Molecular epidemiology of Candida africana isolates collected from vagina swabs in French Guiana.

Previous molecular studies have shown that Candida africana corresponds to the clade 13 of Candia albicans. It has been mostly involved in vulvovaginal candidiasis worldwide but few data exist in South America. The aim of our study was to investigate the prevalence of C. africana in women living in French Guiana. For this, we first set up a fluorescent-intercalating-dye-real time Polymerase Chain Reaction (PCR) targeting the hyphal wall protein 1 gene. The test was applied to 212 C. albicans isolates collected from May to August 2019 from vaginal swabs, allowing the identification of six women harboring C. africana (eight isolates). The in vitro susceptibility of these eight isolates to six antifungal drugs was also evaluated. No demographics or clinical-specific features could be demonstrated. Genetic diversity of those isolates was analyzed through multilocus sequence typing and showed that diploid sequence type 182 was predominant (n = 6) and allowed the report of a new diploid sequence type.

Candida africana, the clade 13 of C. albicans, is characterized by specific genetic and phenotypic traits. Using a new molecular technique, we report a high prevalence of C. africana in vaginal swabs from patients living in French Guiana. The worldwide predominant genotype was detected in all but one patient.

The pathogenic and colonization potential of Candida africana.

The Candida albicans population displays high genetic diversity illustrated by 18-well differentiated genetic clusters. Cluster 13, also known as Candida africana, is an outlying cluster and includes strains first described as atypical C. albicans isolates of vaginal origin, showing apparent tropism for the female genital tract. In our study, we combined in vitro, and in vivo models to explore the colonization and pathogenic potential of C. africana. We report that C. africana has similar fitness to C. albicans when it comes to colonization of the oral and vaginal mucosa, however it has decreased fitness in gastro-intestinal colonization and systemic infection. Interestingly, despite high population homogeneity, our in vitro data highlighted for the first time a variability in terms of growth rate, biofilm formation and filamentation properties between C. africana strains. Overall, our data lays the foundations for exploring specific features of C. africana that might contribute to its apparent niche restriction.

Prevalence of Closely Related Candida albicans Species among Patients with Vulvovaginal Candidiasis in Southern Poland Based on the hwp1 Gene Amplification.

Candida albicans remains the most common species isolated from women with vulvovaginal candidiasis. However, closely related species such as Candida africana and Candida dubliniensis may also occur, although they are often misidentified. The aim of the study was to confirm the phenotypic identification of C. albicans and its closely related species isolated from women with genital tract infections by amplification of the hwp1 (hyphal wall protein 1) gene in a PCR assay. We report a detailed molecular identification of C. albicans and its closely related species among 326 patients in the Malopolska region, Poland. Initial phenotypic identifications were confirmed by amplification of the hwp1 gene. Based on molecular analysis, we revealed 307 strains (94.17%) as C. albicans and 17 as C. dubliniensis (5.22%). No strain of C. africana was detected. Two patients h ad co-infection with C. albicans and C. dubliniensis (0.61%). A PCR assay targeting the hwp1 gene was reliable for correctly identifying species among the C. albicans complex.

Activation of cytokine responses by Candida africana.

Candida africana is a fungal pathogen that rarely causes invasive infections, but is mainly isolated from patients with vaginal infections. Vulvovaginal candidiasis is associated with dysregulated inflammatory responses of the host, however, the innate immune responses against C. africana are currently unknown. In this study, we explored the cytokine production of human peripheral blood mononuclear cells (PBMCs) in response to different C. africana isolates (intra-species diversity), and compared it with that induced by other yeasts belonging to the C. albicans species complex such as C. dubliniensis and C. albicans. Candida africana isolates induced both pro- and anti-inflammatory cytokines broadly similar to other Candida species. Candida africana-stimulated PBMCs tended to produce lower Interleukin (IL)-17 and IL-22 levels in comparison with C. albicans, whereas the induction of trained immunity was similar between C. africana and other Candida species. Overall, our results demonstrate that C. africana induces similar innate immune responses as the other Candida species. Therefore, its propensity to cause vulvovaginal infections is not due to an increased capacity to induce cytokine-related immune pathology. Nor is the infrequent occurrence of invasive infection by C. africana explained by a quantitatively different cytokine induction.

