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.

Candidemia in thoracic solid organ transplant recipients: Characteristics and outcomes relative to matched uninfected and bacteremic thoracic organ transplant recipients

BACKGROUND

Little is understood about the risk factors and outcomes from candidemia in thoracic solid organ transplant recipients.

METHODS

This is a single-center retrospective cohort study of patients undergoing heart or lung transplant between January 1, 2013 and December 31, 2022. We performed two comparisons among heart and lung transplant recipients: (1) recipients with candidemia versus matched, uninfected recipients, and (2) recipients with candidemia versus recipients with bacteremia.

RESULTS

During the study 384 heart and 194 lung transplants were performed. Twenty-one (5.5%) heart and six (3.1%) lung recipients developed candidemia. Heart recipients with candidemia were more likely to have had delayed chest closure (38.1% vs. 0%, p < .0001), temporary mechanical circulatory support (57.1% vs. 11.9%, p = .0003), and repeat surgical chest exploration 76.2% vs. 16.7%, p < .0001) than uninfected controls. Heart and lung recipients who developed candidemia were more likely to have been on renal replacement therapy prior to infection relative to uninfected controls (57.1% vs. 11.9%, p = .0003 and 66.7% vs. 0%, p = .0041, respectively). Heart recipients with candidemia had significantly lower post-transplant survival and lower post-infection survival relative to matched uninfected controls and heart recipients with bacteremia, respectively (p < .0001 and p = .0002, respectively).

CONCLUSIONS

Candidemia following heart and lung transplantation is associated with significant morbidity and mortality. Further research is needed to understand if heart recipients with delayed chest closure, temporary mechanical circulatory support, renal replacement therapy, and repeat surgical chest exploration may benefit from targeted antifungal prophylaxis.

The host transcriptional response to Candidemia is dominated by neutrophil activation and heme biosynthesis and supports novel diagnostic approaches

BACKGROUND

Candidemia is one of the most common nosocomial bloodstream infections in the United States, causing significant morbidity and mortality in hospitalized patients, but the breadth of the host response to Candida infections in human patients remains poorly defined.

METHODS

In order to better define the host response to Candida infection at the transcriptional level, we performed RNA sequencing on serial peripheral blood samples from 48 hospitalized patients with blood cultures positive for Candida species and compared them to patients with other acute viral, bacterial, and non-infectious illnesses. Regularized multinomial regression was utilized to develop pathogen class-specific gene expression classifiers.

RESULTS

Candidemia triggers a unique, robust, and conserved transcriptomic response in human hosts with 1641 genes differentially upregulated compared to healthy controls. Many of these genes corresponded to components of the immune response to fungal infection, heavily weighted toward neutrophil activation, heme biosynthesis, and T cell signaling. We developed pathogen class-specific classifiers from these unique signals capable of identifying and differentiating candidemia, viral, or bacterial infection across a variety of hosts with a high degree of accuracy (auROC 0.98 for candidemia, 0.99 for viral and bacterial infection). This classifier was validated on two separate human cohorts (auROC 0.88 for viral infection and 0.87 for bacterial infection in one cohort; auROC 0.97 in another cohort) and an in vitro model (auROC 0.94 for fungal infection, 0.96 for bacterial, and 0.90 for viral infection).

CONCLUSIONS

Transcriptional analysis of circulating leukocytes in patients with acute Candida infections defines novel aspects of the breadth of the human immune response during candidemia and suggests promising diagnostic approaches for simultaneously differentiating multiple types of clinical illnesses in at-risk, acutely ill patients.

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.

Reemergence of Intravenous Drug Use as Risk Factor for Candidemia, Massachusetts, USA

The epidemic of illicit intravenous drug use (IVDU) in the United States has been accompanied by a surge in drug overdose deaths and infectious sequelae. Candida albicans infections were associated with injection of contaminated impure brown heroin in the 1970s-1990s; however, candidiasis accompanying IVDU became considerably rarer as the purity of the heroin supply increased. We reviewed cases of candidemia occurring over a recent 7-year period in persons >14 years of age at a tertiary care hospital in central Massachusetts. Of the 198 patients with candidemia, 24 cases occurred in patients with a history of IVDU. Compared with non-IVDU patients, those with a history of IVDU were more likely to have non-albicans Candida, be co-infected with hepatitis C, and have end-organ involvement, including endocarditis and osteomyelitis. Thus, IVDU appears to be reemerging as a risk factor for invasive candidiasis.

[Clinical analysis of candidemia in immunocompetent patients]

OBJECTIVE

To investigate the etiological and clinical characteristics of immunocompetent patients with candidemia.

