Current methods for identifying clinically important cryptic Candida species

Lack of Candida africana in Ugandan pregnant women: results from a pilot study using MALDI-ToF

BACKGROUND

Candida africana is an emergent variant that has been listed as a new species or variety within the Candida albicans complex since 2001. It has a worldwide intra-albicans complex pooled prevalence of 1.67% and varies between 0 and 8% depending on geographical region. We present the results of a pilot study on its prevalence in Uganda.

METHODOLOGY

We conducted a cross-sectional study between March and June 2023. We recruited 4 pregnant women from Mulago Specialized Women and Neonatal Hospital, 102 from Kawempe National Referral Hospital, and 48 from Sebbi Hospital. Vaginal swabs were tested using microscopy, culture and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF).

RESULTS

The prevalence of C. africana was zero. Out of the 103 isolates, the majority (81.553%) were identified as Candida albicans, followed by Nakeseomyces glabrata (13.592%) and Pichia kudriavzevii (1.942%). Cyberlindnera jadinii, Candida tropicalis, and Candida parapsilosis each accounted for 0.971% of the isolates.

CONCLUSION

The prevalence of C. africana in Uganda is zero. However, large-scale cross-sectional studies, including studies involving the collection of vaginal samples from both urban and rural settings in Uganda and the use of both MALDI-TOF- and PCR-based laboratory methods, are needed to fully describe the public health burden of C. africana infections.

Prevalence and Species Distribution of Candida Clinical Isolates in a Tertiary Care Hospital in Ecuador Tested from January 2019 to February 2020

The incidence of candidemia in healthcare centers is associated with high morbidity and mortality. Frequency varies significantly among regions, with some species being more prevalent than others in Latin America. In this study, 191 clinical Candida isolates were collected from a major hospital in Ecuador from January 2019 to February 2020 aiming to assess their prevalence and distribution. After data processing, 168 isolates characterized by the VITEK 2 system were subsequently identified by ITS sequencing. Results showed diverse Candida species distributions, with C. albicans and C. tropicalis being the most prevalent across different clinical sources. In hospitalized individuals, C. tropicalis (38%) and C. albicans (37%) were the most prevalent, followed by, C. parapsilosis (16%), C. glabrata (5%), and other non-Candida albicans (NCA) species (6%). Conversely, C. parapsilosis (48%), C. albicans (20%), and C. glabrata (14%), associated with candidemia, were the most common in blood and CSF. Additionally, uncommon NCA species such as C. haemulonii, C. kefyr, and C. pelliculosa were identified in Ecuador for the first time. Discrepancies in species identification were observed between the VITEK 2 system and ITS sequencing, coinciding at 85%. This highlights the need for ongoing surveillance and identification efforts in Ecuador's clinical and epidemiological settings.

The Emerging Pathogen Candida metapsilosis: Biological Aspects, Virulence Factors, Diagnosis, and Treatment

Fungal infections represent a constant and growing menace to public health. This concern is due to the emergence of new fungal species and the increase in antifungal drug resistance. Mycoses caused by Candida species are among the most common nosocomial infections and are associated with high mortality rates when the infection affects deep-seated organs. Candida metapsilosis is part of the Candida parapsilosis complex and has been described as part of the oral microbiota of healthy individuals. Within the complex, this species is considered the least virulent; however, the prevalence has been increasing in recent years, as well as an increment in the resistance to some antifungal drugs. One of the main concerns of candidiasis caused by this species is the wide range of clinical manifestations, ranging from tissue colonization to superficial infections, and in more severe cases it can spread, which makes diagnosis and treatment difficult. The study of virulence factors of this species is limited, however, proteomic comparisons between species indicate that virulence factors in this species could be similar to those already described for C. albicans. However, differences may exist, taking into account changes in the lifestyle of the species. Here, we provide a detailed review of the current literature about this organism, the caused disease, and some sharing aspects with other members of the complex, focusing on its biology, virulence factors, the host-fungus interaction, the identification, diagnosis, and treatment of infection.

Changes in fungal taxonomy: mycological rationale and clinical implications

Numerous fungal species of medical importance have been recently subjected to and will likely continue to undergo nomenclatural changes as a result of the application of molecular approaches to fungal classification together with abandonment of dual nomenclature. Here, we summarize those changes affecting key groups of fungi of medical importance, explaining the mycological (taxonomic) rationale that underpinned the changes and the clinical relevance/importance (where such exists) of the key nomenclatural revisions. Potential mechanisms to mitigate unnecessary taxonomic instability are suggested, together with approaches to raise awareness of important changes to minimize potential clinical confusion.

Phenotypic and genotypic characterization of virulence markers and antifungal susceptibility of oral Candida species from diabetic and non-diabetic hemodialysis patients

BACKGROUND

Patients with chronic kidney disease undergoing hemodialysis are often colonized by Candida species with high possibility of fungal infections. The purposes of this study were to determine the prevalence of Candida species, evaluate antifungal susceptibility profile, biofilm formation, proteinase and phospholipase activities, and the frequency of virulence genes in the Candida species isolated from the oral mucosa of hemodialysis diabetic (DM) and non-diabetic (non-DM) patients.

METHODS

This study identified several species of Candida isolated from 69 DM and 58 non-DM patients on hemodialysis using phenotypic methods and PCR-RFLP technique. The identification of C. albicans and C. glabrata complex was performed by HWP1 gene and four oligonucleotides (UNI-5.8S, GLA-f, BRA-f, and NIV-f), respectively. Antifungal susceptibility to amphotericin B, fluconazole, itraconazole, voriconazole, and caspofungin was assessed according to CLSI M27-A3/S4. The biomass, metabolic activity of biofilm, proteinase (P_rz), phospholipase (P_z), and molecular study for virulence genes were assessed using crystal violet, XTT assay, agar-based hydrolytic enzyme, and PCR technique, respectively.

