Candida species epidemiology 2000-2013: a laboratory-based report

Dryopteris crassirhizoma Nakai.: A review of its botany, traditional use, phytochemistry, pharmacological activity, toxicology and pharmacokinetics

ETHNOPHARMACOLOGICAL RELEVANCE

The Dryopteris crassirhizoma Nakai., a commonly used herb, is known as "Guan Zhong" in China, "Oshida" in Japan and "Gwanjung" in Korea. It has long been used for parasitic infestation, hemorrhages and epidemic influenza.

AIM OF THE REVIEW

The present paper aims to provide an up-to-date review at the advancements of the investigations on the traditional use, phytochemistry, pharmacological activity, toxicology and pharmacokinetics of D. crassirhizoma. Besides, possible trends, therapeutic potentials, and perspectives for future research of this plant are also briefly discussed.

MATERIALS AND METHODS

Relevant information on traditional use, phytochemistry, pharmacological activity, toxicology and pharmacokinetics of D. crassirhizoma was collected through published materials and electronic databases, including the Chinese Pharmacopoeia, Flora of China, Web of Science, PubMed, Baidu Scholar, Google Scholar, and China National Knowledge Infrastructure. 109 papers included in the article and we determined that no major information was missing after many checks. All authors participated in the review process for this article and all research paper are from authoritative published materials and electronic databases.

RESULTS

130 chemical components, among which phloroglucinols are the predominant groups, have been isolated and identified from D. crassirhizoma. D. crassirhizoma with its bioactive compounds is possessed of extensive biological activities, including anti-parasite, anti-microbial, anti-viral, anti-cancer, anti-inflammatory, anti-oxidant, anti-diabetic, bone protective, immunomodulatory, anti-platelet and anti-hyperuricemia activity. Besides, D. crassirhizoma has special toxicology and pharmacokinetics characterization.

CONCLUSIONS

D. crassirhizoma is a traditional Chinese medicine having a long history of application. This review mainly summarized the different chemical components extract from D. crassirhizoma and various reported pharmacological effects. Besides, the toxicology and pharmacokinetics of D. crassirhizoma also be analysed in this review. However, the chemical components of D. crassirhizoma are understudied and require further research to expand its medicinal potential, and it is urgent to design a new extraction scheme, so that the active ingredients can be obtained at a lower cost.

Stephanoascus ciferrii Complex: The Current State of Infections and Drug Resistance in Humans

In recent years, the incidence of fungal infections in humans has increased dramatically, accompanied by an expansion in the number of species implicated as etiological agents, especially environmental fungi never involved before in human infection. Among fungal pathogens, Candida species are the most common opportunistic fungi that can cause local and systemic infections, especially in immunocompromised individuals. Candida albicans (C. albicans) is the most common causative agent of mucosal and healthcare-associated systemic infections. However, during recent decades, there has been a worrying increase in the number of emerging multi-drug-resistant non-albicans Candida (NAC) species, i.e., C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, C. auris, and C. ciferrii. In particular, Candida ciferrii, also known as Stephanoascus ciferrii or Trichomonascus ciferrii, is a heterothallic ascomycete yeast-like fungus that has received attention in recent decades as a cause of local and systemic fungal diseases. Today, the new definition of the S. ciferrii complex, which consists of S. ciferrii, Candida allociferrii, and Candida mucifera, was proposed after sequencing the 18S rRNA gene. Currently, the S. ciferrii complex is mostly associated with non-severe ear and eye infections, although a few cases of severe candidemia have been reported in immunocompromised individuals. Low susceptibility to currently available antifungal drugs is a rising concern, especially in NAC species. In this regard, a high rate of resistance to azoles and more recently also to echinocandins has emerged in the S. ciferrii complex. This review focuses on epidemiological, biological, and clinical aspects of the S. ciferrii complex, including its pathogenicity and drug resistance.

