Epidemiology and antifungal susceptibility of Candida species in a tertiary care hospital, Kolkata, India

Isolation and identification of Candida species from catheter-associated urinary tract infection in Thamar city hospitals, Yemen

BACKGROUND

The incidence of urinary tract infections associated with Candida is increasing in Yemeni public hospitals.

OBJECTIVES

The primary objective of this research was to isolate specific Candida species responsible for catheter-associated urinary tract infections (UTIs) and to examine the antifungal sensitivity of these Candida isolates.

PATIENTS AND METHODS

A total of 200 samples were collected from patients with catheters admitted to multiple hospitals of Thamar city (Yemen). There were 50 positive samples with Candida out of 200 samples. We conducted the primary identification process using the established protocols. Before isolation and identification, all yeast isolates underwent sub-culturing on Sabouraud dextrose agar. We employed the standard microbiological procedures such as Gram staining, colonial morphology analysis, lactophenol cotton blue assay, germ tube formation assessment, colony staining on chrom agar Candida medium, and incubation at 37 °C for 48 h. The assessment of cultures was conducted by evaluating their predominant species. All Candida isolates were tested for antifungal susceptibility using the disk diffusion technique, as indicated by the Clinical and Laboratory Standards Institute (CLSI) M44-A document recommendations.

RESULTS

In this study, the prevalence of Candida species obtained from catheter-associated UTIs was shown to be the highest among individuals aged 51-60 years (28.0%) and the lowest was among those aged 10-20 years (8.0%). Males exhibit higher rates than females, with males accounting for 56.0 and females for 44.0%, respectively. The predominant strain from catheters linked to urinary tract infections was Candida albicans. The Candida isolates had the highest susceptibility to itraconazole, with fluconazole and nystatin at sensitivity rates of 64, 60, and 50%, respectively. Amphotericin B and ketoconazole exhibited the most elevated concentrations. The p value of duration of catheterization < 5 was significant (p = 0.01), as well as significant in anti-fungal susceptibility testing of itraconazole, ketoconazole, and nystatin which are (p = 0.03), (p = 0.04), and (p = 0.03) respectively.

CONCLUSION

Urinary tract infection due to candiduria was more common in patients with indwelling urinary catheter. The catheter-associated urinary tract infection caused by Candida species occurred mainly in old male patients. Candia albicans was the predominant Candida species isolated from urinary tract infection associated with urinary catheter at Thamar city hospitals. This study determined that diabetes and antibiotic use are significant predisposing factors associated with isolation of Candida in specimens submitted by patients at Thamar city hospitals.

Diagnostic Value of Peripheral Blood Smear Tests in Identifying Candida Infections in a Tertiary Care Setting: A Case Series

Invasive fungal infections (IFIs) are a significant cause of morbidity and mortality in hospitalized patients, particularly among neonates and immunocompromised individuals. Candida species are one of the most commonly associated pathogens associated with IFIs. We present a case series of four patients with IFIs. All cases underwent peripheral blood film (PBF) examination, blood culture, and serum galactomannan testing. Budding yeasts were found in the PBF of three out of four cases. The findings were confirmed by culture. While blood culture remains the gold standard for diagnosing IFIs, the PBF test demonstrated its value as a rapid and cost-effective initial screening tool, especially in resource-limited settings. PBF tests can offer valuable preliminary insights, facilitating further diagnostic evaluation and early initiation of antifungal therapy. These findings underscore the potential utility of PBF tests in the early detection and management of IFIs.

Species Distribution and Antifungal Susceptibility Patterns of Candida Isolates: A Cross-Sectional Study From a Tertiary Care Hospital in South India

Background The increasing prevalence of Candida infections and emerging antifungal resistance presents a significant challenge in tertiary healthcare settings. The epidemiological landscape of candidiasis is evolving, with non-albicans Candida species gaining prominence. This cross-sectional study aimed to investigate the distribution patterns of Candida species isolated from various clinical specimens at Srinivasan Medical College and Hospital, Samayapuram, India with particular emphasis on emerging non-albicans species that demonstrate varying virulence and antifungal susceptibility profiles. Methodology The study employed a hospital-based cross-sectional design conducted over six months from October 2023 to March 2024. A sample size of 97 clinical specimens was processed using standardized microbiological procedures, including potassium hydroxide (KOH) mount, Gram staining, and culture on Sabouraud's dextrose agar. Species identification utilized the Germ Tube Test, CHROMagar, and corn-meal agar techniques. Antifungal susceptibility testing was performed via disk diffusion method following Clinical and Laboratory Standards Institute (CLSI) guidelines for fluconazole, voriconazole, itraconazole, and amphotericin B. Statistical analysis employed Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 25.0, Armonk, NY), utilizing descriptive statistics, chi-square tests, and multivariate logistic regression. Results The study population demonstrated a mean age of 47.9 years, comprising 52 female and 45 male patients. Among clinical specimens, urinary samples constituted 51 specimens (52.6%), followed by high vaginal swabs with 23 specimens (23.7%), and sputum with 15 specimens (15.5%). Microbiological analysis revealed 45 isolates of Candida albicans (46.4%), while non-albicans species included 25 isolates of C. tropicalis (25.8%), 20 of C. krusei (20.6%), and 7 of C. glabrata (7.2%). Diabetes mellitus emerged as the predominant risk factor, affecting 38 patients (39.2%). Antifungal susceptibility testing demonstrated complete sensitivity to amphotericin B and voriconazole across all isolates, while 32 isolates showed resistance to itraconazole (33.0%). Fluconazole resistance patterns revealed 19 isolates with acquired resistance (19.6%) and 20 isolates with intrinsic resistance (20.6%). Conclusion The study reveals a significant prevalence of non-albicans Candida species and concerning levels of antifungal resistance, particularly to azoles. These findings emphasize the critical importance of species identification and antifungal susceptibility testing in guiding therapeutic decisions for Candida infections.

