Candida Parapsilosis Sensu Stricto Research Articles

Emergence of multiple fluconazole-resistant Candida parapsilosis sensu stricto clones with persistence and transmission in China.

We explored the epidemiological and molecular characteristics of Candida parapsilosis sensu stricto isolates in China, and their mechanisms of azole resistance. Azole susceptibilities of 2318 non-duplicate isolates were determined using CLSI broth microdilution. Isolates were genotyped by a microsatellite typing method. Molecular resistance mechanisms were also studied and functionally validated by CRISPR/Cas9-based genetic alterations. Fluconazole resistance occurred in 2.4% (n = 56) of isolates, and these isolates showed a higher frequency of distribution in ICU inpatients compared with susceptible isolates (48.2%, n = 27/56 versus 27.8%, 613/2208; P = 0.019). Microsatellite-genotyping analysis yielded 29 genotypes among 56 fluconazole-resistant isolates, of which 10 genotypes, including 37 isolates, belonged to clusters, persisting and transmitting in Chinese hospitals for 1-29 months. Clusters harbouring Erg11Y132F (5/10; 50%) were predominant in China. Among these, the second most dominant cluster MT07, including seven isolates, characteristically harbouring Erg11Y132F and Mrr1Q625K, lent its carriage to being one of the strongest associations with cross-resistance and high MICs of fluconazole (>256 mg/L) and voriconazole (2-8 mg/L), causing transmission across two hospitals. Among mutations tested, Mrr1Q625K led to the highest-level increase of fluconazole MIC (32-fold), while mutations located within or near the predicted transcription factor domain of Tac1 (D440Y, T492M and L518F) conferred cross-resistance to azoles. This study is the first Chinese report of persistence and transmissions of multiple fluconazole-resistant C. parapsilosis sensu stricto clones harbouring Erg11Y132F, and the first demonstration of the mutations Erg11G307A, Mrr1Q625K, Tac1L263S, Tac1D440Y and Tac1T492M as conferring resistance to azoles.

Paradigm Shift: Candida parapsilosis sensu stricto as the Most Prevalent Candida Species Isolated from Bloodstream Infections with Increasing Azole-Non-Susceptibility Rates: Trends from 2015-2022 Survey.

Candidemia is the fourth most common healthcare-related bloodstream infection. In recent years, incidence rates of Candida parapsilosis have been on the rise, with differences in prevalence and antifungal susceptibility between countries. The aim of the present study was to evaluate temporal changes in prevalence and antifungal susceptibility of C. parapsilosis among other species causing candidemia. All candidemia episodes from January 2015 to August 2022 were evaluated in order to depict time trends in prevalence of C. parapsilosis sensu stricto among all Candida species recovered from blood cultures as well as fluconazole- and voriconazole-non-susceptibility rates. Secondary analyses evaluated time trends in prevalence and antifungal non-susceptibility according to clinical settings. The overall prevalence of C. parapsilosis was observed to increase compared to the prevalence of other Candida species over time (p-trend = 0.0124). From 2019, the number of C. parapsilosis sensu stricto isolates surpassed C. albicans, without an increase in incidence rates. Overall rates of fluconazole- and voriconazole-non-susceptible C. parapsilosis sensu stricto were both 3/44 (6.8%) in 2015 and were 32/51 (62.7%) and 27/51 (52.9%), respectively, in 2022 (85% cross-non-susceptibility). The risk of detecting fluconazole- or voriconazole-non-susceptibility was found to be higher in C. parapsilosis compared to other Candida species (odds ratio (OR) = 1.60, 95% CI [1.170, 2.188], p-value < 0.0001 and OR = 12.867, 95% CI [6.934, 23.878], p-value < 0.0001, respectively). This is the first study to report C. parapsilosis sensu stricto as the most prevalent among Candida spp. isolated from blood cultures, with worrisome fluconazole- and voriconazole-non-susceptibility rates, unparalleled among European and North American geographical regions.

Culturable mycobiota of drinking water in Göteborg (Sweden) in comparison to Ljubljana (Slovenia) with implications on human health.