RESULTS

Candida prevalence was 44.9% with 47.8% and 41.4% among DM and non-DM patients, respectively (P = .045). The species identified were C. albicans (49.5%), C. glabrata (16.5%), C. tropicalis (12%), C. kefyr (8.8%), C. parapsilosis (6.6%), C. dubliniensis (3.3%), and C. lusitaniae (3.3%). The antifungal susceptibility profile showed that all Candida isolates were sensitive to amphotericin B, itraconazole, voriconazole, and caspofungin whereas fluconazole resistance was observed in 6.3% (MIC ≥ 64 μg/mL) of C. albicans and 6.6% of C. glabrata (MIC ≥ 64 μg/mL). The susceptible- dose-dependent rate was found in 10.5% of C. albicans. The P_rz values of C. albicans ranged from 0.37 to 0.66 for the DM and 0.44-0.73 for the non-DM group (P < 0.05). The non-albicans Candida (NAC) species produced higher degree of biomass and metabolic activity compared to C. albicans (P < 0.05). Furthermore, significant (p < 0.05) correlations were detected between the biofilm formation with P_rz values and fluconazole MICs. The most detected virulence factors were ALS3 and Sap5.

CONCLUSIONS

These results showed the importance of prevalence of NAC species in hemodialysis patients. Investigating antifungal susceptibility profile made a better understanding of the role of virulence markers in the pathogenesis of Candida strains.

Molecular Investigation of the Fatal Bloodstream Candida orthopsilosis Infection Case following Gastrectomy

Candida orthopsilosis represents a closely related cryptic genospecies of Candida parapsilosis complex-misidentified in routine diagnostic assays. This is emerging in settings where central venous catheters, invasive medical interventions, and echinocandin treatments are most likely to be used. A 59-year-old, non-neutropenic male patient, was admitted to an intensive care unit (ICU) due to respiratory distress syndrome, following a partial gastrectomy. As a result of duodenal stump leakage, re-laparotomy was required, abdominal drains were provided and central line catheters were exchanged. Multiple isolates of Candida orthopsilosis drawn from consecutive blood cultures were identified, despite ongoing echinocandin therapy and confirmed in vitro echinocandins susceptibility of the isolated strain. Species identification was verified via ITS region sequencing. Herein, we report the well-documented—per clinical data and relevant laboratory diagnosis—first case of a bloodstream infection caused by Candida orthopsilosis in Poland.

Candida spp. DNA Extraction in the Age of Molecular Diagnosis

The standard procedure for the detection of candidemia is blood culture, a method that might require 3-5 days for a positive result. Compared with culturing, molecular diagnosis techniques can provide faster diagnosis. The current paper aimed to present the main strengths and constraints of current molecular techniques for Candida spp. DNA extraction, analyzing their efficiency from a time, price, and ease of usage point of view. A comprehensive search was conducted using the PubMed NIH database for peer-reviewed full-text articles published before October 2022. The studies provided adequate data on the diagnosis of the infection with the Candida spp. DNA extraction is a relevant step in yielding pure qualitative DNA to be amplified in molecular diagnostic techniques. The most used fungal DNA extraction strategies are: mechanical (bead beating, ultrasonication, steel-bullet beating), enzymatic (proteinase K, lysozyme, lyticase), and chemical extraction (formic acid, liquid nitrogen, ammonium chloride). More clinical studies are needed to formulate adequate guidelines for fungal DNA extraction as the current paper highlighted discrepancies in the reported outcome.

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

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

Vulvovaginal candidiasis in Iranian women: Molecular identification and antifungal susceptibility pattern

AIM

Vulvovaginal candidiasis (VVC), is a common fungal infection that remains a global concern. The objectives of this study were molecular identification and assessment of the antifungal susceptibility profile of Candida species, causing VVC in southeast Iran.

METHODS

A cross-sectional investigation was carried out on 119 nonpregnant females suspected of VVC between February 2019 and May 2021. Yeast samples were characterized to the species level by conventional and molecular methods. All Candida isolates were examined for in vitro susceptibility profile to six conventional antifungal drugs using Clinical and Laboratory Standards Institute guidelines.

RESULTS

Out of 119 subjects, 52 (43.7%) cases were affected by VVC, out of whom 11 (21.15%) cases had recurrent vulvovaginal candidiasis (RVVC). The species distribution was as follows; Candida albicans (n = 21; 40.4%), C. glabrata (n = 11; 21.2%), C. tropicalis (n = 9; 17.3%), C. parapsilosis (n = 5; 9.7%), C. africana (n = 3; 5.7%), C. famata (n = 1; 1.9%), C. lusitaniae (n = 1; 1.9%), and C. dubliniensis (n = 1; 1.9%). The resistance rate of Candida isolates to fluconazole, itraconazole, and voriconazole were 15.38%, 11.5%, and 3.8%, respectively. Resistance to fluconazole was obtained in 46% (5/11) of RVVC cases but only in 7% (3/41) of VVC cases.

CONCLUSION

This study demonstrated that the majority of VVC cases were caused by non-albicans Candida species which also were resistant to some antifungal agents. Hence, our findings revealed the importance of conducting periodical epidemiological studies to determine changes in species distribution. Moreover, for effective management of treatment and infection, it is imperative to evaluate the susceptibility profiles of Candida species isolated from VVC patients.

Exploring the Antifungal Activity and Action of Saussurea costus Root Extracts against Candida albicans and Non-albicans Species

The isolation and assessment of the active constituents in polar and non-polar crude extracts of Saussurea costus roots as antifungal agents, against Candida albicans and non-C. albicans (NAC) species, was the aim of this current investigation. The SEM “Scanning electron microscopy” imaging provided potential action modes of n-hexane extract (nhhE) toward Candida spp., whereas the TLC-DB “Thin layer chromatography-direct bioautography” was employed for detecting the anticandidal compounds. nhhE had the greatest biocidal activity against all strains and clinical isolates of Candida spp. with maximum zones of inhibition. SEM revealed the occurrence of irregular, dense inclusions of C. albicans cell walls after treatment with nhhE for 12 h. Complete morphological distortions with lysed membranes and deterioration signs appeared in most treated cells of C. parapsilosis. The most effectual compound with anticandidal activity was isolated using TLC-BD and identified as sesquiterpene by GC/MS analysis. The infra-red analysis revealed the presence of lactone ring stretching vibrations at 1766.72 cm−1. The anticandidal activity of nhhE of S. costus roots was confirmed from the results, and the treated cotton fabrics with nhhE of S. costus possessed observable activity against C. albicans. Data could recommend the practical usage of S. costus extracts, particularly nhhE, as influential natural bioactive sources for combating pathogenic Candida spp.