Evaluation of antifungal effect of amphotericin B in comparison with nystatin on Candida species derived from patients undergoing head-and-neck radiotherapy

Background

There is ample evidence showing the development of nystatin-resistant strains in patients undergoing malignancy treatment. Amphotericin B is a polyene antifungal drug that combines with ergosterol to cause cell death and is more effective on fungal species than routine antifungals such as nystatin. This study aimed to compare the effect of nystatin and amphotericin B on fungal species isolated from patients before and during head-and-neck radiotherapy.

Materials and Methods

This in vitro experimental study was performed on samples isolated from patients undergoing head-and-neck radiotherapy before and during radiotherapy at Sayed al-Shohada Hospital in Isfahan, Iran. The isolates were identified by polymerase chain reaction-restriction fragment length polymorphism. Antifungal effects were determined by the microdilution method based on clinical and laboratory standards institute standards and minimum inhibitory concentration (MIC), minimum lethal concentration (MFC), drug sensitivity, and resistance were measured. The data were analyzed by SPSS version 22 (level of significance: 0.05).

Results

Before radiotherapy, all albicans strains were sensitive to nystatin, whereas 71.4% were sensitive to amphotericin B. After radiotherapy, Candida albicans strains were 100% sensitive to nystatin and 75% sensitive to amphotericin B.

Conclusion

The present study showed that before radiotherapy, all species isolated from patients, including C. albicans, C. tropicalis, and C. glabrata, were sensitive to nystatin, whereas a percentage of albicans species showed resistance to amphotericin B. In the 2nd week of radiotherapy, the same as before radiotherapy, all species isolated from patients were sensitive to nystatin, whereas a percentage of albicans species showed resistance to amphotericin B. In general, the current study showed that before and after radiotherapy, the antifungal effect of nystatin is greater than amphotericin B.

Time-to-Positivity for Candida in Bloodstream Infections: Prognostic Implications for Mortality

Background Candida-associated catheter-related bloodstream infections (CRBSIs) present a significant challenge in clinical settings, particularly among patients with central venous catheters (CVCs). Time-to-positivity (TTP) of blood cultures, an indicator of fungal load, may provide insights into infection prognosis and severity. This study evaluates the role of TTP in Candida-associated bloodstream infections and its impact on patient outcomes. Materials and methods This cross-sectional observational study, conducted from July 2023 to June 2024 at Saveetha Medical College, involved collecting blood cultures from intensive care unit (ICU) patients with suspected candidemia. Blood cultures were processed using the BacT/ALERT 3D system (bioMérieux, Marcy l'Étoile, France), with TTP recorded for each Candida-positive culture. Species identification was performed using MALDI-TOF MS (Bruker Daltonics, Germany). Species-specific 30-day mortality was analyzed to assess the impact of TTP on survival. Results Of 7447 blood cultures from ICU patients, 2349 were positive, with a 2.42% prevalence of Candida sp. Among 57 candidemia patients, the median TTP for deceased patients was 24 hours, compared to 25 hours for survivors (p=0.001). C. auris exhibited the highest mortality rate (56.25%) with a median TTP of 16.5 hours, whereas C. albicans had no associated mortality and a median TTP of 28.5 hours. Shorter TTP was consistently associated with higher mortality across Candida species. Conclusion This study highlights the prognostic value of TTP in Candida-associated bloodstream infections, with shorter TTP correlating with higher mortality. The findings underscore the need for rapid diagnosis and aggressive treatment, particularly for high-risk species like C. auris and C. glabrata. Further research is needed to refine the clinical application of TTP and develop targeted treatment strategies.