The European Union currently has no specific regulations on fungi in water. The only country where fungi are listed as the parameter is Sweden, with the maximal number of 100 CFU per 100 mL. The present study thus compared culturable mycobiota from Swedish drinking water with Slovenian, which has no specific requirements for fungi. Fungi were isolated with up to 38 CFU/L from 75% of Swedish samples. The most common were the genera Varicosporellopsis (27.3%), Paracremonium (14.5%), and black yeasts Cadophora, Cyphellophora, and Exophiala (18.2%). Using the same sampling and isolation methods, 90% of tap water samples in Slovenia were positive for fungi, with Aspergillus spp. (46%), Aureobasidium melanogenum (36%), and Exophiala spp. (24%) being the most common. The observed differences between countries are likely the consequence of geographical location, the use of different raw water sources, and water treatment methods. However, the core species and emerging fungi Aspergillus fumigatus, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Bisifusarium dimerum, and Rhodotorula mucilaginosa were isolated in both studies. These findings point out the relevance of tracking the presence of emerging fungi with known effects on health in drinking water and encourage further studies on their transmission from raw water sources to the end-users.

Case of Mixed Infection of Toenail Caused by Candida parapsilosis and Exophiala dermatitidis and In Vitro Effectiveness of Propolis Extract on Mixed Biofilm

Onychomycosis is a chronic fungal nail infection caused by several filamentous and yeast-like fungi, such as the genus Candida spp., of great clinical importance. Black yeasts, such as Exophiala dermatitidis, a closely related Candida spp. species, also act as opportunistic pathogens. Fungi infectious diseases are affected by organisms organized in biofilm in onychomycosis, making treatment even more difficult. This study aimed to evaluate the in vitro susceptibility profile to propolis extract and the ability to form a simple and mixed biofilm of two yeasts isolated from the same onychomycosis infection. The yeasts isolated from a patient with onychomycosis were identified as Candida parapsilosis sensu stricto and Exophiala dermatitidis. Both yeasts were able to form simple and mixed (in combination) biofilms. Notably, C. parapsilosis prevailed when presented in combination. The susceptibility profile of propolis extract showed action against E. dermatitidis and C. parapsilosis in planktonic form, but when the yeasts were in mixed biofilm, we only observed action against E. dermatitidis, until total eradication.

Genotypic Diversity of Candida parapsilosis Complex in Invasive Candidiasis at a Pediatric Tertiary Hospital: A 5-Year Retrospective Study.

Invasive candidiasis (IC) contributes to the morbidity and mortality of hospitalized patients and represents a significant burden to the healthcare system. Previous Brazilian studies have reported the presence of endemic Candida parapsilosis sensu stricto genotypes causing candidemia and clonal transmission involving fluconazole-resistant isolates. We performed a 5-year retrospective analysis of IC cases in a Brazilian tertiary pediatric hospital and conducted a molecular investigation of C. parapsilosis sensu stricto. Non-duplicate C. parapsilosis sensu stricto genotyping was performed by microsatellite analysis. Antifungal susceptibility and biofilm formation were also evaluated. A total of 123 IC episodes were identified, with an IC incidence of 1.24 cases per 1000 hospital admissions and an overall mortality of 34%. The main species were the C. parapsilosis complex (35.8%), Candida albicans (29.2%), and Candida tropicalis (21.9%). All C. parapsilosis sensu stricto were recovered from blood cultures, and 97.5% were biofilm producers. Microsatellite typing identified high genotypic diversity among the isolates. We observed that all isolates were sensitive to amphotericin B, and although one isolate was non-sensitive to fluconazole, only a silent mutation on ERG11 gene was identified. No clear evidence of clonal outbreak or emergence of fluconazole-resistant isolates was found, suggesting that multiple sources may be involved in the epidemiology of IC in children.

Evaluation of MALDI-TOF MS for Identification of Species in the Candida parapsilosis Complex from Candidiasis Cases.

