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Chew KL, Achik R, Osman NH, Octavia S, Teo JWP. Genomic epidemiology of human candidaemia isolates in a tertiary hospital. Microb Genom 2023; 9:mgen001047. [PMID: 37440287 PMCID: PMC10438824 DOI: 10.1099/mgen.0.001047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 05/17/2023] [Indexed: 07/14/2023] Open
Abstract
Invasive candida infections are significant infections that may occur in vulnerable patients with high rates of mortality or morbidity. Drug-resistance rates also appear to be on the rise which further complicate treatment options and outcomes. The aims of this study were to describe the prevalence, molecular epidemiology, and genetic features of Candida bloodstream isolates in a hospital setting. The resistance mechanisms towards the two most commonly administered antifungals, fluconazole and anidulafungin, were determined. Blood culture isolates between 1 January 2018 and 30 June 2021 positive for Candida spp. were included. Susceptibility testing was performed using Etest. Whole-genome-sequencing was performed using Illumina NovaSeq with bioinformatics analysis performed. A total of 203 isolates were sequenced: 56 C. glabrata, 53 C. tropicalis, 44 C. albicans, 36 C. parapsilosis complex (consisting of C. parapsilosis, C. orthopsilosis, and C. metapsilosis), six C. krusei, five C. dubliniensis, and three C. auris. A single cluster of azole-resistant C. tropicalis, and four clusters of C. parapsilosis isolates were observed, suggesting possible transmission occurring over several years. We found 11.3%, and 52.7 % of C. tropicalis and C. parapsilosis, respectively, clustered with other isolates, suggesting exogenous sources may play a significant role of transmission, particularly for C. parapsilosis. The clusters spanned over several years suggesting the possibility of environmental reservoirs contributing to the spread. Limited clonality was seen for C. albicans. Several sequence types appeared to be dominant for C. glabrata, however the SNP differences varied widely, indicating absence of sustained transmission.
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Affiliation(s)
- Ka Lip Chew
- Department of Laboratory Medicine, National University Hospital, Singapore, Singapore
| | - Rosemini Achik
- Department of Laboratory Medicine, National University Hospital, Singapore, Singapore
| | - Nurul Hudaa Osman
- Environmental Health Institute, National Environment Agency, Singapore, Singapore
| | - Sophie Octavia
- Environmental Health Institute, National Environment Agency, Singapore, Singapore
| | - Jeanette W. P. Teo
- Department of Laboratory Medicine, National University Hospital, Singapore, Singapore
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Pokhrel S, Boonmee N, Tulyaprawat O, Pharkjaksu S, Thaipisutikul I, Chairatana P, Ngamskulrungroj P, Mitrpant C. Assessment of Biofilm Formation by Candida albicans Strains Isolated from Hemocultures and Their Role in Pathogenesis in the Zebrafish Model. J Fungi (Basel) 2022; 8:jof8101014. [PMID: 36294579 PMCID: PMC9605499 DOI: 10.3390/jof8101014] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 12/04/2022] Open
Abstract
Candida albicans, an opportunistic pathogen, has the ability to form biofilms in the host or within medical devices in the body. Biofilms have been associated with disseminated/invasive disease with increased severity of infection by disrupting the host immune response and prolonging antifungal treatment. In this study, the in vivo virulence of three strains with different biofilm formation strengths, that is, non-, weak-, and strong biofilm formers, was evaluated using the zebrafish model. The survival assay and fungal tissue burden were measured. Biofilm-related gene expressions were also investigated. The survival of zebrafish, inoculated with strong biofilms forming C. albicans,, was significantly shorter than strains without biofilms forming C. albicans. However, there were no statistical differences in the burden of viable colonogenic cell number between the groups of the three strains tested. We observed that the stronger the biofilm formation, the higher up-regulation of biofilm-associated genes. The biofilm-forming strain (140 and 57), injected into zebrafish larvae, possessed a higher level of expression of genes associated with adhesion, attachment, filamentation, and cell proliferation, including eap1, als3, hwp1, bcr1, and mkc1 at 8 h. The results suggested that, despite the difference in genetic background, biofilm formation is an important virulence factor for the pathogenesis of C. albicans. However, the association between biofilm formation strength and in vivo virulence is controversial and needs to be further studied.
