Identification of Molecular and Genetic Resistance Mechanisms in a Candida auris Isolate in a Tertiary Care Center in Türkiye.

BACKGROUND: Candida auris is a multidrug-resistant pathogen that causes nosocomial outbreaks and high mortality. We conducted this study to investigate the molecular mechanisms of antifungal resistance in our clinical isolate of C. auris with a high level of resistance to three main classes of antifungals. MATERIAL AND METHODS: A clinical C. auris isolate was identified by MALDI-TOF MS and antifungal susceptibilities were determined by the Sensititre YeastOne YO10 panel. After sequencing the whole genome of the microorganism with Oxford Nanopore NGS Technologies, a phylogenetic tree was drawn as a cladogram to detect where the C. auris clade to this study's assembly belongs. RESULTS: The C. auris isolate in this study (MaCa01) was determined to be a part of the clade I (South Asian). The resistance-related genes indicated that MaCa01 would most likely be highly resistant to fluconazole (CDR1, TAC1b, and ERG11), none or little resistant to amphotericin B (AmpB) and echinocandins, and sensitive to flucytosine. The mutations found in the above-mentioned genes in the Türkiye C. auris isolate reveals an antifungal resistance pattern. This molecular resistance pattern was found consistent with the interpretation of MIC values of the antifungals according to CDC tentative breakpoints. CONCLUSION: We detected the well-known antifungal resistance mutations, responsible for azole resistance in C. auris. Despite no ERG2, ERG6, and FKS mutation identified, the isolate was found to be resistant to AmpB and caspofungin based on the CDC tentative breakpoints which could be related to unidentified mutations.

Nosocomial infection of C. auris in COVID-19 Intensive Care Unit in Türkiye and Phylogenetic Analysis of Isolates.

BACKGROUND: The difficulties in the identification of C. auris and the delays in the implementation of infection control precautions contribute to outbreaks. This study analyzed 10 patients with COVID-19 and C. auris candidemia, their characteristic and clinical features and phylogenetic features, and the antifungal susceptibilities of the isolates. METHOD: C. auris were detected in the COVID-19 ICU of a university hospital between January and August 2021. Identification to species level was performed using MALDI-TOF MS. Antifungal susceptibilities were determined by the Sensititre YeastOne YO10 panel. The isolates were whole genome sequenced to assess genetic relatedness and a phylogenetic tree was drawn including various C. auris clades. RESULTS: The mean growth time in blood cultures was 38.8 h. C. auris candidemia developed on the average 27th day of ICU admission. All were susceptible to anidulafungin and micafungin, while they were resistant to fluconazole and amphotericin B. Only three isolates were found to be resistant to caspofungin. All patients died. With the WGS method, all isolates were found in a close resemblance to each other in terms of total nucleotide similarity (with a minimum of 96% pairwise alignment). Our isolates showed the closest similarity to South Asian clade (Clade I). CONCLUSIONS: This study is the first to evaluate the phylogenetic characteristics of C. auris using WGS and to determine antifungal susceptibilities in Türkiye on COVID-19 patients. The mortality rate was very high in patients who have both COVID-19 and C. auris candidemia.

Frequency of azole resistance in clinical and environmental strains of Aspergillus fumigatus in Turkey: a multicentre study.

OBJECTIVES: Aspergillus fumigatus causes several diseases in humans and azole resistance in A. fumigatus strains is an important issue. The aim of this multicentre epidemiological study was to investigate the prevalence of azole resistance in clinical and environmental A. fumigatus isolates in Turkey. METHODS: Twenty-one centres participated in this study from 1 May 2018 to 1 October 2019. One participant from each centre was asked to collect environmental and clinical A. fumigatus isolates. Azole resistance was screened for using EUCAST agar screening methodology (EUCAST E.DEF 10.1) and was confirmed by the EUCAST E.DEF 9.3 reference microdilution method. Isolates with a phenotypic resistance pattern were sequenced for the cyp51A gene and microsatellite genotyping was used to determine the genetic relationships between the resistant strains. RESULTS: In total, resistance was found in 1.3% of the strains that were isolated from environmental samples and 3.3% of the strains that were isolated from clinical samples. Mutations in the cyp51A gene were detected in 9 (47.4%) of the 19 azole-resistant isolates, all of which were found to be TR34/L98H mutations. Microsatellite genotyping clearly differentiated the strains with the TR34/L98H mutation in the cyp51A gene from the strains with no mutation in this gene. CONCLUSIONS: The rate of observed azole resistance of A. fumigatus isolates was low in this study, but the fact that more than half of the examined strains had the wild-type cyp51A gene supports the idea that other mechanisms of resistance are gradually increasing.