EpiCandIn: An open online resource for epidemiology of Candida infections in India

Background & objectives Candida spp. cause candidiasis in humans under conditions disrupting the host defence. While Candida albicans is the most reported cause of candidiasis, there is a surge in the incidence of infections by non-albicans Candida species (NACs), such as C. tropicalis, C. glabrata and C. auris. These species can infect all organs of the human body. To effectively manage these outbreaks, it is important to track the epidemiology of candidiasis. A consolidated resource describing the landscape of candidiasis in India is absent. Methods To address this gap, we have developed an online resource named Epidemiology of Candida Infections in India (EpiCandIn) by manually curating published literature on Candida infections in the Indian population obtained from PubMed and ScienceDirect databases. Results EpiCandIn contains data available since 1972 from 51 sites across 16 States and four Union Territories of India. It provides information on geographical location, Candida species, niche affected, disease characteristics and drug therapy details extracted from the publications. This resource is integrated with visualization tools. Interpretation & conclusions EpiCandIn will be useful for public health researchers and policymakers as it will help them gain insights into the emerging trends and management of Candida infections in India. It can be accessed at epicandin.bicnirrh.res.in.

Candida-An emerging and re-emerging pathogen

Candida contains a wide range of organisms, and more than 17 different Candida species have been linked to human infections. Newer species are emerging and Candida albicans and other Species are re-emerging. Isolated strains showing increased antifungal resistance, which necessitates the need for new antifungal drugs. Candida Spp can cause a wide range of mycoses, including invasive candidiasis, which can be deep, widespread, and extremely painful. The majority of the time, it spreads by endogenous Candidaemia. They adhere to host tissues and medical equipment, form biofilms, and release enzymes that break down proteins. Conventional techniques and molecular techniques have made laboratory diagnosis of Candida easy. However, Candida infections are more common in immunocmpromised and hospitalised patients.

Changes in urban soil yeast communities after a reduction in household waste during the COVID-19 pandemic

The soils of streets, urban parks and suburban areas were examined for yeasts in the summer of 2020 on the territory of the southern cities of Russia and the Republic of Crimea: Krasnodar, Maykop, Sochi and Simferopol. The results of this study are compared with the results of a previous study carried out in these cities in 2019. This study was conducted three months after the lockdown due to the COVID-19 pandemic, which led to a sustained decline in household waste deposition in these areas. The number of tourists visiting these southern cities decreased significantly, and the number of walkers and visitors to urban parks fell sharply. In 2020, after the decline of household waste loads, the yeast abundance was slightly but reliably higher than in 2019. A total of 30 yeast species were observed - 11 ascomycetes and 19 basidiomycetes. This was more than in 2019 and was caused by twice as many autochthonous basidiomycetous yeast species (natural core community), which were found in urban soils only after the reduction in household waste in the environment - Apiotrichum dulcitum, A. laibachii, Saitozyma podzolica Solicoccozyma terricola. And at the same time, the proportion of clinically significant (opportunistic) yeasts, Candida sake and Meyerozyma guilliermondii, was much lower in 2020 than in 2019. Thus, the observed changes in yeast communities in urban soils could be a short-time response of the microbial community to a reduction in household waste.

A New Variant of Mutational and Polymorphic Signatures in the ERG11 Gene of Fluconazole-Resistant Candida albicans

Background

Resistance to antifungal drugs for treating Candida infections remains a major concern globally despite the range of medications available. Most of these drugs target key proteins essential to the life cycle of the organism. An enzyme essential for fungal cell membrane integrity, lanosterol 14–α demethylase (CYP51), is encoded by the ERG11 gene in Candida species. This enzyme is the target of azole–based drugs. The organism has, however, devised molecular adaptations to evade the activity of these drugs.

Materials and Methods

Classical methods were employed to characterize clinical isolates sampled from women and dogs of reproductive age. For fluconazole efficacy studies, CLSI guidelines on drug susceptibility testing were used. To understand the susceptibility pattern, various molecular and structural analytic approaches, including sequencing, in silico site-directed mutagenesis, and protein-ligand profiling, were applied to the ERG11 gene and CYP51 protein sequences. Several platforms, comprising Clustal Omega, Pymol plugin manager, Pymol molecular visualizer, Chimera–curated Dynameomics rotamer library, protein–ligand interaction profiler, Charmm36 force field, GROMACS, Geneious, and Mega7, were employed for this analysis.

Results

The following Candida species distribution was obtained: 37.84% C. albicans, 8.12% C. glabrata, 10.81% C. krusei, 5.41% C. tropicalis, and 37.84% of other unidentified Candida species. Two codons in the nucleotide sequence of the wild-type (CTC and CCA) coding for LEU–370 and PRO–375, respectively, were mutated to L370S and P375H in the resistant strain. The mutation stabilized the protein at the expense of the heme moiety. We found that the susceptible isolate from dogs (Can–iso–029/dog) is closely related to the most resistant isolate from humans.

Conclusion

Taken together, our results showed new mutations in the heme-binding pocket of caCYP51 that explain the resistance to fluconazole exhibited by the Candida isolates. So far, the L370S and P375H resistance-linked mutations have not been previously reported.

