-virulence genotypes (ST5/VNI and VGIIIa/serotype B) did not produce higher virulence factors levels than other genotypes. Overall, high genetic variability and recombination rates were found for the pre-HIV-pandemic era among strains of the C. neoformans/C. gattii species complexes. Whole genome analysis and in vivo virulence studies would clarify the evolution of the genetic diversity and/or virulence of isolates of the C. neoformans/C. gattii species complexes during the pre- and post-HIV-pandemic eras. Since the beginning of the HIV pandemic in 1980, infections due to isolates of the Cryptococcus neoformans/C. gattii species complexes have caused many deaths worldwide, especially in the HIV-infected population. Annually, approximately one-third, of all AIDS-related deaths,—representing more than 1,000,000 cases,—are caused by cryptococcosis. Since 1980, extensive molecular epidemiological surveys have been conducted, and the VNI molecular type has been found to be responsible for more than 90% of cryptococcosis in HIV patients. Whether the high VNI prevalence is associated with the HIV pandemic remains controversial as information on the isolates of the pre-HIV pandemic era is lacking. Therefore, this study of the molecular epidemiology and in vitro characteristics of the strains from the pre-HIV-pandemic era was undertaken. We found that only 64% of cryptococcosis was caused by VNI, and 9 sequence types existed only in the pre-HIV pandemic era. Unlike what was already known about the strains collected during the HIV pandemic era, ST5 and VGIIIa,—supposedly high virulence genotypes,—did not express higher virulence factors than other genotypes. These results implied that the HIV pandemic altered both the molecular epidemiology and virulence of Cryptococcus neoformans/C. gattii species complexes have been altered during HIV pandemic. However, detailed mechanism of these alteration remains to be deciphered further.
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Molecular Epidemiology Reveals Low Genetic Diversity among Cryptococcus neoformans Isolates from People Living with HIV in Lima, Peru, during the Pre-HAART Era. Pathogens 2020; 9:pathogens9080665. [PMID: 32824653 PMCID: PMC7459599 DOI: 10.3390/pathogens9080665] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 02/07/2023] Open
Abstract
Cryptococcosis, a mycosis presenting mostly as meningoencephalitis, affecting predominantly human immunodeficiency virus (HIV)-infected people, is mainly caused by Cryptococcus neoformans. The genetic variation of 48 C. neoformans isolates, recovered from 20 HIV-positive people in Lima, Peru, during the pre-highly active antiretroviral therapy (HAART) era, was studied retrospectively. The mating type of the isolates was determined by PCR, and the serotype by agglutination and CAP59-restriction fragment length polymorphism (RFLP). Genetic diversity was assessed by URA5-RFLP, PCR-fingerprinting, amplified fragment length polymorphism (AFLP), and multilocus sequence typing (MLST). All isolates were mating type alpha, with 39 molecular type VNI, seven VNII, corresponding to C. neoformans var. grubii serotype A, and two VNIII AD hybrids. Overall, the cryptococcal population from HIV-positive people in Lima shows a low degree of genetic diversity. In most patients with persistent cryptococcal infection, the same genotype was recovered during the follow-up. In four patients with relapse and one with therapy failure, different genotypes were found in isolates from the re-infection and from the isolate recovered at the end of the treatment. In one patient, two genotypes were found in the first cryptococcosis episode. This study contributes data from Peru to the ongoing worldwide population genetic analysis of Cryptococcus.
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Firacative C, Khan A, Duan S, Ferreira-Paim K, Leemon D, Meyer W. Rearing and Maintenance of Galleria mellonella and Its Application to Study Fungal Virulence. J Fungi (Basel) 2020; 6:jof6030130. [PMID: 32784766 PMCID: PMC7558789 DOI: 10.3390/jof6030130] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 12/18/2022] Open
Abstract
Galleria mellonella larvae have been widely used as alternative non-mammalian models for the study of fungal virulence and pathogenesis. The larvae can be acquired in small volumes from worm farms, pet stores, or other independent suppliers commonly found in the United States and parts of Europe. However, in countries with no or limited commercial availability, the process of shipping these larvae can cause them stress, resulting in decreased or altered immunity. Furthermore, the conditions used to rear these larvae including diet, humidity, temperature, and maintenance procedures vary among the suppliers. Variation in these factors can affect the response of G. mellonella larvae to infection, thereby decreasing the reproducibility of fungal virulence experiments. There is a critical need for standardized procedures and incubation conditions for rearing G. mellonella to produce quality, unstressed larvae with the least genetic variability. In order to standardize these procedures, cost-effective protocols for the propagation and maintenance of G. mellonella larvae using an artificial diet, which has been successfully used in our own laboratory, requiring minimal equipment and expertise, are herein described. Examples for the application of this model in fungal pathogenicity and gene knockout studies as feasible alternatives for traditionally used animal models are also provided.
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Affiliation(s)
- Carolina Firacative
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Westmead 2145, NSW, Australia; (C.F.); (A.K.); (S.D.); (K.F.-P.)
- Studies in Translational Microbiology and Emerging Diseases Research Group (MICROS), School of Medicine and Health Sciences, Universidad del Rosario, Bogota 111221, Colombia
| | - Aziza Khan
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Westmead 2145, NSW, Australia; (C.F.); (A.K.); (S.D.); (K.F.-P.)
| | - Shuyao Duan
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Westmead 2145, NSW, Australia; (C.F.); (A.K.); (S.D.); (K.F.-P.)
| | - Kennio Ferreira-Paim
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Westmead 2145, NSW, Australia; (C.F.); (A.K.); (S.D.); (K.F.-P.)
- Infectious Disease Department, Triangulo Mineiro Federal University, Uberaba 38025-440, Brazil
| | - Diana Leemon
- Agri Science Queensland, Department of Agriculture and Fisheries and Forestry, Brisbane 4102, QLD, Australia;
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Westmead 2145, NSW, Australia; (C.F.); (A.K.); (S.D.); (K.F.-P.)
- Correspondence: ; Tel.: +61-2-86273430
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