Phenotypically identified Candida parapsilosis is actually a complex of 3 member species named Candida parapsilosis sensu stricto (CPSS), Candida orthopsilosis (CO), and Candida metapsilosis (CM), which can be identified only by molecular methods and automated methods such as MALDI-TOF mass spectrometry (MS). This study was undertaken to evaluate the VITEK MS, which uses the principle of MALDI-TOF MS for the identification of member species of C. parapsilosis complex (CPC). In this cross-sectional study, 126 presumptively identified and stocked isolates of CPC were included. Definite identification to species level was done by VITEK MS and PCR as the gold standard method. Clinico-demographic characters and risk factors were analyzed. Antifungal susceptibility testing was performed for fluconazole and voriconazole. Twelve isolates were not identified as CPC either by VITEK MS or PCR and hence were excluded from the analysis. Out of 114 CPC isolates, 89 (78.1%), 18 (15.8%), and 7 (6.1%) isolates were identified as CPSS, CO, and CM, respectively, by VITEK MS. PCR identified 84 (79.2%), 15 (14.2%), and 7 (6.6%) isolates as CPSS, CO, and CM, respectively. However, PCR did not detect 8 isolates of CPSS detected by VITEK MS. VITEK MS showed 95.3% agreement in species identification and showed a kappa coefficient of 0.87, which is almost perfect agreement. Predominant isolations of all 3 species were from blood. Resistance was observed more in CPSS for both the azoles. MALDI-TOF MS can be used as a rapid, reliable, cost-effective method to identify the species of CPC.

Genome analysis of five recently described species of the CUG-Ser clade uncovers Candida theae as a new hybrid lineage with pathogenic potential in the Candida parapsilosis species complex.

Candida parapsilosis species complex comprises three important pathogenic species: Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. The majority of C. orthopsilosis and all C. metapsilosis isolates sequenced thus far are hybrids, and most of the parental lineages remain unidentified. This led to the hypothesis that hybrids with pathogenic potential were formed by the hybridization of non-pathogenic lineages that thrive in the environment. In a search for the missing hybrid parentals, and aiming to get a better understanding of the evolution of the species complex, we sequenced, assembled and analysed the genome of five close relatives isolated from the environment: Candida jiufengensis, Candida pseudojiufengensis, Candida oxycetoniae, Candida margitis and Candida theae. We found that the linear conformation of mitochondrial genomes in Candida species emerged multiple times independently. Furthermore, our analyses discarded the possible involvement of these species in the mentioned hybridizations, but identified C. theae as an additional hybrid in the species complex. Importantly, C. theae was recently associated with a case of infection, and we also uncovered the hybrid nature of this clinical isolate. Altogether, our results reinforce the hypothesis that hybridization is widespread among Candida species, and potentially contributes to the emergence of lineages with opportunistic pathogenic behaviour.

Oral dysbiosis exacerbates the virulence of Candida parapsilosis sensu stricto via up-regulation of the CPH2 biofilm master gene

Candida parapsilosis sensu stricto is the second to third most frequent cause of candidemia. Studies place this yeast as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. We hypothesize that a buccal environment in dysbiosis enhances the virulence of C. parapsilosis sensu stricto. Objective: To evaluate at the phenotype and molecular level the production of biofilm in oral isolates of C. parapsilosis sensu stricto and correlate the results with the clinical origin (dysbiosis versus eubiosis). Material and methods: The biofilm-forming ability was compared in 50 oral isolates of C. parapsilosis sensu stricto obtained from patients with and without oral dysbiosis; by quantification of biofilm biomass and metabolic activity. The results were corroborated by optical and confocal fluorescence microscopy, and correlated with the transcriptional activity of CPH2, by RT-qPCR. The data were analyzed by Excel 2010, and InfoStat 2018, with a 95% confidence interval. Results: The metabolic activity in biofilm was significantly higher in oral dysbiosis relative to control (p = 0.0025). Basal expression of CPH2 increased 2.8 times more in oral dysbiosis related to the control condition and showed no significant differences with pathogenic isolates of this same yeast, derived from onychomycosis lesions. Conclusion: The oral cavity in dysbiosis increases the virulence of C. parapsilosis sensu stricto due to possible changes in epigenetic marks. This finding suggests that the oral cavity in dysbiosis may be an alternative route to the skin in the epidemiology of nosocomial candidemia.

