Candidemia in Internal Medicine: Facing the New Challenge

The Impact of Epidemiological Trends and Guideline Adherence on Candidemia-Associated Mortality: A 14-Year Study in Northeastern Italy

Invasive candidiasis represents a major global health concern, with incidence and mortality rates expected to rise due to medical advancements and unavoidable risk factors. This retrospective, multicentric study was conducted in eight hospitals in a northeastern Italian region, enrolling adult patients diagnosed with candidemia from 1 January 2018 to 31 December 2022. Epidemiological trends and clinical characteristics were analyzed and compared to those from a prior regional study (2009-2011), allowing a fourteen-year comparative evaluation. A shift in species distribution was observed, with a decline in Candida albicans (from 65.7% to 57.8%) and a rise in non-albicans species, particularly the Candida parapsilosis complex (from 16.1% to 18.2%). Guideline adherence was assessed applying the EQUAL Candida score; scores ≥ than 11.5 were independently associated with improved in-hospital survival (HR 3.51, p < 0.001). Among individual score components, empiric echinocandin therapy and central venous catheter removal correlated with better outcomes. Centers with routine infectious disease (ID) consultations showed higher survival and adherence, reinforcing the value of specialist involvement. These findings support local epidemiological and management practice surveillance program adoption to address context-specific gaps, promote the adoption of best practices in Candida BSI management-as expanded ID specialist consultations and education programs-and, ultimately, reduce candidemia-related mortality rates.

Epidemiology and outcomes of Candida spp. bloodstream infections in cancer patients: a comparative retrospective study from a German tertiary cancer center

BACKGROUND

Bloodstream infections (BSI) due to Candida spp. significantly contribute to morbidity and mortality among cancer patients. Understanding their clinical course, risk factors, and outcomes compared to bacterial BSI is essential.

AIM

We aim to elucidate the epidemiology and risk factors associated with Candida BSI compared to bacterial BSI in cancer patients.

METHODS

We analyzed epidemiological data of Candida BSI versus bacterial BSI among cancer patients, primarily with hematological malignancies. Blood cultures were obtained upon clinical suspicion, with species identification by VITEK 2 and MALDI-TOF. Susceptibility testing utilized VITEK 2 or antibiotic gradient tests.

RESULTS

Candida BSI was associated with higher 30-day mortality compared to bacterial BSI (Hazard ratio (HR) 4.5, 95% CI 2.5-8.1, p < 0.001) occurring predominantly in patients with relapsed/refractory disease. Univariate analysis identified risk factors for Candida BSI: hypoalbuminemia (Odds ratio (OR) 9.13, 95% CI 2.7-57, p = 0.003), prior ICU/MC stay (OR 3.91, 95% CI 1.38-9.65, p = 0.005), palliative treatment (OR 3.42, 95% CI 1.52-7.4, p = 0.002), parenteral nutrition (OR 2.44, 95% CI 0.9-5.5, p = 0.039) and prior allogeneic HSCT (OR 2.28, 95% CI 0.92-5.13, p = 0.056). Risk factors identified by multivariate analysis were palliative therapy (OR 5.23, 95% CI 3.14-8.71, p = 0.001), hypoalbuminemia (OR 9.02, 95% CI 4.23-19.2, p = 0.004), and prior ICU/IMC stay (OR 4, 95% CI 2.31-6.92, p = 0.011). In patients with confirmed Candida BSI, delayed initiation of antifungal was associated with worse outcomes.

CONCLUSION

Compared to bacterial BSI events, Candida BSI are associated with significantly higher 30-day mortality, primarily affecting heavily pretreated patients with relapsed or refractory disease.

Virulence and resistance factors of Nakaseomyces glabratus (formerly known as Candida glabrata) in Europe: A systematic review

BACKGROUND

Nakaseomyces glabratus (N. glabratus) formerly known as Candida glabrata (C. glabrata), is an endogenous opportunistic pathogen, which is generally located in the gastrointestinal tract but can spread in immunocompromised patients. N. glabratus is the second most common pathogen that causes candidemia in several countries. N. glabratus virulence factors may increase antifungal resistance and reduce the number of available treatment options. High resistance to azoles and increasing resistance to echinocandins have been previously reported in N. glabratus.