Candida africana has been reported to cause vulvovaginal candidiasis. This study shows that C. africana induces broadly similar cytokine production and trained immunity as other Candida species. Its propensity to cause vaginal infections is not due to an enhanced capacity to cause immune dysregulation.

Overview on the Infections Related to Rare Candida Species.

Atypical Candida spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common Candida spp. is still Candida albicans; however, in the last decades, there has been an increase in non-Candida albicans Candida species infections (e.g., Candida glabrata, Candida parapsilosis, and Candida tropicalis). Furthermore, in the last 10 years, the reports on uncommon yeasts, such as Candida lusitaniae, Candida intermedia, or Candida norvegensis, have also worryingly increased. This review summarizes the information, mostly related to the last decade, regarding the infections, diagnosis, treatment, and resistance of these uncommon Candida species. In general, there has been an increase in the number of articles associated with the incidence of these species. Additionally, in several cases, there was a suggestive antifungal resistance, particularly with azoles, which is troublesome for therapeutic success.

Molecular identification and antifungal susceptibility profiles of Candida dubliniensis and Candida africana isolated from vulvovaginal candidiasis: A single-centre experience in Iran.

BACKGROUND: Vulvovaginal candidiasis (VVC) is a common and debilitating long-term illness affecting million women worldwide. This disease is caused mainly by Candida albicans and a lesser extent by other species, including the two phylogenetically closely related pathogens Candida africana and Candida dubliniensis. OBJECTIVES: In this study, we report detailed molecular epidemiological data about the occurrence of these two pathogenic yeasts in Iranian patients affected by VVC, or its chronic recurrent form (RVVC), and provide, for the first time, data on the antifungal activity of two new drugs, efinaconazole (EFN) and luliconazole (LUL). METHODS: A total of 133 vaginal yeast isolates, presumptively identified as C albicans by phenotypic and restriction analysis of rDNA, were further analysed by using a specific molecular method targeting the HWP1 gene. All C africana and C dubliniensis isolates were also tested for their in vitro susceptibility to a panel of modern and classical antifungal drugs. RESULTS AND CONCLUSIONS: Based on the molecular results, among 133 germ-tube positive isolates, we identify 119 C albicans (89.47%), 11 C africana (8.27%) and 3 C dubliniensis (2.26%) isolates. C africana and C dubliniensis showed low MIC values for most of the antifungal drugs tested, especially for EFN and LUL, which exhibited a remarkable antifungal activity. High MIC values were observed only for nystatin and terbinafine. Although C albicans remains the most common Candida species recovered from Iranian VVC/RVVC patients, our data show that its prevalence may be slightly overestimated due to the presence of difficult-to-identify closely related yeast, especially C africana.

Differentiation of Candida albicans complex species isolated from invasive and non-invasive infections using HWP1 gene size polymorphism.

BACKGROUND AND PURPOSE: Taxonomy of Candida is controversial and has changed due to the investigation of the novel species. Candida africana and Candida dubliniensis are new members of the C. albicans complex that are currently gaining both clinical and epidemiologic significance. This study aimed to report the prevalence of C. africana among the strains isolated from patients using hyphal wall protein 1 (HWP1) gene size polymorphism. MATERIALS AND METHODS: In total, 235 yeasts confirmed as C. albicans complex based on chromogenic media and internal transcribed spacers sequencing isolated from various clinical forms of invasive and non-invasive candidiasis mainly candidemia were re-identified using HWP1 gene polymorphisms. The HWP1-polymerase chain reaction amplicons were re-confirmed by sequencing and BLAST analysis. RESULTS: Based on the HWP1 gene size polymorphism, 223 strains were identified as C. albicans (94.89%) from which 7 isolates produced two DNA fragments (850 and 941 bp). The C. dubliniensis (n=4, 1.7%), C. africana (n=1, 0.42%), and mix of C. albicans and C. africana (n=7, 2.97%) were also identified. CONCLUSION: It can be said that C. albicans remains the most common Candida species, while C. dubliniensis and C. africana are rarely found among the patient isolates. Due to limited information on the molecular epidemiology of this novel yeast, more studies using molecular methods are recommended.

Robust, Comprehensive Molecular, and Phenotypical Characterisation of Atypical Candida albicans Clinical Isolates From Bogotá, Colombia.

