The susceptibility patterns of Candida species isolated from urine samples to posaconazole and caspofungin

The prevalence of multidrug resistance in uropathogens of patients admitted in the intensive care unit of a tertiary care hospital

Urinary tract infections (UTIs) are among the most common bacterial infections, posing significant public health challenges due to increasing antimicrobial resistance (AMR). This study aims to assess the prevalence, demographic characteristics, microbial profile, and antimicrobial resistance patterns in Indian patients with UTIs admitted to intensive care unit. A total of 154 patients with positive UTIs were included in this cross-sectional study. The prevalence data including demographics, microbial isolates, and antimicrobial susceptibility patterns were collected. Additionally, risk factors for multidrug resistance uropathogens were assessed using multivariate analyses. The patient cohort had diverse demographic, with a slight male predominance of 52.6% (n = 81). The most common comorbidities were hypertension 59.1% (n = 91) and diabetes mellitus 54.5% (n = 84). The microbial profile was dominated by gram-negative bacteria, particularly Escherichia coli 26.62% (n = 41) and Klebsiella pneumoniae 17.53% (n = 27). The predominant gram-positive and fungal isolate was Enterococcus faecium 7.14% (n = 11) and Candida spp. 18.83% (n = 29), respectively. Substantial resistance was noted against common antimicrobials, with variations across different pathogens. Gram-negative bacteria, particularly Escherichia coli and Klebsiella pneumoniae, exhibited high MDR rates, emphasizing the challenge of antimicrobial resistance. Multivariate logistic regression identified age groups 50-65 and over 65, and prolonged catheterization as significant risk factors for MDR infections. A significantly high resistance rate among pathogens emphasizes the need for judicious antimicrobial use. Our findings emphasize the necessity of ongoing surveillance and tailored interventions based on local pathogen prevalence and antibiogram data to effectively address the threat of AMR threat for better management of UTI management in ICU settings.

Assessment of Risk Factors and Clinical Outcomes in Hospitalized COVID-19 Patients with Candida spp. Co-infections: Species Distribution and Antifungal Susceptibility Patterns of Isolates

INTRODUCTION

Fungal co-infections are considered an important complication in hospitalized patients with SARS-CoV-2 that can be attributed to disease aggravation, increased mortality, and poor outcomes. This study was conducted to determine the species distribution and antifungal susceptibility patterns of Candida isolates from hospitalized COVID-19 patients in Shiraz, Iran, in addition to associated risk factors and outcomes of co-infections with Candida species.

MATERIALS AND METHODS

In this single-center study, a total of 106 hospitalized COVID-19 patients were evaluated for clinical characteristics and outcomes. Species identification was performed by ITS1-5.8S-ITS2 gene sequencing. Antifungal susceptibility testing to fluconazole, itraconazole, voriconazole, posaconazole, caspofungin, amphotericin B, and nystatin was determined according to the M27-A3/S4 CLSI protocol.

RESULTS

Candida species were recovered from 48% (51/106) of hospitalized COVID-19 patients. Statistical analysis showed that patients who had heart failure, bacterial co-infection, and were receiving empirical antifungal therapy had a higher risk of developing Candida co-infection. In total, 71 Candida isolates were recovered, of which C. albicans (69%) was the most prevalent isolate. The majority of the Candida isolates were susceptible to all classes of tested antifungal drugs.

DISCUSSION

Our results elucidate a high rate of Candida co-infections among hospitalized COVID-19 patients. Comorbidities such as heart failure, HTN, COPD, bacterial infections as well as therapeutic interventions including catheterization, mechanical ventilation, and ICU admission increased the risk of Candida spp. isolation from the bloodstream, respiratory tract and urine samples, which led to a higher in-hospital mortality rate. Additionally, obtained data clarified that empirical antifungal therapy was not as successful as anticipated.

Vaginal candidiasis in Konya area: Etiology, risk factors, virulence patterns, and antifungal susceptibility