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

Background

Vulvovaginal candidiasis (VVC) is a common and debilitating long‐term illness affecting million women worldwide. This disease is caused mainly by Candida albicans and a lesser extent by other species, including the two phylogenetically closely related pathogens Candida africana and Candida dubliniensis.

Objectives

In this study, we report detailed molecular epidemiological data about the occurrence of these two pathogenic yeasts in Iranian patients affected by VVC, or its chronic recurrent form (RVVC), and provide, for the first time, data on the antifungal activity of two new drugs, efinaconazole (EFN) and luliconazole (LUL).

Methods

A total of 133 vaginal yeast isolates, presumptively identified as Calbicans by phenotypic and restriction analysis of rDNA, were further analysed by using a specific molecular method targeting the HWP1 gene. All Cafricana and Cdubliniensis isolates were also tested for their in vitro susceptibility to a panel of modern and classical antifungal drugs.

Results and Conclusions

Based on the molecular results, among 133 germ‐tube positive isolates, we identify 119 Calbicans (89.47%), 11 Cafricana (8.27%) and 3 Cdubliniensis (2.26%) isolates. Cafricana and Cdubliniensis showed low MIC values for most of the antifungal drugs tested, especially for EFN and LUL, which exhibited a remarkable antifungal activity. High MIC values were observed only for nystatin and terbinafine. Although Calbicans remains the most common Candida species recovered from Iranian VVC/RVVC patients, our data show that its prevalence may be slightly overestimated due to the presence of difficult‐to‐identify closely related yeast, especially Cafricana.

MALDI-TOF MS Overcomes Misidentification of the Uncommon Human Pathogen Candida famata by Routine Phenotypic Identification Methods

Candida famata has been associated with the identifiable Candida infections that takes place in human and the identification error of this species possibly will result in misinterpretation of antifungal susceptibility and improper diagnosis; which will have a major effect on the prognosis and therapy of patients. Our objective is to correctly identify Candida spp. collected from patients at the intensive care units, New Cairo University teaching hospital in Cairo-Egypt using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Hundred clinically isolated yeast strains were identified using API 20C AUX obtained from patients receiving care at intensive care units. ATB FUNGUS 3 strips were used to detect the minimum inhibitory concentration. Thirty-three non duplicate strains identified as C. famata were subjected to re-identification by MALDI-TOF MS. Our results revealed that isolates were initially identified as C. famata 33%, C. tropicalis 15%, C. albicans 12% and C. parapsillosis 10% using the phenotypic techniques. MALDI-TOF MS analyses results showed that the 33 C. famata isolates are C. tropicalis (n = 29), Trichosporon asahii (n = 2), C. parapsilosis (n = 1), and Aeromonas sobria (n = 1). Antifungal resistance was low in the Candida species, except for reduced susceptibility to itraconazole among C. krusei strains. This report shows that misidentification of C. famata is frequent when using conventional phenotypic methods of identification which result in challenges in treating fungal infections. MALDI-TOF MS is an accurate convenient substitute to classical approaches for fungal identification. In general, antifungal multidrug resistance is uncommon in our studied Candida species and yeast isolates.

Unambiguous identification of fungi: where do we stand and how accurate and precise is fungal DNA barcoding?

True fungi (Fungi) and fungus-like organisms (e.g. Mycetozoa, Oomycota) constitute the second largest group of organisms based on global richness estimates, with around 3 million predicted species. Compared to plants and animals, fungi have simple body plans with often morphologically and ecologically obscure structures. This poses challenges for accurate and precise identifications. Here we provide a conceptual framework for the identification of fungi, encouraging the approach of integrative (polyphasic) taxonomy for species delimitation, i.e. the combination of genealogy (phylogeny), phenotype (including autecology), and reproductive biology (when feasible). This allows objective evaluation of diagnostic characters, either phenotypic or molecular or both. Verification of identifications is crucial but often neglected. Because of clade-specific evolutionary histories, there is currently no single tool for the identification of fungi, although DNA barcoding using the internal transcribed spacer (ITS) remains a first diagnosis, particularly in metabarcoding studies. Secondary DNA barcodes are increasingly implemented for groups where ITS does not provide sufficient precision. Issues of pairwise sequence similarity-based identifications and OTU clustering are discussed, and multiple sequence alignment-based phylogenetic approaches with subsequent verification are recommended as more accurate alternatives. In metabarcoding approaches, the trade-off between speed and accuracy and precision of molecular identifications must be carefully considered. Intragenomic variation of the ITS and other barcoding markers should be properly documented, as phylotype diversity is not necessarily a proxy of species richness. Important strategies to improve molecular identification of fungi are: (1) broadly document intraspecific and intragenomic variation of barcoding markers; (2) substantially expand sequence repositories, focusing on undersampled clades and missing taxa; (3) improve curation of sequence labels in primary repositories and substantially increase the number of sequences based on verified material; (4) link sequence data to digital information of voucher specimens including imagery. In parallel, technological improvements to genome sequencing offer promising alternatives to DNA barcoding in the future. Despite the prevalence of DNA-based fungal taxonomy, phenotype-based approaches remain an important strategy to catalog the global diversity of fungi and establish initial species hypotheses.

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.