Candida albicans is commensal in human microbiota and is known to be the commonest opportunistic pathogen, having variable clinical outcomes that can lead to up to 60% mortality. Such wide clinical behaviour can be attributed to its phenotypical plasticity and high genetic diversity. This study characterised 10 Colombian clinical isolates which had already been identified as C. albicans by molecular tests; however, previous bioinformatics analysis of protein mass spectra and phenotypical characteristics has shown that this group of isolates has atypical behaviour, sharing characteristics of both C. africana and C. albicans. This study was aimed at evaluating atypical isolates' pathogenic capability in the Galleria mellonella model; susceptibility profiles were determined and MLST was used for molecular characterisation. Cluster analysis, enabling unbiased bootstrap to classify the isolates and establish their cluster membership and e-BURST, was used for establishing clonal complexes (CC). Both approaches involved using representative MLST data from the 18 traditional C. albicans clades, as well as C. albicans-associated and minor species. Ten atypical isolates were distributed as follows: 6/10 (B71, B41, B60, R6, R41, and R282) were grouped into a statistically well-supported atypical cluster (AC) and constituted a differentiated CC 6; 2/10 of the isolates were clearly grouped in clade 1 and were concurrent in CC 4 (B80, B44). Another 2/10 atypical isolates were grouped in clade 10 and concurred in CC 7 (R425, R111); most atypical isolates were related to geographically distant isolates and some represented new ST. Isolates B41 and R41 in the AC had greater virulence. Isolate B44 was fluconazole-resistant and was grouped in clade 1. The atypical nature of the isolates studied here was demonstrated by the contrast between phenotypical traits (C. africana-like), molecular markers (C. albicans-like), virulence, and antifungal resistance, highlighting the widely described genetic plasticity for this genus. Our results showed that the atypical isolates forming well-differentiated groups belonged to C. albicans. Our findings could contribute towards developing molecular epidemiology approaches for managing hospital-acquired infection.

Candida africana and Candida dubliniensis as causes of pediatric candiduria: A study using HWP1 gene size polymorphism.

BACKGROUND: Candida species cause a wide spectrum of disease entities. Candida africana and Candida dubliniensis-members of Candida albicans complex-are currently gaining both clinical and epidemiologic significance. MATERIALS AND METHODS: Totally, 150 pediatric isolates that had previously been identified as C. albicans species complex based on a positive germ tube test were included. The isolates were cultured on CHROMagar Candida medium to ensure their purity and the results of germ tube test. For definitive speciation, PCR amplification and size polymorphism of the hyphal wall protein 1 (HWP1) gene was used. The results of HWP1-PCR were confirmed by sequencing the amplified fragments for randomly selected isolates of C. africana and C. dubliniensis. RESULTS: All 150 isolates included in this study were reconfirmed as C. albicans complex on chromogenic media. Based on the HWP1 gene size polymorphism, 141 (94%) isolates were identified as C. albicans, 2 (1.33%) as C. africana, and 1 (0.67%) as C. dubliniensis. The remaining 6 (4%) C. albicans complex isolates were a mix of C. albicans and C. africana. All isolates of C. africana and C. dubliniensis have been recovered from cases of candiduria. CONCLUSION: C. africana, either alone or mixed with C. albicans, could be a cause of candiduria among pediatric patients and should not be ignored.

Candida africana vulvovaginitis: Prevalence and geographical distribution.

Candida africana has been recovered principally as a causative agent of vulvovaginal candidiasis (VVC) from different countries, which is likely to be misidentified as the typical Candida albicans or Candida dubliniensis. The current study aimed to characterize C. albicans species complex obtained from VVC based on conventional and molecular assays. Furthermore, in vitro antifungal susceptibility testing was performed based on CLSI documents. Additionally, due to low knowledge concerning C. africana infections, we reviewed all published papers from 1991 to 2019. One hundred forty-four out of 287 patients were identified with Candida infection, among whom 151 isolates of Candida were obtained. Candida albicans 109 (72.1%), Candida glabrata 21 (13.9%), Candida krusei 8 (5.2%), Candida tropicalis 5 (3.3%), Candida africana 3 (1.9%), Candida parapsilosis 3 (1.9%) and C. dubliniensis 2 (1.3%) were isolated from patients. MIC results showed that C. africana isolates were susceptible to all tested antifungal drugs. Candida africana infections were more prevalent in Africa. One hundred fifteen (40.6%) of patients with C. africana candidiasis were from seven African countries, and Madagascar and Angola had the majority of cases. The epidemiological data, phenotypic, clinical features, ecologic similarity, and antifungal susceptibility profiles for better understanding of the pathogenic mechanisms and optimal treatment underlying non-CandidaalbicansCandida vulvovaginitis are highly recommended.

