Increasing candidaemia incidence from 2004 to 2015 with a shift in epidemiology in patients preexposed to antifungals

Candida albicans cDNA library screening reveals novel potential diagnostic targets for invasive candidiasis

The detection of patterns associated with the invasive form of Candida albicans, such as Candida albicans germ tube antibodies (CAGTA), is a useful complement to blood culture for Invasive Candidiasis (IC) diagnosis. As CAGTA are detected by a non-standardisable and non-automatable technique, a Candida albicans cDNA expression library was screened with CAGTA isolated from serum of an animal model of invasive candidiasis, and five protein targets were identified: hyphally regulated cell wall protein 1 (Hyr1), enolase 1 (Eno1), coatomer subunit gamma (Sec21), a metallo-aminopeptidase (Ape2) and cystathionine gamma-lyase (Cys3). Homology with proteins from other organisms rules out Cys3 as a good biomarker while Sec21 results suggest that it is not in the germ tubes surface but secreted to the external environment. Our analysis propose Ape2, Sec21 and a region of Hyr1 different from the one currently being studied for immunoprotection as potential biomarker candidates for the diagnosis of IC.

The Diagnostic Accuracy of Procalcitonin and Its Combination with Other Biomarkers for Candidemia in Critically Ill Patients

Background: The aim of this study was to investigate the usefulness of serum procalcitonin (PCT), C-reactive protein (CRP), neutrophil to lymphocyte count ratio (NLR), and their combination, in distinguishing candidemia from bacteremia in intensive care unit (ICU) patients. Methods: This is a retrospective study in ICU patients with documented bloodstream infections (BSIs) and with both serum PCT and CRP measurements on the day of the positive blood sample. Illness severity was assessed by sequential organ failure assessment (SOFA) score on both admission and BSI day. Demographic, clinical, and laboratory data, including PCT and CRP levels and NLR on the day of the BSI, were recorded. Results: A total of 63 patients were included in the analysis, of whom 32 had bacteremia and 31 had candidemia. PCT, CRP, and NLR values were all significantly lower in candidemia compared with bacteremia (0.29 (0.14-0.69) vs. 1.73 (0.5-6.9) ng/mL, p < 0.001, 6.3 (2.4-11.8) vs. 19 (10.7-24.8) mg/dl, p < 0.001 and 6 (3.7-8.6) vs. 9.8 (5.3-16.3), p = 0.001, respectively). PCT was an independent risk factor for candidemia diagnosis (OR 0.153, 95%CI: 0.04-0.58, p = 0.006). A multivariable model consisting of the above three variables had better predictive ability (AUC-ROC = 0.88, p < 0.001), for candidemia diagnosis, as compared to that of PCT, CRP, and NLR, whose AUC-ROCs were all lower (0.81, p < 0.001, 0.78, p < 0.001, and 0.68, p = 0.015, respectively). Conclusions: A combination of routinely available laboratory tests, such as PCT, CRP, and NLR, could prove useful for the early identification of ICU patients with candidemia.

Hospital distribution, seasonality, time trends and antifungal susceptibility profiles of all Aspergillus species isolated from clinical samples from 2015 to 2022 in a tertiary care hospital

BACKGROUND

Aspergillus species cause a variety of serious clinical conditions with increasing trend in antifungal resistance. The present study aimed at evaluating hospital epidemiology and antifungal susceptibility of all isolates recorded in our clinical database since its implementation.

METHODS

Data on date of isolation, biological samples, patients' age and sex, clinical settings, and antifungal susceptibility tests for all Aspergillus spp. isolated from 2015 to 2022 were extracted from the clinical database. Score test for trend of odds, non-parametric Mann Kendall trend test and logistic regression analysis were used to analyze prevalence, incidence, and seasonality of Aspergillus spp. isolates.

RESULTS

A total of 1126 Aspergillus spp. isolates were evaluated. A. fumigatus was the most prevalent (44.1%) followed by A. niger (22.3%), A. flavus (17.7%) and A. terreus (10.6%). A. niger prevalence increased over time in intensive care units (p-trend = 0.0051). Overall, 16 (1.5%) were not susceptible to one azole compound, and 108 (10.9%) to amphotericin B, with A. niger showing the highest percentage (21.9%). The risk of detecting A. fumigatus was higher in June, (OR = 2.14, 95% CI [1.16; 3.98] p = 0.016) and reduced during September (OR = 0.48, 95% CI [0.27; 0.87] p = 0.015) and October as compared to January (OR = 0.39, 95% CI [0.21; 0.70] p = 0.002. A. niger showed a reduced risk of isolation from all clinical samples in the month of June as compared to January (OR = 0.34, 95% CI [0.14; 0.79] p = 0.012). Seasonal trend for A. flavus showed a higher risk of detection in September (OR = 2.7, 95% CI [1.18; 6.18] p = 0.019), October (OR = 2.32, 95% CI [1.01; 5.35] p = 0.048) and November (OR = 2.42, 95% CI [1.01; 5.79] p = 0.047) as compared to January.

CONCLUSIONS

This is the first study to analyze, at once, data regarding prevalence, time trends, seasonality, species distribution and antifungal susceptibility profiles of all Aspergillus spp. isolates over a 8-year period in a tertiary care center. Surprisingly no increase in azole resistance was observed over time.

Role of source control in critically ill candidemic patients: a multicenter retrospective study

PURPOSE

Candidemia is associated with high mortality especially in critically ill patients. Our aim was to identify predictors of mortality among critically ill patients with candidemia with a focus on early interventions that can improve prognosis.

METHODS

Multicenter retrospective study.

SETTING

This retrospective study was conducted in Intensive Care Units from three European university hospitals from 2015 to 2021. Adult patients with at least one positive blood culture for Candida spp. were included. Patients who did not require source control were excluded. Primary outcome was 14-day mortality.

RESULTS

A total of 409 episodes of candidemia were included. Most candidemias were catheter related (173; 41%), followed by unknown origin (170; 40%). Septic shock developed in 43% episodes. Overall, 14-day mortality rate was 29%. In Cox proportional hazards regression model, septic shock (P 0.001; HR 2.20, CI 1.38-3.50), SOFA score ≥ 10 points (P 0.008; HR 1.83, CI 1.18-2.86), and prior SARS-CoV-2 infection (P 0.003; HR 1.87, CI 1.23-2.85) were associated with 14-day mortality, while combined early appropriate antifungal treatment and source control (P < 0.001; HR 0.15, CI 0.08-0.28), and early source control without appropriate antifungal treatment (P < 0.001; HR 0.23, CI 0.12-0.47) were associated with better survival compared to those without neither early appropriate antifungal treatment nor source control.

CONCLUSION

Early source control was associated with better outcome among candidemic critically ill patients.

Association between selective digestive decontamination and decreased rate of acquired candidemia in mechanically ventilated ICU patients: a multicenter nationwide study

BACKGROUND

Candidemia is a high-risk complication among intensive care unit (ICU) patients. While selective digestive decontamination (SDD) has been shown to be effective in preventing ICU-acquired bacterial secondary infection, its effects on ICU-acquired candidemia (ICAC) remain poorly explored. Therefore, we sought to assess the effects of SDD on ICAC.

METHOD

Using the REA-REZO network, we included adult patients receiving mechanical ventilation for at least 48 h from January 2017 to January 2023. Non-parsimonious propensity score matching with a 1:1 ratio was performed to investigate the association between SDD and the rate of ICAC.