Solidago virgaurea L. Plant Extract Targeted Against Candida albicans to Reduce Oral Microbial Biomass: a Double Blind Randomized Trial on Healthy Adults

Oral microbiome plays an important part on oral health and endogenous bacteria and fungi should not be eradicated. However, their proliferation must be controlled by oral hygiene care. In vitro, Solidago virgaurea ssp. virgaurea L. (SV) plant extract inhibits the adherence and hyphal formation of a fungus, Candida albicans. It reduces the biomass of Candida-bacterial biofilms but not fungal or bacterial growth. Unlike chemical antiseptics, like triclosan and chlorhexidine for instance, SV is a plant extract easily biodegradable. The purpose of this study was to assess the in vivo effectiveness of SV extract in reducing oral biomass. A randomized, double-blind clinical study, with dental plaque evaluation designed to assess the effectiveness of a fluorinated toothpaste containing SV (Bucovia™, Givaudan, Vernier, Switzerland) was conducted. Sixty-six subjects (SV group n = 33 vs. control n = 33) brushed their teeth twice a day for a 4-week period. Supragingival dental plaque was sampled. Total bacterial load (broad spectral bacterial quantitative Polymerase Chain Reaction (qPCR)), C. albicans and seven bacterial species were quantified by qPCR. In the Intervention group, there was a decrease of Total bacterial load (ΔD0D28 p = 0.005 and ΔD14D28 p = 0.026), Streptococcus mutans (ΔD0D14 p = 0.024) and C. albicans (ΔD0D28 p = 0.022). In the Control group Total bacterial load tended to decrease from baseline to day 28 (ΔD0D28 p = 0.062 and ΔD14D28 p = 0.009). Plaque Index and Gingival Index improved in both groups.

Differentiation of Candida albicans Species Complex by Tobacco Agar Obtained from Different Cigarette Brands Available in Colombia

Introduction. The Candida albicans complex is formed by Candida albicans, Candida dubliniensis, and a biovar of C. albicans named Candida africana. These yeasts are recognized as globally distributed clinical pathogens and share most phenotypic characteristics, which makes their discrimination by conventional methods difficult. Aim. To evaluate the efficacy of different brands of cigarettes in the preparation of tobacco agar, for the differentiation of these related yeasts. Methodology. Tobacco agar was prepared using six brands and four varieties of cigarettes, and 125 clinical isolates previously identified by PCR and Maldi-Tof were used. To determine whether the results of the microbiological tests were associated with similarities in the chemical components of cigarettes, thin-layer chromatography was performed. Results. Candida dubliniensis colonies presented hue differences according to the incubation temperature and the brand or variety of cigarette used, except in the tobacco agar produced with Marlboro Xpress cigarette, where its differentiation was not possible. The chromatograms showed few differences among apolar and medium polarity extract components. Conclusions. Tobacco agar is a low-cost tool used for the differentiation of Candida dubliniensis; however, incubation temperature and cigarette brand affect the performance of the media. No relationship was found between the microbiological results and the chemical similarity of the extracts of the cigarettes by chromatography.

Rapid identification of the Candida glabrata species complex by high-resolution melting curve analysis

Background

Candida glabrata is a common pathogen that causes invasive candidiasis. Among non‐albicans Candida infections, C glabrata infections are associated with the highest fatality rates. Candida glabrata sensu stricto, Candida nivariensis, and Candida bracarensis have been identified and together form the C glabrata species complex. It is difficult to detect the two rare species by traditional laboratory methods. This study established a method for the rapid identification of members of the C glabrata species complex based on high‐resolution melting curve (HRM) analysis and evaluated its practical application.

Methods

The internal transcribed spacer (ITS) region was used as target gene region to design specific primers. HRM analysis was performed with three subspecies of the C glabrata species complex and negative controls to test its specificity and sensitivity. To evaluate its practical application, the HRM technique was tested with clinical isolates, and the results were compared with the DNA sequencing results.

Results

Differences were detected among the melting profiles of the members of the C glabrata species complex. The negative controls were not amplified, indicating the high specificity of the method. The minimum detection limits of C glabrata sensu stricto, C nivariensis, and C bracarensis were approximately 1 × 10¹ copies/µL or less. The results of the HRM analysis of the clinical isolates were consistent with the DNA sequencing results.

Conclusions

The HRM method is sensitive and can be used to rapidly identify the members of the C glabrata species complex. The method can allow early and targeted treatment of patients with invasive candidiasis.

An Overview on Conventional and Non-Conventional Therapeutic Approaches for the Treatment of Candidiasis and Underlying Resistance Mechanisms in Clinical Strains

Fungal infections and, in particular, those caused by species of the Candida genus, are growing at an alarming rate and have high associated rates of mortality and morbidity. These infections, generally referred as candidiasis, range from common superficial rushes caused by an overgrowth of the yeasts in mucosal surfaces to life-threatening disseminated mycoses. The success of currently used antifungal drugs to treat candidiasis is being endangered by the continuous emergence of resistant strains, specially among non-albicans Candida species. In this review article, the mechanisms of action of currently used antifungals, with emphasis on the mechanisms of resistance reported in clinical isolates, are reviewed. Novel approaches being taken to successfully inhibit growth of pathogenic Candida species, in particular those based on the exploration of natural or synthetic chemicals or on the activity of live probiotics, are also reviewed. It is expected that these novel approaches, either used alone or in combination with traditional antifungals, may contribute to foster the identification of novel anti-Candida therapies.

Identification of Cryptic Species of Four Candida Complexes in a Culture Collection

Candida spp. are one of the most common causes of fungal infections worldwide. The taxonomy of Candida is controversial and has undergone recent changes due to novel genetically related species. Therefore, some complexes of cryptic species have been proposed. In clinical settings, the correct identification of Candida species is relevant since some species are associated with high resistance to antifungal drugs and increased virulence. This study aimed to identify the species of four Candida complexes (C. albicans, C. glabrata, C. parapsilosis, and C. haemulonii) by molecular methods. This is the first report of six cryptic Candida species in Honduras: C. dubliniensis, C. africana, C. duobushaemulonii, C. orthopsilosis, and C. metapsilosis, and it is also the first report of the allele hwp1-2 of C. albicans sensu stricto. It was not possible to demonstrate the existence of C. auris among the isolates of the C. haemulonii complex. We also propose a simple method based on PCR-RFLP for the discrimination of the multi-resistant pathogen C. auris within the C. haemulonii complex.