Low prevalence of antifungal resistant Candida africana, in the C. albicans complex causing vulvovaginal candidiasis.

The Candida (C.) albicans complex includes C. albicans, C. dubliniensis, C. stellatoidea, and C. africana, with the last mentioned as an important emerging agent of vulvovaginal candidiasis (VVC). The aim of the study was to identify C. africana and C. dubliniensis and assess their drug susceptibility in vaginitis. One-hundred Candida isolates of the C. albicans complex from women diagnosed with vaginitis and from vaginal samples in the culture collection of a medical mycology laboratory were examined. Species of the C. albicans complex were identified with conventional and molecular methods using polymerase chain reaction (PCR) for amplification and sequencing of the internal transcribed spacer (ITS) region, PCR for partial amplification of hyphal wall protein 1 (HWP1) gene and duplex PCR. The effects of antifungal drugs were evaluated according to standard broth microdilution protocols. Ninety-seven C. albicans (97%) and three C. africana (3%) isolates were identified. Results of susceptibility testing revealed one isolate of C. africana to be resistant to both clotrimazole and fluconazole, and one showed reduced susceptibility to itraconazole. Identification of Candida species especially C. africana in vaginitis is crucial, there are varying levels of resistance to antifungal drugs.

Isolation of Candida africana in oral candidiasis: First report among cancer patients in Iran.

BACKGROUND AND PURPOSE: Oropharyngeal candidiasis (OPC) is a fungal infection of the oral cavity caused by the members of C. albicans complex. Although C. africana, as a part of the complex, is considered to be mostly responsible for the development of vulvovaginal candidiasis, it may be associated with a wider clinical spectrum. CASE REPORT: This report described two cases diagnosed with oral candidiasis during the receipt of treatment for malignancies. Conventional and molecular tests were performed on the samples collected from the patients' oral cavities. The test results revealed C. africana as the causative agent of oral candidiasis. Furthermore, in vitro antifungal susceptibility test indicated the full susceptibility of all C. africana isolates to caspofungin. However, the data were also suggestive of the resistance against fluconazole and amphotericin B. Caspofungin was used as the main antifungal agent for the treatment of oral candidiasis, resulting in the improvement of thrush in patients. The resistance of C. africana to fluconazole and amphotericin B suggests the necessity of performing in vitro susceptibility testing on the isolates for the selection of appropriate antifungal agents. CONCLUSION: As the findings indicated, the achievement of knowledge regarding C. africana as an emerging non-albicans Candida species and its antifungal susceptibility profile is crucial to select antifungal prophylaxis and empirical therapy for oral candidiasis in cancer patients undergoing chemotherapy. NONE: non.

Genetic diversity of Candida albicans isolates recovered from hospital environments and patients with severe acquired brain injuries.

Although the epidemiology of pathogenic Candida species causing invasive human diseases is changing, Candida albicans still remains the most common cause of bloodstream infections worldwide. The propensity of this pathogen to cause infections is undoubtedly the result of its unique genetic plasticity that allow it to adapt and respond quickly to a myriad of changing conditions both in the host and in the environment. For this reason, we decided to investigate the genetic diversity of this important fungal pathogen in a particular category of patients with severe neurological deficits including the hospital environments where they are hospitalized. Genetic diversity of 21 C. albicans isolates recovered from blood, hands of healthcare workers and hospital environments was evaluated by using multilocus sequence typing (MLST) which revealed a high genetic heterogeneity with a set of 18 diploid sequence types (DSTs) recovered among 21 isolates investigated. Interestingly, 13 of these 18 MLST genotypes were completely new and added to the C. albicans MLST central database. Six eBURST clonal complexes (CC-1, CC-2, CC-6, CC-9, CC-27 and CC-42) and three singletons contained all DSTs found in this study. Among all the new DSTs identified, DST3388 was the most intriguing as this genotype was recovered from a typical C. albicans isolate clustering within the MLST-Clade 13, the most divergent evolutionary lineage within C. albicans population containing only isolates with unusual phenotypes originally known as Candida africana. In conclusion, the results of this study expand our understanding of the molecular epidemiology and global population structure of C. albicans suggesting that further studies on different categories of patients and hospital environments are needed to better understand how the population of this species adapts and evolves in heterogeneous hosts and changing environments.