OBJECTIVE

To establish the distribution of N. glabratus isolates in Europe and its drug susceptibility/resistance in each country over the last 7 years.

METHODS

The search was performed across three databases: PubMed, Scopus and Scielo, using the MeSH terms: "Candida glabrata", "Nakaseomyces glabratus", "Europe", "resistance" and "Epidemiology" exclusively in English. All available information from January 2002 to December 2022 was included, excluding reviews, meta-analyses and book chapters.

RESULTS

Fifty-seven articles with information on antifungal susceptibility in Europe were retrieved and analysed with a total of 15,400 reported C. glabrata isolates. Remarkably, nations that presented the maximum number of cases during the study period included the United Kingdom (n = 7241, 47.02%), France (n = 3190, 20.71%), Spain (n = 900, 5.84%), Hungary (n = 745, 4.84%) and Italy (n = 486, 3.16%). C. glabrata isolates presented resistance to azoles [voriconazole (n = 2225, 14.45%), fluconazole (n = 1612, 10.47%), itraconazole (n = 337, 2.19%) and clotrimazole (n = 89, 0.58%)], increased resistance to echinocandins, especially to anidulafungin (n = 138, 0.89%), and high sensitivity to amphotericin B.

CONCLUSIONS

The number of candidemia cases associated with triazole-resistant N. glabratus isolates have been increasing in Europe. Therefore, echinocandins and amphotericin B can be considered optional empirical treatments; however, antifungal susceptibility testing is required to determine the best therapeutic options.

Prevalence, Species Distribution and Resistance of Candidemia in Pediatric and Adult Patients in a Northeast Italy University Hospital

Candidemia and invasive candidiasis (IC) are causes of morbidity and mortality in healthcare settings, with notable differences between children and adults. Understanding the species distribution and antimicrobial susceptibility profiles of clinical isolates can guide empiric therapy in patients at risk of IC. This study investigated the incidence and antifungal susceptibility patterns of yeasts involved in IC in pediatric and adult patients from 2019 to 2023. The average incidence of IC was 0.715 per 1000 patients, increasing over the study period; infants had the highest incidence rates. Over half of the IC episodes occurred in intensive care units (ICUs). Non-albicans Candida (NAC) species represented the most frequently isolated species in adults and children (55.96% and 50.0%, respectively), with the prevalence of C. parapsilosis (26.45% and 14.7%, respectively), N. glabratus (14.97% and 8.82%, respectively) and C. tropicalis (4.36% and 2.94%, respectively). C. lusitaniae was identified in 14.7% of pediatric IC cases. In NAC species, antifungal resistance has also increased over the five years of the study: 69.12% were resistant to azoles and 7.35% were resistant to micafungin. Resistance was higher in pediatric patients. Our study highlights differences in IC characteristics between pediatric and adult populations and emphasizes the importance of targeted antifungal stewardship in ICU patients with NAC invasive infections.

Analysis of clinical Candida parapsilosis isolates reveals copy number variation in key fluconazole resistance genes

We used whole-genome sequencing to analyze a collection of 35 fluconazole-resistant and 7 susceptible Candida parapsilosis isolates together with coverage analysis and GWAS techniques to identify new mechanisms of fluconazole resistance. Phylogenetic analysis shows that although the collection is diverse, two persistent clinical lineages were identified. We identified copy number variation (CNV) of two genes, ERG11 and CDR1B, in resistant isolates. Two strains have a CNV at the ERG11 locus; the entire ORF is amplified in one, and only the promoter region is amplified in the other. We show that the annotated telomeric gene CDR1B is actually an artifactual in silico fusion of two highly similar neighboring CDR genes due to an assembly error in the C. parapsilosis CDC317 reference genome. We report highly variable copy numbers of the CDR1B region across the collection. Several strains have increased the expansion of the two genes into a tandem array of new chimeric genes. Other strains have experienced a deletion between the two genes creating a single gene with a reciprocal chimerism. We find translocations, duplications, and gene conversion across the CDR gene family in the C. parapsilosis species complex, showing that it is a highly dynamic family.