RESULTS

A total of 94 437 patients receiving at least 48 h of mechanical ventilation were included throughout the study period. Of those, 3 001 were treated with SDD and 651 patients developed ICAC. The propensity score matching included 2 931 patients in the SDD group and in the standard care group. In the matched cohort analysis as well as in the overall population, the rate of ICAC was lower in patients receiving SDD (0.8% versus 0.3%; p = 0.012 and 0.7% versus 0.3%; p = 0.006, respectively). Patients with ICAC had higher mortality rate (48.4% versus 29.8%; p < 0.001). Finally, mortality rates as well as ICU length of stay in the matched populations did not differ according to SDD (31.0% versus 31.1%; p = 0.910 and 9 days [5-18] versus 9 days [5-17]; p = 0.513, respectively).

CONCLUSION

In this study with a low prevalence of ICAC, SDD was associated with a lower rate of ICAC that did not translate to higher survival.

Decreased echinocandin susceptibility in Candida parapsilosis causing candidemia and emergence of a pan-echinocandin resistant case in China

Candida parapsilosis is becoming a predominant non-albicans cause of invasive candidiasis (IC). Echinocandins are the preferred choice for IC treatment and prophylaxis. Resistance to echinocandins in C. parapsilosis has emerged in several countries, but little is known about the susceptibility profile in China or about mechanisms of resistance. Here, we investigated the echinocandin susceptibilities of 2523 C. parapsilosis isolates collected from China and further explored the resistance mechanism among echinocandin-resistant isolates. Anidulafungin exhibited the highest MICs (MIC_50/90, 1 and 2 µg/mL; GM, 0.948 µg/mL), while caspofungin showed better activity (0.5 and 1 µg/mL; 0.498 µg/mL). Significantly higher echinocandin MICs were observed among blood-derived isolates compared to others, especially for caspofungin (GM, 1.348 µg/mL vs 0.478 µg/mL). Isolates from ICU and surgical wards also showed higher MICs. Twenty isolates showed intermediate phenotypes for at least one echinocandin. One was resistant to all three echinocandins, fluconazole and voriconazole, which caused breakthrough IC during long-term exposure to micafungin. WGS revealed this isolate carried a mutation S656P in hotspot1 region of Fks1. Bioinformatics analyses suggested that this mutation might lead to an altered protein conformation. CRISPR Cas9-mediated introduction of this mutation into a susceptible reference C. parapsilosis strain increased MICs of all echinocandins 64-fold, with similar results found in the subspecies, C. orthopsilosis and C. metapsilosis. This is the first report of a multi-azole resistant and pan-echinocandin resistant C. parapsilosis isolate, and the identification of a FKS1^S656P conferring pan-echinocandin resistance. Our study underscores the necessity of rigorous management of antifungal use and of monitoring for antifungal susceptibility.

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

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

Recombinase Polymerase Amplification Assay with Lateral Flow Strips for Rapid Detection of Candidiasis Due to Candida parapsilosis

Candida parapsilosis is a common cause of candidiasis among hospitalized patients, often surpassing Candida albicans. Due to the recent increase in C. parapsilosis infections, there is an urgent need for rapid, sensitive, and real-time on-site detection of nucleic acids for timely diagnosis of candidiasis. We developed an assay for detection of C. parapsilosis by combining recombinase polymerase amplification (RPA) with a lateral flow strip (LFS). The RPA-LFS assay was used to amplify the beta-1,3-glucan synthase catalytic subunit 2 (FKS2) gene of C. parapsilosis with a primer-probe set optimized by introducing base mismatches (four bases modified by the probe and one by the reverse primer) to achieve specific and sensitive detection of clinical samples. The RPA assays can rapidly amplify and visualize a target gene within 30 min, while the entire process can be completed within 40 min by pre-processing the sample. The product of RPA has two chemical labels, FITC and Biotin, of the amplification product can be carefully on the strip. The sensitivity and specificity of the RPA-LFS assay were determined by analysis of 35 common clinical pathogens and 281 clinical samples against quantitative PCR. The results confirmed that the proposed RPA-LFS assay is a reliable molecular diagnostic method for the detection of C. parapsilosis to meet the urgent need for rapid, specific, sensitive, and portable field testing.

A Predictive Model for 30-Day Mortality of Fungemia in ICUs

Background

Few predictive models have been established to predict the risk of 30-day mortality from fungemia. This study aims to create a nomogram to predict the 30-day mortality of fungemia in ICUs.

Methods

Data of ICU patients with fungemia from both the Medical Information Mart for Intensive Care (MIMIC-III) database and the Grade-III Class-A hospital in China were collected. The data extracted from the MIMIC-III database functioned as the training dataset, which was used to construct a predictive model for 30-day mortality risk in ICU patients with fungemia; the data from the hospital functioned as the validation dataset, which was used to validate the model. A predictive model for 30-day mortality risk in ICU patients with fungemia was then built based on R software. Such indicators as C-index and calibration curve were utilized to evaluate the prediction ability of the model. Data of ICU patients with fungemia from the hospital were used as a validation dataset to validate the model.

Results

Predictive models were constructed by age, international normalized ratio (INR), renal failure, liver disease, respiratory rate (RR), glucocorticoid therapy, antifungal therapy, and platelets. The C-index value of the models was 0.838 (95% CI: 0.79096-0.88504). Attested by external validation results, the model has satisfactory predictive ability.

Conclusion

The 30-day mortality risk predictive model for ICU patients with fungemia constructed in this study has good predictive ability and may hopefully provide a 30-day mortality risk screening tool for ICU patients with fungemia.

Sterylglucosides in Fungi

Sterylglucosides (SGs) are sterol conjugates widely distributed in nature. Although their universal presence in all living organisms suggests the importance of this kind of glycolipids, they are yet poorly understood. The glycosylation of sterols confers a more hydrophilic character, modifying biophysical properties of cell membranes and altering immunogenicity of the cells. In fungi, SGs regulate different cell pathways to help overcome oxygen and pH challenges, as well as help to accomplish cell recycling and other membrane functions. At the same time, the level of these lipids is highly controlled, especially in wild-type fungi. In addition, modulating SGs metabolism is becoming a novel tool for vaccine and antifungal development. In the present review, we bring together multiple observations to emphasize the underestimated importance of SGs for fungal cell functions.

Prevalence and species distribution of Candida bloodstream infection in children and adults in two teaching university hospitals in Egypt: first report of Candida kefyr

BACKGROUND

Candidemia is a pervasive problem associated with significant morbidity and mortality in health care settings. This study aimed to determine the changing distribution of Candida species and the emergence of uncommon species.

METHODS

This was a cross-sectional study performed in two Cairo University hospitals between 2019 and 2020. All Candida species isolates recovered from blood cultures of adults and pediatrics patients admitted to the hospitals were included. Candida isolates were identified by chromogenic Candida agar and Vitek2 YST identification card. Candida kefyr was confirmed by chip array.

RESULTS

Candida species were responsible for 1.6% of bloodstream infections in adults and 10.8% in pediatric patients. C. albicans was the most prevalent species representing 27.8% in adults and 48.3% in pediatrics. Non-albicans species (NAC) represented the most isolated Candida species among adults and pediatrics (72.2% and 51.6%, respectively) with the predominance of C. tropicalis (27.8% and 22.5%, respectively) followed by C. parapsilosis (16.7% and 10.8%, respectively). The uncommon Candida, which is Candida species other than C. albicans, C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei, represents 16.6% and 14% of all candidemia in adults and pediatrics, respectively. Only one of each of C. lusitaniae, C. utilis, and C. kefyr were detected in adults. C. lusitaniae was the most frequently recovered uncommon Candida among pediatrics resulting in 6.4% of candidemia followed by C. famata (4.3%), C. utilis (2.2%), and C. kefyr (1.1%).