Contrasting Strategies: Human Eukaryotic Versus Bacterial Microbiome Research

Most discussions of human microbiome research have focused on bacterial investigations and findings. Our target is to understand how human eukaryotic microbiome research is developing, its potential distinctiveness, and how problems can be addressed. We start with an overview of the entire eukaryotic microbiome literature (578 papers), show tendencies in the human‐based microbiome literature, and then compare the eukaryotic field to more developed human bacterial microbiome research. We are particularly concerned with problems of interpretation that are already apparent in human bacterial microbiome research (e.g. disease causality, probiotic interventions, evolutionary claims). We show where each field converges and diverges, and what this might mean for progress in human eukaryotic microbiome research. Our analysis then makes constructive suggestions for the future of the field.

Unequivocal identification of an underestimated opportunistic yeast species, Cyberlindnera fabianii, and its close relatives using a dual-function PCR and literature review of published cases

Although Cyberlindnera fabinaii is a rare opportunist yeast species, its ability to cause septicemia, produce biofilm, and rapid acquisition of resistance to fluconazole and voriconazole, reinforced the urge for its identification from its closely related species. Widely used biochemical assays mainly identify Cyberlindnera fabinaii as Cyberlindnera jadinii and Wickerhamomyces anomalus, resulting in underestimation of this yeast in clinical settings. Moreover, the urge for a reliable molecular means of identification remains unsolved for 28 years. In order to unequivocally differentiate Cy. fabianii, Cy. mississipiensis, Cy. jadinii, and W. anomalus, we designed a dual-function multiplex polymerase chain reaction (PCR) assay. Challenging our dual-function multiplex PCR assay with 30 most clinically important yeast species, proved its specificity. Although conventional PCR could differentiate four target species, the real-time PCR counterpart due to Tm overlap misidentified Cy. mississipiensis as Cy. jadinii. Alongside of presenting a comprehensive literature review of published cases of Cy. fabianii from 1990 to 2018, we collected various clinical isolates from Tehran, Shiraz, and Fasa (July 1, 2017, to December 31, 2017) to find a passive relative distribution of these closely-related species in Iran. Subjecting our Iranian collection of yeast isolates to matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS and LSU and ITS rDNA sequencing revealed six isolates of Cy. fabianii (central venous catheter n = 2 and vaginal swabs n = 4) and one isolate of Cy. jadinii (vaginal swabs). Due to the use of biochemical assays in global ARTEMIS study, we encourage reidentification of clinical isolates of Cy. jadinii and Cy. jadinii using MALDI-TOF or Sanger sequencing that might lead to correcting the distribution of this fungus.

Advances in Chemical and Biological Methods to Identify Microorganisms-From Past to Present

Fast detection and identification of microorganisms is a challenging and significant feature from industry to medicine. Standard approaches are known to be very time-consuming and labor-intensive (e.g., culture media and biochemical tests). Conversely, screening techniques demand a quick and low-cost grouping of bacterial/fungal isolates and current analysis call for broad reports of microorganisms, involving the application of molecular techniques (e.g., 16S ribosomal RNA gene sequencing based on polymerase chain reaction). The goal of this review is to present the past and the present methods of detection and identification of microorganisms, and to discuss their advantages and their limitations.

Comparison of 21-Plex PCR and API 20C AUX, MALDI-TOF MS, and rDNA Sequencing for a Wide Range of Clinically Isolated Yeast Species: Improved Identification by Combining 21-Plex PCR and API 20C AUX as an Alternative Strategy for Developing Countries

Occurrence of non-Candida albicans Candida (NCAC) species that are associated with elevated MIC values and therapeutic failures are increasing. As a result, timely and accurate means of identification to the species level is becoming an essential part of diagnostic practices in clinical settings. In this study, 301 clinically isolated yeast strains recovered from various anatomical sites [Blood (n = 145), other sites (n = 156)] were used to assess the accuracy and practicality of API 20C AUX and 21-plex PCR compared to MALDI-TOF MS and large subunit rDNA (LSU rDNA). MALDI-TOF MS correctly identified 98.33% of yeast isolates, 100% of top five Candida species, 95.7% of rare yeast species, while 1.3% of isolates were misidentified. API 20C AUX correctly identified 83.7% of yeast isolates, 97.2% of top five Candida species, 61.8% of rare yeast species, while 16.2% of yeast isolates were misidentified. The 21-plex PCR, accurately identified 87.3% of yeast isolates, 100% of top five Candida species, 72% of rare yeast species, but it misidentified 1.3% of rare yeast species while 9.9% of whole yeast isolates were not identified. The combination of rapidity of 21-plex PCR and comprehensiveness of API 20C AUX, led to correct identification of 92% of included yeast isolates. Due to expensiveness of MALDI-TOF MS and sequencing, this combination strategy could be the most accurate and inexpensive alternative identification strategy for developing countries. Moreover, by the advent and development of cost-effective, reliable, and rapid PCR machines that cost 130 US dollars, 21-plex could be integrated in routine laboratories of developing and resource-limited countries to specifically identify 95% causative agents of yeast-related infections in human. Databases of MALDI-TOF MS, API 20C AUX, and the number of target species identified by 21-plex require further improvement to keep up with the diverse spectrum of yeast species.