Candidemia Among ICU Patients: Species Characterisation, Resistance Pattern and Association With Candida Score: A Prospective Study

Introduction

Candidiasis is a significant cause of morbidity and mortality in immunocompromised patients admitted in intensive care units. Identification of Candida species is essential for effective treatment. However, in absence of proven fungemia, guidelines to initiate therapy are yet to be defined.

Materials and methods

During the study (16 months: September 2018 to December 2019), samples (urine, sputum, blood, tracheal aspirate, urinary catheter) were collected from ICU patients and prospectively evaluated. Microscopy, culture, and antifungal susceptibility testing were performed as per standard laboratory protocol. Demographic details and risk factors were noted from case records and correlated with Candida score.

Results

One hundred twenty-five non-duplicate samples (120 patients) positive on culture were included in the study. The most common co-morbid condition associated with fungemia was diabetes mellitus. The most common risk factor was total parenteral nutrition. Non-albicansCandida(C. tropicalis) was predominant. Candida species showed good sensitivity to voriconazole (80%) followed by fluconazole (67.78%) and amphotericin (62.22%). Twenty-nine patients had a Candida score of more than three.

Conclusion

Fluconazole available in both oral and parenteral formulations is an effective antifungal agent against the candida spp. Voriconazole should be reserved for non-responders. Rising resistance to common antifungals among Candida albicans is a matter of concern.

Differential Response of Candida Species Morphologies and Isolates to Fluconazole and Boric Acid

Candida albicans is the most prevalent cause of vulvovaginal candidiasis ("yeast infection" or VVC) and recurrent vulvovaginal candidiasis (RVVC), although the incidence of non-albicans yeast species is increasing. The azole fluconazole is the primary antifungal drug used to treat RVVC, yet isolates from some species have intrinsic resistance to fluconazole, and recurrent infection can occur even with fluconazole-susceptible populations. The second-line broad-spectrum antimicrobial drug, boric acid, is an alternative treatment that has been found to successfully treat complicated VVC infections. Far less is known about how boric acid inhibits growth of yeast isolates in different morphologies compared to fluconazole. We found significant differences in drug resistance and drug tolerance (the ability of a subpopulation to grow slowly in high levels of drug) between C. albicans, Candida glabrata, and Candida parapsilosis isolates, with the specific relationships dependent on both drug and phenotype. Population-level variation for both susceptibility and tolerance was broader for fluconazole than boric acid in all species. Unlike fluconazole, which neither prevented hyphal formation nor disrupted mature biofilms, boric acid inhibited C. albicans hyphal formation and reduced mature biofilm biomass and metabolic activity in all isolates in a dose-dependent manner. Variation in planktonic response did not generally predict biofilm phenotypes for either drug. Overall, our findings illustrate that boric acid is broadly effective at inhibiting growth across many isolates and morphologies, which could explain why it is an effective treatment for RVVC.

Changing Trends of Candida Species and Antifungal Susceptibility Profile of Candida Bloodstream Isolates: A 5-Year Retrospective Survey

Background: Candida species have emerged as one of the most common causes of bloodstream infections (BSIs). There are limited data on the distribution of Candida spp. and susceptibility by year. Objectives: In this study, we analyzed changes in the distribution of Candida spp. and their antifungal susceptibility profiles from blood cultures. Methods: Records from January 2016 to December 2020 were obtained from the microbiology laboratory in Istanbul. Antifungal susceptibility tests were performed using the VITEK 2 compact system and evaluated according to EUCAST breakpoints. A total of 241 unique candidemia episodes were included in this study. Results: Candida albicans was the predominant pathogen (n = 95, 39.42%), followed by C. parapsilosis (n = 82, 34.02%), C. glabrata (n = 18, 7.47%), C. tropicalis (n = 17, 7.05%), C. krusei (n = 15, 6.22%), and other Candida spp. (n = 14, 5.79%). There was no statistically significant difference in the percentage of episodes of Candida spp. After data analysis, a tendency to shift from C. albicans to C. parapsilosis was observed in the period analyzed in this study. Candida albicans was the most common species in intensive care units (ICUs), hematology and hemopoietic stem cell transplantation units, and surgical clinics, with C. parapsilosis predominant in medical clinics. In general, micafungin susceptibility was the highest, and fluconazole was the lowest. There was reduced sensitivity to fluconazole and voriconazole for C. albicans and C. parapsilosis over 5 years. Conclusions: Detecting changes in the distribution of Candida spp. and antifungal susceptibility over time will lead to the selection of appropriate empirical therapy and monitor phenomena of antifungal resistance. Empirical treatment with antifungal agents is associated with high costs, toxicities, and risk of antifungal resistance. Therefore, it is mandatory to determine and monitor Candida spp. and antifungal susceptibility testing to select appropriate antifungal agents.