CONCLUSIONS

C. albicans is still the primary species isolated from pediatrics and adults with candidemia despite the considerable shift to the non-albicans species. C. tropicalis and C. parapsilosis are the most prevalent NAC. The increased prevalence of uncommon Candida species is alarming and necessitates a prompt stewardship program.

Epidemiology of Candidemia and Fluconazole Resistance in an ICU before and during the COVID-19 Pandemic Era

The objectives of this study were to investigate the incidence of candidemia, as well as the factors associated with Candida species distribution and fluconazole resistance, among patients admitted to the intensive care unit (ICU) during the COVID-19 pandemic, as compared to two pre-pandemic periods. All patients admitted to the ICU due to COVID-19 from March 2020 to October 2021, as well as during two pre-pandemic periods (2005–2008 and 2012–2015), who developed candidemia, were included. During the COVID-19 study period, the incidence of candidemia was 10.2%, significantly higher compared with 3.2% and 4.2% in the two pre-pandemic periods, respectively. The proportion of non-albicans Candida species increased (from 60.6% to 62.3% and 75.8%, respectively), with a predominance of C. parapsilosis. A marked increase in fluconazole resistance (from 31% to 37.7% and 48.4%, respectively) was also observed. Regarding the total patient population with candidemia (n = 205), fluconazole resistance was independently associated with ICU length of stay (LOS) before candidemia (OR 1.03; CI: 1.01–1.06, p = 0.003), whereas the presence of shock at candidemia onset was associated with C. albicans (OR 6.89; CI: 2.2–25, p = 0.001), and with fluconazole-susceptible species (OR 0.23; CI: 0.07–0.64, p = 0.006). In conclusion, substantial increases in the incidence of candidemia, in non-albicansCandida species, and in fluconazole resistance were found in patients admitted to the ICU due to COVID-19, compared to pre-pandemic periods. At candidemia onset, prolonged ICU LOS was associated with fluconazole-resistant and the presence of shock with fluconazole-susceptible species.

The effect of antifungal resistance development on the virulence of Candida species

In recent years, the relevance of diseases associated with fungal pathogens increased worldwide. Members of the Candida genus are responsible for the greatest number of fungal bloodstream infections every year. Epidemiological data consistently indicate a modest shift toward non-albicans species, albeit Candidaalbicans is still the most recognizable species within the genus. As a result, the number of clinically relevant pathogens has increased, and, despite their distinct pathogenicity features, the applicable antifungal agents remained the same. For bloodstream infections, only three classes of drugs are routinely used, namely polyenes, azoles and echinocandins. Antifungal resistance toward all three antifungal drug classes frequently occurs in clinical settings. Compared with the broad range of literature on virulence and antifungal resistance of Candida species separately, only a small portion of studies examined the effect of resistance on virulence. These studies found that resistance to polyenes and echinocandins concluded in significant decrease in the virulence in different Candida species. Meanwhile, in some cases, resistance to azole type antifungals resulted in increased virulence depending on the species and isolates. These findings underline the importance of studies aiming to dissect the connections of virulence and resistance in Candida species.

Attributable mortality of candidemia at a German tertiary hospital from 1997 to 2001 before the introduction of echinocandins

OBJECTIVES

The relevance of candidemia has increased over the last decades due to higher incidence rates in an ageing society. Studies on amphotericin B and fluconazole have shown high attributable mortality rates of 38% and 49% in the United States. Incidence rates and locational factors might have an impact on the mortality rates at the University Hospital of Cologne (UHC), Germany.

METHODS

We performed a matched case-control study including 57 patients with candidemia, hospitalised at the UHC between 1 July 1997 and 30 June 2001. Controls were matched by age, sex, admission date, treatment on intensive care unit (ICU), number of days at risk, underlying diseases, surgical procedures and the Charlson Comorbidity Index.

RESULTS

The incidence of candidemia was 3.5 per 10 000 admissions. For cases and controls, we observed in-hospital-mortality rates of 33.3% and 11.8%, and a 30-day mortality of 23.5% and 7.8% respectively. The attributable mortality rate to candidemia was 21.5%, and at 30 days, it was 15.7%. Underlying conditions were more frequent in cases than in controls, especially central venous catheter (80% vs 33%, P < .001), chronic cardiovascular disease (39.2% vs 25.5%, P = .138), treatment on ICU (31.4% vs 13.7%, P = .033) and chronic liver disease (21.6% vs 0%, P < .001).

CONCLUSIONS

The attributable mortality of candidemia at the UHC between 1997 and 2001 was lower compared to studies performed in the United States with a similar design. Contributing factors might be lower incidence rates and less comorbidities in our study.

Distribution of genetically characterized yeasts and its antifungals susceptibility in the hospital environment

Candida spp. is one of the main pathogens associated with nosocomial infection in Brazil and worldwide. The aim of this study was to evaluate the distribution of Candida yeasts in the ICU and their susceptibility to the antifungal agents terbinafine and fluconazole. The samples were collected by swabbing nine surfaces in the ICU of a hospital located in Pelotas, RS. These isolates were genetically characterized by sequencing the internal transcript spacer (ITS) using the primers ITS1 and ITS4. The test against antifungals was performed by Microdilution in Broth (CLSI-M27-A4). 64 yeasts identified as Candida parapsilosis (45.31%; n = 29), Meyerozyma (Pichia) guilliermondii (28.12%; n = 18), Claviceps lusitaneae (25%; n = 16) and Candida tropicalis (1, 56%; n = 1) mostly at the counter used for handling medicines and food distribution (68.75%; n = 44). Susceptibility to antifungals varied between species. These results describe potentially pathogenic Candida species as contaminants in the ICU environment. The study environment is a potential source of exogenous infection for hospitalized patients.

Case Report: A Candida Meningitis in an Immunocompetent Patient Detected Through the Next-Generation Sequencing

Background: Fungal infections of the central nervous system (CNS) are not commonly seen clinically. Clinical diagnosis of fungal infections often depend on the pathogen culture and the clinical features. This method is time-consuming and insensitive, which can lead to misdiagnosis. The authors introduce an adult patient with fungal infections diagnosed by next-generation sequencing (NGS).

Case: The patient was a 60-year-old male Chinese who had both hypermyotonia of the lower extremities and fever. The auxiliary examinations such as MRI, CT, and cerebrospinal fluid (CSF) analysis showed obvious abnormalities. Because of the difficulties in diagnosis, it was hard to determine the treatment plan. The NGS detected specific sequences of Candida albicans in 3 days. The patient was then treated with liposomal amphotericin B and fluconazole. About 3 weeks later, the symptoms of the patient improved significantly and he was discharged from the hospital.

Conclusion: Compared with the routine cultural method, NGS has made a huge advancement in infection diagnosis and targeting antimicrobial therapy for CNS infection.

Risk factors for invasive candida infection in critically ill patients - a systematic review and meta-analysis

Background

Current guidelines recommend empirical antifungal therapy in patients with sepsis with high risk of invasive Candida infection. However, many different risk factors have been derived from multiple studies. These risk factors lack specificity, and broad application would render most ICU patients eligible for empirical antifungal therapy.

Research Question

What risk factors for invasive Candida infection can be identified by a systematic review and meta-analysis?

Study Design and Methods

We searched PubMed, Web of Science, ScienceDirect, Biomed Central, and Cochrane and extracted the raw and adjusted OR for each risk factor associated with invasive Candida infection. We calculated pooled ORs for risk factors present in more than one study.