Prevalence of human pathogens of the clade Nakaseomyces in a culture collection-the first report on Candida bracarensis in Poland

Human pathogens belonging to the Nakaseomyces clade include Candida glabrata sensu stricto, Candida nivariensis and Candida bracarensis. Their highly similar phenotypic characteristics often lead to misidentification by conventional laboratory methods. Therefore, limited information on the true epidemiology of the Candida glabrata species complex is available. Due to life-threatening infections caused by these species, it is crucial to supplement this knowledge. The aim of the study was to estimate the prevalence of C. bracarensis and C. nivariensis in a culture collection of C. glabrata complex isolates. The study covered 353 isolates identified by biochemical methods as C. glabrata, collected from paediatric and adult patients hospitalised at four medical centres in Southern Poland. The multiplex PCR was used to identify the strains. Further species confirmation was performed via sequencing and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) analysis. One isolate was recognised as C. bracarensis (0.28%). To our knowledge, it is the first isolate in Poland. C. glabrata sensu stricto species has been confirmed for all the remaining isolates. No C. nivariensis was found. Our study has shown that the prevalence of C. nivariensis and C. bracarensis strains is infrequent. However, it should be emphasised that the incidence of these strains may differ locally and depend on environmental factors and the population.

Identification of nine cryptic species of Candida albicans, C. glabrata, and C. parapsilosis complexes using one-step multiplex PCR

Background

Candida albicans, Candida glabrata, and Candida parapsilosis are three prevalent causes of candidiasis, worldwide. These species are considered as nine medically important complex species. Limited knowledge about these newly recognized species prompted us to develop a one-step, multiplex PCR to detect and identify them in clinical settings.

Methods

Primers targeting Hyphal Wall Protein I gene for the C. albicans, C. dubliniensis, C. africana, Intergenic Spacer for the C. glabrata, C. nivariensis, C. bracarensis, and Intein and ITS rDNA for the C. parapsilosis, C. orthopsilosis, and C. metapsilosis were designed. Using 168 CBS reference strains and 280 clinical isolates, the specificity and reproducibility of the developed assay were evaluated.

Results

Our developed assay successfully identified and distinguished all the nine species. No cross-reaction with closely- and distantly-related yeast species, Aspergillus species and human DNA was observed, resulting in 100% specificity. The ambiguous results obtained by MALDI-TOF for C. albicans and C. africana were corrected by our 9-plex PCR assay. This assay identified all the cryptic complex species from two test sets from Iran and China, correctly.

Conclusions

Our developed multiplex assay is accurate, specific, cost/time-saving, and works without the tedious DNA extraction steps. It could be integrated into routine clinical laboratories and as a reliable identification tool and has the potential to be implemented into epidemiological studies to broaden the limited knowledge of cryptic species complexes.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3381-5) contains supplementary material, which is available to authorized users.

YEAST PANEL multiplex PCR for identification of clinically important yeast species: stepwise diagnostic strategy, useful for developing countries

Identification of opportunistic yeasts in developing countries is mainly performed by phenotypic assays, which are time-consuming and prone to errors. Wrong species identification may result in suboptimal treatment and inaccurate epidemiological data. To improve rapidity and accuracy of species identification, a diagnostic strategy using a stepwise "YEAST PANEL multiplex PCR assays" targeting 21 clinically important yeast species of Candida, Trichosporon, Rhodotorula, Cryptococcus, and Geotrichum was designed. Four hundred CBS reference strains were used for optimization and specificity testing. Eight hundred clinical species were prepared in blinded sets for multiplex polymerase chain reaction (PCR) and matrix-assisted laser desorption time of flight mass spectrophotometry (MALDI-TOF MS) investigation. Results obtained from YEAST PANEL multiplex PCR assay were 100% consistent with those of MALDI-TOF MS. Utilization of pure colony testing showed distinct amplicons for each species, thus eliminating the need for DNA extraction. The targeted yeast species of this assay are responsible for 95% of the yeast infections. In conclusion, due to the high accuracy and coverage of a broad range of yeasts, this assay could be useful for identification in routine laboratories and epidemiological studies.

[Identification of Candida yeasts: Conventional methods and MALDI-TOF MS]

BACKGROUND

Invasive fungal infections are increasing, and Candida yeasts are the main cause. Species other than Candida albicans are becoming more frequent, and some of them may have variable patterns of susceptibility to antifungal agents, making it important to identify them correctly. Conventional identification methods used by most laboratories may present with drawbacks. Mass spectrometry (MALDI-TOF MS) has emerged as an alternative method.

AIMS

The aim of this study was to evaluate the concordance of the identification, at species level, by conventional methods (API) and MALDI-TOF MS.

METHODS

The following species and number of isolates were studied: Candida parapsilosis (28), Candida glabrata (34), Candida krusei (24), Candida tropicalis (45), Candida guilliermondii (30), C. albicans (28), Candida dubliniensis (6), Candida kefyr (1), and Candida lipolytica (1) from the strain collection of Autonomous City of Buenos Aires Mycology Network (RMCABA). The strains C. parapsilosis 22019, C. glabrata 90030, C. krusei 6258 and C. albicans 68548 from the American Type Culture Collection (ATCC) were also included. Discrepancies were resolved by genotyping.

RESULTS AND CONCLUSIONS

The direct concordance between the conventional identification method and MALDI-TOF MS was 92.5% (186/201).

In Vitro Characterization of a Biaryl Amide Anti-virulence Compound Targeting Candida albicans Filamentation and Biofilm Formation

We have previously identified a small molecule compound, N-[3-(allyloxy)-phenyl]-4-methoxybenzamide (9029936), that exerts potent inhibitory activity against filamentation and biofilm formation by the Candida albicans SC5314 strain and represents a lead candidate for the development of anti-virulence approaches against C. albicans infections. Here we present data from a series of experiments to further characterize its in vitro activity and drug-like characteristics. We demonstrate the activity of this compound against a panel of C. albicans clinical isolates, including several displaying resistance to current antifungals; as well as against a set of C. albicans gain of function strains in key transcriptional regulators of antifungal drug resistance. The compound also inhibits filamentation and biofilm formation in the closely related species C. dubliniensis, but not C. glabrata or C. tropicalis. Combinatorial studies reveal the potential of compound 9029936 to be used together with currently available conventional antifungals. Results of serial passage experiments indicate that repeated exposure to this compound does not elicit resistance. Viability staining of C. albicans in the presence of high concentrations of compound 9029936 confirms that the compound is not toxic to fungal cells, and cytological staining using image flow cytometry analysis reveals that treatment with the lead compound affects hyphal length, with additional effects on cell wall and integrity of the membrane system. In vitro pharmacological profiling provides further evidence that the lead compound displays a safe profile, underscoring its excellent “drug-like” characteristics. Altogether these results confirm the potential of this compound to be further developed as a true anti-virulence agent for the treatment of C. albicans infections, including those refractory to treatment with conventional antifungal agents.