Clinical, Laboratory, Radiological, Bronchoscopic, and Outcome Characteristics of Pulmonary Fungal Infection in Children in PICU in Central China: A Case Series

OBJECTIVE

Fungal infections are common in pediatric intensive care units (PICUs), but the monitoring methods are limited. This study analyzed the differences in clinical features, diagnosis, and treatment between PICU patients with and without fungal infection.

METHODS

This retrospective study analyzed PICU patients at the Maternal and Child Health Hospital of Hubei Province diagnosed with severe pneumonia between January 2015 and January 2020. The patients were divided into the fungal (F) and non-fungal (NF) infection groups. Levels of 1,3-beta-D-glucan (BDG) and galactomannan (GM) in serum and bronchoalveolar lavage fluid (BALF) were analyzed. Chest computed tomography (CT) images were reviewed.

RESULTS

A total of 357 patients were included. In the F group, fever, moist rales, coarse rales, shortness of breath, and sepsis were more common (all P < 0.05); PICU time, hospitalization duration, and BDG- and GM-positive rates in serum and BALF were all significantly higher than in the NF group (all P < 0.05). The BDG- and GM-positive rates in serum and BALF were higher in the F than in the NF group (all P < 0.05). The abnormal lymphocyte ratios in serum were higher in the F group (all P < 0.05). Wedge-shaped, patchy, streaky shadows and subpleural reticulation were higher in CT images of the F group (all P < 0.05). Tracheobronchial stenosis was more common in pulmonary fibroscopy results of the F group (P = 0.04).

CONCLUSION

PICU pneumonia patients with fungal infection have specific clinical and laboratory features compared with those without fungal infection, including higher rates of BALF, serum BDG, GM positivity and tracheobronchial stenosis.

Prevalence and antifungal drug resistance of nosocomial Candida species isolated from two university hospitals in Egypt

Background and Purpose:

There is a significant rise in morbidity and mortality of infections caused by Candida. Candida spp. infections are currently ranked fourth among nosocomial infections which are difficult to diagnose and refractory to therapy. Given the differences in susceptibility among various spp., identification of Candida spp. is an important step that leads to the selection of a suitable antifungal.

Materials and Methods:

A prevalence study was conducted on 122 Candida isolates. The Candida spp. were identified using Chromogenic agar and polymerase chain reaction (PCR). The antifungal susceptibility (AFS) of Candida spp. to amphotericin B, fluconazole, voriconazole, and caspofungin was determined by the disc diffusion method.

Results:

In total, 122 Candida clinical isolates were investigated in this study. Candida albicans with 57.4% (70 isolates) had the highest prevalence rate, while 52 isolates (42.6%) were non-albicansCandida species (NAC). The NAC include Candida krusei (20.4%), Candida tropicalis (6.5%), Candida parapsilolsis (5.7%), Candida dubliniensis (4.9%), and Candida glabrata (4.9%). The AFS showed that the resistance rates of Candida spp. to fluconazole and voriconazole were 13.1% (16 isolates) and 9.8% (12 isolates), respectively. Moreover, only five isolates (4.1%) were resistant to caspofungin. Furthermore, there was no resistance against amphotericin B. The spp. that showed the highest resistance were C. glabrata and C. tropicalis, while the lowest resistance was observed in C. albicans and C. dubliniensis.

Conclusion:

In conclusion, rapid identification of clinical Candida isolates and standard AFS are essential procedures for controlling the rise of resistant NAC spp. in clinical settings. Usage of fluconazole should be restricted, especially in patients with recurrent Candida infections.

Clinical Profile of Non-neutropenic Patients with Invasive Candidiasis: A Retrospective Study in a Tertiary Care Center

Introduction: Invasive candidiasis (IC) is a major cause of morbidity and mortality in critically ill patients in the intensive care unit (ICU). In this study, we aim to analyze the clinical profile, species distribution, and susceptibility pattern of patients with IC. Methods: Case records of non-neutropenic patients ≥18 years of age with IC between January 2016 and June 2019 at a tertiary care referral hospital were analyzed. IC was defined as either candidemia or isolation of Candida species from a sterile site (such as CSF; ascitic, pleural, or pericardial fluid; or pus or tissue from an intraoperative sample) in a patient with clinical signs and symptoms of infection. Results: A total of 114 patients were analyzed, out of which 105 (92.1%) patients had bloodstream infection (BSI) due to Candida and 9 (7.9%) had IC identified from a sterile site. Central line-associated blood stream infection (27 patients, 23.6%) and a gastrointestinal source (30 patients, 26.3%) were the most common presumed sources for candidemia. The commonest species was Candida tropicalis 42 (36.8%), followed by Candida glabrata 20 (17.5%). Serum beta-D-glucan (BDG) was done only in 32 patients of the 114 (35.3%); among those who were tested, 5 (15.6%) had a BDG value of less than 80 pg/mL despite having Candida BSI. Fluconazole sensitivity was 69.5% overall. At 14 days after diagnosis of IC, 49.1% had recovered, with the remainder having an unfavorable outcome (32.4% had died and 18.4% had left against medical advice). Clinical significance: IC is a major concern in Indian ICUs, with a satisfactory outcome in only half of our patients. Serum BDG is a valuable test to diagnose blood culture-negative IC, but more studies are needed to determine its role in the exclusion of IC, as we had a small minority of patients with negative tests despite proven IC. Conclusion: We recommend sending two sets of blood cultures and serum BDG assay for all suspected patients. Initiating empiric antifungal therapy with an echinocandin is advisable, in view of increasing azole resistance and the emergence of Candida auris, with de-escalation to fluconazole for sensitive isolates after clinical stability and blood culture clearance. How to cite this article: Sridharan S, Gopalakrishnan R, Nambi PS, Kumar S, Sethuraman N, Ramasubramanian V. Indian J Crit Care Med 2021;25(3):267-272.