Anti-Staphylococcal, Anti-Candida, and Free-Radical Scavenging Potential of Soil Fungal Metabolites: A Study Supported by Phenolic Characterization and Molecular Docking Analysis

Staphylococcus and Candida are recognized as causative agents in numerous diseases, and the rise of multidrug-resistant strains emphasizes the need to explore natural sources, such as fungi, for effective antimicrobial agents. This study aims to assess the in vitro anti-staphylococcal and anti-candidal potential of ethyl acetate extracts from various soil-derived fungal isolates. The investigation includes isolating and identifying fungal strains as well as determining their antioxidative activities, characterizing their phenolic substances through HPLC analysis, and conducting in silico molecular docking assessments of the phenolics' binding affinities to the target proteins, Staphylococcus aureus tyrosyl-tRNA synthetase and Candida albicans secreted aspartic protease 2. Out of nine fungal species tested, two highly potent isolates were identified through ITS ribosomal gene sequencing: Aspergillus terreus AUMC 15447 and A. nidulans AUMC 15444. Results indicated that A. terreus AUMC 15447 and A. nidulans AUMC 15444 extracts effectively inhibited S. aureus (concentration range: 25-0.39 mg/mL), with the A. nidulans AUMC 15444 extract demonstrating significant suppression of Candida spp. (concentration range: 3.125-0.39 mg/mL). The A. terreus AUMC 15447 extract exhibited an IC50 of 0.47 mg/mL toward DPPH radical-scavenging activity. HPLC analysis of the fungal extracts, employing 18 standards, revealed varying degrees of detected phenolics in terms of their presence and quantities. Docking investigations highlighted rutin as a potent inhibitor, showing high affinity (-16.43 kcal/mol and -12.35 kcal/mol) for S. aureus tyrosyl-tRNA synthetase and C. albicans secreted aspartic protease 2, respectively. The findings suggest that fungal metabolites, particularly phenolics, hold significant promise for the development of safe medications to combat pathogenic infections.

Successful treatment of fungal ball-associated tinea capitis in a healthy infant: An unusual presentation

Key Clinical Message

Presentation of tinea capitis with fungal mass in an infant is extremely rare. Tinea capitis with and without abscess formation is prone to be misdiagnosed in infants and should be considered as a differential diagnosis of inflammatory hair loss in infants and toddlers as well as school-aged children.

Abstract

Tinea capitis is the scalp fungal infection that most often affects early school children. It rarely affects neonates and adults. The presentation of fungal ball in the setting of tinea capitis is extremely rare. Herein, we describe a 7-month-old girl with a fungal ball associated with tinea capitis with a scalp mass adjacent to the scalp dermatophytosis. To our knowledge, this is the first case of fungal ball in a healthy infant with tinea capitis.

Antimicrobial Acylphloroglucinol Meroterpenoids and Acylphloroglucinols from Dryopteris crassirhizoma

Ten novel meroterpenoids, dryoptins/11″-epi-dryoptins A~E (1: ~10: ) with an unprecedented skeleton consisting of dimeric or trimeric acylphloroglucinols and dehydrotheonelline, two undescribed acylphloroglucinol-nerolidol meroterpenoids (11: ~12: ), and ten known acylphloroglucinol derivatives (13: ~22: ), were isolated from D. crassirhizoma. The novel structures including absolute configurations were established by comprehensive spectroscopic analyses and quantum chemical electronic circular dichroism (ECD) calculations. A biosynthetic pathway of 1: ~10: was assumed. The trimeric acylphloroglucinol meroterpenoids 7: /8: showed significant antifungal activity against standard Candida albicans with a MIC₅₀ value of 1.61 µg/mL [fluconazole (FLC): 3.41 µg/mL], and when combined with FLC, the principal components 20: and 21: exhibited strong antifungal activities against FLC-resistant C. albicans with MIC₅₀ values of 8.39 and 7.16 µg/mL (FLC: > 100 µg/mL), respectively. Moreover, compounds 2, 5: /6, 18, 19: , and 21: exhibited inhibitory effects against several pathogenic fungi and bacteria, with MIC₅₀ values of 6.25 ~ 50 µg/mL.