Oral Dysbiosis Exacerbates Candida parapsilosis Sensu Stricto Biofilm Production via Up-Regulation of the CPH2 Biofilm Master Gene

Introduction: Candida parapsilosis sensu stricto is the second to third most frequent cause of candidemia. Studies place this yeast as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. We hypothesize that a buccal environment in dysbiosis enhances the virulence of C. parapsilosis sensu stricto. Objective: To evaluate the phenotype and molecular level of the production of biofilm in oral isolates of Candida parapsilosis sensu stricto and correlate the results with the clinical origin (dysbiosis versus eubiosis). Materials and Methods: The biofilm-forming ability was compared in 50 oral isolates of Candida parapsilosis sensu stricto obtained from patients with and without oral dysbiosis; by quantification of metabolic activity. The results were corroborated by confocal fluorescence microscopy, and correlated with the transcriptional activity of CPH2, by RT-qPCR. The data were analysed by Excel 2010, and InfoStat 2018, with a 95% confidence interval. Results: The metabolic activity in biofilm was significantly higher in oral dysbiosis relative to control (p = 0.0025). Basal expression of CPH2 increased 2.8 times more in oral dysbiosis related to the control condition and showed no significant differences with pathogenic isolates of this same yeast, derived from onychomycosis lesions. Conclusion: The oral cavity in dysbiosis increases the virulence of C. parapsilosis sensu stricto due to possible changes in epigenetic marks. This finding suggests that the oral cavity in dysbiosis may be an alternative route to the skin in the epidemiology of nosocomial candidemia.

A case series of medically managed Candida parapsilosis complex prosthetic valve endocarditis

BackgroundIn recent years, Candida parapsilosis is recognized as a species complex and is composed of Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Candida parapsilosis complex prosthetic valve endocarditis (PVE) is rare and the survival rate is still low despite of optimal therapeutic strategies. In our report, it is novel to report cases as Candida parapsilosis complex PVE at species and identify Candida parapsilosis using MALDI-TOF MS.Case presentationA series of 4 cases of Candida parapsilosis complex PVE from our institution was reported. Three were infected by Candida parapsilosis sensu stricto and one was infected by Candida metapsilosis. The condition of two cases got better and the other died.ConclusionsMore attention should be paid to Candida parapsilosis complex PVE and early diagnosis and prompt antibiotic therapy may play a role in the treatment for Candida parapsilosis complex PVE. It is recommended to identify Candida parapsilosis complex at species level and MALDI-TOF MS as an easy, fast and efficient identification method is worth promoting in clinical microbiology

High colonization by Candida parapsilosis sensu stricto on hands and surfaces in an adult intensive care unit

BackgroundYeasts of the Candida parapsilosis complex have frequently been reported as agents of fungal infection in Brazil and worldwide, most of the cases are related to hospital-acquired infection. C. parapsilosis is the third most common cause of candidemia, and the hands of hospital workers as well as hospital surfaces have been suggested as possible sources. ObjectivesIn this study we verified the frequency of C. parapsilosis on the hands of workers and on surfaces in the adult intensive care unit (AICU) of a tertiary hospital in Paraná-Brazil. MethodsSurface samples were collected with swabs moistened with saline, and a plastic bag with distilled water was used to collect samples from hands. The yeasts were identified by morphology, MALDI-TOF mass spectrometry and PCR-RFLP of the secondary alcohol dehydrogenase-encoding gene (SADH) after digestion with the restriction enzyme BanI. Results and conclusionsA total of 223 yeast were found, of which 101 (45.29%) were identified as C. parapsilosis sensu stricto. Of these, 46.66% (n=35) were found on surfaces and 44.59% (n=66) on the hands of the employees. The analysis of C. parapsilosis strains by microsatellite loci (CP1, CP4, CP6 and B5) showed 80 different genotypes. Their antifungal susceptibility profile, evaluated by the microdilution broth method, revealed that C. parapsilosis was sensitive to amphotericin B, fluconazole and voriconazole, but not to micafungin. The results revealed the heterogeneity of the yeast population, suggesting that there is no common source of contamination in the AICU of this hospital.

Echinocandin resistance in Candida parapsilosis sensu stricto: Role of alterations in CHS3, FKS1 and Rho gene expression