Vulvovaginal candidiasis (VVC), a common genital tract infection, is known to affect millions of women worldwide. In this study, it was aimed to determine the prevalence, virulence, possible risk factors and antifungal susceptibility model of Candida species. Vaginal swab samples were taken from patients aged 18 years and older who presented to the gynecology outpatient clinic with signs and symptoms suggestive of vulvovaginitis. Demographic data were recorded using a questionnaire. Standard microbiological methods were used for the identification of the isolates. Broth microdilution method was used to determine the antifungal susceptibility of Candida isolates. Virulence factors of Candida strains were determined by performing proteinase, phospholipase, hemolytic and biofilm activity tests. Sequencing of the isolates identified as Candida were performed using ITS 1-4 primers. Vaginal discharge (OR: 3.365; 95% CI: 1.595-7.101), burning complaint (OR: 9.098; 95% CI: 2.284-36.232) and history of allergy (OR: 3.396; 95% CI: 0.968) were risk factors. The results showed that the most common isolated strain was Candida albicans (57%). It was found that the prevalence of C. glabrata remained at 26%, 44 of the C. albicans isolates presented proteinase, 35 had phospholipase, 47 had biofilm, and 47 had hemolytic activity. In this study, susceptible dose-dependent and resistant rates of all Candida strains were found for fluconazole as 9% and 16%, respectively. Host and organism-related factors should be considered in the clinical treatment of VVC, and continuous monitoring of changes in the prevalence of Candida species and susceptibility rates is required for effective antifungal therapy.

Genetic Analysis of Candida glabrata from Candiduric Patients Using Microsatellite Length Polymorphism, Antifungal Susceptibility, and Enzymatic Profiles

Background: Candida glabrata is the second agent of candiduria with increased resistance to antifungals. Microsatellite length polymorphism (MLP) is one of the genotyping techniques used in the epidemiological investigation to improve clinical management. Objectives: We aimed to detect different genotypes of C. glabrata isolates using six microsatellite markers and the MLP technique. Moreover, our genotypes' association with other countries' genotypes was illustrated using a minimum spanning tree. We investigated in vitro antifungal susceptibility and enzymatic activity profiles of the isolates. Methods: Six microsatellite markers were amplified using multiplex-PCR for 22 C. glabrata strains isolated from urine in pediatric patients admitted to the Abuzar Children's Hospital in Ahvaz, Iran. The PCR products were presented for fragment analysis, and the size of the alleles was determined. Antifungal susceptibility tests and extracellular enzyme activities were also performed. Results: Nineteen multilocus genotypes were detected so that 22.7% of the strains had identical genotypes. The isolates were wild-type for amphotericin B (0.0625 - 2 µg/mL), itraconazole (0.125 - 2 µg/mL), and voriconazole (0.0078 - 0.00625 µg/mL). All the isolates were sensitive to fluconazole at the minimum inhibitory concentration (MIC) range (0.0312 - 16 μg/mL), and three of them were resistant to caspofungin (MIC ≥ 0.5 μg/mL). Moreover, 72.7 and 68.2% of the isolates had no phospholipase and esterase activities. The highest potency of enzymatic activity was obtained in hemolysin and proteinase enzymes. A high genetic diversity (19 genotypes of the 22 isolates) existed among the urinary C. glabrata isolates. Based on the minimum spanning tree, two clusters of our genotypes were related to C. glabrata genotypes in a previous study in Iran, and the third cluster was entirely connected with Chinese genotypes. Conclusions: Most of the isolates were the non-wild type for posaconazole but were rarely resistant to other antifungals. Hemolysin and proteinase secreted as the main virulence factors among the urinary C. glabrata isolates.

Caracterización de Candida spp. aisladas a partir de urocultivos en la ciudad de Medellín

Candida spp. es un agente etiológico importante en infecciones del tracto urinario, principalmente en población con terapia antimicótica de amplio espectro y con catéteres urinarios. Candida albicans es la especie más frecuente, pero otras especies han surgido como patógenos emergentes. En este trabajo se recolectaron aislamientos de Candida spp. de urocultivos de pacientes que consultaron en Dinamica IPS entre enero 2016 y noviembre 2017. Para estimar la frecuencia de las especies y observar los patrones de sensibilidad, se realizó la identificación fenotípica y su perfil de sensibilidad con el sistema comercial Vitek 2® (BioMérieux, Inc.), adicionalmente se evaluaron mediante análisis de las secuencia y filogenética ITS1-5.8S-ITS2. En el estudio se incluyeron 78 aislamientos de Candida spp. Las frecuencias de especies de Candida identificadas empleando las herramientas moleculares fueron: C. albicans (38,5%), C. tropicalis (23,1%), C. glabrata (21,8%), C. parapsilosis (10,3%), C. metapsilosis y C. krusei (2,5%) y C. guillermondi (1,3%). La identificación por métodos moleculares y por el sistema Vitek 2 fue: C. albicans (93,3%), C. glabrata (94,1 %), C. tropicalis (83,3%), C. parapsilosis (75%) C. guilliermondii y C. krusei (100%). La sensibilidad de todos los aislamientos al fluconazol fue 93,6%.

Determination of antimicotic susceptibility pattern of Candida species isolated from patients with symptomatic candiduria

Background

The present study was conducted to determine antimicotic susceptibility of Candida species (sp.) from patients with symptomatic candiduria.