Cryptococcus meningitis presented with multiple cerebral infarcts in an immunocompetent patient.

Cryptococcus neoformans is generally observed with immunosuppressive conditions. Rarely, it may be seen in immunocompetent individuals and presented with non-specific conditions. We described an immunocompetent case of cryptococcal meningitis presented with multiple cerebral infarcts. Despite the late diagnosis and emergence of hydrocephalus during treatment, the patient was recovered without any sequelae. In immunocompetent patients, the conventional diagnostics tests may be negative because of the low fungal load. If it is available, the Biofire FilmArray meningitis panel has high sensitivity and specificity for diagnosis.

[Distribution of Yeast Species Isolated from Blood Cultures for a Six Year Period in Turkey: a Multicentre Study]. / Türkiye'de Alti Yillik Zaman Dilimi Içerisinde Kan Kültürlerinden Soyutlanan Maya Mantarlarinin Tür Dagilimi: Çok Merkezli Bir Çalisma.

Bloodstream infections due to yeast species especially Candida spp. have been reported to be important healthcare associated infections with high mortality and morbidity rates. Candidemia causes prolonged hospital stays as well as increased cost. In order to prevent or treat these life-threatening bloodstream infections successfully, nationwide epidemiological data should be available about the etiological agents of these infections. Multi-centre national epidemiological data on yeast bloodstream infections in Turkey is lacking. A retrospective study was designed and data from six different centres in Turkey between 2011 and 2016 years were gathered and analysed for the distribution and frequency of yeast species in order to assist clinicians in their choice of early and appropriate antifungal therapy. All laboratories used automated blood culture systems for the isolation of blood strains. All the participating centres performed the identification of their own isolates by conventional methods using germ tube test, morphology on corn meal agar with tween 80 and chromogenic media and the identification was confirmed by API 20C AUX, API ID 32C or matrix-assisted laser desorption/ionization time of flight mass spectrophotometry (MALDI-TOF MS) systems. The analysis of the results was performed on the basis of intensive care units (ICUs), other inpatient clinics (OICs) and totally all clinics (ACs). Totally 2547 yeast isolates were determined from six participating centres during six years. According to the total ACs results, Candida albicans was the most prevalent species (43.1%), followed by Candida parapsilosis complex (29.1%), Candida glabrata (10.1%), Candida tropicalis (7.5%), Candida krusei (2.4%) and Candida kefyr (1.6%) and the remaining (6.2%) of them consisted of other yeast species. The distribution of the Candida species did not show statistically significant difference between the years, however the increase of C.parapsilosis complex in 2016 was statistically significant, (p= 0.02). During the study period, totally 1054 yeast isolates were obtained from the ICUs of the centres. C.albicans predominated with 476 (45.2%) isolates and C.parapsilosis complex (28.7%), C.glabrata (10.7%) and C.tropicalis (7.3%) were the other leading species in ICUs. Among 1493 isolates of the OICs of six centres participated in the study, C.albicans was the most prevalent species with 622 (41.7%) isolates. The other frequent species of OICs were C.parapsilosis complex (29.5%), C.glabrata (9.6%) and C.tropicalis (7.6%) resembling ICU results. It can be concluded that C.albicans is still the leading cause of bloodstream infections in the six different centres located in various geographical areas of Turkey.