Understanding clinical outcomes and factors influencing mortality in intensive care unit patients with COVID-19-associated candidemia

BACKGROUND

During the COVID pandemic, research has shown an increase in candidemia cases following severe COVID infection and the identification of risk factors associated with candidemia. However, there is a lack of studies that specifically explore clinical outcomes and mortality rates related to candidemia after COVID infection.

OBJECTIVES

The aim of this international study was to evaluate the clinical outcomes and identify factors influencing mortality in patients who developed candidemia during their COVID infection.

PATIENTS/METHODS

This study included adult patients (18 years of age or older) admitted to the intensive care unit (ICU) and diagnosed with COVID-associated candidemia (CAC). The research was conducted through ID-IRI network and in collaboration with 34 medical centres across 18 countries retrospectively, spanning from the beginning of the COVID pandemic until December 2021.

RESULTS

A total of 293 patients diagnosed with CAC were included. The median age of the patients was 67, and 63% of them were male. The most common Candida species detected was C. albicans. The crude 30-day mortality rate was recorded at 62.4%. The logistic regression analysis identified several factors significantly impacting mortality, including age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.07, p < .0005), SOFA score (OR 1.307, 95% CI 1.17-1.45, p < .0005), invasive mechanical ventilation (OR 7.95, 95% CI 1.44-43.83, p < .017) and duration of mechanical ventilation (OR 0.98, 95% CI 0.96-0.99, p < .020).

CONCLUSIONS

By recognising these prognostic factors, medical professionals can customise their treatment approaches to offer more targeted care, leading to improved patient outcomes and higher survival rates for individuals with COVID-associated candidemia.

Candida parapsilosis complex in the clinical setting

Representatives of the Candida parapsilosis complex are important yeast species causing human infections, including candidaemia as one of the leading diseases. This complex comprises C. parapsilosis, Candida orthopsilosis and Candida metapsilosis, and causes a wide range of clinical presentations from colonization to superficial and disseminated infections with a high prevalence in preterm-born infants and the potential to cause outbreaks in hospital settings. Compared with other Candida species, the C. parapsilosis complex shows high minimal inhibitory concentrations for echinocandin drugs due to a naturally occurring FKS1 polymorphism. The emergence of clonal outbreaks of strains with resistance to commonly used antifungals, such as fluconazole, is causing concern. In this Review, we present the latest medical data covering epidemiology, diagnosis, resistance and current treatment approaches for the C. parapsilosis complex. We describe its main clinical manifestations in adults and children and highlight new treatment options. We compare the three sister species, examining key elements of microbiology and clinical characteristics, including the population at risk, disease manifestation and colonization status. Finally, we provide a comprehensive resource for clinicians and researchers focusing on Candida species infections and the C. parapsilosis complex, aiming to bridge the emerging translational knowledge and future therapeutic challenges associated with this human pathogen.

Analysis of clinical Candida parapsilosis isolates reveals copy number variation in key fluconazole resistance genes

We used whole-genome sequencing to analyse a collection of 35 fluconazole resistant and 7 susceptible Candida parapsilosis isolates together with coverage analysis and GWAS techniques to identify new mechanisms of fluconazole resistance. Phylogenetic analysis shows that although the collection is diverse, two probable outbreak groups were identified. We identified copy number variation of two genes, ERG11 and CDR1B, in resistant isolates. Two strains have a CNV at the ERG11 locus; the entire ORF is amplified in one, and only the promoter region is amplified in the other. We show the annotated telomeric gene CDR1B is actually an artefactual in silico fusion of two highly similar neighbouring CDR genes due to an assembly error in the C. parapsilosis CDC317 reference genome. We report highly variable copy numbers of the CDR1B region across the collection. Several strains have increased expansion of the two genes into a tandem array of new chimeric genes. Other strains have experienced a deletion between the two genes creating a single gene with a reciprocal chimerism. We find translocations, duplications, and gene conversion across the CDR gene family in the C. parapsilosis species complex, showing that it is a highly dynamic family.