Materials and Methods

Identification of Candida sp. and determination of efficacy of most routine antifungals were done using polymerase chain reaction-restriction fragment length polymorphism method and E-test, respectively.

Results

The results from susceptibility test reveal that caspofungin and amphotericin B have high antifungal activity against both albicans (100% and 96%, respectively) and nonalbicans (95.11% and 72.72%, respectively) isolates.

Conclusion

The present study suggests that caspofungin and amphotericin B have the excellent ability to eradicate both Candida groups that showed decreased susceptibility to other compounds.

Combination of Posaconazole and Amphotericin B in the Treatment of Candida glabrata Biofilms

Candidemia cases have been increasing, especially among immunosuppressed patients. Candida glabrata is one of the most resistant Candida species, especially to the azole drugs, resulting in a high demand for therapeutic alternatives. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and minimum biofilm eradication concentration (MBEC) were determined for posaconazole (Pcz) and amphotericin B (AmB). The drug combinations of both drugs were evaluated on pre-formed biofilms of C. glabrata ATCC 2001, through XTT (2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay, colony forming units (CFU), crystal violet, and the fractional inhibitory concentration index (FICI). C. glabrata revealed higher susceptibility and biofilm reduction in the presence of AmB alone, but both drugs revealed a good capacity in the biomass elimination. In the majority of the tested combinations, the interactions were defined as indifferent (FICI ≤ 4). The combination of the two drugs does not seem to bring a clear advantage in the treatment of biofilms of C. glabrata.

Candiduria; a review article with specific data from Iran

Although, several categories of nosocomial infections are presented during the recent years, urinary tract infections (UTIs) considered as one of the most important systemic infections. The presence of Candida species in the urinary tract system (Candiduria) is seen in only 10-15% of the cases with UTI, however candiduria has been considered as more problematic infection for patients, laboratory workers and physicians. Due to increasing numbers of several predisposing factors, such as antibacterial agents, urinary tract instrumentation, diabetes mellitus, invasive therapies, and prolonged hospital stay, candiduria develops among the hospitalized patients, especially hospitalized in intensive care units (ICUs) and neonatal intensive care units (NICUs). According to the epidemiological studies, Candida albicans is the most common isolated species from candiduric patients. However, during the recent years, due to increasing resistance to antifungal drugs, non-albicans Candida species including, C. glabrata, C. krusei, C. parapsilosis and C. tropicalis have been also implicated. We found that the mean prevalence of candiduria among Iranian patients was lower (16.5%) than worldwide ratio and also males were more frequently affected than females (M:F, 1.2:1). Similar to other countries, C. albicans was most common infectious agent followed by non-albicans Candida species including, C. glabrata, C. tropicalis and C. krusei.

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran: comparison of colonizing and infecting isolates

Background

Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to ten university hospitals in Iran.

Methods

In totally, 846 Candida species were isolated from more than 4000 clinical samples and identified by the API 20 C AUX system. Antifungal susceptibility testing was performed by broth microdilution method according to CLSI.

Results

The most frequent Candida species isolated from all patients was Candida albicans (510/846). The epidemiological cutoff value and percentage of wild-type species for amphotericin B and fluconazole in Candida albicans, Candida tropicalis, Candida glabrata and Candida krusei were 0.5 μg/ml (95%) and 4 μg/ml (96%); 1 μg/ml (95%) and 8 μg/ml (95%); 0.5 μg/ml (99%) and 19 μg/ml (98%); and 4 μg/ml (95%) and 64 μg/ml (95%), respectively. The MIC90 and epidemiological cutoff values to posaconazole in Candida krusei were 0.5 μg/ml. There were significant differences between infecting and colonizing isolates of Candida tropicalis in MIC 90 values of amphotericin B, and isolates of Candida glabrata in values of amphotericin B, caspofungin, and voriconazole (P < 0.05).

Conclusions

Our findings suggest that the susceptibility patterns of Candida species (colonizing and infecting isolates) in immunocompromised patients are not the same and acquired resistance was seen in some species.

Candida glabrata Biofilms: How Far Have We Come?

Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata's biofilms are emerging. In this article, the knowledge available on C. glabrata's resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them.

Isolation, molecular identification, and antifungal susceptibility profiles of vaginal isolates of Candida species

BACKGROUND AND OBJECTIVES

Vulvovaginal candidiasis is a common fungal infection among women during reproductive ages. Although, Candida albicans is accounted as the main etiologic agent of vaginitis, non-albicans species have arisen during last years. Resistant to antifungal drugs especially, fluconazole has been more reported by researchers from around the World. The aims of this study were to determine the prevalence of vulvovaginal candidiasis among suspected patients with vaginitis, the frequency of Candida species, and the susceptibility profiles of isolates to caspofungin, fluconazole and clotrimazole.