Results

We included 34 studies in our meta-analysis resulting in the assessment of 29 possible risk factors. Risk factors for invasive Candida infection included demographic factors, comorbid conditions, and medical interventions. Although demographic factors do not play a role for the development of invasive Candida infection, comorbid conditions (eg, HIV, Candida colonization) and medical interventions have a significant impact. The risk factors associated with the highest risk for invasive Candida infection were broad-spectrum antibiotics (OR, 5.6; 95% CI, 3.6-8.8), blood transfusion (OR, 4.9; 95% CI, 1.5-16.3), Candida colonization (OR, 4.7; 95% CI, 1.6-14.3), central venous catheter (OR, 4.7; 95% CI, 2.7-8.1), and total parenteral nutrition (OR, 4.6; 95% CI, 3.3-6.3). However, dependence between the various risk factors is probably high.

Interpretation

Our systematic review and meta-analysis identified patient- and treatment-related factors that were associated with the risk for the development of invasive Candida infection in the ICU. Most of the factors identified were either related to medical interventions during intensive care or to comorbid conditions.

Increasing morbidity and mortality of candidemia over one decade in a Swiss university hospital

Background

The epidemiology of candidemia is evolving with raising concern about the emergence of intrinsically resistant non‐albicans Candida species and acquisition of antifungal resistance. In addition to microbiological surveys, epidemiological studies including clinical data are needed to assess the impact of candidemia on morbidity and mortality.

Objectives

To assess the clinical and microbiological trends of candidemia in a Swiss university hospital.

Patients/Methods.

This single‐centre retrospective study compared the incidence of candidemia, Candida species distribution, antifungal resistance profiles, clinical characteristics and outcomes between two periods separated by one decade.

Results

A total of 170 candidemic episodes were included (68 from period 1, 2004‐2006, and 102 from period 2, 2014‐2017). Incidence of candidemia (0.85 to 0.97 episode/10,000 patient‐days), species distribution (55%–57% C albicans) and antifungal susceptibilities remained unchanged. During period 2, candidemia was more frequently observed in intensive care units (ICU, 38% vs 19% in period 1, P = .01) and amongst older patients (median age 68 vs 59 years old, P < .01) with more immunosuppressive conditions (24% vs 9%, P = .01). Candidemia in period 2 was more frequently followed by septic shock (23% vs 7% in period 1, P = .01) and ICU admission (42% vs 12%, P < .01) and was associated with higher mortality (34% vs 18%, P = .03). Overall, factors associated with mortality in multivariate analyses included cirrhosis, solid malignancies and ICU stay at the time of candidemia.

Conclusions

Despite stable incidence, species distribution and antifungal resistance of candidemia, an epidemiological shift of the disease towards older and more critically ill patients was observed, with higher mortality rates.

Deciphering of Candida parapsilosis induced immune response in Drosophila melanogaster

Candida infections are the most prevalent cause of serious human mycoses and are the third most common pathogens isolated from bloodstream infections in hospitalized patients. C. parapsilosis is a member of the non-albicans spp., which have a predilection for causing life-threatening disease in neonates and hospitalized pediatric patients. In this study, we utilized a Drosophila melanogaster infection model to analyze the immunological responses to C. parapsilosis. Our results demonstrate that the Toll pathway in Drosophila controls C. parapsilosis proliferation as the Toll signaling mutant MyD88^-/- flies are highly susceptible to C. parapsilosis. We also confirmed that the MyD88^-/- fly is a convenient invertebrate animal model to analyze virulence properties of different species and strains from the C. parapsilosis sensu lato complex as C. orthopsilosis, C. metapsilosis proved to be less virulent than C. parapsilosis sensu stricto and the N-mannan deficient C. parapsilosis och1Δ/Δ strain showed attenuated pathogenicity in this immunodeficient Drosophila background. We also found that Persephone protease is not required for detection and activation of Toll pathway during C. parapsilosis infection. Furthermore, we observed that Drosophila β-glucan receptor deficient flies where more sensitive to C. parapsilosis compared to wild-type flies; however, we could not find a clear dependence on the recognition of this receptor and the cell wall β-glucan exposure-induced host response. These studies establish this D. melanogaster infection model as an efficient tool in deciphering immune responses to C. parapsilosis as well as for assessing virulence factors produced by this emerging fungal predator.

Update 2016-2018 of the Nationwide Danish Fungaemia Surveillance Study: Epidemiologic Changes in a 15-Year Perspective

As part of a national surveillance programme initiated in 2004, fungal blood isolates from 2016–2018 underwent species identification and EUCAST susceptibility testing. The epidemiology was described and compared to data from previous years. In 2016–2018, 1454 unique isolates were included. The fungaemia rate was 8.13/100,000 inhabitants compared to 8.64, 9.03, and 8.38 in 2004–2007, 2008–2011, and 2012–2015, respectively. Half of the cases (52.8%) involved patients 60–79 years old and the incidence was highest in males ≥70 years old. Candida albicans accounted for 42.1% of all isolates and Candida glabrata for 32.1%. C. albicans was more frequent in males (p = 0.03) and C. glabrata in females (p = 0.03). During the four periods, the proportion of C. albicans decreased (p < 0.001), and C. glabrata increased (p < 0.001). Consequently, fluconazole susceptibility gradually decreased from 68.5% to 59.0% (p < 0.001). Acquired fluconazole resistance was found in 4.6% Candida isolates in 2016–2018. Acquired echinocandin resistance increased during the four periods 0.0%, 0.6%, 1.7% to 1.5% (p < 0.0001). Sixteen echinocandin-resistant isolates from 2016–2018 harboured well-known FKS resistance-mutations and one echinocandin-resistant C. albicans had an FKS mutation outside the hotspot (P1354P/S) of unknown importance. In C. glabrata specifically, echinocandin resistance was detected in 12/460 (2.6%) in 2016–2018 whereas multidrug-class resistance was rare (1/460 isolates (0.2%)). Since the increase in incidence during 2004–2011, the incidence has stabilised. In contrast, the species distribution has changed gradually over the 15 years, with increased C. glabrata at the expense of C. albicans. The consequent decreased fluconazole susceptibility and the emergence of acquired echinocandin resistance complicates the management of fungaemia and calls for antifungal drug development.

Deciphering the epidemiology of invasive candidiasis in the intensive care unit: is it possible?

Invasive candidiasis (IC) has emerged in the last decades as an important cause of morbidity, mortality, and economic load in the intensive care unit (ICU). The epidemiology of IC is still a difficult and unsolved enigma for the literature. Accurate estimation of the true burden of IC is difficult due to variation in definitions and limitations inherent to available case-finding methodologies. Candidemia and intra-abdominal candidiasis (IAC) are the two predominant types of IC in ICU. During the last two decades, an increase in the incidence of candidemia has been constantly reported particularly in the expanding populations of elderly or immunosuppressed patents, with a parallel change in Candida species (spp.) distribution worldwide. Epidemiological shift in non-albicans spp. has reached worrisome trends. Recently, a novel, multidrug-resistant Candida spp., Candida auris, has globally emerged as a nosocomial pathogen causing a broad range of healthcare-associated invasive infections. Epidemiological profile of IAC remains imprecise. Though antifungal drugs are available for Candida infections, mortality rates continue to be high, estimated to be up to 50%. Increased use of fluconazole and echinocandins has been associated with the emergence of resistance to these drugs, which affects particularly C. albicans and C. glabrata. Crucial priorities for clinicians are to recognize the epidemiological trends of IC as well as the emergence of resistance to antifungal agents to improve diagnostic techniques and strategies, develop international surveillance networks and antifungal stewardship programmes for a better epidemiological control of IC.