Genotypes and population genetics of cryptococcus neoformans and cryptococcus gattii species complexes in Europe and the mediterranean area.

A total of 476 European isolates (310 Cryptococcus neoformans var. grubii, 150 C. neoformans var. neoformans, and 16 C. gattii species complex) from both clinical and environmental sources were analyzed by multi-locus sequence typing. Phylogenetic and population genetic analyses were performed. Sequence analysis identified 74 sequence types among C. neoformans var. neoformans (VNIV), 65 among C. neoformans var. grubii (56 VNI, 8 VNII, 1 VNB), and 5 among the C. gattii species complex (4 VGI and 1 VGIV) isolates. ST23 was the most frequent genotype (22%) among VNI isolates which were mostly grouped in a large clonal cluster including 50% of isolates. Among VNIV isolates, a predominant genotype was not identified. A high percentage of autochthonous STs were identified in both VNI (71%) and VNIV (96%) group of isolates. The 16 European C. gattii species complex isolates analyzed in the present study originated all from the environment and all belonged to a large cluster endemic in the Mediterranean area. Population genetic analysis confirmed that VNI group of isolates were characterized by low variability and clonal expansion while VNIV by a higher variability and a number of recombination events. However, when VNI and VNIV environmental isolates were compared, they showed a similar population structure with a high percentage of shared mutations and the absence of fixed mutations. Also linkage disequilibrium analysis reveals differences between clinical and environmental isolates showing a key role of PLB1 allele combinations in host infection as well as the key role of LAC1 allele combinations for survival of the fungus in the environment. The present study shows that genetic comparison of clinical and environmental isolates represents a first step to understand the genetic characteristics that cause the shift of some genotypes from a saprophytic to a parasitic life style.

First multicentre report of in vitro resistance rates in candidaemia isolates in Turkey.

OBJECTIVES: This study investigated the antifungal resistance rates of isolates from candidaemia patients in 12 tertiary-care centres in Turkey. METHODS: A total of 1991 Candida spp. isolates from 12 centres isolated from 1997-2017 were included in the study. Species/species complex (SC) identification was performed using conventional methods in all centres, occasionally accompanied by MALDI-TOF/MS. Antifungal susceptibility testing was performed for amphotericin B, fluconazole, itraconazole, posaconazole, voriconazole and micafungin (as echinocandin class representative) using the CLSI microdilution method. Resistance rates were determined according to CLSI clinical breakpoints (CBPs). For drugs and species with undetermined CBPs, epidemiological cut-off values were used for wild-type (WT)/non-WT categorisation. RESULTS: No or low rates of resistance were detected in general for tested Candida spp. isolates. Specifically, overall resistance to fluconazole in isolates of Candida parapsilosis SC and Candida glabrata SC were 7.7% and 0.9%, respectively. Resistance rates for C. parapsilosis SC varied extensively from one center to other (0-47.1%). Importantly, no echinocandin resistance was detected. Rates of non-WT isolates were also generally low: fluconazole against Candida lusitaniae, 4.3%; posaconazole against C. parapsilosis SC, 3.5%; posaconazole against Candida krusei, 1.9%; and voriconazole against C. glabrata SC, 0.5%. CONCLUSION: This is the first multicentre report of antifungal resistance rates among candidaemia isolates in Turkey, suggesting low resistance rates in general. Due to varying rates of fluconazole resistance in C. parapsilosis SC isolates that was detected at remarkably high levels in some centres, further studies are warranted to explore the source, clonal relatedness and resistance mechanisms of the isolates.

Fundamental niche prediction of the pathogenic yeasts Cryptococcus neoformans and Cryptococcus gattii in Europe.