A Case of Misdiagnosed as Upper Urinary Tract Obstruction Caused by the Fungal Ball

Upper urinary tract obstruction caused by fungal balls is a rare urinary system disease. We admitted an elderly man with symptoms of urinary tract infection and diabetes mellitus. When the patient was transported into the hospital, a CT scan revealed right renal pelvis dilatation and gas buildup, routine urinalysis showing full field of view of white blood cells and middle urinary bacteria and fungi cultures came back negative, leading to the incorrect diagnosis of emphysematous pyelonephritis with Aerogenes infection. When the diagnosis is confirmed, surgery and antifungal therapy are used to deal with both the obstruction and the fungal ball.

Discovery of Novel 7-Hydroxy-5-oxo-4,5-dihydrothieno[3,2-b]pyridine-6-carboxamide Derivatives with Potent and Selective Antifungal Activity against Cryptococcus Species

Cryptococcus neoformans and Cryptococcus gattii can cause fatal invasive infections, especially in immunocompromised patients. However, few antifungal drugs are available to help treat cryptococcosis. In this study, by compound library screening, we presented the first report of hit compound P163-0892, which had potent in vitro and in vivo antifungal activity against Cryptococcus spp. In vitro tests showed that P163-0892 was not cytotoxic and had highly selective and strong antifungal activities against Cryptococcus spp. with MIC values less than 1 μg/mL. Synergism of P163-0892 and fluconazole was also observed in vitro. The in vivo antifungal efficacy of P163-0892 was assessed in a wax moth larval fungal infection model, and treatment with 10 mg/kg P163-0892 caused a significant reduction in fungal burden and significant extension of the survival time. Taken together, our data indicate that the hit compound P163-0892 warrants further investigation as a novel anti-Cryptococcus agent.

A novel use for an old drug: resistance reversal in Candida albicans by combining dihydroartemisinin with fluconazole

Aim: To investigate the effects of dihydroartemisinin combined with fluconazole against C. albicans in vitro and to explore the underlying mechanisms. Materials & methods: Checkerboard microdilution assay and time-kill curve method were employed to evaluate the static and dynamic antifungal effects against C. albicans. Reactive oxygen species (ROS) was measured by a fluorescent probe. Results: Combination of dihydroartemisinin and fluconazole exerted potent synergy against planktonic cells and biofilms of fluconazole-resistant C. albicans, with the fractional inhibitory concentration index values less than 0.07. A potent fungistatic activity of this drug combination could still be observed after 18 h. The accumulation of ROS induced by the drug combination might contribute to the synergy. Conclusion: Dihydroartemisinin reversed the resistance of C. albicans to fluconazole.

Vaginal microbiota and the potential of Lactobacillus derivatives in maintaining vaginal health

Human vagina is colonised by a diverse array of microorganisms that make up the normal microbiota and mycobiota. Lactobacillus is the most frequently isolated microorganism from the healthy human vagina, this includes Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii. These vaginal lactobacilli have been touted to prevent invasion of pathogens by keeping their population in check. However, the disruption of vaginal ecosystem contributes to the overgrowth of pathogens which causes complicated vaginal infections such as bacterial vaginosis (BV), sexually transmitted infections (STIs), and vulvovaginal candidiasis (VVC). Predisposing factors such as menses, pregnancy, sexual practice, uncontrolled usage of antibiotics, and vaginal douching can alter the microbial community. Therefore, the composition of vaginal microbiota serves an important role in determining vagina health. Owing to their Generally Recognised as Safe (GRAS) status, lactobacilli have been widely utilised as one of the alternatives besides conventional antimicrobial treatment against vaginal pathogens for the prevention of chronic vaginitis and the restoration of vaginal ecosystem. In addition, the effectiveness of Lactobacillus as prophylaxis has also been well-founded in long-term administration. This review aimed to highlight the beneficial effects of lactobacilli derivatives (i.e. surface-active molecules) with anti-biofilm, antioxidant, pathogen-inhibition, and immunomodulation activities in developing remedies for vaginal infections. We also discuss the current challenges in the implementation of the use of lactobacilli derivatives in promotion of human health. In the current review, we intend to provide insights for the development of lactobacilli derivatives as a complementary or alternative medicine to conventional probiotic therapy in vaginal health.