Wickerhamomyces anomalous: A Rare Cause of Fungemia Causing Febrile Neutropenia in Acute Lymphoblastic Leukemia

Candida bloodstream infection is the major cause of increased morbidity and mortality (20-49%) in hospitalized patients in both paediatric and adult age groups. Due to the increase in the number of immunocompromised patients, other important species such as Trichosporon asahii and Debaryomyces hansenii are emerging. One such organism, Wickerhamomyces anomalous, previously known as Pichia anomala (teleomorph stages of several Candida species), is increasingly being reported as a cause of fungemia in neonatal intensive care units and is now increasingly being reported in a lot of immunosuppressive conditions such as interstitial lung disease, endocarditis, enteritis, corticosteroids, and chemotherapy uptake. Though this yeast is ubiquitous in nature, systemic infections from isolated cases and sporadic outbreaks with high mortality have been reported in ICUs, which emphasize the importance to consider this fungus within the diagnostic possibilities. Here, we report a case of catheter-related bloodstream infection (CRBSI) caused by W. anomalus in a leukemic immunosuppressed patient who was successfully treated by early detection and treatment of this emerging fungus.

Biofilm-Producing Candida Species Causing Oropharyngeal Candidiasis in HIV Patients Attending Sukraraj Tropical and Infectious Diseases Hospital in Kathmandu, Nepal

Introduction

Oropharyngeal candidiasis are the commonest fungal infections among HIV-positive patients. The main objective of this study was to explore biofilm-producing Candida species causing oropharyngeal infections among HIV patients attending Sukraraj Tropical and Infectious Diseases Hospital (STIDH) in Kathmandu, Nepal.

Methods

Oropharyngeal swabs were collected from the HIV-positive patients between July and December 2019. A total of 174 oropharyngeal swabs were cultured on Sabouraud Dextrose Agar (SDA). All samples were inoculated on SDA slants supplemented with chloramphenicol and underwent incubation at 37°C for 24-48 hours. Any visible growth reported was processed for the identification of the species. Candida species were differentiated based on the growth and colour of the isolates on CHROM agar candida. Biofilm production in Candida species was determined by the microtiter plate method (MPM). Antifungal susceptibility testing was performed using the disc diffusion method.

Results

Among 174 oropharyngeal samples, 23.6% (n=41/174) of them had oropharyngeal infections and 36.6% of the oropharyngeal infections (15/41) had CD4 T-lymphocytes count below 200 cells/mm³ who were also active tobacco users (p<0.05). Among Candidial growth, 61% (25/41) were Candida albicans and 39% (16/41) were non-albicans. Of 41 Candida spp., 65% (27/41) were biofilm producers. An equal proportion of Candida albicans (4 isolates) and non-albicans (4 isolates) were strong biofilm producers. C. albicans isolates were sensitive towards clotrimazole (96%; 24/25) and fluconazole (92%; 23/25), whereas sensitivity towards ketoconazole was only 48% (12/25). Non-albicans Candida was highly sensitive to amphotericin-B (62.5%; 10/16) followed by clotrimazole (56.2%; 9/16). The biofilm-producing Candida isolates showed the highest resistivity (51.9%; 14/27) to ketoconazole and lowest (22.2%; 6/27) to clotrimazole.

Conclusion

Oropharyngeal candidiasis is a common opportunistic infection among HIV-infected individuals. The majority of cases of oropharyngeal candidiasis are caused by biofilm producers Candida albicans and non-albicans Candida. Biofilm producers Candida were more resistant towards commonly used antifungal drugs.

Distribution of Pathogenic Yeasts in Different Clinical Samples: Their Identification, Antifungal Susceptibility Pattern, and Cell Invasion Assays

Introduction

Species of genus Candida are part of the common microbiota of humans; however, some of the Candida species are known opportunistic pathogens. Formation of biofilms, resistance to antifungal drugs, and increase in asymptomatic infections demands more studies on isolation, identification and characterization of Candida from clinical samples.

Methods

The present manuscript deals with assessment of authentic yeast identification by three methods viz., DNA sequencing of 28S rRNA gene, protein profiles using MALDI-TOF MS, and colony coloration on chromogenic media. Antifungal susceptibility and in vitro cell invasion assays were performed to further characterize these isolates.