Multilocus sequence typing analysis of Candida africana from vulvovaginal candidiasis.

BACKGROUND: Candida africana is distributed worldwide and colonized in human genitalia and cause mainly vulvovaginal candidiasis (VVC). We report the multilocus sequence typing (MLST) analysis of C. africana from VVC. METHODS: MLST analysis of 43 strains of C. africana, which were isolated from vaginal specimens of patients with VVC, was performed. The enzymatic activity of phospholipase, esterase and haemolysis enzyme production was evaluated.The level of virulent genes and resistant genes mRNA expression was determined by using real-time PCR. Antifungal susceptibilities of the isolates were assayed by using the broth microdilution method. The statistical of the results was determined by the T test and Pearson chi-squared test. RESULTS: The MLST analysis revealed a substantial degree of genetic homogeneity. The DST782 and DST182 were the main MLST genotypes in C. africana. All the patients were symptomatic and with a high mycological cure rate when treated with commonly used antifungal agents.There were statistically significant differences in biofilm formation and phospholipase activity between C. africana and C.albicans. The level of virulent genes and resistant genes mRNA expression was higher in fluconazole-resistant strains. All C. africana isolates were susceptible to fluconazole, itraconazole, voriconazole, caspofungin, and micafungin. These isolates also exhibited low MICs to amphotericin B, flucytosine, and posaconazole. CONCLUSIONS: Candida africana appear to be with a low level of sequence variation in MLST loci. Candida africana, a lower virulence candida, is susceptible to commonly used antifungal agents. This paper was presented at the conference of 8th Trend in Medical Mycology (6-9 October 2017, Belgrade, Serbia) and was published on conference abstract.

Candida africana in recurrent vulvovaginal candidiasis (RVVC) patients: frequency and phenotypic and genotypic characteristics.

PURPOSE: Up to 75 % of all women develop vulvovaginal candidiasis (VVC), with symptoms such as vulvar erythema, pruritus and abnormal vaginal discharge. Despite the global distribution of Candida africana, its role in recurrent vulvovaginal candidiasis (RVVC) is still unclear and requires further investigation. Here, we report on the frequency of C. africana among clinical isolates from patients with RVVC in Bushehr in southern Iran. METHODOLOGY: Isolated Candida strains were identified by ITS-PCR-RFLP. Hyphal wall protein 1 (HWP1) was amplified to differentiate C. africana and the resulting sequences were subjected to phylogenetic analyses with a view to identifying similarities and differences in nucleotides. RESULTS: Ten out of 119 strains originally identified as C. albicans turned out to be C. africana. Pairwise nucleotide alignment of HWP1 DNA sequences showed 100 % similarity between C. africana strains. Inter-species variation between Iranian C. africana HWP1 sequences and the only three available C. africana type sequences in GenBank revealed 99.7-100 % nucleotide similarity. Phylogenetic analysis of the HWP1 DNA sequences of 10 Iranian C. africana isolates, the 3 C. africana sequences available in GenBank and 2 representative Iranian C. albicans sequences revealed that all 11 Iranian C. africana strains formed a well-supported cluster separated from the remaining C. africana. CONCLUSION: In our sample, C. africana was only isolated from 7.8 % of the patients with RVVC. While size polymorphisms in HPW1 genes allowed us to differentiate C. africana from C. albicans, no evidence of sequence variation within the Iranian C. africana isolates was observed.

Whole RNA-Sequencing and Transcriptome Assembly of Candida albicans and Candida africana under Chlamydospore-Inducing Conditions.