Molecular identification and antifungal susceptibility profile of yeast from vulvovaginal candidiasis

BACKGROUND

Accurate identification Candida is important for successful therapy and epidemiology study. The aim of research is to study API 20C yeast identification system identification rate by using molecular identification as gold standard and tested the antifungal susceptibility of Candida from patients with vulvovaginal candidiasis (VVC).

METHODS

In total, 3574 yeast isolates were obtained from patients with VVC. API 20C yeast identification, molecular identification and in vitro antifungal susceptibility were performed.

RESULTS

C. albicans was the predominant Candida species [2748 isolates, 76.9%] in VVC. The isolates from vaginal samples represented 22 species based on molecular identification. The API 20C system identifies only 11 of the species encountered during the study period. Based on the API 20C system, 3273 (91.78%) isolates were correctly identified to the species level. The correct identification rate of the API 20C system for rare yeast was 15.29% (26/170 isolates). Antifungal susceptibility was tested in a total of 1844 isolates of Candida from patients with VVC. C. albicans was susceptible to most of the tested antifungals. The MICs of azoles for C. glabrata were higher than those for C. albicans. The MICs of echinocandins for C. parapsilosis were higher than those for C. albicans.

CONCLUSIONS

The API 20C yeast identification system can be used to reliably identify the most common Candida species while molecular methods are necessary for the identification of closely related, emerging, and rare yeast species. The results from this study suggest that much of the previous studies on the epidemiology of VVC should be re-thought. C. albicans was susceptible to most of the tested antifungals.

Anti-Fungal Efficacy and Mechanisms of Flavonoids

The prevalence of fungal infections is growing at an alarming pace and the pathogenesis is still not clearly understood. Recurrence of these fungal diseases is often due to their evolutionary avoidance of antifungal resistance. The development of suitable novel antimicrobial agents for fungal diseases continues to be a major problem in the current clinical field. Hence, it is urgently necessary to develop surrogate agents that are more effective than conventional available drugs. Among the remarkable innovations from earlier investigations on natural-drugs, flavonoids are a group of plant-derived substances capable of promoting many valuable effects on humans. The identification of flavonoids with possible antifungal effects at small concentrations or in synergistic combinations could help to overcome this problem. A combination of flavonoids with available drugs is an excellent approach to reduce the side effects and toxicity. This review focuses on various naturally occurring flavonoids and their antifungal activities, modes of action, and synergetic use in combination with conventional drugs.

Diagnostic Performance of a Novel Multiplex PCR Assay for Candidemia among ICU Patients

Candidemia poses a major threat to ICU patients and is routinely diagnosed by blood culture, which is known for its low sensitivity and long turnaround times. We compared the performance of a novel, Candida-specific multiplex real-time PCR assay (Fungiplex^® Candida IVD Real-Time PCR Kit) with blood culture and another established diagnostic real-time PCR assay (LightCycler SeptiFast Test) with respect to Candida detection from whole blood samples. Clinical samples from 58 patients were analyzed by standard blood culture (BC) and simultaneously tested with the Fungiplex Candida PCR (FP) and the SeptiFast test (SF) for molecular detection of Candida spp. Compared to BC, the FP test showed high diagnostic power, with a sensitivity of 100% and a specificity of 94.1%. Overall diagnostic accuracy reached 94.6%. Using SF, we found a sensitivity of 60%, a specificity of 96.1%, and an overall diagnostic accuracy of 92.9%. The Fungiplex Candida PCR has shown good sensitivity and specificity on clinical samples of high-risk patients for direct detection of Candida species in whole blood samples. Together with conventional diagnostics (BC and antigen testing), this new multiplex PCR assay may contribute to a rapid and accurate diagnosis of candidiasis.