Molecular diagnosis, phylogenetic analysis, and antifungal susceptibility profiles of Candida species isolated from neutropenic oncological patients

BACKGROUND

Neutropenia is the most important cause of life-threatening invasive fungal infections (IFIs). Here, we studied the frequency and antifungal susceptibility profiles of Candida species that colonized or caused infections among neutropenic patients with solid or hematological malignancies.

METHODS

A total of 362 clinical samples were collected from 138 patients. After initial isolation using a mix of mycological methods, isolates were screened using chromogenic culture media. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied for molecular identification. Positive or suspected cases were confirmed using the reference method of sequencing. Antifungal susceptibility testing for voriconazole and caspofungin was carried out using the microbroth dilution method. An in-silico assay was applied for phylogenetic analysis.

RESULTS

Thirty-four Candida strains were isolated. C. albicans (47.06%) and C. glabrata (29.41%) were the most frequent strains. Antifungal treatment reduced the chance of Candida colonization by almost 76% in neutropenic patients (OR: 1.759; 95% CI: 1.349 to 2.390; p value: 0.000). An unusual and non-resistant strain, C. lambica, was reported from the bloodstream of a 56-year-old man with hematologic malignancy (HM). Eight isolates were non-susceptible, and one isolate was resistant to voriconazole. Also, four isolates were non-susceptible to caspofungin.

CONCLUSION

We can conclude that there is a cause-and-effect relationship between neutropenia, HM background, and Candida species separated from neutropenic patients, which can lead to possible infections. Further and repetitive studies are recommended using different molecular methods for better prediction and management of fungal infections in neutropenic patients.

Autophagy and LC3-associated phagocytosis contribute negatively to the killing capability of THP-1-derived macrophages against Candida albicans at the mid-stage

In innate immunity, macrophages play critical roles in defending against pathogens via the lysosomal degradation function of autophagy. Two distinct autophagy pathways have been identified in decades: canonical autophagy (referred to as autophagy) and LC3-associated phagocytosis (LAP). Since several conflicting findings about the anti-Candida capability of autophagy (or LAP) have been reported, they serve as the foe or friend for Candida survival is still unclearly. The current study showed that the fungicidal process of THP-1-derived macrophages (THP-1-MФ) against Candida albicans is divided into three stages as follows, the early stage (the first 12 h, increasing in the killing capability), the mid-stage (12-24 h, no change in killing capability), and the late stage (24-48 h, decreasing of the killing capability). Autophagic protein LC3B-II reached the peak in THP-1-MФ after 24 h inoculated either with C.albicans or whole glucan particles (WGP). Thus, both anti-Candida roles of autophagy and the LAP pathway have been detected at the mid-stage. For autophagy, after 24 h inoculation with C.albicans, ULK1 increased, but p-ATG13(s318) decreased obviously in THP-1-MФ, and the killing assay showed that autophagy is unhelpful for Candida killing capability. For the LAP pathway, Rubicon and ROS raised significantly in THP-1-MФ after 24 h inoculated with C.albicans; each inhibition would sharply cut down the LC3B-II accumulation, which indicated that LAP had been induced. However, mCherry-GFP-LC3 fluorescent assay exhibited that LAP phago-lysosomal fusion has been blocked, and Rubicon knockdown facilitated the Candida killing activity. These data indicated that autophagy presented as redundant to Candida defense, and LAP phago-lysosomal fusion obstruction impairs the Candida killing capability of THP-1-MФ at the mid-stage. That may explain the no change in Candida killing capability at the mid-stage.