Candida albicans is the most common cause of life-threatening fungal infections in humans, especially in immunocompromised individuals. Crucial to its success as an opportunistic pathogen is the considerable dynamism of its genome, which readily undergoes genetic changes generating new phenotypes and shaping the evolution of new strains. Candida africana is an intriguing C. albicans biovariant strain that exhibits remarkable genetic and phenotypic differences when compared with standard C. albicans isolates. Candida africana is well-known for its low degree of virulence compared with C. albicans and for its inability to produce chlamydospores that C. albicans, characteristically, produces under certain environmental conditions. Chlamydospores are large, spherical structures, whose biological function is still unknown. For this reason, we have sequenced, assembled, and annotated the whole transcriptomes obtained from an efficient C. albicans chlamydospore-producing clinical strain (GE1), compared with the natural chlamydospore-negative C. africana clinical strain (CBS 11016). The transcriptomes of both C. albicans (GE1) and C. africana (CBS 11016) clinical strains, grown under chlamydospore-inducing conditions, were sequenced and assembled into 7,442 (GE1 strain) and 8,370 (CBS 11016 strain) high quality transcripts, respectively. The release of the first assembly of the C. africana transcriptome will allow future comparative studies to better understand the biology and evolution of this important human fungal pathogen.

Prevalence of Candida albicans, Candida dubliniensis and Candida africana in pregnant women suffering from vulvovaginal candidiasis in Argentina.

BACKGROUND: Vulvovaginal candidiasis (VVC) is a vulvovaginitis commonly diagnosed in gynecology care. In recent years, the taxonomy of the most important pathogenic Candida species, such as Candida albicans have undergone significant changes. AIMS: This study examined the prevalence of C. albicans, Candida africana, and Candida dubliniensis in vaginal specimens from 210 pregnant women suffering from vulvovaginitis or having asymptomatic colonization. METHODS: Phenotypic and molecular methods were used for the identification of the species. RESULTS: During the studied period, 55 isolates of Candida or other yeasts were obtained from specimens collected from 52 patients suffering from vulvovaginitis (24.8%). C. albicans was the predominant Candida species in 42 isolates (80.7%), either alone or in combination with other species of the genus (5.7%, n=3). Additionally, nine isolates of C. albicans (50%) were obtained from asymptomatic patients (n=18). C. dubliniensis was the causative agent in 2 (3.8%) cases of VVC, and was also isolated in one asymptomatic patient. Molecular assays were carried out using specific PCR to amplify the ACT1-associated intron sequence of C. dubliniensis. The amplification of the HWP1 gene also correctly identified isolates of the species C. albicans and C. dubliniensis. No C. africana was isolated in this work. Some C. albicans isolates were either homozygous or heterozygous at the HWP1 locus. The distribution of heterozygous and homozygous C. albicans isolates at the HWP1 locus was very similar among patients suffering from VVC and asymptomatic patients (p=0.897). CONCLUSIONS: The presence of C. albicans and C. dubliniensis, and the absence of C. africana in pregnant is noteworthy.

Whole Genome-Based Amplified Fragment Length Polymorphism Analysis Reveals Genetic Diversity in Candida africana.

This study aimed at investigating the genetic diversity of a panel of Candida africana strains recovered from vaginal samples in different countries. All fungal strains were heterozygous at the mating-type-like locus and belonged to the genotype A of Candida albicans. Moreover, all examined C. africana strains lack N-acetylglucosamine assimilation and sequence analysis of the HXK1 gene showed a distinctive polymorphism that impair the utilization of this amino sugar in this yeast. Multi-locus sequencing of seven housekeeping genes revealed a substantial genetic homogeneity among the strains, except for the CaMPIb, SYA1 and VPS13 loci which contributed significantly to the classification of our set of C. africana strains into six existing diploid sequence types. Amplified fragment length polymorphism fingerprint analysis yielded greater genotypic heterogeneity among the C. africana strains. Overall the data reported here show that in C. africana genetic diversity occurs and the existence of this intriguing group of C. albicans strains with specific phenotypes associated could be useful for future comparative studies in order to better understand the genetics and evolution of this important human pathogen.

Postantifungal effect of caspofungin against the Candida albicans and Candida parapsilosis clades.