The Synergism of the Small Molecule ENOblock and Fluconazole Against Fluconazole-Resistant Candida albicans

Candida albicans is the most common opportunistic fungal pathogen which can cause life-threatening bloodstream infections known as candidaemia. It is very important to discover new drugs and targets for the treatment of candidaemia. In this study, we first investigated the combination antifungal effects of the small molecule ENOblock and fluconazole (FLC) against FLC-resistant C. albicans. A checkerboard microdilution assay showed that ENOblock has a significant synergistic effect in combination with FLC against FLC-resistant C. albicans. The time-kill curve further confirmed the synergism of this compound with FLC against FLC-resistant C. albicans. Moreover, we demonstrated the significant inhibitory effects of ENOblock alone and in combination with FLC against C. albicans hypha and biofilm formation. Furthermore, the XTT assay showed that ENOblock has relatively low toxicity to human umbilical vein endothelial cells. The in vivo antifungal efficacy of ENOblock was further assessed in a murine model of systemic C. albicans infection. Although ENOblock alone was not sufficient to treat C. albicans infection, the combination of FLC and ENOblock showed significant in vivo activity against FLC-resistant C. albicans. Finally, using surface plasmon resonance analysis as well as an inhibition assay, we determined that ENOblock directly interacted with CaEno1 and significantly inhibited the transglutaminase activity of this enzyme, which is involved in the growth and morphogenesis of C. albicans. In summary, these results demonstrate the synergistic effects of FLC and ENOblock against FLC-resistant C. albicans, and indicate that inhibition of the transglutaminase activity of CaEno1 by ENOblock might confer an advantage for the synergism of FLC and ENOblock, suggesting the potential of ENOblock as a new antifungal candidate.

Anti-Candida activity of existing antibiotics and their derivatives when used alone or in combination with antifungals

Fungal infections are a growing challenge in immunocompromised patients, especially candidiasis. The prolonged use of traditional antifungals to treat Candida infection has caused the emergence of drug resistance, especially fluconazole. Therefore, new therapeutic strategies for Candida infection are warranted. Recently, attention has been paid to the anti-Candida activity of antibiotics and their derivatives. Studies revealed that a series of antibiotics/derivatives displayed potential anti-Candida activity and some of them could significantly increase the susceptibility of antifungals. Interestingly, the derivatives of aminoglycosides were even more active than fluconazole/itraconazole/posaconazole. This article reviews the anti-Candida activities and mechanisms of antibiotics/derivatives used alone or in combination with antifungals. This review will helpfully provide novel insights for overcoming Candida resistance and discovering new antifungals.

Scalp infection by Candida Albicans in an immunocompetent patient: a description of a rare case

Candida is a large genus of yeast, consisting of about 150 species, among which C.albicans is the most prevalent fungal species of the human microbiota. C. albicans is the most important fungal opportunistic pathogen that can cause infection when the host becomes debilitated or immunocompromised. We report a case of a scalp infection by C.albicans in a patient without an obvious immunocompromised state.

Identification and antifungal susceptibility profiles of Kodamaea ohmeri based on a seven-year multicenter surveillance study

Background

Kodamaea ohmeri has been a rare fungal pathogen in the past decades but is now becoming more common in various invasive fungal diseases, with high mortality. There are limited data on the occurrence and distribution of K. ohmeri.

Methods

Sixty-two K. ohmeri isolates collected from 24 hospitals in China over a 7-year period were studied. Performance of three phenotypic methods in the identification of this organism was assessed against a gold standard, 26S rDNA sequencing. Original identification results submitted by the participating local hospitals were reviewed. The Sensititre YeastOne YO10 (SYY) was evaluated in determining the in vitro antifungal susceptibilities using standard broth microdilution method (BMD) as a reference, and essential agreement (EA) was calculated.

Results

Accurate species identification was achieved in 82.3% and 96.8% of the cases by Vitek 2 Compact and Vitek mass spectrometry (MS), respectively. For Bruker MS, 12.9% and 96.8% of the isolates were correctly identified to species level using the direct transfer and protein extraction methods, respectively. Only 29 (46.8%) isolates were initially correctly identified as K. ohmeri by the local hospitals. The highest misidentification rate (100%, 16/16) was observed in CHROMagar. According to BMD, the highest MIC₉₀ was seen in fluconazole (8 μg/mL), followed by 1 μg/mL for micafungin, caspofungin, 5-fluorocytosine, and amphotericin B, 0.5 μg/mL for itraconazole, 0.25 μg/mL for posaconazole and voriconazole. Significant differences in EAs for different drugs were observed, ranging from 95.2% for amphotericin B to 22.6% for itraconazole between SYY and BMD.