Prognostic Trends and Current Challenges in Candidemia: A Comparative Analysis of Two Multicenter Cohorts within the Past Decade

Candidemia remains a major public health challenge due to its high mortality rates, especially in developing countries. Monitoring epidemiological trends may provide insights for better clinical outcomes. This study aimed to describe trends in the epidemiology, therapeutic practices, and mortality in candidemia through a retrospective comparative analysis between two surveillance cohorts of all candidemic adults at eleven tertiary hospitals in Brazil, from 2010-2011 (Period I) versus 2017-2018 (Period II). A total of 616 cases were diagnosed, with 247 being from Period II. These patients were more likely to have three or more coexisting comorbidities [72 (29.1%) vs. 60 (16.3%), p < 0.001], had a prior history of in-hospital admissions more often [102 (40.3%) vs. 79 (21.4%), p = 0.001], and presented with candidemia earlier after admission, within 15 days (0-328) vs. 19 (0-188), p = 0.01. Echinocandins were more frequently prescribed [102 (41.3%) vs. 50 (13.6%), p = 0.001], but time to antifungal initiation [2 days (0-14) vs. 2 (0-13), p = 0.369] and CVC removal within 48 h [90/185 (48.6%) vs. 148/319 (46.4%), p = 0.644] remained unchanged. Additionally, many patients went untreated in both periods I and II [87 (23.6%) vs. 43 (17.4%), p = 0.07], respectively. Unfortunately, no improvements in mortality rates at 14 days [123 (33.6%) vs. 93 (37.7%), p = 0.343] or at 30 days [188 (51.4%) vs. 120 (48.6%), p = 0.511] were observed. In conclusion, mortality rates remain exceedingly high despite therapeutic advances, probably associated with an increase in patients' complexity and suboptimal therapeutic interventions. Management strategies should be tailored to suit epidemiological changes, expedite diagnosis to reduce the number of untreated eligible patients and guarantee early antifungal initiation and source control.

Multicentre Surveillance of Candida Species from Blood Cultures during the SARS-CoV-2 Pandemic in Southern Europe (CANCoVEU Project)

Introduction: Surveillance of Candida species isolates from blood cultures (BCs) in Europe is considered fragmented, unable to allow the definition of targets of antifungal stewardship recommendations especially during the SARS-CoV-2 pandemic. Methods: We performed a multicentric retrospective study including all consecutive BC Candida isolates from six Southern European tertiary hospitals (1st January 2020 to 31st December 2021). Etiology, antifungal susceptibility patterns, and clinical setting were analyzed and compared. Results: C. albicans was the dominant species (45.1%), while C. auris was undetected. Candida species positive BC events increased significantly in COVID-19 ICUs in 2021 but decreased in other ICUs. Resistance to azole increased significantly and remained very high in C. albicans (fluconazole from 0.7% to 4.5%, p = 0.03) and C. parapsilosis complex (fluconazole up to 24.5% and voriconazole up to 8.9%), respectively. Resistance to caspofungin was remarkable in C. tropicalis (10%) and C. krusei (20%), while resistance to at least one echinocandin increased in 2021, especially in C. parapsilosis complex (from 0.8% to 5.1%, p = 0.05). Although no significant differences were observed over the study period, fluconazole and echinocandin resistance increased in COVID-19 ICUs by up to 14% and 5.8%, respectively, but remained undetected in non-intensive COVID-19 wards. Conclusions: Antifungal stewardship activities aimed at monitoring resistance to echinocandin in C. tropicalis and C. krusei, and against the spread of fluconazole resistant C. parapsilosis complex isolates are highly desirable. In COVID-19 patients, antifungal resistance was mostly present when the illness had a critical course.

Candidiasis and Other Emerging Yeasts

Purpose of Review

The review presents a comprehensive and updated information on the contemporary status of invasive candidiasis (IC), other emerging yeast infections, and the challenges they present in terms of at-risk population, specific virulence attributes, and antifungal susceptibility profile.

Recent Findings

With the advancement in medical field, there has been parallel expansion of vulnerable populations over the past two decades. This had led to the emergence of a variety of rare yeasts in healthcare settings, both Candida and non-Candida yeast causing sporadic cases and outbreaks. The advancements in diagnostic modalities have enabled accurate identification of rare Candida species and non-Candida yeast (NCY) of clinical importance. Their distribution and susceptibility profile vary across different geographical regions, thus necessitating surveillance of local epidemiology of these infections to improve patient outcomes.