Fundamental niche prediction of Cryptococcus neoformans and Cryptococcus gattii in Europe is an important tool to understand where these pathogenic yeasts have a high probability to survive in the environment and therefore to identify the areas with high risk of infection. In this study, occurrence data for C. neoformans and C. gattii were compared by MaxEnt software with several bioclimatic conditions as well as with soil characteristics and land use. The results showed that C. gattii distribution can be predicted with high probability along the Mediterranean coast. The analysis of variables showed that its distribution is limited by low temperatures during the coldest season, and by heavy precipitations in the driest season. C. neoformans var. grubii is able to colonize the same areas of C. gattii but is more tolerant to cold winter temperatures and summer precipitations. In contrast, the C. neoformans var. neoformans map was completely different. The best conditions for its survival were displayed in sub-continental areas and not along the Mediterranean coasts. In conclusion, we produced for the first time detailed prediction maps of the species and varieties of the C. neoformans and C. gattii species complex in Europe and Mediterranean area.

Risk factors, characteristics, and outcomes of candidemia in an adult intensive care unit in Turkey.

Thirty-six patients with candidemia and 37 control patients were included consecutively to determine the characteristics of candidemia episodes. The patients with candidemia had higher mortality with higher Sequential Organ Failure Assessment scores and frequency of use of a central venous catheter, total parenteral nutrition, and broad-spectrum antibiotics; chronic renal failure with replacement therapy; and longer stay in an intensive care unit. Candida albicans was the predominant species followed by Candida glabrata, Candida tropicalis, and Candida parapsilosis. All isolates of C glabrata were itraconazole-resistant.

Environmental distribution of Cryptococcus neoformans and C. gattii around the Mediterranean basin.

In order to elucidate the distribution of Cryptococcus neoformans and C. gattii in the Mediterranean basin, an extensive environmental survey was carried out during 2012-2015. A total of 302 sites located in 12 countries were sampled, 6436 samples from 3765 trees were collected and 5% of trees were found to be colonized by cryptococcal yeasts. Cryptococcus neoformans was isolated from 177 trees and C. gattii from 13. Cryptococcus neoformans colonized 27% of Ceratonia, 10% of Olea, Platanus and Prunus trees and a lower percentage of other tree genera. The 13 C. gattii isolates were collected from five Eucalyptus, four Ceratonia, two Pinus and two Olea trees. Cryptococcus neoformans was distributed all around the Mediterranean basin, whereas C. gattii was isolated in Greece, Southern Italy and Spain, in agreement with previous findings from both clinical and environmental sources. Among C. neoformans isolates, VNI was the prevalent molecular type but VNII, VNIV and VNIII hybrid strains were also isolated. With the exception of a single VGIV isolate, all C. gattii isolates were VGI. The results confirmed the presence of both Cryptococcus species in the Mediterranean environment, and showed that both carob and olive trees represent an important niche for these yeasts.

Postoperative keratitis due to Paecilomyces: a rare pediatric case.

Fungal infections like Paecilomyces keratitis have emerged in childhood recently. The diagnosis and treatment of Paecilomyces keratitis is difficult and the outcome is usually poor. Corneal culture should be performed on fungal media such as Sabouraud glucose neopeptone agar (SDA) as soon as possible for diagnosis. We report a rare case of Paecilomyces keratitis in an immunocompetent child, which was unresponsive to amphotericin B. The case was managed by a multidisciplinary approach involving the departments of ophthalmology, microbiology and pediatric infectious diseases. We want to draw attention once again that fungal keratitis caused by unusual agents are increasing. Physicians should consider fungal causes of keratitis, in patients with some predisposing factors like ocular surgery and prolonged use of topical corticosteroids.

[Neonatal Candida infections and the antifungal susceptibilities of the related Candida species]. / Neonatal kandida enfeksiyonlari ve etkenlerinin antifungal duyarliliklari