METHODS

The clinical and microbiological data of patients diagnosed as candidemia admitted in Peking University Third Hospital from January 2010 to June 2016 were retrospectively analyzed. Underlying diseases, Candida spp. colonization, clinical manifestations, microbiological data, treatment and the outcome were compared between the HIV-negative immunocompromised (IC) and nonimmunocompromised (NIC) patients.

RESULTS

A total of 62 cases diagnosed as candidemia were analyzed including 36 men and 26 women, with 16 to 100 years of age [(66.02±17.65) years]. There were 30 NIC and 32 HIV-negative IC patients respectively. In the NIC patients, there were 19 cases (19/30, 63.33%) with admission in intensive care unit (ICU), 21 (21/30, 70.00%) associated diabetes mellitus or uncontrolled hyperglycemia and 22 (22/30,73.33%) receiving invasive mechanical ventilation, while in the HIV-negative IC patients, there were 8 (8/32, 25.00%), 13 (13/32, 40.63%) and 7 (7/32, 21.88%) respectively (P<0.05). The NIC patients had higher acute physiology and chronic health evaluation (APACHE II) scores and sequential organ failure assessment (SOFA) scores both at admission (19.98±5.81, 6.04±6.14) and candidemia onset (25.61±6.52, 12.75±8.42) than the HIV-negative IC patients (APACHEII 15.09±5.82, 22.15±5.98) and SOFA 2.87±2.73, 7.66±5.64 respectively (P<0.05). In the NIC patients, twenty-one cases (21/30, 70.00%) died in hospital, while 14 cases (14/32, 43.75%) in HIV-negative IC. The crude mortality was significantly different between the two groups (P<0.05). By blood culture, Canidia albicans remained the the most prevalent isolates in all the patients. Clinical manifestation, Candida spp. colonization, etiology and drug susceptibility were also similar between NIC and HIV-negative IC patients (P>0.05).

CONCLUSION

Candidemia in NIC patients tends to occur in those who are much more critically ill, more often admitted in ICU, and more frequently have diabetes mellitus or uncontrolled hyperglycemia and receive invasive mechanical ventilation than HIV-negative IC patients. NIC patients also have poorer prognosis than HIV-negative IC patients. Clinical manifestations, and microbiological characteristics are similar between HIV-negative IC and NIC patients.

Candidemia in the patient with malignancy

Invasive fungal infections are a common life-threatening disease and a major cause of morbidity, particularly in patients with malignancies, and Candida spp. is the most common isolated fungi in bloodstream. Candidemia is the focus of this review, which covers an approach to diagnosis and treatment, with an emphasis on patients with malignancies. Acute leukemia, lymphoma, or myelodysplastic syndrome are the most common hematological malignancies associated with candidemia, while among solid tumors, gastrointestinal cancer has the majority of fungemia cases. Epidemiologic trends show there is a discrepancy between malignancies, where there is an important prevalence of non-albicans Candida in hematological malignancy patients. Diagnosis is challenging, and a high index of suspicion is required to select at-risk patients for early empiric therapy with the goal of reducing mortality. There is an increased effort to improve understanding of individualized approaches to the patient based on precision medicine and to improve diagnosis in the future. The basis of treatment is prompt therapy with echinocandins and target therapy based on susceptibility and minimum inhibitory concentrations (MICs).

Diabetes, malignancy and age as predictors of Candida glabrata bloodstream infection: A re-evaluation of the risk factors

OBJECTIVE

Echinocandins and azoles are widely used in the treatment of candidaemia. Guidelines of the Infectious Diseases Society of America recommend commencing treatment with an echinocandin in candidaemic patients with risk factors for Candida glabrata i.e. patients who are elderly, or who have diabetes or malignancy, or those with recent prescription of azoles. We attempted to validate whether age, diabetes and malignancy are associated with C. glabrata candidaemia.

PATIENTS, MATERIALS AND METHODS

Information in relation to demographics, patient associated risk factors, and laboratory parameters were collected from the casenotes and the laboratory information system. We then analysed the distribution of the risk factors (age, diabetes, and malignancy) in candidaemic patients with C. glabrata and patients with species other than C. glabrata (excluding Candida krusei).