Conclusion

Our study emphasizes the need for accurate identification of clinical K. ohmeri isolates and the importance of validating antifungal susceptibility by standard BMD.

Inhibition of adhesion-specific genes by Solidago virgaurea extract causes loss of Candida albicans biofilm integrity

AIMS

Candida albicans biofilms are commonly associated with severe oral infections. We previously discovered that a crude extract from the Solidago virgaurea plant (SV extract) was a potent inhibitor of C. albicans biofilm formation. Here, we further investigate the mechanisms underlying C. albicans biofilm inhibition by the SV extract.

METHODS AND RESULTS

The SV extract was shown to inhibit laboratory and clinical C. albicans isolates adherence and hyphal transition on inert support and epithelial human cells, without affecting viability and growth of planktonic yeasts. Interestingly, RT-PCR-based experiments demonstrated that some key genes involved in adhesion and hyphal morphological switch (e.g. Hwp1p, Ece1p, Als3p) were strongly down-regulated by the SV extract. Moreover, antimicrobial synergy testing (checkerboard assay) demonstrated that antifungal effects of miconazole, nystatin or a common antiseptic mouthwash were synergistically improved when used in combination with the SV extract.

CONCLUSIONS

The SV extract prevents C. albicans biofilm formation through direct inhibition of key adherence and hyphae-associated genes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Biofilm is considered as a key virulence factor of C. albicans infection. Our discovery of an inhibitor specifically acting on genes involved in biofilm formation paves the way for the future development of a new class of antifungal product.

Effect of Nicotinamide Against Candida albicans

Nicotinamide (NAM) has a long history in clinical applications and can be safely used for treating various diseases. In recent years, NAM was found to exhibit antimicrobial activities, inhibiting the growth of Plasmodium falciparum, Mycobacterium tuberculosis, and human immunodeficiency virus (HIV). Here we investigated the activity of NAM against Candida albicans, one of the most prevalent human fungal pathogens. Our results showed that NAM exhibited significant antifungal activity against C. albicans, including fluconazole-resistant isolates. NAM could also effectively suppress biofilm formation. In addition, NAM exhibited antifungal activity against non-Candida albicans species and Cryptococcus neoformans. Combination of NAM and fluconazole showed an even strong antifungal activity. The antifungal activity of NAM was further confirmed in a mouse model of disseminated candidiasis. Confocal laser scanning microscopy revealed that NAM increased cell wall β-glucans exposure and chitin content while decreased mannan level. Furthermore, by screening the C. albicans homozygous deletion mutant library, the C. albicans mutant lacking GIN4, which encodes a septin regulatory protein kinase and is essential for the maintenance of cell wall integrity, was identified to be high sensitive to NAM. These findings suggested that NAM might exhibit antifungal activities through affecting cell wall organization.

Virulence factors of Candida spp. obtained from blood cultures of patients with candidemia attended at tertiary hospitals in Northeast Brazil

BACKGROUND

Yeasts of the Candida genus are one of the most common causes of bloodstream infections associated with high rates of morbidity and mortality, mainly affecting immunocompromised patients. We aimed to identify yeasts obtained from blood cultures of patients interned at tertiary hospitals in Brazil.

METHODS

We evaluated some of the major virulence factors of Candida spp., including the ability to adhere to human buccal epithelial cells, biofilm formation, hemolytic and phospholipase activity.

RESULTS

We analyzed 70 isolates of Candida spp. obtained from March 2011 and March 2015. Candida spp. showed different peculiarities in terms of expression of virulence factors evaluated in vitro. C. albicans strains were more adherent to HBEC than all the other Candida species. C. tropicalis strains were considered strong biofilm producers. Strains belonging to the C. parapsilosis species complex were able to produce hemolysins, while C. glabrata was also able to lyse erythrocytes and to produce phospholipase.

CONCLUSION

These results suggest that Non-Candida albicans Candida species are also able to express virulence factors which play an important role in bloodstream infectious caused by these yeasts.