Among nosocomial infections in the newborns, the incidence of fungal infections has been rising over the last decades. Fluconazole has been a new option for treatment however, expanded use of the drug brought up the development of resistance. In this study, species of the Candida isolates from neonates with candida infections, their antifungal susceptibilities and the effectiveness of the therapy were evaluated. All the species of Candida isolates from blood, urine and sterile body fluids of 54 neonates and their antifungal susceptibilities were evaluated retrospectively over the 13-year period. Demographic characteristics, risk factors, infection foci, Candida species causing infection and their in vitro susceptibilities for fluconazole (FCZ) and amphotericin B (AMB) and treatment responses were analyzed. The antifungal susceptibility testing of isolates was performed by microdilution technique. The median birth weight and gestational age of the study groups were 1735 (660-3990) g and 33 (24-40) weeks, respectively. Among the patients, 19 (35%) were term, while 35 (65%) were preterm [< 32 weeks n = 20 (37%), < 28 weeks n = 7 (13%)]. The percentage of low birth weight infants was 65% (42% was < 1500 g, 13% was < 1000 g). Candida spp. were isolated mostly from blood samples (63%), followed by urine (46%), cerebrospinal fluid (CSF; 5%), peritoneal fluid (3%) and endotracheal aspirate (2%). Multifocal growth was determined in 10 (18%) cases. The isolated species were C.albicans (n =36) as being the most common isolate followed by C.parapsilosis (n = 12), C.tropicalis (n = 1), C.kefyr (n = 1), C.lusitaniae (n = 1), C.pelluculosa (n = 1) and Candida spp. (n = 2). Prior antibiotic use, long term hospitalization, total parenteral nutrition and use of lipid solutions, prematurity and catheter use were determined as the most frequently associated factors causing candidal infections. A congenital abnormality, mainly myeloschisis and hydrocephaly, was detected in 18 (33%) of the cases. Overall FCZ resistance rate was 5.5% and the rate of resistance according to the species was 2.8% for C.albicans and 11% for non-albicans isolates. No resistance was observed to AMB. Initial treatment was FCZ for 78% and AMB for 22% of the newborns. The treatment was switched to AMB in 15 (28%) cases because of no clinical or laboratory response to FCZ although only three of these babies showed resistance to FCZ (MIC ≥ 64 mcg/ml). Among the cases with no clinical/microbiological response, C.albicans was the most frequently (66%) isolated species followed by non-albicans species (33%). All of the isolates in the study group were susceptible to AMB and the rate of FCZ resistance was 5.5%. However, it was noted that the clinical treatment failure was higher than the resistance rate when FCZ was considered. Although antifungal susceptibility tests are helpful for guiding the therapy, in vivo and in vitro differences should be taken into account in case of treatment failure encountered with the use of in vitro effective agents.

[Morphotyping, genotyping and investigation of some virulence factors in different morphotypes of Candida parapsilosis clinical isolates]. / Candida parapsilosis klinik izolatlarinin morfotiplendirilmesi, genotiplendirilmesi ve farkli morfotiplerde bazi virülans faktörlerinin arastirilmasi

In recent years there is an increase in frequency of systemic candidiasis cases caused by Candida parapsilosis. However there isn't any standardized genotyping method to be used in epidemiology of those infections. In this study we aimed to determine utility of morphotyping instead of genotyping to study the epidemiology of 53 C.parapsilosis strains isolated from blood (n= 40) and urine (n= 13) cultures of inpatients at Marmara University Hospital, Istanbul, Turkey. The isolates were morphotyped according to their surface and color properties on Sabouraud-triphenyltetrazolium agar (STTZ) and surface characteristics on malt extract agar (MA) media and 10 different subgroups were obtained. In order to genotype the strains, RAPD-PCR (Random Amplified Polymorphic DNA-Polymerase Chain Reaction) method was used and three different genotypes were obtained comprising mostly type II (90.6%). One of the putative virulence factors investigated in the isolates was phospholipase activity. Phospholipase production was not detected in any of the strains on egg-yolk agar (pH: 4.2). Esterase activity of the strains on Tween-80 agar was negative except for one. In order to observe acid proteinase activity, bovine serum albumin containing (pH: 5.0) agar was used and in 11.3% of the strains no acid proteinase activity was seen while in 75.5% moderate (+), in 13.2% strong (++) activity was detected. Slime production was investigated in 8% glucose containing Sabouraud broth (SB) medium and 67.9 % of the strains were found to be negative; while 20.7% were weakly (+), 7.5% were moderately (++) and 3.7% were strongly (+++) positive. Hydrophobicity of the strains was evaluated by using hexadecane hydrocarbon adherence assay and one isolate was weakly hydrophobic while the remaining strains were found to be moderately hydrophobic. We could not observe superiority of morphotyping over genotyping. Additionally no property was found to associate with a certain morphotype, in terms of virulence factors.