MATERIALS AND METHODS

One hundred and twenty suspected women with vaginitis were examined by specialist physician and sampled using moisture swabs. Swabs were inoculated on CHROMagar Candida plates, incubated at 35°C and detected all isolated Candida species using morphological, microcopy and molecular methods. The antifungal susceptibility tests with caspofungin, fluconazole and clotrimazole were applied using microdilution and Resazurin dye methods against all isolated yeasts.

RESULTS

The cultures were positive for 34(28.3%) samples and three Candida species including; C. albicans (88.2%), C. glabrata (8.8%) and C. kefyr (2.9%). Our study shows that only one isolate of C. albicans was resistant to caspofungin at the concentration of 2 μg/ml after 24h incubation that increased to 2 isolates after 48h incubation. All isolates were sensitive to fluconazole at the MIC ranges of 1-0.25 μg/ml, while 88.2% of them were inhibited at 0.25 μg/mL of clotrimazole. Candida albicans remains the most common agent of fungal vaginitis.

CONCLUSION

Although all of Candida isolates were susceptible to fluconazole in vitro, it should be used with caution for empirical therapy due to more resistant rates in clinic. In addition, due to valuable sensitivity of all tested strains to caspofungin, it potentially can be presented as the first line therapy for Candida vaginitis.

Mannose-Binding Lectin Serum Levels in Patients With Candiduria

Background:

Candida species are normal mycoflora of human body which are capable to cause urinary tract infection (UTI). Mannose-binding lectin (MBL) is a kind of innate immune system and decreasing plasma levels of MBL may disrupt the natural immune response and increase susceptibility to infections.

Objectives:

The aim of the present study was to assess MBL in the serum of patients with candiduria and compare them with control.

Patients and Methods:

The blood and urine samples were collected from 335 patients (hospitalized in Golestan hospital, Ahvaz) using standard methods and the growing colonies on CHROMagar were identified using routine diagnostic tests. MBL activity in the serum of 45 patients with candiduria and 45 controls was measured using Eastbiopharm enzyme-linked immunosorbent assay (ELISA) kit.

Results:

In this study, 45 (13.4 %) urine samples were positive for Candida species (17 males and 28 females). The most common isolated yeast was Candida albicans (34%), followed by C. glabrata (32.1%), C. tropicalis (9.4%), other Candida species (22.6%), and Rhodotorula species (1.9%). The mean serum levels of MBL were 0.85 ± 0.01 ng/mL and 1.02 ± 0.03 ng/mL among candiduric patients and controls, respectively, and there was no significant difference between the two groups (P = 0.6).

Conclusions:

Our results showed that there was no significant relationship between MBL serum levels and candiduria.

Analysis of Subcellular Prefoldin 1 Redistribution During Rabies Virus Infection

Background:

Rabies virus (RABV) is one of the old deadly zoonotic viruses. It attacks the central nervous system and causes acute encephalitis in humans and animals. Host factors are known to be essential for virus infection and replication in cells. The identification of the key host factors required for RABV infection may provide important information on RABV replication and may provide new potential targets for RABV drug discovery.

Objectives:

This study aimed to investigate the change in the subcellular distribution and expression of the host protein Prefoldin subunit 1 (PFDN1) in RABV-infected cells and the viral expression of plasmids in the transfected cells.

Materials and Methods:

Mouse Neuro-2a (N2a) cells were infected by RABV or transfected with the plasmids of the nucleoprotein (N) and/or phosphoprotein (P) gene of RABV. The subcellular distribution of PFDN1 was analyzed by confocal microscopy, and the transcription levels of PFDN1 in the N and/or P gene of the RABV-transfected or RABV-infected N2a cells were assessed via real-time quantitative polymerase chain reaction.

Results:

Confocal microscopy showed that PFDN1 was colocalized with the N protein of RABV in the infected N2a cells and was mainly recruited to the characteristic Negri-Body-Like (NBL) structures in the cytoplasm, as well as the cotransfection of the N and P genes of RABV. The transcription of PFDN1 in the RABV-infected N2a cells was upregulated, whereas the transfection of the N and/or P genes did not result in the upregulation of PFDN1.

Conclusions:

The results of this work demonstrated that the subcellular distribution of PFDN1 was altered in the RABV-infected N2a cells and colocalized with the N protein of RABV in the NBL structures.