RESULTS

Over a 42-month period (April 2011-September 2017), 124 patients had candidaemia. We analysed data for 119 patients of whom 33 (27.7%) had C. glabrata and the remaining 86 (72.2%) were infected with other species. Sixty-five patients were elderly (age≥65), 40 had some form of malignancy, 34 had diabetes, and 4 patients were prescribed azoles in the 30 days prior to candidaemia (many patients had multiple risk factors). Comparing patients with C. glabrata to patients infected with other species, we found no association with diabetes (39.3% vs. 24.4%, P=0.1), malignancy (36.3 vs. 32.5%, P=0.69), and age (54.5% vs. 54.6%, P=0.99).

CONCLUSIONS

Diabetes, malignancy and age are not reliable predictors of candidaemia due to C. glabrata.

Comparison of E,E-Farnesol Secretion and the Clinical Characteristics of Candida albicans Bloodstream Isolates from Different Multilocus Sequence Typing Clades

Using multilocus sequence typing (MLST), Candida albicans can be subdivided into 18 different clades. Farnesol, a quorum-sensing molecule secreted by C. albicans, is thought to play an important role in the development of C. albicans biofilms and is also a virulence factor. This study evaluated whether C. albicans bloodstream infection (BSI) strains belonging to different MLST clades secrete different levels of E,E-farnesol (FOH) and whether they have different clinical characteristics. In total, 149 C. albicans BSI isolates from ten Korean hospitals belonging to clades 18 (n = 28), 4 (n = 23), 1 (n = 22), 12 (n = 17), and other clades (n = 59) were assessed. For each isolate, the FOH level in 24-hour biofilms was determined in filtered (0.45 μm) culture supernatant using high-performance liquid chromatography. Marked differences in FOH secretion from biofilms (0.10–6.99 μM) were observed among the 149 BSI isolates. Clade 18 isolates secreted significantly more FOH than did non-clade 18 isolates (mean ± SEM; 2.66 ± 0.22 vs. 1.69 ± 0.10 μM; P < 0.001). Patients with isolates belonging to clade 18 had a lower mean severity of illness than other patients, as measured using the “acute physiology and chronic health evaluation” (APACHE) III score (14.4 ± 1.1 vs. 18.0 ± 0.7; P < 0.05). This study provides evidence that C. albicans BSI isolates belonging to the most prevalent MLST clade (clade 18) in Korea are characterized by increased levels of FOH secretion and less severe illness.

Utility of in-house fluconazole disk diffusion susceptibility testing in the treatment of candidemia

Among 302 first candidemia episodes, 210 (69.6%) were initially treated with an echinocandin or polyene (E/P) antifungal drug. In 137 (72.5%) patients with fluconazole-susceptible isolates, treatment was changed to fluconazole based on disk diffusion susceptibility testing. Clinical outcomes were not compromised in patients receiving E/P who were de-escalated to fluconazole for treatment of candidemia based on disk diffusion results.

Candidemia from an upper urinary tract infection complicated by candida endophthalmitis

A 51-year-old Japanese woman developed candidemia as an outpatient secondary to a Candida albicans upper urinary tract infection complicated by previously undiagnosed type 2 diabetes mellitus with poor glycemic control and ureterolithiasis. The patient did not have any risk factors typically associated with candidemia, such as an indwelling vascular catheter, parenteral nutrition or broad-spectrum antibiotic use. During the clinical course, her condition was complicated by unilateral candida endophthalmitis, which progressed despite the administration of systemic antifungal agents and ultimately required vitreous surgery. The etiology of candidemia in this patient and the reason she developed progressive ocular symptoms after starting antifungal treatment are reviewed.

Causative agents of nosocomial bloodstream infections and their antimicrobial susceptibility patterns

The aim of this study was to retrospectively investigate nosocomial bloodstream infections (NBI) and their antimicrobial susceptibility patterns at Afyon Kocatepe University (AKU) Hospital, Turkey, from January 2006 to December 2011 and to determine the risk factors for nosocomial BSI. Subjects were aged > or = 18 years. The data were obtained from patient files. Five hundred seventy-nine nosocomial infections in 461 patients were included in the study. Eighty-four point six percent was primary and 15.4% were secondary infections. Gram-positive cocci were the most common organisms. When compared year by year there was an increasing trend in antibacterial resistant gram-negative bacilli. The most common infection risk factors were H2 histamine receptor blocker use and blood transfusions. Regular surveillance of BSI is important to monitor changes in the types of microorganisms and their resistance patterns.