ObjectivesThe rate of resistance of Candida parapsilosis to echinocandins remains unexplored in Iran. The main aims of this study were to investigate the susceptibility patterns and possible mechanisms of echinocandin resistance in echinocandin-resistant clinical C. parapsilosis isolates in Iran. MethodsA total of 105 isolates of C. parapsilosis sensu stricto underwent antifungal susceptibility testing to echinocandins by the broth microdilution reference method. Sequences of the CpERG3 and CpFKS1 genes were analysed using MEGA6 software, and alterations in CHS3, FKS1 and Rho gene expression were evaluated by quantitative reverse transcription (RT-qPCR). REST® software was used to analyse the results. ResultsThe rate of echinocandin cross-resistance was 2.9% (3/105). No substitutions were detected in Fks1p except for the naturally occurring P660A amino acid substitution observed in isolates both with high and low minimum inhibitory concentrations (MICs). Moreover, the G111R amino acid substitution was not found in Erg3p. Following echinocandin exposure, expression of Rho and FKS1 genes was significantly increased in resistant isolates, whilst the CHS3 gene showed no change. ConclusionAlterations in the expression of some key genes may be responsible for echinocandin resistance among C. parapsilosis isolates. Understanding the mechanisms responsible for drug resistance in C. parapsilosis is not only crucial for the development of new antifungals but is also important in choosing appropriate antifungals for patient treatment at the earliest stage.

In vitro activity of isavuconazole against clinically isolated yeasts from Chile.

Isavuconazole is the last antifungal agent approved by the FDA and available for treatment of fungal infections. In the present study, the in vitro activity of isavuconazole against several yeasts was investigated. Two hundred forty-six isolates were included: 64 Candida albicans, 53 Candida parapsilosis sensu stricto, 48 Cryptococcus neoformans species complex, 27 C. glabrata sensu stricto, 17 C. lusitaniae, 17 C. tropicalis, 5 C. orthopsilosis, 4 C. krusei, 3 C. guilliermondii sensu stricto, 3 C. pelliculosa, 2 C. dubliniensis, 1 C. auris, 1 C. fermentati and 1 Trichosporon asahii. All isolates were recovered from clinical isolates from Chile, being 221 from hemoculture, 22 from cerebrospinal fluid, 1 pleural fluid, and 1 from tissue culture. The minimal inhibitory concentrations (MICs) and minimal fungicidal concentrations (MFCs) of isavuconazole were determined. Isavuconazole demonstrated good in vitro activity against all species tested. MIC90 values and MFC ranges of isavuconazole for Candida albicans were 0.03mg/L and 0.03- > 16mg/L respectively. Non-Candida albicans species isolates were inhibited by ≤ 1mg/L, with MFC ranges from < 0.03- > 16mg/L. Also, isavuconazole was active against the non-Candida yeasts, being inhibited with MIC values ≤ 0.06mg/L. Isavuconazole has exhibited potent in vitro activity against clinical isolates of Candida spp., Cryptococcus neoformans species complex, and other clinical yeast in Chile. Despite the results obtained in the present work, additional clinical studies are necessary to verify the level of efficacy of this azole.

Prevalence and Antifungal Susceptibility of Pathogenic Yeasts in China: A 10-Year Retrospective Study in a Teaching Hospital.

To determine the dynamic changes of pathogenic yeast prevalence and antifungal susceptibility patterns in tertiary hospitals in China, we analyzed 527 yeast isolates preserved in the Research Center for Medical Mycology at Peking University, Beijing, China, between Jan 2010 and Dec 2019 and correctly identified 19 yeast species by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and ribosomal DNA sequencing. Antifungal susceptibility testing was performed following a Sensititre YeastOne colorimetric microdilution panel with nine clinically available antifungals. The Clinical and Laboratory Standards Institute (CLSI)-approved standard M27-A3 (S4) and newly revised clinical breakpoints or species-specific and method-specific epidemiological cutoff values were used for the interpretation of susceptibility test data. In this study, although Candida albicans was the predominant single species, non-C. albicans species constituted >50% of isolates in 6 out of 10 years, and more rare species were present in the recent 5 years. The non-C. albicans species identified most frequently were Candida parapsilosis sensu stricto, Candida tropicalis, and Candida glabrata. The prevalence of fluconazole and voriconazole resistance in the C. parapsilosis sensu stricto population was <3%, but C. tropicalis exhibited decreased susceptibility to fluconazole (42, 57.5%) and voriconazole (31, 42.5%), and 22 (30.1%) C. tropicalis isolates exhibited wild-type minimum inhibitory concentrations (MICs) to posaconazole. Furthermore, fluconazole and voriconazole cross-resistance prevalence in C. tropicalis was 19 (26.1%). The overall prevalence of fluconazole resistance in the C. glabrata population was 14 (26.9%), and prevalence of isolates exhibiting voriconazole non-wild-type MICs was 33 (63.5%). High-level echinocandin resistance was mainly observed in C. glabrata, and the prevalence rates of isolate resistance to anidulafungin, micafungin, and caspofungin were 5 (9.6%), 5 (9.6%), and 4 (7.7%), respectively. Moreover, one C. glabrata isolate showed multidrug resistant to azoles, echinocandins, and flucytosine. Overall, the 10-year surveillance study showed the increasing prevalence of non-C. albicans species over time; the emergence of azole resistance in C. tropicalis and multidrug resistance in C. glabrata over the years reinforced the need for epidemiological surveillance and monitoring.

