Genetic diversity of medically important and emerging Candida species causing invasive infection

Author(s)

Merseguel, Karina Bellinghausen ^[1] ; Nishikaku, Angela Satie ^[1] ; Rodrigues, Anderson Messias ^[2] ; Padovan, Ana Carolina ^{[1, 3]} ; Carmona e Ferreira, Renata ^[4] ; de Azevedo Melo, Analy Salles ^[1] ; da Silva Briones, Marcelo Ribeiro ^[4] ; Colombo, Arnaldo Lopes ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Med, Lab Especial Micol LEMI, Disciplina Infectol, BR-04039032 Sao Paulo - Brazil

^[2] Univ Fed Sao Paulo, Dept Microbiol Imunol & Parasitol, Disciplina Biol Celular, BR-04039032 Sao Paulo - Brazil

^[3] Univ Fed Alfenas, Inst Ciencias Biomed, Dept Microbiol & Imunol, Alfenas, MG - Brazil

^[4] Univ Fed Sao Paulo, Dept Microbiol Imunol & Parasitol, Lab Genom Evolut & Biocomplexidade, BR-04039032 Sao Paulo - Brazil

• Document type: Journal article
• Source: BMC INFECTIOUS DISEASES; v. 15, FEB 13 2015.
• Web of Science Citations: 34

Abstract

Background: Genetic variation in the ribosomal DNA (rDNA) internal transcribed spacer (ITS) region has been studied among fungi. However, the numbers of ITS sequence polymorphisms in the various Candida species and their associations with sources of invasive fungal infections remain poorly investigated. Here, we characterized the intraspecific and interspecific ITS diversity of Candida spp. strains collected from patients with bloodstream or oroesophageal candidiasis. Methods: We selected cultures of representative medically important species of Candida as well as some rare and emerging pathogens. Identification was performed by micromorphology and by biochemical testing using an ID32C (R) system, as well as by the sequencing of rDNA ITS. The presence of intraspecific ITS polymorphisms was characterized based on haplotype networks, and interspecific diversity was characterized based on Bayesian phylogenetic analysis. Results: Among 300 Candida strains, we identified 76 C. albicans, 14 C. dubliniensis, 40 C. tropicalis, 47 C. glabrata, 34 C. parapsilosis (sensu stricto), 31 C. orthopsilosis, 3 C. metapsilosis, 21 Meyerozyma guilliermondii (C. guilliermondii), 12 Pichia kudriavzevii (C. krusei), 6 Clavispora lusitaniae (C. lusitaniae), 3 C. intermedia, 6 Wickerhamomyces anomalus (C. pelliculosa), and 2 C. haemulonii strains, and 1 C. duobushaemulonii, 1 Kluyveromyces marxianus (C. kefyr), 1 Meyerozyma caribbica (C. fermentati), 1 Pichia norvegensis (C. norvegensis), and 1 Lodderomyces elongisporus strain. Out of a total of seven isolates with inconsistent ID32C (R) profiles, ITS sequencing identified one C. lusitaniae strain, three C. intermedia strains, two C. haemulonii strains and one C. duobushaemulonii strain. Analysis of ITS variability revealed a greater number of haplotypes among C. albicans, C. tropicalis, C. glabrata and C. lusitaniae, which are predominantly related to endogenous sources of acquisition. Bayesian analysis confirmed the major phylogenetic relationships among the isolates and the molecular identification of the different Candida spp. Conclusions: Molecular studies based on ITS sequencing are necessary to identify closely related and emerging species. Polymorphism analysis of the ITS rDNA region demonstrated its utility as a genetic marker for species identification and phylogenetic relationships as well as for drawing inferences concerning the natural history of hematogenous infections caused by medically important and emerging Candida species. (AU)

• FAPESP's process: 07/08575-1 - Hematogenic candidiasis: a multidisciplinary approach for the improvement of diagnostic tools and caracterization of biomarkers related to its prognosis
• Grantee: Arnaldo Lopes Colombo
• Support Opportunities: Research Projects - Thematic Grants