Killing and postantifungal effects could be relevant for the selection of optimal dosing schedules. This study aims to compare time-kill and postantifungal effects with caspofungin on Candida albicans (C. albicans, Candida dubliniensis, Candida africana) and Candida parapsilosis (C. parapsilosis, Candida metapsilosis, Candida orthopsilosis) clades. In the postantifungal effect experiments, strains were exposed to caspofungin for 1 h at concentrations 0.12-8 µg/mL. Time-kill experiments were conducted at the same concentrations. Caspofungin exhibited a significant and prolonged postantifungal effect (>37 h) with 2 µg/mL against the most strains of C. albicans clade. Against the C. parapsilosis clade, the postantifungal effect was <12 h at 8 µg/mL, except for two strains. Caspofungin was fungicidal against C. albicans, C. dubliniensis and C. metapsilosis.

Prevalencia y sensibilidad a los antifúngicos de Candida albicans y sus especies relacionadas, Candida dubliniensis y Candida africana aisladas de muestras vulvovaginales en un hospital de Argentina / Prevalence and antifungal susceptibility of Candida albicans and its related species Candida dubliniensis and Candida africana isolated from vulvovaginal samples in a hospital of Argentina

Candida africana taxonomical status is controversial. It was proposed as a separate species within the Candida albicans species complex; however, phylogenetic analyses suggested that it is an unusual variety of C. albicans. The prevalence of C. albicans-related species (Candida dubliniensis and C. africana) as vulvovaginal pathogens is not known in Argentina. Moreover, data on antifungal susceptibility of isolates causing vulvovaginal candidiasis is scarce. The aims of this study were to establish the prevalence of C. dubliniensis and C. africana in vaginal samples and to evaluate the antifungal susceptibilities of vaginal C. albicans species complex strains. We used a molecular-based method coupled with a new pooled DNA extraction methodology to differentiate C. dubliniensis and C. africana in a collection of 287 strains originally identified as C. albicans isolated from an Argentinian hospital during 2013. Antifungal susceptibilities to fluconazole, clotrimazole, itraconazole, voriconazole, nystatin, amphotericin B and terbinafine were evaluated by using the CLSI M27-A3 and M27-S4 documents. Of the 287 isolates, 4 C. dubliniensis and one C. africana strains (1.39% and 0.35% prevalence, respectively) were identified. This is the first description of C. africana in Argentina and its identification was confirmed by sequencing the ITS2 region and the hwp1 gene. C. dubliniensis and C. africana strains showed very low MIC values for all the tested antifungals. Fluconazole-reduced-susceptibility and azole cross-resistance were observed in 3.55% and 1.41% of the C. albicans isolates, respectively. These results demonstrate that antifungal resistance is still a rare phenomenon in this kind of isolates.

La clasificación taxonómica de Candida africana está en discusión, es considerada una nueva especie dentro del complejo C. albicans o una variedad inusual de C. albicans. La prevalencia de las especies relacionadas a C. albicans (C. dubliniensis y C. africana) como agentes de vulvovaginitis en Argentina se desconoce. Los objetivos de este trabajo fueron determinar la prevalencia de C. dubliniensis y C. africana en muestras vaginales y evaluar la sensibilidad a los antifúngicos de aislamientos vaginales de las especies del complejo C. albicans. Para diferenciar C. dubliniensis y C. africana utilizamos un método molecular asociado a un nuevo método de extracción de ADN. Se utilizó una colección de 287 cepas originalmente identificadas como C. albicans aisladas durante 2013 en un hospital de Argentina. Se evaluó la sensibilidad a fluconazol, clotrimazol, itraconazol, voriconazol, nistatina, anfotericina B y terbinafina utilizando los documentos M27-A3 y M27-S4 del CLSI. De los 287 aislamientos, se identificaron 4 C. dubliniensis y 1 C. africana (1,39 y 0,35% de prevalencia, respectivamente). Esta es la primera descripción de C. africana en Argentina. Su identificación fue confirmada por secuenciación de la región ITS2 y del gen hwp1. Las cepas identificadas como C. dubliniensis y C. africana mostraron valores de CIM muy bajos para todos los antifúngicos probados. En los aislamientos de C. albicans, la sensibilidad reducida al fluconazol y la resistencia cruzada a todos los azoles se observó en el 3,55% y el 1,41%, respectivamente. Estos resultados demuestran que la resistencia a los antifúngicos es todavía un fenómeno raro en este tipo de aislamientos.