Prophylactic feeding with immune-enhanced diet ameliorates chemoradiation-induced gastrointestinal injury in rats.

PURPOSE: To investigate the protective effect of immune-enhanced diet (IED) on chemoradiation-induced injury of the gastrointestinal mucosa. MATERIALS AND METHODS: Forty-eight Sprague-Dawley rats were divided into control (C, n=6), irradiation (IR, n=14), fluoropyrimidine (5-FU, n=14)-treated, IR + 5-FU (n=14)-treated groups. Half of each irradiated and/or 5-FU-treated groups were previously fed with IED containing arginine, omega-3-fatty acids and RNA fragments, while the other half were fed a standard rat diet (SD) for eight days before the induction of IR or injection of 5-FU. In IR groups, whole abdominal irradiation (11 Gy) was performed with 6 MV photons. In the 5-FU groups, fluoropyrimidine (100 mg/kg) was administered intraperitoneally 30 min prior to irradiation. All animals were sacrificed on the 4th day of IR or 5-FU injection. RESULTS: Bacterial colony counts in the ceca and mesenteric lymph nodes of IED-fed rats, which have received either 5-FU and/or irradiation were significantly lower than the corresponding SD-fed groups. Morphometric results revealed that gastric, ileal and colonic injuries were less in IED-treated IR or IR + 5-FU + IED groups, as compared to SD-fed groups. However, IED did not alter DNA fragmentation ratios. CONCLUSION: Prophylactic feeding of IED has a protective effect on chemoradiation-induced gastrointestinal injury, which appears to involve the eradication of bacterial overgrowth.

Seminested PCR for detection and identification of Candida species directly from blood culture bottles.

We investigated the performance of a seminested PCR (snPCR) assay carried out directly from overnight incubated blood culture bottles of 50 newborn intensive care unit (NICU) patients with suspected candidemia and compared these, for sensitivity, specificity and reliability with results from blood cultures. All positive blood cultures (n = 17) yielded positive results for snPCR, which detected the same Candida species, as did the yeast isolates of which 13 were C. parapsilosis and 4 were C. albicans. With both assays showing 32 negative samples and one sample positive with snPCR but negative with blood culture, sensitivity and specificity of snPCR were 100% and 97%, respectively. The patient with contradictory results exhibited a positive blood culture one week later yielding the same species as identified by snPCR. These are the first data demonstrating that snPCR from overnight blood culture bottles can be a potential tool for rapid detection and identification of Candida species, allowing follow-up of the "gold standard" blood culturing, as well.

[Mating types, sexual reproduction and ploidy in fungi: effects on virulence]. / Mantarlarda çaprazlasma tipleri, eseyli çogalma ve ploidinin virülans üzerine etkileri.