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Affiliation(s)
- Sabi Pokhrel
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Nawarat Boonmee
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Orawan Tulyaprawat
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Sujiraphong Pharkjaksu
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Iyarit Thaipisutikul
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Phoom Chairatana
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Popchai Ngamskulrungroj
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Chalermchai Mitrpant
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Correspondence:
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Genome plasticity in Candida albicans: A cutting-edge strategy for evolution, adaptation, and survival. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 99:105256. [PMID: 35231665 DOI: 10.1016/j.meegid.2022.105256] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/12/2021] [Accepted: 02/22/2022] [Indexed: 12/15/2022]
Abstract
Candida albicans is the most implicated fungal species that grows as a commensal or opportunistic pathogen in the human host. It is associated with many life-threatening infections, especially in immunocompromised persons. The genome of Candida albicans is very flexible and can withstand a wide assortment of variations in a continuously changing environment. Thus, genome plasticity is central to its adaptation and has long been of considerable interest. C. albicans has a diploid heterozygous genome that is highly dynamic and can display variation from small to large scale chromosomal rearrangement and aneuploidy, which have implications in drug resistance, virulence, and pathogenicity. This review presents an up-to-date overview of recent genomic studies involving C. albicans. It discusses the accumulating evidence that shows how mitotic recombination events, ploidy dynamics, aneuploidy, and loss of heterozygosity (LOH) influence evolution, adaptation, and survival in C. albicans. Understanding the factors that affect the genome is crucial for a proper understanding of species and rapid development and adjustment of therapeutic strategies to mitigate their spread.
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Song N, Kan S, Pang Q, Mei H, Zheng H, Li D, Cui F, Lv G, An R, Li P, Xiong Z, Fan S, Zhang M, Chen Y, Qiao Q, Liang X, Cui M, Li D, Liao Q, Li X, Liu W. A prospective study on vulvovaginal candidiasis: multicentre molecular epidemiology of pathogenic yeasts in China. J Eur Acad Dermatol Venereol 2021; 36:566-572. [PMID: 34908189 DOI: 10.1111/jdv.17874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 11/17/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Vulvovaginal candidiasis (VVC) is frequent in women of reproductive age, but very limited data are available on the epidemiology in cases of VVC in China. OBJECTIVES The current study has been conducted to reveal the prevalence, species distribution of yeast causing VVC and molecular genetics of Candida albicans in China. METHODS Vaginal swabs were collected from 543 VVC outpatients recruited in 12 hospitals in China between September 2017 and March 2018. They were preliminarily incubated on Sabouraud dextrose agar and then positive subjects of which were then transmitted to our institute for further identification. CHROMagar™ was used to isolate Candida species, and all isolates were finally identified by DNA sequencing. Multilocus sequence typing (MLST) was used to analyse phylogenetic relationships of the various C. albicans isolates. RESULTS Eleven different yeast species were identified in 543 isolates, among which C. albicans (84.7%) was the most frequent, followed by C. glabrata (8.7%). We obtained 117 unique diploid sequence types from 451 clinical C. albicans isolates and 92 isolates (20.4%) belonged to a New Clade. All the strains appearing in the New Clade were from northern China and they were isolated from non-recurrent VVC. CONCLUSIONS Our findings suggest that C. albicans are still the main cause of VVC in China and the majority of C. albicans isolates belongs to Clade 1 with DST 79 and DST 45 being two most common. Moreover, the New Clade revealed in our study seems to be specific to northern China.