Results

Comparison of three methods showed that DNA sequence analysis correctly identified more than 99.4% of the isolates up to species level as compared to 89% by MALDI-TOF MS. In this study, we isolated a total of 176 yeasts from clinical samples and preliminary morphological characters indicated that these yeast isolates belong to the genus Candida. The species distribution of isolates was as follows: 75 isolates of Candida albicans (42.61%), 50 of C. tropicalis (28.40%), 22 of C. glabrata (12.5%), 14 of C. parapsilosis (7.95%) and 4 of Clavispora lusitaniae (2.27%). Other species like Cyberlindnera fabianii, Issatchenkia orientalis, Kluyveromyces marxianus, Kodamaea ohmeri, Lodderomyces sp., and Trichosporon asahii were less than 2%. Antifungal susceptibility assay performed with 157 isolates showed that most of the isolates were resistant to the four azoles viz., clotrimazole, fluconazole, itraconazole, and ketoconazole, and the frequency of resistance was more in non-albicans Candida isolates. The susceptibility to azole drugs ranged from 7% to 48%, while 75% of the tested yeasts were susceptible to nystatin. Moreover, 88 isolates were also tested for their capacity to invade human cells using HeLa cells. In vitro invasion assay showed that most of the C. albicans isolates showed epithelial cell invasion as compared to isolates belonging to C. glabrata, C. parapsilosis and C. tropicalis.

Discussion

The identification of yeasts of clinical origin by sequencing of 28S rRNA gene performed better than MALDI-TOF MS. The present study reiterates the world scenario wherein there is a shift from Candida strains to emerging opportunistic pathogens which were earlier regarded as environmental strains. The present study enlightens the current understanding of identification methods for clinical yeast isolates, increased antifungal drug resistance, epithelial cell invasion as a virulence factor, and diversity of yeasts in Indian clinical samples.

In vitro activity of four triazole antifungal drugs against clinically common and uncommon yeast species

Background and Purpose:

Incidence of fungal infections caused by opportunistic fungal pathogens, such as yeasts and yeast-like species, has undergone an increase in otherwise healthy individuals. These pathogens account for high mortality and show reduced susceptibility to the routine antifungal drugs. Accordingly, antifungal susceptibility testing is an urgent need in the determination of the susceptibility spectrum of antifungals and selection of appropriate antifungal agents for the management of patients with fungal infection.

Materials and Methods:

The present study was conducted on 110 yeast strains belonging to 15 species recovered from clinical specimens. Susceptibility of the isolates to four antifungal drugs (i.e., fluconazole, itraconazole, voriconazole, and posaconazole) was tested according to the Clinical and Laboratory Standards Institute guidelines M27-A3 and M27-S4.

Results:

Fluconazole exhibited no activity against 4.3% (n=2) of C. albicans isolates, whereas the remaining 44 isolates had a minimum inhibitory concentration (MIC) range of 0.125-4 μg/ml. Voriconazole had the lowest geometric mean MIC (0.03 µg/ml) against all isolated yeast species, followed by posaconazole (0.07 µg/ml), itraconazole (0.10 µg/ml), and fluconazole (0.60 µg/ml). Overall, all of the isolates had reduced voriconazole MICs with a MIC range of 0.016-0.5 μg/ml, except for one isolate of C. albicans that had a MIC of 1 μg/ml. Candida haemulonii as a multidrug-resistant fungus showed a fluconazole MIC of > 64 μg/ml.

Conclusion:

The current study provides insight into the antifungal susceptibility profiles of clinically common and uncommon yeast species to four triazole antifungal agents. According to our findings, voriconazole was the most active agent. Awareness about antifungal susceptibility patterns is highly helpful in the selection of appropriate antifungal drugs and identification of the efficiency of the currently used agents.

An alarming rise of non-albicans Candida species and uncommon yeasts in the clinical samples; a combination of various molecular techniques for identification of etiologic agents

OBJECTIVE

Yeasts are unicellular microorganisms may cause systemic infection in immunocompromised patients. The aim of this study was to identify yeast strains isolated from clinical specimens using molecular techniques.

RESULTS

A total of 202 yeast strains isolated from 341 clinical samples between February 2017 and May 2019. All clinical isolates were identified using phenotypic and molecular tests including PCR-RFLP, duplex-PCR, multiplex-PCR, and PCR-sequencing. The most yeast fungal isolates were obtained from urine (66.8%), nail (9.4%), skin lesion (7.9%), bronchoalveolar lavage (5.9%), and blood (3.9%). One hundred and twenty-one Candida species were identified as non-albicans versus 76 Candida albicans. Trichosporon asahii, and Pichia terricola were uncommon non-Candida yeasts isolated from urine samples. For the first time, we isolated P. terricola as etiological agent of urinary tract infection in a pregnant female. Since Candida species show different levels of resistance to antifungal agents, precise identification of clinical isolates is critical for better treatment of infection.