Evaluation of candidemia and antifungal consumption in a large tertiary care Italian hospital over a 12-year period

PURPOSE

An early adequate antifungal therapy based on the knowledge of local epidemiology can reduce the candidemia-attributable mortality and the length of hospitalization. We performed a retrospective study to analyze the epidemiology of candidemia and the antifungal consumption in our hospital.

METHODS

We analyzed Candida spp. isolated from the blood, and their susceptibility profile from 2005 to 2016 in Careggi University Hospital, Florence, Italy. We also performed a stratified analysis by clinical setting where Candida spp. were isolated (Medical Wards, Surgery, Intensive Care Unit-ICU). Then, we retrospectively reviewed the annual consumption of antifungal agents and calculated the defined daily dosing for 10,000 hospital days.

RESULTS

The rate of candidemia was higher in ICU than other settings and Candida albicans was the first cause of candidemia (61.2%). After adjustment for hospital days, the rate of C. albicans showed a statistically significant parabolic trend (p < 0.001), with a peak of incidence in 2010. After 2010, we observed a reduction of candidemia due to both C. albicans and non-albicans species. Between 2005 and 2015, we reported an increasing increased use of echinocandins. As far as resistance profile is concerned, only one Candida glabrata isolate was resistant to caspofungin (1.9%) and 30% of C. glabrata were resistant to fluconazole.

CONCLUSIONS

Our data describe C. albicans as the first cause of candidemia in all the studied settings and the low rate of echinocandin resistance, despite their increased use over the study period. ICU was confirmed as the setting with the highest incidence of candidemia.

Potent In Vitro Synergism of Fluconazole and Osthole against Fluconazole-Resistant Candida albicans

Osthole is a natural coumarin that exhibits wide biological and pharmacological activities such as neuroprotective, osteogenic, immunomodulation, antitumor, and anti-inflammatory effects. In this study, we investigated the antifungal effects of osthole in vitro A checkerboard microdilution assay showed that osthole has significant synergistic effect with fluconazole against fluconazole-resistant Candida albicans Similar results were obtained from a growth curve assay. Meanwhile, XTT reduction assay demonstrated the synergism of fluconazole and osthole against C. albicans biofilm formation. Microarray results showed that the expression of genes involved in the oxidation-reduction process, energy metabolism, and transportation changed significantly after the combined treatment with fluconazole and osthole, and further results showed that endogenous reactive oxygen species (ROS) was significantly increased in the combination group. In conclusion, these results demonstrate the synergism of fluconazole and osthole against fluconazole-resistant C. albicans and indicate that endogenous ROS augmentation might contribute to the synergism of fluconazole and osthole.

Antifungal effects of phytocompounds on Candida species alone and in combination with fluconazole

Invasive fungal infections caused by Candida spp. remain the most predominant nosocomial fungal infections. Owing to the increased use of antifungal agents, resistance of Candida spp. to antimycotics has emerged frequently, especially to fluconazole (FLC). To cope with this issue, new efforts have been dedicated to discovering novel antimycotics or new agents that can enhance the susceptibility of Candida spp. to existing antimycotics. The secondary metabolites of plants represent a large library of compounds that are important sources for new drugs or compounds suitable for further modification. Research on the anti-Candida activities of phytocompounds has been carried out in recent years and the results showed that a series of phytocompounds have anti-Candida properties, such as phenylpropanoids, flavonoids, terpenoids and alkaloids. Among these phytocompounds, some displayed potent antifungal activity, with minimum inhibitory concentrations (MICs) of ≤8 µg/mL, and several compounds were even more effective against drug-resistant Candida spp. than FLC or itraconazole (e.g. honokiol, magnolol and shikonin). Interestingly, quite a few phytocompounds not only displayed anti-Candida activity alone but also synergised with FLC against Candida spp., even leading to a reversal of FLC resistance. This review focuses on summarising the anti-Candida activities of phytocompounds as well as the interactions of phytocompounds with FLC. In addition, we briefly overview the synergistic mechanisms and present the structure of the antimycotic phytocompounds. Hopefully, this analysis will provide insight into antifungal agent discovery and new approaches against antifungal drug resistance.