Sexual reproduction provides natural selection and adaptation of the organisms to environmental conditions by allowing benefical mutations to spread and by diluting deleterious mutations. In recent years new findings which indicate the role of sexual reproduction in fungal pathogenicity, have been obtained. However, the pathogenic fungi limit their sexual cycles to generate clonal populations instead of recombinants, to enable themselves to adapt to the new conditions in the environment and in the host such as antimicrobial therapy. Cryptococcus neoformans being a haploid organism has a laboratory diagnosed sexual cycle and mating cell types "a and alpha". Nutrient limitation stimulates production of pheromones that induce cell-cell fusion and the resulting dikaryon undergoes filamentous transition, karyogamy and meiosis in basidia and chains of very infective basidiospores develop. The "a" and "alpha" alleles take place in MAT (Mating Type) locus. Strains of "alpha" mating-type predominate in environment and clinical isolates and, in "a-alpha" coinfection model, alpha-cells exhibit more pathogenic behaviour than congenic "a" cells. In the most common pathogenic variety grubii, (serotype A) there is no difference in the virulence of cells of opposite mating types but, during co-infection alpha-cells more easily cross the blood-brain barrier. Additionally, alpha strains produce increased amounts of melanin and urease which enhance invasion of central nervous system. In C. neoformans a novel sexual cycle named as same-sex (monokaryotic) mating has been discovered. Alpha-alpha cells engage in sex without an "a" partner that can contribute to generate diversity and produce infectious haploid basidiospores. This process is also called as "parasexual" recombination. Another aspect for C. neoformans biological property is naturally occuring AD hybrid strains between var. grubii (serotype A) and var. neoformans (serotype D) via sexual crosses. Those strains often contain both mating types, either aADalpha or alphaADa. In Candida albicans due to its diploid property, most strains are a/alpha heterozygous at the mating-type locus and contain both mating-type alleles. Thus, the tetraploid cells (a/a/alpha/alpha) generated during mating can turn to diploid state (a/a and alpha/alpha) by random chromosome loss via parasexual process but without meiosis, within the host. Tetraploids were found to be less virulent in murine infections and could be cleared more rapidly than the diploids. In C. albicans, control of white-opaque switching is believed to be regulated in part by the mating locus, suggesting switch may be involved in mating. Like these 2 opportunistic pathogens, in Pneumocystis jiroveci, Histoplasma capsulatum and Aspergillus spp. genetic studies are being carried out to identify genes related to mating types, sexual cycle, virulence and resistance to antifungal drugs, and the interactions between them.

Hypertonic sabouraud dextrose agar as a substrate for differentiation of Candida dubliniensis.

In this study, we aimed to detect the proportion of Candida dubliniensis among yeast strains previously identified as C. albicans by using several phenotypic methods and PCR.For this purpose, we screened 300 strains by using phenotypic tests suggested for the identification of C. dubliniensis in the literature, but we detected high proportion of false-positive reactions. Only two strains (0.6%) were detected as true C. dubliniensis by PCR and API ID 32C methods. Moreover, these two strains gave the expected results with all the phenotypic tests, including modified salt tolerance test for C. dubliniensis.In conclusion, none of the phenotypic methods, except for the modified salt tolerance test, revealed 100% successful results in discrimination of C. albicans and C. dubliniensis species. However, in the tobacco agar test, the rate of false positivity was as low as 0.6%. We suggest that in the case of absence of PCR and other automatized identification systems, these two phenotypic tests can be used in routine laboratories to obtain a presumptive result.

Two possible cases of Trichosporon infections in bone-marrow-transplanted children: the first case of T. japonicum isolated from clinical specimens.

Trichosporon spp. are emerging as opportunistic agents that cause systemic diseases in immunocompromised hosts. Trichosporonosis carries a poor prognosis in neutropenic patients. Trichosporon japonicum was isolated from the air and named by Sugita et al. Here we present the first case of T. japonicum isolated from a clinical specimen. Two cases of acute myeloid leukemia who had Trichosporon isolates are discussed because of their rarity and growing importance. T. asahii was isolated from the throat, feces and urine of the first patient. T. japonicum was isolated from the sputum of the second patient. Both cases produced high MICs to itraconazole, and low MICs to fluconazole and voriconazole. In virulance factor investigations there was (++) biofilm formation in T. japonicum but not in T. asahii. Conventional mycological studies were not adequate for the identification of the isolate at the species level. In our second case as in the first one, the isolate was identified as T. asahii with 99.9% accuracy by API 20C AUX. Although two T. asahii isolates from the same patient yielded identical typing profiles by arbitrary primed-PCR, the isolates of the two different patients showed different arbitrary primed-PCR typing profiles. However, the genetic identification of the other patient's strain gave the result of T. japonicum.