Factors associated with the development of ocular candidiasis and ocular prognosis with echinocandin therapy for candidemia

Purpose

To evaluate the factors associated with the development of ocular candidiasis (OC) and ocular prognosis with echinocandin therapy for candidemia.

Methods

The medical records of 56 consecutive patients with a positive blood culture for Candida species between November 2016 and October 2019 were retrospectively reviewed. Information on patient characteristics, isolated Candida species, treatment details for candidemia, and ocular findings were extracted to identify factors associated with OC development.

Results

The leading pathogen of candidemia was Candida albicans (C.albicans) (41.1%). Of 56 patients, 18 (32.1%) were diagnosed with chorioretinitis, categorized as either probable (8 patients) or possible OC (10 patients). There was no case of endophthalmitis with vitritis. The incidence of probable OC was not significantly different between the groups treated with echinocandins and other antifungal drugs (15.2% vs. 11.1%, p = 1.00). In all probable OC cases, systemic antifungal therapy was switched from echinocandins to azoles, and no case progressed to endophthalmitis. A multivariate logistic analysis revealed that female sex (adjusted odds ratio [aOR], 8.93; 95% confidence interval [CI], 1.09–72.9) and C. albicans (aOR, 23.6; 95% CI, 1.8–281) were independent factors associated with the development of probable OC.

Conclusion

One-seventh of patients with candidemia developed probable OC. Given the evidence of female and C. albicans as the factors associated with OC development, careful ophthalmologic management is required with these factors, especially in candidemia. Although echinocandins had no correlation with OC development and did not lead to the deterioration of ocular prognosis, further investigation is required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12348-021-00248-0.

Molecular genotyping of Candida albicans isolated from different sites may trace the etiological infection routes: Observation in China

BACKGROUND

Invasive candidiasis is a growing concern worldwide, especially in immunocompromised patients, including ICU patients.

OBJECTIVES

As Candida albicans is the leading cause of candidaemia, it is important to investigate the evolution of C. albicans in patients with candidaemia.

METHODS

We analysed 238 strains of C. albicans isolated from different body sites. Antifungal susceptibility testing, CAI loci genotyping and multilocus sequence typing (MLST) of all isolates were performed. The relationships among the total isolates that differed in sequence at only one of the seven housekeeping gene loci were analysed using eBURST.

RESULTS

Multilocus sequence typing analysis in 238 isolates by combining seven housekeeping alleles revealed 175 diploid sequence types, in which 84 were newly identified. eBURST analysis for these data recognised 19 clonal complexes (CCs) and 79 singletons. Besides, seventy-three CAI genotypes were identified. Blood isolates showed maximum genotypes (49), and the dominant genotypes were CAI 17-21 and CAI 21-21. Oral isolates possessed 25 CAI genotypes, and the dominant genotypes were CAI 17-21 and CAI 21-21 as well. Since isolates with CAI allele numbers <30 showed easier transmission, CAI 17-21 and CAI 21-21 were the most frequently transmitted. Finally, the CAI genotypes were classified into six groups.

CONCLUSIONS

This work revealed the oral and blood strains isolated from the patients with candidaemia in ICU shared the identical dominant CAI genotypes. Our data expanded the C. albicans MLST database and helped with understanding the evolution and spread of invasive candidiasis.

Antifungal Activity of Minocycline and Azoles Against Fluconazole-Resistant Candida Species

Candida species are the most common fungal pathogens to infect humans, and can cause life-threatening illnesses in individuals with compromised immune systems. Fluconazole (FLU) is the most frequently administered antifungal drug, but its therapeutic efficacy has been limited by the emergence of drug-resistant strains. When co-administered with minocycline (MIN), FLU can synergistically treat clinical Candida albicans isolates in vitro and in vivo. However, there have been few reports regarding the synergistic efficacy of MIN and azoles when used to treat FLU-resistant Candida species, including Candida auris. Herein, we conducted a microdilution assay wherein we found that MIN and posaconazole (POS) showed the best in vitro synergy effect, functioning against 94% (29/31) of tested strains, whereas combinations of MIN+itraconazole (ITC), MIN+voriconazole (VOR), and MIN+VOR exhibited synergistic activity against 84 (26/31), 65 (20/31), and 45% (14/31) of tested strains, respectively. No antagonistic activity was observed for any of these combinations. In vivo experiments were conducted in Galleria mellonella, revealing that combination treatment with MIN and azoles improved survival rates of larvae infected with FLU-resistant Candida. Together, these results highlight MIN as a promising synergistic compound that can be used to improve the efficacy of azoles in the treatment of FLU-resistant Candida infections.

Epidemiology of Candidemia: Three-Year Results from a Croatian Tertiary Care Hospital

Invasive candidosis is the most common invasive fungal infection in hospitalized patients and is associated with a high mortality rate. This is the first study from a Croatian tertiary care hospital describing epidemiology, risk factors and species distribution in patients with candidemia. A three-year retrospective observational study, from 2018 to 2020, was performed at the University Hospital Centre Zagreb, Zagreb, Croatia. A total of 160 patients with candidemia (n = 170 isolates) were enrolled. Candidemia incidence increased from 0.47 to 0.69 per 1000 admissions in 2018 and 2020, respectively. Ninety-five patients (58.38%) were in the intensive care unit. The main risk factors for candidemia were central venous catheter (CVC) (84.38%), previous surgical procedure (56.88%) and invasive mechanical ventilation (42.50%). Candida albicans was identified in 43.53% of isolates, followed by C. parapsilosis (31.76%) and C. glabrata (12.36%), C. krusei (5.29%), C. tropicalis (2.35%) and C. lusitaniae (2.35%). The study discovered a shift to non-albicansCandida species, particularly C. parapsilosis, and made it possible to determine the main tasks we should focus on to prevent candidemia in the hospital, these being mainly infection control measures directed towards prevention of catheter-related bloodstream infections, specifically comprising hand hygiene and CVC bundles of care. The potential benefit of fluconazole prophylaxis in certain populations of surgical patients could also be considered.

Trends in the Epidemiology of Candidemia in Intensive Care Units From 2006 to 2017: Results From the Korean National Healthcare-Associated Infections Surveillance System

Candidemia is an important healthcare-associated infection (HAI) in intensive care units (ICUs). However, limited research has been conducted on candidemia in the Republic of Korea. We aimed to analyze the secular trends in the incidence and distribution of candidemia in ICUs over 12-years using data from the Korean National Healthcare-Associated Infections Surveillance System (KONIS). KONIS was established in 2006 and has performed prospective surveillance of HAIs including bloodstream infections (BSIs) in ICUs. We evaluated the trends in the distribution of causative pathogens and the incidence of candidemia. From 2006 to 2017, 2,248 candidemia cases occurred in 9,184,264 patient-days (PDs). The pooled mean incidence rates of candidemia significantly decreased from 3.05 cases/10,000 PDs in 2006 to 2.5 cases/10,000 PDs in 2017 (P = 0.001). Nevertheless, the proportion of candidemia gradually increased from 15.2% in 2006 to 16.6% in 2017 (P = 0.001). The most frequent causative pathogen of BSIs from 2006 to 2012 was Staphylococcus aureus; however, Candida spp. emerged as the most frequent causative pathogen since 2013. C. albicans (39.9%) was the most common among Candida spp. causing BSIs, followed by Candida tropicalis (20.2%) and Candida parapsilosis (18.2%). The proportion of candidemia caused by C. glabrata significantly increased from 8.9% in 2006 to 17.9% in 2017 (P < 0.001). There was no significant change in the distribution of Candida spp. by year (P = 0.285). The most common source of BSIs was central lines associated BSI (92.5%). There was a significant increase in the proportion of candidemia by year in hospitals with organ transplant wards (from 18.9% in 2006 to 21.1% in 2017, P = 0.003), hospitals with <500 beds (from 2.7% in 2006 to 13.6% in 2017, P < 0.001), and surgical ICUs (from 16.2% in 2006 to 21.7% in 2017, P = 0.003). The proportion of candidemia has increased in Korea, especially in hospitals with <500 beds and surgical ICUs. Thus, appropriate infection control programs are needed.