Successful treatment of recurrent candidemia due to candidal thrombophlebitis associated with a central venous catheter using a combination of fosfluconazole and micafungin

We herein report the case of an 85-year-old woman presenting with right internal jugular vein candidal thrombophlebitis associated with central venous catheters (CTCVC). The infecting agent was Candida albicans, which caused recurrent candidemia five times in total. Micafungin (MCFG) alone was ineffective; however, the combination of MCFG with fosfluconazole (F-FLCZ) successfully treated the patient without a need for any anticoagulant or surgical therapies. To the extent of our knowledge, this is the first report of CTCVC being successfully treated with a combination of F-FLCZ and MCFG. These new antifungal agents have better efficacy, tolerability and bioavailability; therefore, they can be useful alternatives to classical combination therapies such as amphotericin-B and 5-fluorocytosine.

[Evaluation of epidemiological characteristics and risk factors of candidemia in adult patients in a tertiary-care hospital]

Candida species which are currently the fourth most common cause of nosocomial bloodstream infections, are associated with a significant morbidity and mortality. The aim of this retrospective case-control study which included adult patients was to determine the epidemiology of candidemia and to evaluate risk factors for the development of candidemia and mortality at a tertiary-care education hospital over a 1-year period. A total of 38 candidemia cases (23 were male; age range: 17-82 yrs; mean age: 61.4 ± 13.5 years) were identified among 22.507 patients hospitalized during the study period (January 1-December 31, 2008) and the overall incidence was found as 16.8 per 10.000 hospital admissions. Control group (n= 36; 22 were male; mean age: 60.9 ± 16.3 years) was selected among patients who had no signs and symptoms of candidemia and had negative blood cultures during the study period. Thirty-six (95%) patients with candidemia were identified as nosocomial infection. The most frequently isolated species were C.albicans (55.2%) and C.parapsilosis (28.9%) and the primarily identified origin of infection was central venous catheter use (39%). Candida spp. İsolation was most frequent in patients hospitalized in intensive care units (13/38; 34.2%), followed by surgery (n= 8; 21%) and chest diseases (n= 5; 13). Univariate analysis revealed that presence of a central venous catheter [odds ratio (OR): 4.33; 95% confidence interval (CI): 1.63-11.47, p= 0.003] and the length of hospitalization (OR: 0.97; CI: 0.94-1.00, p= 0.01) were the most frequently associated factors with an increased risk of candidemia compared to controls. However, multivariate analysis exhibited presence of a central venous catheter (OR: 2.90; CI: 1.04 8.11, p= 0.04) as the only independent risk factor for the development of candidemia. Therapy was initiated with intravenous fluconazole (mean duration of therapy 13.2 ± 6.25 days) and in three patients following fluconazol use step-up therapy was initiated. Total mortality rate was 58% (22/38) in our case series. Risk factors for mortality due to candidemia in the univariate analysis were detected as no response to antifungal treatment (OR: 0.23; CI: 0.11-0.51, p< 0.001), underlying disease other than trauma (OR: 0.06; CI: 0.003-1.24, p= 0.02), and high Charlson index (OR: 0.60; CI: 0.38-0.93, p= 0.03), however those factors were not found significant by multivariate analysis. There was also a statistically significant correlation between Charlson index and treatment response (mean Charlson index was 3.5 ± 1.9 in therapy-responded patients and 4.8 ± 1.8 in non-responders; p= 0.03). Since the risk of developing candidemia was significantly higher in severely diseased patients using central venous catheter or with prolonged hospitalization, response to antifungal therapy may be insufficient, leading to higher mortality.

Candida albicans heme oxygenase and its product CO contribute to pathogenesis of candidemia and alter systemic chemokine and cytokine expression

Mammalian heme oxygenases play important roles in immune regulation by producing immunosuppressive CO. The pathogenic yeast Candida albicans encodes a heme oxygenase, Hmx1, that is specifically induced by the host protein hemoglobin, suggesting a role in the pathogenesis of disseminated bloodstream infections. We show that exposing mice to therapeutic levels of CO increases C. albicans virulence, whereas an HMX1 null strain has decreased virulence in murine disseminated candidiasis. Levels of several regulatory cytokines and chemokines are decreased in mice infected with the null strain, and initial lesions in the kidney are more rapidly cleared after polymorphonuclear leukocyte infiltration. Reconstitution of one or both alleles restores virulence to the level of wild type. Growth in vitro and initial organ burdens in infected mice are not decreased and host iron overload does not restore virulence for the null strain, suggesting that early growth in the host is not limited by Hmx1-mediated iron scavenging. In contrast, inhaled CO partially reverses the virulence defect of the null strain and restores several host cytokine responses to wild-type levels. Collectively, these results show that C. albicans Hmx1 expression and CO production limit the host immune response and contribute to the pathogenesis of candidemia.