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Affiliation(s)
- N Song
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - S Kan
- Shanghai Skin Disease Hospital, Department of Medical Mycology, Tongji University School of Medicine, Shanghai, China
| | - Q Pang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
| | - H Mei
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - H Zheng
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - D Li
- Department of Microbiology/Immunology, Georgetown University, Washington, DC, USA
| | - F Cui
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - G Lv
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - R An
- The First Affiliated Teaching Hospital of Xi'an Jiaotong University, Xi'an, China
| | - P Li
- Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, Nanjing, China
| | - Z Xiong
- The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - S Fan
- Peking University Shenzhen Hospital, Shenzhen, China
| | - M Zhang
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Y Chen
- The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Q Qiao
- The Affiliated Hospital of Inner Mongolia Medical University, Huhehaote, China
| | - X Liang
- Peking University People's Hospital, Beijing, China
| | - M Cui
- Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - D Li
- The Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Q Liao
- Department of Obstetrics and Gynecology, Beijing Tsinghua Changgung Hospital, School of Clinical Medical, Tsinghua University, Beijing, China
| | - X Li
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - W Liu
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
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Boonsilp S, Homkaew A, Phumisantiphong U, Nutalai D, Wongsuk T. Species Distribution, Antifungal Susceptibility, and Molecular Epidemiology of Candida Species Causing Candidemia in a Tertiary Care Hospital in Bangkok, Thailand. J Fungi (Basel) 2021; 7:jof7070577. [PMID: 34356956 PMCID: PMC8303137 DOI: 10.3390/jof7070577] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 12/29/2022] Open
Abstract
Candida species represent a common cause of bloodstream infection (BSI). Given the emergence of non-albicans Candida (NAC) associated with treatment failure, investigations into the species distribution, fungal susceptibility profile, and molecular epidemiology of pathogens are necessary to optimize the treatment of candidemia and explore the transmission of drug resistance for control management. This study evaluated the prevalence, antifungal susceptibility, and molecular characteristics of Candida species causing BSI in a tertiary-level hospital in Bangkok, Thailand. In total, 54 Candida isolates were recovered from 49 patients with candidemia. C. tropicalis was the most prevalent species (33.3%), followed by C. albicans (29.6%). Most Candida species were susceptible to various antifungal agents, excluding C. glabrata and C. tropicalis, which had increased rates of non-susceptibility to azoles. Most C. glabrata isolates were non-susceptible to echinocandins, especially caspofungin. The population structure of C. albicans was highly diverse, with clade 17 predominance. GoeBURST analysis of C. tropicalis revealed associations between genotype and fluconazole resistance in a particular clonal complex. The population structure of C. glabrata appeared to have a low level of genetic diversity in MLST loci. Collectively, these data might provide a fundamental database contributing to the development of novel antifungal agents and diagnostic tests.
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Affiliation(s)
- Siriphan Boonsilp
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand;
- Correspondence: (S.B.); (T.W.)
| | - Anchalee Homkaew
- Division of Central Laboratory and Blood Bank, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand; (A.H.); (D.N.)
| | - Uraporn Phumisantiphong
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand;
- Division of Central Laboratory and Blood Bank, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand; (A.H.); (D.N.)
| | - Daranee Nutalai
- Division of Central Laboratory and Blood Bank, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand; (A.H.); (D.N.)
| | - Thanwa Wongsuk
- Department of Clinical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand;
- Correspondence: (S.B.); (T.W.)