Triazole Evolution of Candida parapsilosis Results in Cross-Resistance to Other Antifungal Drugs, Influences Stress Responses, and Alters Virulence in an Antifungal Drug-Dependent Manner

Candida parapsilosis causes life-threatening fungal infections. In the last 2 decades, the increasing number of azole-resistant C. parapsilosis clinical isolates has been attributable to the overuse and misuse of fluconazole, the first-line antifungal agent most commonly used in several countries. To date, the range of applicable antifungal drugs is limited. As a consequence, it is essential to understand the possible mechanisms of antifungal resistance development and their effect on virulence in order to optimize antifungal treatment strategies in the clinical setting. Our results revealed that the prolonged exposure to azoles resulted not only in azole resistance but also in cross-resistance development. Our data further indicate that resistance development may occur through different mechanisms that can also alter the virulence of C. parapsilosis. These results highlight the consequences of prolonged drug usage and suggest the need for developing alternative antifungal treatment strategies in clinical practice.

The number of invasive infections caused by Candida species is increasing worldwide. The incidence of candidiasis cases caused by non-albicans Candida species, such as Candida parapsilosis, is also increasing, and non-albicans Candida species are currently responsible for more invasive infections than C. albicans. Additionally, while the development of azole resistance during invasive disease with C. albicans remains uncommon, azole-resistant C. parapsilosis strains are frequently isolated in the hospital setting. In this study, we applied direct selection to generate azole-adapted and azole-evolved C. parapsilosis strains in order to examine the effect of azole resistance development on fungal viability and pathogenesis progression. Depending on the drug applied, the different evolved strains developed distinct cross-resistance patterns: the fluconazole-evolved (FLU^EVO) and voriconazole-evolved (VOR^EVO) strains gained resistance to fluconazole and voriconazole only, while posaconazole evolution resulted in cross-resistance to all azoles and the posaconazole-evolved (POS^EVO) strains showed higher echinocandin MIC values than the FLU^EVO and VOR^EVO strains. Whole-genome sequencing results identified the development of different resistance mechanisms in the evolved strains: the FLU^EVO and VOR^EVO strains harbored amino acid substitutions in Mrr1p (A808T and N394Y, respectively), and the POS^EVO strain harbored an amino acid change in Erg3p (D14Y). By revealing increased efflux pump activity in both the FLU^EVO and the VOR^EVO strains, along with the altered sterol composition of the POS^EVO strain, we now highlight the impact of the above-mentioned amino acid changes in C. parapsilosis azole resistance development. We further revealed that the virulence of this species was only slightly or partially affected by fluconazole and voriconazole adaptation, while it significantly decreased after posaconazole adaptation. Our results suggest that triazole adaptation can result in azole cross-resistance and that this process may also result in virulence alterations in C. parapsilosis, depending on the applied drug.

IMPORTANCECandida parapsilosis causes life-threatening fungal infections. In the last 2 decades, the increasing number of azole-resistant C. parapsilosis clinical isolates has been attributable to the overuse and misuse of fluconazole, the first-line antifungal agent most commonly used in several countries. To date, the range of applicable antifungal drugs is limited. As a consequence, it is essential to understand the possible mechanisms of antifungal resistance development and their effect on virulence in order to optimize antifungal treatment strategies in the clinical setting. Our results revealed that the prolonged exposure to azoles resulted not only in azole resistance but also in cross-resistance development. Our data further indicate that resistance development may occur through different mechanisms that can also alter the virulence of C. parapsilosis. These results highlight the consequences of prolonged drug usage and suggest the need for developing alternative antifungal treatment strategies in clinical practice.

Epidemiology, clinical characteristics, and outcome of candidemia in critically ill patients in Germany: a single-center retrospective 10-year analysis

Background

Despite advances in the management of bloodstream infections (BSI) caused by Candida spp., the mortality still remains high in critically ill patients. The worldwide epidemiology of yeast-related BSI is subject to changing species distribution and resistance patterns, challenging antifungal treatment strategies. The aim of this single-center study was to identify predictors of mortality after 28 and 180 days in a cohort of mixed surgical and medical critically ill patients with candidemia.

Methods

Patients, who had been treated for laboratory-confirmed BSI caused by Candida spp. in one of 12 intensive care units (ICU) at a University hospital between 2008 and 2017, were retrospectively identified. We retrieved data including clinical characteristics, Candida species distribution, and antifungal management from electronic health records to identify risk factors for mortality at 28 and 180 days using a Cox regression model.

Results

A total of 391 patients had blood cultures positive for Candida spp. (incidence 4.8/1000 ICU admissions). The mortality rate after 28 days was 47% (n = 185) and increased to 60% (n = 234) after 180 days. Age (HR 1.02 [95% CI 1.01–1.03]), a history of liver cirrhosis (HR 1.54 [95% CI 1.07–2.20]), septic shock (HR 2.41 [95% CI 1.73–3.37]), the Sepsis-related Organ Failure Assessment score (HR 1.12 [95% CI 1.07–1.17]), Candida score (HR 1.25 [95% CI 1.11–1.40]), and the length of ICU stay at culture positivity (HR 1.01 [95% CI 1.00–1.01]) were significant risk factors for death at 180 days. Patients, who had abdominal surgery (HR 0.66 [95% CI 0.48–0.91]) and patients, who received adequate (HR 0.36 [95% CI 0.24–0.52]) or non-adequate (HR 0.31 [95% CI 0.16–0.62]) antifungal treatment, had a reduced mortality risk compared to medical admission and no antifungal treatment, respectively.

Conclusions

The mortality of critically ill patients with Candida BSI is high and is mainly determined by disease severity, multiorgan dysfunction, and antifungal management rather than species distribution and susceptibility. Our results underline the importance of timely treatment of candidemia. However, controversies remain on the optimal definition of adequate antifungal management.

[Invasive candidiasis: A view to central nervous system infection]

Candidemia is the most frequent invasive mycosis in hospitalized patients worldwide. Fungal infection in central nervous system is a life-threatening complication which aggravates patients' prognosis. This article summarizes relevant aspects on the clinical characteristics of this pathology, mechanisms of fungus invasion, local immune response to Candida albicans and the impact of genetic defects on innate immune receptors that increase susceptibility to the acquisition of this form of mycosis.

In vitro and ex vivo biofilms of dermatophytes: a new panorama for the study of antifungal drugs

This study describes an ex vivo model that creates an environment for dermatophyte biofilm growth, with features that resemble those of in vivo conditions, designing a new panorama for the study of antifungal susceptibility. Regarding planktonic susceptibility, MIC ranges were 0.125-1 µg ml^-1 for griseofulvin and 0.000097-0.25 µg ml^-1 for itraconazole and terbinafine. sMIC50 ranges were 2->512 µg ml^-1 for griseofulvin and 0.25->64 µg ml^-1 for itraconazole and terbinafine. CLSM images demonstrated a reduction in the amount of cells within the biofilm, but hyphae and conidia were still observed and biofilm biomass was maintained. SEM analysis demonstrated a retraction in the biofilm matrix, but fungal structures and water channels were preserved. These results show that ex vivo biofilms are more tolerant to antifungal drugs than in vitro biofilms, suggesting that environmental and nutritional conditions created by this ex vivo model favor biofilm growth and robustness, and hence drug tolerance.