Multilocus sequence typing of Candida tropicalis shows clonal cluster enrichment in azole-resistant isolates from patients in Shanghai, China

To explore the putative correlation between the multilocus sequence types (MLST) and antifungal susceptibility of clinical Candida tropicalis isolates in Mainland China. Eighty-two clinical C. tropicalis isolates were collected from sixty-nine patients at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, from July 2012 to February 2015, and antifungal susceptibility tests were performed. Genetic profiles of those 82 isolates (30 azole-resistant and 52 azole-susceptible) were characterised by multilocus sequence typing. Phylogenetic analysis of the data was conducted with the clustering method, using UPGMA (unweighted pair group method with arithmetic averages) and the minimal spanning tree algorithm. MLST clonal clusters were analysed using the eBURST V3 package. Of the six gene fragments identified in multilocus sequence typing, SAPT4 presented the highest typing efficiency, whereas SAPT2 was the least efficient. Of the 44 diploid sequence types (DSTs) differentiated, 32 DSTs and 12 genotypes were identified as new to the C. tropicalis DST database. Twenty (45.45%) of the 44 DSTs were assigned to seven major groups based on eBURST analysis. Of these, Group 6, which contained DST 376, DST 505, DST 506 and DST 507, accounted for 76.7% of the 30 azole-resistant isolates. However, the genetic relationships among the azole-susceptible isolates were relatively decentralised. This MLST analysis of the putative correlation between the MLST types and antifungal susceptibility of clinical C. tropicalis isolates in Mainland China shows that DSTs 376, 505, 506 and 507 are closely related azole-resistant C. tropicalis clones.

Molecular analysis of fungal populations in patients with oral candidiasis using next-generation sequencing

Oral candidiasis is closely associated with changes in oral fungal biodiversity and is caused primarily by Candida albicans. However, the widespread use of empiric and prophylactic antifungal drugs has caused a shift in fungal biodiversity towards other Candida or yeast species. Recently, next-generation sequencing (NGS) has provided an improvement over conventional culture techniques, allowing rapid comprehensive analysis of oral fungal biodiversity. In this study, we used NGS to examine the oral fungal biodiversity of 27 patients with pseudomembranous oral candidiasis (POC) and 66 healthy controls. The total number of fungal species in patients with POC and healthy controls was 67 and 86, respectively. The copy number of total PCR products and the proportion of non-C. albicans, especially C. dubliniensis, in patients with POC, were higher than those in healthy controls. The detection patterns in patients with POC were similar to those in controls after antifungal treatment. Interestingly, the number of fungal species and the copy number of total PCR products in healthy controls increased with aging. These results suggest that high fungal biodiversity and aging might be involved in the pathogenesis of oral candidiasis. We therefore conclude that NGS is a useful technique for investigating oral candida infections.

Isolation and Characterization of an Atypical Metschnikowia sp. Strain from the Skin Scraping of a Dermatitis Patient

A yeast-like organism was isolated from the skin scraping sample of a stasis dermatitis patient in the Mycology Unit Department of Medical Microbiology, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia. The isolate produced no pigment and was not identifiable using chromogenic agar and API 20C AUX. The fungus was identified as Metschnikowia sp. strain UM 1034, which is close to that of Metschnikowia drosophilae based on ITS- and D1/D2 domain-based phylogenetic analysis. However, the physiology of the strain was not associated to M. drosophilae. This pathogen exhibited low sensitivity to all tested azoles, echinocandins, 5-flucytosine and amphotericin B. This study provided insight into Metschnikowia sp. strain UM 1034 phenotype profiles using a Biolog phenotypic microarray (PM). The isolate utilized 373 nutrients of 760 nutrient sources and could adapt to a broad range of osmotic and pH environments. To our knowledge, this is the first report of the isolation of Metschnikowia non-pulcherrima sp. from skin scraping, revealing this rare yeast species as a potential human pathogen that may be misidentified as Candida sp. using conventional methods. Metschnikowia sp. strain UM 1034 can survive in flexible and diverse environments with a generalist lifestyle.