Identification of Candida Species from Clinical Samples in a Honduran Tertiary Hospital

Candida species are one of the most important causes of human infections, especially in hospitals and among immunocompromised patients. The correct and rapid etiological identification of yeast infections is important to provide adequate therapy, reduce mortality, and control outbreaks. In this study, Candida species were identified in patients with suspected fungal infection, and phenotypic and genotypic identification methods were compared. A total of 167 axenic fungal cultures and 46 clinical samples were analyzed by HardyCHROM^®, MicroScan^®(Omron Microscan Systems Inc, Renton, WA, USA), and PCR-RFLP (Restriction Fragment Length Polymorphisms). The species of the C. albicans complex were the most frequent, followed by C. tropicalis and C. glabrata. Less common but clinically relevant species of Candida were also isolated. The comparison between the three methods was concordant, especially for the most common Candida species. Fungal DNA amplification was successful in all clinical samples.

Surveillance study of the prevalence, species distribution, antifungal susceptibility, risk factors and mortality of invasive candidiasis in a tertiary teaching hospital in Southwest China

BACKGROUND

Invasive candidiasis (IC) is the most common invasive fungal infection. The epidemiology of IC in hospitalized patients has been widely investigated in many metropolitan cities; however, little information from medium and small cities is known.

METHODS

A 5-year retrospective study was carried out to analyze the prevalence, species distribution, antifungal susceptibility, risk factors and mortality of inpatients with invasive Candida infection in a regional tertiary teaching hospital in Southwest China.

RESULTS

A total of 243 inpatients with invasive Candida infection during the five-year study period were identified, with a mean annual incidence of 0.41 cases per 1000 admissions and a 30-day mortality rate of 12.3%. The species distributions of Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei, Candida parapsilosis and other Candida species was 45.3, 30.0, 15.2, 4.9, 2.1 and 2.5%, respectively. The total resistance rates of fluconazole (FCA), itraconazole (ITR) and voriconazole (VRC) were 18.6, 23.1 and 18.5%, respectively. Respiratory dysfunction, pulmonary infection, cardiovascular disease, chronic/acute renal failure, mechanical ventilation, abdominal surgery, intensive care in adults, septic shock and IC due to C. albicans were associated with 30-day mortality (P < 0.05) according to the univariate analyses. Respiratory dysfunction [odds ratio (OR), 9.80; 95% confidence interval (CI), 3.24-29.63; P < 0.001] and IC due to C. albicans (OR, 3.35; 95% CI, 1.13-9.92; P = 0.029) were the independent predictors of 30-day mortality.

CONCLUSIONS

This report shows that the incidence and mortality rates are lower and that the resistance rates to azoles are higher in medium and small cities than in large cities and that the species distributions and risk factors in medium and small cities are different from those in large cities in China. It is necessary to conduct epidemiological surveillance in medium and small cities to provide reference data for the surveillance of inpatients with IC infections.

Effectiveness of Phytoactive Molecules on Transcriptional Expression, Biofilm Matrix, and Cell Wall Components of Candida glabrata and Its Clinical Isolates

Toxicity challenges by antifungal arsenals and emergence of multidrug resistance scenario has posed a serious threat to global community. To cope up with this alarming situation, phytoactive molecules are richest, safest, and most effective source of broad spectrum antimicrobial compounds. In the present investigation, six phytoactive molecules [cinnamaldehyde (CIN), epigallocatechin, vanillin, eugenol (EUG), furanone, and epigallocatechin gallate] were studied against Candida glabrata and its clinical isolates. Among these, CIN and EUG which are active components of cinnamon and clove essential oils, respectively, exhibited maximum inhibition against planktonic growth of C. glabrata at a concentration of 64 and 128 μg mL-1, respectively. These two molecules effectively inhibited and eradicated approximately 80% biofilm of C. glabrata and its clinical isolates from biomaterials. CIN and EUG increased reactive oxygen species generation, cell lysis, and ergosterol content in plasma membrane and reduced virulence attributes (phospholipase and proteinase) as well as catalase activity of C. glabrata cells. Reduction of mitochondrial membrane potential with increased release of cytochrome c from mitochondria to cytosol indicated initiation of early apoptosis in CIN- and EUG-treated C. glabrata cells. Transcriptional analysis showed that multidrug transporter (CDR1) and ergosterol biosynthesis genes were downregulated in the presence of CIN, while getting upregulated in EUG-treated cells. Interestingly, genes such as 1,3-β-glucan synthase (FKS1), GPI-anchored protein (KRE1), and sterol importer (AUS1) were downregulated upon treatment of CIN/EUG. These results provided molecular-level insights about the antifungal mechanism of CIN and EUG against C. glabrata including its resistant clinical isolate. The current data established that CIN and EUG can be potentially formulated in new antifungal strategies.