Species distribution and antifungal susceptibilities of bloodstream Candida isolates: a nine-years single center survey

This study analyzed the epidemiology of bloodstream infections due to Candida spp. in a tertiary referral hospital of Ancona, Italy, and their susceptibility to antifungals. The retrospective observational study from January 2010 to December 2018 identified 504 episodes of candidemia in 461 patients. Although Candida albicans remained the species most frequently isolated, Candida spp. other than C. albicans caused 49% of the overall episodes of candidemia. According to CLSI interpretation, most of the isolates resulted susceptible to antifungals. Azoles vs Candida tropicalis represented an exception. Echinocandin non-susceptibility was rare across the species. In conclusion, with the exception of C. tropicalis, the isolation of a non-susceptible Candida strains against azoles, echinocandins and amphotericin B was a rare event.

Mecanismos de resistencia a fluconazol expresados por Candida glabrata: una situación para considerar en la terapéutica

Introducción: Los esfuerzos terapéuticos orientados a atender las micosis por Candida spp. se han enfocado en el empleo de azoles; sin embargo, en la literatura científica se discute su beneficio, por los amplios y descritos mecanismos de resistencia. Objetivo: Describir los mecanismos de resistencia al fluconazol expresados por la especie Candida glabrata, con la intención de que sean considerados dentro de las variables de elegibilidad para la intervención. Método: Se realizó una revisión integrativa utilizando la pregunta orientadora: ¿cuáles son los mecanismos de resistencia al fluconazol expresados por la especie Candida glabrata? Veintinueve estudios obtenidos de la base de datos PubMed cumplieron los criterios del análisis crítico propuesto por el instrumento PRISMA, utilizado para la selección de los artículos incluidos para su revisión en este manuscrito. Las categorías bajo las cuales se organizaron los elementos de análisis fueron: sobrexpresión de bombas de eflujo y modificaciones en la enzima lanosterol 14-alfa-desmetilasa. Resultados: Los mecanismos de resistencia al fluconazol expresados por Candida glabrata están determinados principalmente por la regulación a la alza de bombas de adenosina-trifosfato Binding Cassette (ABC) y por la modificación del punto de unión con su blanco farmacológico: la enzima lanosterol 14-alfa-desmetilasa. Conclusión: Los mecanismos de resistencia expresados por Candida glabrata se asocian con la modificación estructural de la diana farmacológica y la sobreexpresión de bombas de eflujo de manera diferencial a otras especies. Se sugiere que Candida glabrata es intrínsecamente menos susceptible al fluconazol.

Epidemiological features of nosocomial candidaemia in neonates, infants and children: A multicentre study in Iran

Nosocomial bloodstream candidaemia is a life-threatening fungal infection with high morbidity and mortality, especially among paediatric patients undergoing intensive immunosuppressive therapy. Limited data on the epidemiology of candidaemia and susceptibility profiles are available for Iran. To characterise candidaemia epidemiology, comorbidity risk factors, species distribution, and antifungal susceptibility profiles among paediatric patients in Iran. This observational cross-sectional study enrolled 26 189 patients <18 years old at three reference paediatric hospitals in Mazandaran and Tehran over 2 years. Blood samples from patients with suspected fungal bloodstream infection were analysed using the BACTEC culture system. Fungal isolates were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF) and DNA sequencing. Antifungal susceptibility testing was performed using the Clinical and Laboratory Standards Institute broth microdilution guideline. We observed 109 episodes of nosocomial candidaemia in paediatric patients with or without immunosuppressive therapy. The most common healthcare-associated factor was central vascular catheter use (97%). The all-cause mortality rate was 40%, of which 48% was attributable to candidaemia. While Candida albicans was the most frequent causative agent (49%), emerging and uncommon Candida species were also isolated. Candidaemia mortality by non-albicans Candida species was significantly higher than that by C. albicans (P < .05). All fluconazole-resistant species were non-albicans Candida species. Uncommon Candida species with reduced susceptibility to antifungals are emerging as major agents of nosocomial candidaemia in high-risk paediatric patients in Iran. Appropriate source control, antifungal regimens and improved antifungal stewardship are warranted for managing and decreasing the burden of nosocomial candidaemia.

Changing epidemiology of candidaemia: Increase in fluconazole-resistant Candida parapsilosis

AIM

During the last decade a continuous increase in non-albicans species isolation has been observed with Candida parapsilosis being one of the leading species. Aim of this study was to describe the epidemiology of candidemia, particularly of C parapsilosis, its predictors and clinical outcome.

MATERIALS AND METHODS

Incidences of candidemia was evaluated analyzing data from both a prospective collection (2012-2016) and a retrospective one (2008-2011). Predictors and outcome were based only on the prospective phase. C parapsilosis potential clusters were analysed by randomly amplified polymorphic DNA (RAPD) technique.

RESULTS

1240 episodes were identified. Incidences of candidemia increased from 1.97 episodes/10 000 patient-days in 2008 to 4.59/10 000 patient-days in 2016 (P < .001), mainly due to an increase of C parapsilosis (incidence rate ratio, IRR: 1.04, P < .001). 33.0% of C parapsilosis strains were resistant to fluconazole; no resistance to echinocandins was found. Independent predictors of C parapsilosis candidemia were time of infection (P = .007), previous use of echinocandins (P < .0001) and year in which the episode was registered (P < .0001). 30 days mortality was 32.4% for C parapsilosis, with a significant difference compared to C non-parapsilosis. Potential clonal C parapsilosis strains were detected by genetic analyses, showing RAPD profile A as the most represented (72.6% of isolates).

DISCUSSION

C parapsilosis candidemia is an emerging issue in our center, possibly attributed to some extent to horizontal transmission of the pathogen, as confirmed by the analysis of isolates similarities. Further microbiological and epidemiological investigations are needed in order to identify the most effective measures to reduce the rate of this infection.

Sugar Sensing and Signaling in Candida albicans and Candida glabrata

Candida species, such as Candida albicans and Candida glabrata, cause infections at different host sites because they adapt their metabolism depending on the available nutrients. They are able to proliferate under both nutrient-rich and nutrient-poor conditions. This adaptation is what makes these fungi successful pathogens. For both species, sugars are very important nutrients and as the sugar level differs depending on the host niche, different sugar sensing systems must be present. Saccharomyces cerevisiae has been used as a model for the identification of these sugar sensing systems. One of the main carbon sources for yeast is glucose, for which three different pathways have been described. First, two transporter-like proteins, ScSnf3 and ScRgt2, sense glucose levels resulting in the induction of different hexose transporter genes. This situation is comparable in C. albicans and C. glabrata, where sensing of glucose by CaHgt4 and CgSnf3, respectively, also results in hexose transporter gene induction. The second glucose sensing mechanism in S. cerevisiae is via the G-protein coupled receptor ScGpr1, which causes the activation of the cAMP/PKA pathway, resulting in rapid adaptation to the presence of glucose. The main components of this glucose sensing system are also conserved in C. albicans and C. glabrata. However, it seems that the ligand(s) for CaGpr1 are not sugars but lactate and methionine. In C. glabrata, this pathway has not yet been investigated. Finally, the glucose repression pathway ensures repression of respiration and repression of the use of alternative carbon sources. This pathway is not well characterized in Candida species. It is important to note that, apart from glucose, other sugars and sugar-analogs, such as N-acetylglucosamine in the case of C. albicans, are also important carbon sources. In these fungal pathogens, sensing sugars is important for a number of virulence attributes, including adhesion, oxidative stress resistance, biofilm formation, morphogenesis, invasion, and antifungal drug tolerance. In this review, the sugar sensing and signaling mechanisms in these Candida species are compared to S. cerevisiae.