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Invasive Fungal Diseases in Children with Acute Leukemia and Severe Aplastic Anemia. Mediterr J Hematol Infect Dis 2021; 13:e2021039. [PMID: 34276908 PMCID: PMC8265365 DOI: 10.4084/mjhid.2021.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022] Open
Abstract
Although the outcomes of childhood leukemia and severe aplastic anemia (SAA) have improved, infectious complications are still the major concern. Particularly worrisome are invasive fungal diseases (IFDs), one of the most common causes of infectious-related deaths in patients with prolonged neutropenia. A retrospective study was conducted of IFDs in pediatric patients with newly diagnosed or relapsed acute leukemia, or with SAA, at Siriraj Hospital, Mahidol University, Thailand. There were 241 patients: 150 with acute lymphoblastic leukemia (ALL), 35 with acute myeloid leukemia (AML), 31 with relapsed leukemia, and 25 with SAA. Their median age was 5.4 years (range, 0.3–16.0 years). The overall IFD prevalence was 10.7%, with a breakdown in the ALL, AML, relapsed leukemia, and SAA patients of 8%, 11.4%, 19.3%, and 16%, respectively. Pulmonary IFD caused by invasive aspergillosis was the most common, accounting for 38.5% of all infection sites. Candidemia was present in 34.6% of the IFD patients; Candida tropicalis was the most common organism. The overall case-fatality rate was 38.5%, with the highest rate found in relapsed leukemia (75%). The incidences of IFDs in patients with relapsed leukemia and SAA who received fungal prophylaxis were significantly lower than in those who did not (P = N/A and 0.04, respectively). IFDs in Thai children with hematological diseases appeared to be prevalent, with a high fatality rate. The usage of antifungal prophylaxes should be considered for patients with SAA to prevent IFDs.
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Mroczyńska M, Brillowska-Dąbrowska A. Virulence of Clinical Candida Isolates. Pathogens 2021; 10:pathogens10040466. [PMID: 33921490 PMCID: PMC8070227 DOI: 10.3390/pathogens10040466] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/07/2021] [Accepted: 04/09/2021] [Indexed: 02/07/2023] Open
Abstract
The factors enabling Candida spp. infections are secretion of hydrolytic enzymes, adherence to surfaces, biofilm formation or morphological transition, and fitness attributes. The aim of this study was to investigate the correlation between known extracellular virulence factors and survival of Galleria mellonella larvae infected with clinical Candida. The 25 isolates were tested and the activity of proteinases among 24/24, phospholipases among 7/22, esterases among 14/23, hemolysins among 18/24, and biofilm formation ability among 18/25 isolates was confirmed. Pathogenicity investigation using G. mellonella larvae as host model demonstrated that C. albicans isolates and C. glabrata isolate were the most virulent and C. krusei isolates were avirulent. C. parapsilosis virulence was identified as varied, C. inconspicua were moderately virulent, and one C. palmioleophila isolate was of low virulence and the remaining isolates of this species were moderately virulent. According to our study, virulence of Candida isolates is related to the expression of proteases, hemolysins, and esterases.
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Molecular Diversity and Genetic Relatedness of Candida albicans Isolates from Birds in Hungary. Mycopathologia 2021; 186:237-244. [PMID: 33512664 PMCID: PMC8106574 DOI: 10.1007/s11046-021-00527-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 01/10/2021] [Indexed: 10/29/2022]
Abstract
The molecular epidemiology of Candida albicans infections in animals has been rarely studied. In this study, multilocus sequence typing was used to characterise the genetic diversity and population structure of 24 avian origin C. albicans isolates collected from different birds with candidiasis and compared to human isolates. Fourteen diploid sequence types (DSTs) including six new DSTs were determined. Cluster analysis revealed that isolates grouped into 8 clades. Bird isolates mainly belonged to minor clades and Clade 15 with DST 172 was the most common (11 isolates; 45.8%). The remaining isolates were clustered into Clade 7 (5 isolates; 20.8%), Clade 10 (4 isolates; 16.6%), Clade 8 (2 isolates; 8.3%), Clade 4 (1 isolate; 4.2%) and Clade 16 (1 isolate; 4.2%). Unweighted pair group method with arithmetic averages (UPGMA) and eBURST analyses showed that the genetic construction of avian origin C. albicans population is fairly diverse. Although species-specific lineages were not found, some degree of separation in the evolution of bird and human strains could be observed.