Phenotype-driven strategies for screening Candida parapsilosis complex for molecular identification

In this study, phenotypic methods presented >80% agreement with the molecular identification of 59 Candida parapsilosis complex. Growth at 15% NaCl or pH 7.0 significantly reduced cfu-counts of Candida orthopsilosis, suggesting these conditions may support the development of phenotypic methods for the differentiation of the cryptic species of C. parapsilosis complex.

BODIPYs to the rescue: Potential applications in photodynamic inactivation

4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives have been proposed in several potential biomedical applications. BODIPYs absorb strongly in blue-green region with high fluorescence emission, properties that convert them in effective fluorophores in the field of biological labeling. However, BODIPY structures can be conveniently modified by heavy atoms substitution to obtain photosensitizers with applications in photodynamic therapy. Also, external heavy atoms effect can be used to increase the photodynamic activity of these compounds. In recent years, BODIPYs have been proposed as phototherapeutic agents for the photodynamic inactivation of microorganisms. Therefore, BODIPY structures need to be optimized to produce an efficient photocytotoxic activity. In this way, amphiphilic cationic BODIPYs can selectively bind to microbial cells, inducing an effective photokilling of pathogenic microbial cells. This review summarizes the attributes of BODIPY derivatives for applications as antimicrobial photosensitizing agents.

Importance of Resolving Fungal Nomenclature: the Case of Multiple Pathogenic Species in the Cryptococcus Genus

Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoformans were raised to species level, and the same was done for five genotypes within C. gattii. In a recent perspective (K. J. Kwon-Chung et al., mSphere 2:e00357-16, 2017, https://doi.org/10.1128/mSphere.00357-16), it was argued that this taxonomic proposal was premature and without consensus in the community. Although the authors of the perspective recognized the existence of genetic diversity, they preferred the use of the informal nomenclature "C. neoformans species complex" and "C. gattii species complex." Here we highlight the advantage of recognizing these seven species, as ignoring these species will impede deciphering further biologically and clinically relevant differences between them, which may in turn delay future clinical advances.

Prevalence of Candida africana and Candida dubliniensis, in vulvovaginal candidiasis: First Turkish Candida africana isolates from vulvovaginal candidiasis

INTRODUCTION

Candida africana and C. dubliniensis are closely related species of C. albicans. Current phenotypic methods are not suitable to accurately distinguish all the species belonging to the C. albicans complex. Several molecular-based methods have recently been designed for discriminating among closely related Candida species. The aim of this study was to establish the prevalence of C. dubliniensis and C. africana in vulvovaginal samples with phenotypic and genotypic methods.

MATERIALS AND METHODS

We re-examined 376 vulvovaginal C. albicans complex isolates. All the isolates were identified with morphological features and HWP1 gene polymorphisms. ITS and D1/D2 sequencing, carbohydrate assimilation, MALDI-TOF MS profiles and antifungal susceptibilities were evaluated for C. africana and C. dubliniensis isolates.

RESULTS

Of the 376 isolates, three C. africana and three C. dubliniensis isolates (0.8% and 0.8% prevalence, respectively) were identified by molecular methods (HPW1, ITS and D1/D2) Phenotypically, C. africana differed from C. albicans and C. dubliniensis by formation of no/rare pseudohyphae, absence of chlamydospores and, the development of turquoise green colonies on CHROMagar. MALDI-TOF MS and API ID 32C could not revealed C. africana isolates. C. africana and C. dubliniensis isolates showed very low MIC values for all the tested antifungals.

DISCUSSION

This first report of C. africana from Turkey provides additional data for epidemiological, phenotypic features and antimicrobial susceptibility profiles. This study also highlights the importance of using genotypic methods in combination with phenotypic methods.

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

BACKGROUND

Vulvovaginal candidiasis (VVC) is a vulvovaginitis commonly diagnosed in gynecology care. In recent years, the taxonomy of the most important pathogenic Candida species, such as Candida albicans have undergone significant changes.

AIMS

This study examined the prevalence of C. albicans, Candida africana, and Candida dubliniensis in vaginal specimens from 210 pregnant women suffering from vulvovaginitis or having asymptomatic colonization.

METHODS

Phenotypic and molecular methods were used for the identification of the species.

RESULTS

During the studied period, 55 isolates of Candida or other yeasts were obtained from specimens collected from 52 patients suffering from vulvovaginitis (24.8%). C. albicans was the predominant Candida species in 42 isolates (80.7%), either alone or in combination with other species of the genus (5.7%, n=3). Additionally, nine isolates of C. albicans (50%) were obtained from asymptomatic patients (n=18). C. dubliniensis was the causative agent in 2 (3.8%) cases of VVC, and was also isolated in one asymptomatic patient. Molecular assays were carried out using specific PCR to amplify the ACT1-associated intron sequence of C. dubliniensis. The amplification of the HWP1 gene also correctly identified isolates of the species C. albicans and C. dubliniensis. No C. africana was isolated in this work. Some C. albicans isolates were either homozygous or heterozygous at the HWP1 locus. The distribution of heterozygous and homozygous C. albicans isolates at the HWP1 locus was very similar among patients suffering from VVC and asymptomatic patients (p=0.897).