Summary

The challenges in management of IC have been complicated with emergence of newer species and resistance traits. C. tropicalis has already overtaken C. albicans in many Asian ICUs, while C. auris is rising rapidly worldwide. Recent genomic research has reclassified several yeasts into newer genera, and an updated version of MALDI-TOF MS or ITS sequencing is necessary for accurate identification. Having a knowledge of the differences in predisposing factors, epidemiology and susceptibility profile of already established pathogenic yeasts, as well as new emerging yeasts, are imperative for better patient management.

Antifungal Combinations against Candida Species: From Bench to Bedside

Candida spp. is the major causative agent of fungal infections in hospitalized patients and the fourth most common cause of nosocomial bloodstream infection (BSI). The availability of standardized methods for testing the in vitro activity of antifungals along with the expanding of antifungal armamentarium, the rising of drug-resistance and the persistence of a high mortality rate in systemic candidiasis have led to an increased interest in combination therapy. Therefore, we aimed to review the scientific literature concerning the antifungal combinations against Candida. A literature search performed in PubMed yielded 92 studies published from 2000 to 2021: 29 articles referring to in vitro studies, six articles referring to either in vitro and in vivo (i.e., animal models) studies and 57 clinical articles. Pre-clinical studies involved 735 isolates of Candida species and 12 unique types of antifungal combination approaches including azoles plus echinocandins (19%), polyenes plus echinocandins (16%), polyenes plus azoles (13%), polyenes plus 5-flucytosine ([5-FC], 13%), azoles plus 5-FC (11%) and other types of combinations (28%). Results varied greatly, often being species-, drug- and methodology-dependent. Some combinatorial regimens exerted a synergistic effect against difficult-to-treat Candida species (i.e., azoles plus echinocandins; polyenes plus 5-FC) or they were more effective than monotherapy in prevent or reducing biofilm formation and in speeding the clearance of infected tissues (i.e., polyenes plus echinocandins). In 283 patients with documented Candida infections (>90% systemic candidiasis/BSI), an antifungal combination approach could be evaluated. Combinations included: azoles plus echinocandins (36%), 5-FC-combination therapies (24%), polyenes plus azoles (18%), polyenes plus echinocandins (16%) and other types of combination therapy (6%). Case reports describing combination therapies yielded favorable response in most cases, including difficult-to-treat fungal infections (i.e., endocarditis, osteoarticular infections, CNS infections) or difficult-to-treat fungal pathogens. The only randomized trial comparing amphotericin-B deoxycholate (AMB) plus FLU vs. AMB alone for treatment of BSI in nonneutropenic patients showed that the combination trended toward improved success and more-rapid clearance from the bloodstream. In summary, antifungal combinations against Candida have produced great interest in the past two decades. To establish whether this approach can become a reliable treatment option, additional in vitro and clinical data are warranted.

The Diagnostic Relevance of β-D-Glucan for Candidemia within Internal Medicine Wards

Candidemia diagnosis is based on the combination of clinical, microbiological and laboratory data. We aimed to evaluate performances and accuracy of (1,3)-β-D-glucan (BDG) at various cut-offs in internal medicine patients. An observational retrospective−prospective study was performed. Patients with at least two determinations of BDG and paired, associated blood cultures within ±48 h were considered. A total of 140 patients were included: 26 with Candida spp. blood-stream infections (BSI) and 114 without candidemia. Patients with candidemia were older and had higher BDG values, need of parenteral nutrition, higher colonization by Candida in more than one site, presence of percutaneous gastrostomy and higher Candida or Charlson scores. BDG maintained the best compromise between sensitivity, specificity and optimal negative predictive value was 150 pg/mL. BDG values at cut-off of 150 pg/mL increase the strength of association between BDG and development of candidemia (Odds Ratio—OR 5.58; CI 2.48−12.53 vs. OR 1.06; CI 1.003−1.008). Analyzing BDG > 150 pg/mL along with Candida score > 2 and Charlson score > 4, the strength of the association amongst BDG, clinical scores and development of candidemia is increased. The overall clinical evaluation with the help of scores that consider BDG values > 150 pg/mL, Candida score > 2 and Charlson score > 4 in combination seems to predict better the need of antifungal empiric treatment.