Epidemiology of yeast species causing bloodstream infection in Tehran, Iran (2015-2017); superiority of 21-plex PCR over the Vitek 2 system for yeast identification.

Introduction. Given the limited number of candidaemia studies in Iran, the profile of yeast species causing bloodstream infections (BSIs), especially in adults, remains limited. Although biochemical assays are widely used in developing countries, they produce erroneous results, especially for rare yeast species.Aim. We aimed to assess the profile of yeast species causing BSIs and to compare the accuracy of the Vitek 2 system and 21-plex PCR.Methodology. Yeast blood isolates were retrospectively collected from patients recruited from two tertiary care training hospitals in Tehran from 2015 to 2017. Relevant clinical data were mined. Identification was performed by automated Vitek 2, 21-plex PCR and sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2).Results. In total, 137 yeast isolates were recovered from 107 patients. The overall all-cause 30-day mortality rate was 47.7 %. Fluconazole was the most widely used systemic antifungal. Candida albicans (58/137, 42.3 %), Candida glabrata (30/137, 21.9 %), Candida parapsilosis sensu stricto (23/137, 16.8 %), Candida tropicalis (10/137, 7.3 %) and Pichia kudriavzevii (Candida krusei) (4/137, 2.9 %) constituted almost 90 % of the isolates and 10 % of the species detected were rare yeast species (12/137; 8.7 %). The 21-plex PCR method correctly identified 97.1 % of the isolates, a higher percentage than the Vitek 2 showed (87.6 %).Conclusion. C. albicans was the main cause of yeast-derived fungaemia in this study. Future prospective studies are warranted to closely monitor the epidemiological landscape of yeast species causing BSIs in Iran. The superiority of 21-plex PCR over automated Vitek 2 indicates its potential clinical utility as an alternative identification tool use in developing countries.

The oral cavity promotes virulence of Candida parapsilosis sensu stricto via up-regulation of BCR1

Candida parapsilosis sensu stricto behaves as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. Studies have suggested the influence of the ecological niche in the virulence of C. parapsilosis. Given this background, we hypothesize that the conditions of the niche affect the virulence of C. parapsilosis sensu stricto due to inheritable epigenetic changes. Measure and compare the virulence, at the phenotype and molecular level, of clinical isolates of C. parapsilosis sensu stricto from different niches and clinical conditions. Biofilm-forming ability was compared in 20 clinical isolates of C. parapsilosis sensu stricto obtained from blood (candidemia), skin (onychomycosis), and oral cavity (eubiosis and dysbiosis); by quantification of biofilm biomass, and metabolic activity. The results were corroborated by optical microscopy and correlated with the basal expression of the global biofilm regulator BCR1 by RT-PCR. Biofilm production and baseline BCR1 expression were significantly different depending on the ecological niche and the clinical origin of the isolates. The oral cavity exerts a preponderant role in the modulation of the virulence of this yeast via regulation of BCR1. The biofilm-forming ability in C. parapsilosis sensu stricto is dependent on the strain, but can be modulated by environmental conditions or ecological niche via epigenetic regulation of global biofilm regulators such as BCR1.

Comparative in vitro activities of seven antifungal drugs against clinical isolates of Candida parapsilosis complex