CONCLUSIONS

The presence of C. albicans and C. dubliniensis, and the absence of C. africana in pregnant is noteworthy.

Hyphal wall protein 1 gene: A potential marker for the identification of different Candida species and phylogenetic analysis

BACKGROUND AND PURPOSE

Hyphal wall protein 1 (HWP1) is an important adhesin which usually is expressed on the germ tube and hyphal surface produced by different Candida species. The hyphal wall protein-coding gene (HWP1) was evaluated as a novel identification and phylogenetic marker in Candida tropicalis, C. orthopsilosis, C. parapsilosis and C. glabrata.

MATERIALS AND METHODS

Initially, four specific primer pairs were designed, and the target was amplified and finally sequenced. A total of 77 Candida isolates from four different species were included in the study. Consensus sequences were used for the evaluation of phylogenetic tree using the CLC Genome Workbench, GENEIOUS, and MEGA softwares and the levels of nucleotide and amino acid polymorphism were assessed.

RESULTS

According to the results, the specific amplified fragments of HWP1 gene were useful for the differentiation of four species. Intra-species variation was observed only in C. tropicalis with two DNA types. The phylogenetic tree of Candida species based on the HWP1 gene showed consistency in topology with those inferred from other gene sequences.

CONCLUSION

We found that HWP1 gene was an excellent marker for the identification of non-albicansCandida species as well as the phylogenetic analysis of the most clinically significant Candida species.

Molecular characterization of Candida isolates from intensive care unit patients, Krakow, Poland

BACKGROUND

Over the last decades, Candida species have emerged as important pathogens in immunocompromised patients. Nosocomial infections are mainly of endogenous origin. Nevertheless, some cases of exogenous candidiasis have also been reported.

AIMS

The aim of this study was to evaluate the genetic relatedness between Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei and Candida kefyr isolates recovered from intensive care unit (ICU) patients.

METHODS

A total of 132 Candida clinical isolates (62 C. albicans, 40 C. glabrata, 13 C. tropicalis, 11 C. krusei, 6 C. kefyr), obtained from specimens of endotracheal aspirate, urine and blood taken from patients of a tertiary hospital in Poland, were included in the study. Species identification was performed by PCR method and genetic relatedness was assessed by randomly amplified polymorphic DNA assay (RAPD) with five primers.

RESULTS

The RAPD analysis revealed high genetic diversity among the studied Candida isolates, indicating that most of the strains were from endogenous sources. Only two clonal strains of C. glabrata isolated from different patients were observed, suggesting a possible cross-transmission of these pathogens.

CONCLUSIONS

Our study confirmed the high discriminatory power of the RAPD assay. This genotyping method can be applied to local epidemiological studies of Candida species.

Molecular study of the Candida parapsilosis complex in Sfax, Tunisia

Candida parapsilosis, which was previously considered to be a complex of three genetically distinct groups, has emerged as a significant agent of nosocomial infections. Recently, this complex was separated into three species: C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis In Tunisia, data pertaining to these fungi are limited. Thus, the purpose of our study was to determine by BanI PCR-RFLP and ITS sequencing, the occurrence of Candida parapsilosis complex among 182 isolates identified as C. parapsilosis by phenotypical methods. C. parapsilosis sensu stricto represented 94.5% of all isolates, while C. metapsilosis and. C. orthopsilosis were identified in 3.3% and 2.2%, respectively. Sequence analysis of internal transcribed spacer region confirmed and revealed only one genotype among the C. parapsilosis sensu stricto strains, three genotypes among six C. metapsilosis strains and two genotypes among four C. orthopsilosis strains.

Recent Progress in the Diagnosis of Pathogenic Candida Species in Blood Culture

Candidemia has become an emerging invasive fungal disease. Prompt treatment with appropriate antifungal agent is crucial to reduce the mortality of candidemia. The conventional blood culture method, which is considered the gold standard for candidemia diagnosis, has a low sensitivity and is time-consuming to perform. Recently, several novel advanced diagnostic methods that have a higher sensitivity and a shorter turnaround time than the conventional blood culture method have been developed for the early detection of Candida in blood samples or in blood culture broth. Most of these newer methods were developed using various molecular techniques, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, peptide nucleic acid fluorescence in situ hybridization, and a number of DNA-based techniques including in-house and commercial polymerase chain reactions. In this article, we review and summarize the novel molecular methods that have been recently used for the detection and identification of Candida organisms in blood specimens.

Synthesis and properties of 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl] chlorin as potential broad-spectrum antimicrobial photosensitizers

A novel 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]chlorin (TAPC) was synthesized by reduction of the corresponding porphyrin TAPP with p-toluenesulfonhydrazide, followed by selective oxidation with o-chloranil. Spectroscopic properties and the photodynamic activity of these photosensitizers were compared in N,N-dimethylformamide. An increase in the absorption band at 650nm was found for the chlorin derivative with respect to TAPP. These photosensitizers emit red fluorescence with quantum yields of 0.15. Both compounds were able to photosensitize singlet molecular oxygen with quantum yields of about 0.5. Also, the formation of superoxide anion radical was detected in the presence of TAPC or TAPP and NADH. Photodynamic inactivation was investigated on a Gram-positive bacterium Staphylococcus aureus, a Gram-negative bacterium Escherichia coli and a fungal yeast Candida albicans cells. In vitro experiments showed that TAPC or TAPP were rapidly bound to microbial cells at short incubation periods. These photosensitizers, without intrinsic positive charges, contain four basic amino groups. These substituents can be protonated at physiological pH, increasing the interaction with the cell envelopment. Photosensitized inactivation improved with an increase of both photosensitizer concentrations and irradiation times. After 15min irradiation, a 7 log reduction of S. aureus was found for treated with 1μM photosensitizer. Similar result was obtained with E. coli after using 5μM photosensitizer and 30min irradiation. Also, the last conditions produced a decrease of 5 log in C. albicans cells. Therefore, TAPC was highly effective as a broad-spectrum antimicrobial photosensitizer.