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Wu YM, Lee CH, Cheng YC, Lu JJ, Wang SH. Association between CAI microsatellite, multilocus sequence typing, and clinical significance within Candida albicans isolates. Med Mycol 2020; 59:498-504. [PMID: 33099643 DOI: 10.1093/mmy/myaa090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/09/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022] Open
Abstract
Candida albicans bloodstream infection (BSI) is epidemiologically important because of its increasing frequency and serious outcome. Strain typing and delineation of the species are essential for understanding the phylogenetic relationship and clinical significance. Microsatellite CAI genotyping and multilocus sequence typing (MLST) were performed on 285 C. albicans bloodstream isolates from patients in Chang Gung Memorial Hospital at Linkou (CGMHL), Taiwan from 2003 to 2011. Data regarding demographics, comorbidities, risk factors, and clinical outcomes were recorded within adult patients with C. albicans BSI. Both CAI genotyping and MLST yielded comparable discriminatory power for C. albicans characterization. Besides, the distribution of CAI repetition showed a satisfactory phylogenetic association, which could be a good alternative method in the molecular phylogenetics of C. albicans and epidemiological studies. As for the clinical scenario, clade 17 isolates with CAI alleles either possessing 29 or more repetitions were related to higher 14-day and 30-day mortality, and shorter median survival days.
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Affiliation(s)
- Yen-Mu Wu
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.,Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Hua Lee
- Department of Laboratory Medicine, Chang-Gung Memorial Hospital Linkou, Taoyuan, Taiwan
| | - Yi-Chuan Cheng
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Chang-Gung Memorial Hospital Linkou, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan.,Department of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shao-Hung Wang
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi, Taiwan
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Tulyaprawat O, Pharkjaksu S, Chongtrakool P, Ngamskulrungroj P. An Association of an eBURST Group With Triazole Resistance of Candida tropicalis Blood Isolates. Front Microbiol 2020; 11:934. [PMID: 32508774 PMCID: PMC7248567 DOI: 10.3389/fmicb.2020.00934] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/20/2020] [Indexed: 12/12/2022] Open
Abstract
Candidemia, a bloodstream infection caused by genus Candida, has a high mortality rate. Candida albicans was previously reported to be the most common causative species among candidemia patients. However, during the past 10 years in Thailand, Candida tropicalis has been recovered from blood more frequently than C. albicans. The cause of this shift in the prevalence of Candida spp. remains unexplored. We conducted in vitro virulence studies and antifungal susceptibility profiles of 48 C. tropicalis blood isolates collected during 2015-2017. To compare to global isolates of C. tropicalis, multilocus sequence typing (MLST), a minimum spanning tree, and an eBURST analysis were also conducted. C. tropicalis and C. albicans were the most (47-48.7%) and second-most (21.5-33.9%) common species to be isolated from candidemia patients, respectively. Of the C. tropicalis blood isolates, 29.2, 0, 100, and 93.8% exhibited proteinase activity, phospholipase activity, hemolytic activity, and biofilm formation, respectively. Moreover, 20.8% (10/48) of the isolates were resistant to voriconazole and fluconazole, and also showed high minimum inhibitory concentrations (MICs) to posaconazole and itraconazole. In contrast, most of the isolates were susceptible to anidulafungin (97.9%), micafungin (97.9%), and caspofungin (97.9%), and showed low MICs to amphotericin B (100%) and 5-flucytosine (100%). The MLST identified 22 diploid sequence types. Based on the eBURST analysis and minimum spanning tree, 9 out of 13 members (69.2%) of an eBURST group 3 were resistant to voriconazole and fluconazole, and also showed high MICs to posaconazole and itraconazole. Association analysis revealed the eBURST group 3 was significantly associated with the four triazole resistance (p < 0.001). In conclusion, the eBURST group 3 was associated with the triazole resistance and resistance to many antifungal drugs might be collectively responsible for the prevalence shift.
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Affiliation(s)
| | | | | | - Popchai Ngamskulrungroj
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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