ObjectiveCandida parapsilosis species complex, an important set of non-albicans Candida species, is known to cause candidaemia particularly in neonates and infants. However, the incidence has increased in recent years, owing to higher numbers of at individuals at risk for these infections. Our objective was to evaluate the in vitro susceptibility of clinical isolates of C. parapsilosis complex isolates from Iran to seven antifungal drugs. Material and methodsOne hundred-one clinical isolates of C. parapsilosis species complex cultured from humans were included. Species identification had been previously confirmed by combined phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry-based assay and reconfirmed by DNA sequence analysis of the ITS rDNA region and D1/D2 gene. Minimum inhibitory concentrations (MICs) for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, micafungin and anidulafungin were determined against well-characterized isolates by broth microdilution susceptibility testing according to the CLSI M27-A3 guideline. ResultsSpecies identifications were performed on 101 isolates, of which 88 (87.2%) C. parapsilosis sensu stricto and 13 (12.8%) C. orthopsilosis. Amphotericin B and posaconazole were the most active drugs with 100% of isolates being wild-type (WT). Voriconazole and micafungin, 99% of isolates were WT. The low activity was recorded for fluconazole and itraconazole with 93.1% and 89.1% of isolates being WT, respectively. At the species level, all Candida parapsilosis sensu stricto isolates were WT to amphotericin B and posaconazole and all Candida orthopsilosis isolates were WT to amphotericin B, voriconazole, posaconazole, anidulafungin and micafungin. In contrast, the highest rate of non-WT was observed in C. orthopsilosis to itraconazole (4 of 13, 30.8%). ConclusionsAlthough almost all of the tested drugs demonstrated potent activity against C. parapsilosis species complex, it seems that more especially C. orthopsilosis isolates had decreased susceptibility to itraconazole. Further studies are needed to determine how these findings may switch into in vivo efficacy.

Utility of two PCR-RFLP-based techniques for identification of Candida parapsilosis complex blood isolates.

Candida parapsilosis is the second or third most frequently isolated Candida species related to nosocomial infections, even overtaking Candida albicans in some hospitals. C.parapsilosis constitutes a complex of closely related species: Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Accurate detection of these species is of importance, as the incidence of C.orthopsilosis has been reported to surpass that of Candida krusei. To evaluate the diagnostic utility of two PCR-RFLP methods targeting the SADH and FKS1 genes and to determine the prevalence of cryptic species in 96 bloodstream isolates of C.parapsilosis from 93 patients. Restriction patterns of the SADH and FKS1 genes were analysed, and sequencing of the D1/D2 regions of the ribosomal RNA was used to evaluate the reliability of both PCR-RFLP methods. In our study, 77 C.parapsilosis sensu stricto, 13 C.orthopsilosis and five C.metapsilosis were identified by sequencing. Both PCR-RFLP methods demonstrated strong agreement with D1/D2 sequencing in the identification of C.parapsilosis and C.orthopsilosis, while both methods were unable to identify the C.metapsilosis isolates. Moreover, unexpected restriction patterns were observed for two isolates on SADH PCR-RFLP and for four isolates on FKS1 PCR-RFLP. Mixed bloodstream infections of C.parapsilosis sensu stricto and C.orthopsilosis were detected for three patients, for which differential growth characteristics were observed. The molecular method chosen for identification could have an impact on determination of the real prevalence of C.metapsilosis in candidaemia, and mixed fungaemias can remain undetected.

Candida Parapsilosis Sensu Stricto Can Act as a Pathobiont in Conditions of Oral Dysbiosis

Recent publications have reported high prevalence of Candida parapsilosis Sensu Stricto in oral cavity niches. Our research group performed a pilot study in 2017 which showed that of the psilosis complex, Candida parapsilosis Sensu Stricto is the species most frequently isolated from oral cavity niches. Under inflammatory conditions, the probability of recovering it is almost four times higher, and it displays higher biofilm-forming capacity in-vitro, differing significantly from isolates of the same species obtained in conditions of eubiosis.

One-Pot Synthesis and Antifungal Activity of Nontoxic Silver-Loaded Hydroxyapatite Nanocomposites against Candida Species

The impact of fungal diseases and the development of antimicrobial agents against pathogenic fungi have emerged as a main global healthcare challenge. In this study, the antifungal activity of silver-loaded hydroxyapatite (Ag/HAP) nanocomposites (NCs) with different Ag content synthesized by a one-pot microwave-assisted solvothermal method was evaluated against sensitive and resistant Candida species. The NCs’ composition and morphology were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy analysis. Antifungal studies were conducted by a microdilution method according to a protocol from the Clinical and Laboratory Standards Institute. The main inhibitory effect was observed against Candida krusei, with a minimum inhibitory concentration (MIC) of 31.2 μg/mL, followed by Candida parapsilosis sensu stricto and Candida tropicalis (62.5 μg/mL) and C...