Invasive candidiasis and candidemia in pediatric and neonatal patients: A review of current guidelines

Several international and national guidelines have been proposed for the treatment and prevention of invasive candidiasis/candidemia (IC/C) in both neonatal and pediatric patients. This article is a review of the current guidelines, recommendations, and expert panel consensus of a number of associations and conferences on the prevention and management of IC and candidemia in both pediatric and neonatal patients. The investigated resources included the Infectious Diseases Society of America, the European Conference on Infection in Leukaemia, the European Society of Clinical Microbiology and Infectious Diseases, the German Speaking Mycological Society/Paul-Ehrlich Society for Chemotherapy, as well as the Canadian, Middle Eastern, and Australian guidelines. Echinocandins and liposomal amphotericin B (L-AmB) are the first-line agents in the treatment of IC and candidemia both for immunocompetent and immunocompromised pediatric patients. The recommendations suggested to keep patients under sterile conditions for at least 14 days after blood cultures as the prompt initiation of antifungal treatment. Guidelines addressing the neonates recommended to use L-AmB, deoxycholate AmB (D-AmB), and fluconazole based on three main principles of no previous exposure to azoles, the prompt initiation of antifungal treatment, and control of predisposing underlying conditions. Despite minor differences among the investigated guidelines, general treatment recommendations suggest the prompt initiation of antifungal treatment and control of all predisposing underlying conditions.

Echinocandin-Induced Microevolution of Candida parapsilosis Influences Virulence and Abiotic Stress Tolerance

Candida species are a major cause of life-threatening bloodstream infections worldwide. Although Candida albicans is responsible for the vast majority of infections, the clinical relevance of other Candida species has also emerged over the last twenty years. This shift might be due in part to changes in clinical guidelines, as echinocandins became the first line of therapeutics for the treatment. Candida parapsilosis is an emerging non-albicans Candida species that exhibits lower susceptibility levels to these drugs. Candida species frequently display resistance to echinocandins, and the mechanism for this is well-known in C. albicans and Candida glabrata, where it is mediated by amino acid substitutions at defined locations of the β-1,3-glucan synthase, Fks1p. In C. parapsilosis isolates, Fks1p harbors an intrinsic amino acid change at position 660 of the hot spot 1 (HS1) region, which is thought to be responsible for the high MIC values. Less is known about acquired substitutions in this species. In this study, we used directed evolution experiments to generate C. parapsilosis strains with acquired resistance to caspofungin, anidulafungin, and micafungin. We showed that cross-resistance was dependent on the type of echinocandin used to generate the evolved strains. During their characterization, all mutant strains showed attenuated virulence in vivo and also displayed alterations in the exposure of inner cell wall components. The evolved strains harbored 251 amino acid changes, including three in the HS1, HS2, and HS3 regions of Fks1p. Altogether, our results demonstrate a direct connection between acquired antifungal resistance and virulence of C. parapsilosisIMPORTANCECandida parapsilosis is an opportunistic fungal pathogen with the ability to cause infections in immunocompromised patients. Echinocandins are the currently recommended first line of treatment for all Candida species. Resistance of Candida albicans to this drug type is well characterized. C. parapsilosis strains have the lowest in vitro susceptibility to echinocandins; however, patients with such infections typically respond well to echinocandin therapy. There is little knowledge of acquired resistance in C. parapsilosis and its consequences on other characteristics such as virulence properties. In this study, we aimed to dissect how acquired echinocandin resistance influences the pathogenicity of C. parapsilosis and to develop explanations for why echinocandins are clinically effective in the setting of acquired resistance.

Clonal Spread of Candida glabrata Bloodstream Isolates and Fluconazole Resistance Affected by Prolonged Exposure: a 12-Year Single-Center Study in Belgium

Candida glabrata is a major cause of candidemia in immunocompromised patients and is characterized by a high-level of fluconazole resistance. In the present study, the acquisition of antifungal resistance and potential clonal spread of C. glabrata were explored at a single center over a 12-year period by analyzing 187 independent clinical C. glabrata bloodstream isolates. One strain was found to be micafungin resistant due to a mutation in the FKS2 gene. Fluconazole resistance remained stable throughout the period and was observed in 20 (10.7%) of the isolates. An analysis of the antifungal consumption data revealed that recent prior exposure to fluconazole increased the risk to be infected by a resistant strain. In particular, the duration of the treatment was significantly longer for patients infected by a resistant isolate, while the total and mean daily doses received did not impact the acquisition of resistance in C. glabrata No link between genotype and resistance was found. However, multilocus variable-number tandem-repeat analyses indicated a potential intrahospital spread of some isolates between patients. These isolates shared the same genetic profiles, and infected patients were hospitalized in the same unit during an overlapping period. Finally, quantitative real-time PCR analyses showed that, unlike that for other ABC efflux pumps, the expression of CgCDR1 was significantly greater in resistant strains, suggesting that it would be more involved in fluconazole (FLC) resistance. Our study provides additional evidence that the proper administration of fluconazole is required to limit resistance and that strict hand hygiene is necessary to avoid the possible spreading of C. glabrata isolates between patients.

Fluconazole impacts the extracellular matrix of fluconazole-susceptible and -resistant Candida albicans and Candida glabrata biofilms

Background: Fluconazole (FLZ) is a drug commonly used for the treatment of Candida infections. However, β-glucans in the extracellular matrices (ECMs) hinder FLZ penetration into Candida biofilms, while extracellular DNA (eDNA) contributes to the biofilm architecture and resistance. Methods: This study characterized biofilms of FLZ-sensitive (S) and -resistant (R) Candida albicans and Candida glabrata in the presence or absence of FLZ focusing on the ECM traits. Biofilms of C. albicans American Type Culture Collection (ATCC) 90028 (CaS), C. albicans ATCC 96901 (CaR), C. glabrata ATCC 2001 (CgS), and C. glabrata ATCC 200918 (CgR) were grown in RPMI medium with or without FLZ at 5× the minimum inhibitory concentration (37°C/48 h). Biofilms were assessed by colony-forming unit (CFU)/mL, biomass, and ECM components (alkali-soluble polysaccharides [ASP], water-soluble polysaccharides [WSP], eDNA, and proteins). Scanning electron microscopy (SEM) was also performed. Data were analyzed by parametric and nonparametric tests (α  =  0.05). Results: In biofilms, FLZ reduced the CFU/mL of all strains (p < 0.001), except for CaS (p = 0.937). However, the ASP quantity in CaS was significantly reduced by FLZ (p = 0.034), while the drug had no effect on the ASP levels in other strains (p > 0.05). Total biomasses and WSP were significantly reduced by FLZ in the ECM of all yeasts (p < 0.001), but levels of eDNA and proteins were unaffected (p > 0.05). FLZ affected the cell morphology and biofilm structure by hindering hyphae formation in CaS and CaR biofilms, by decreasing the number of cells in CgS and CgR biofilms, and by yielding sparsely spaced cell agglomerates on the substrate. Conclusion: FLZ impacts biofilms of C. albicans and C. glabrata as evident by reduced biomass. This reduced biomass coincided with lowered cell numbers and quantity of WSPs. Hyphal production by C. albicans was also reduced.