Candida Associated Bloodstream Infections in Pediatric Hematology Patients: A Single Center Experience

Biofilm formation and increased mortality among cancer patients with candidemia in a Peruvian reference center

BACKGROUND

Candidemia is an invasive mycosis with an increasing global incidence and high mortality rates in cancer patients. The production of biofilms by some strains of Candida constitutes a mechanism that limits the action of antifungal agents; however, there is limited and conflicting evidence about its role in the risk of death. This study aimed to determine whether biofilm formation is associated with mortality in cancer patients with candidemia.

METHODS

This retrospective cohort study included patients treated at Peru's oncologic reference center between June 2015 and October 2017. Data were collected by monitoring patients for 30 days from the diagnosis of candidemia until the date of death or hospital discharge. Statistical analyses evaluated the association between biofilm production determined by XTT reduction and mortality, adjusting for demographic, clinical, and microbiological factors assessed by the hospital routinary activities. Survival analysis and bivariate and multivariate Cox regression were used, estimating the hazard ratio (HR) as a measure of association with a significance level of p < 0.05.

RESULTS

A total of 140 patients with candidemia were included in the study. The high mortality observed on the first day of post-diagnosis follow-up (81.0%) among 21 patients who were not treated with either antifungal or antimicrobial drugs led to stratification of the analyses according to whether they received treatment. In untreated patients, there was a mortality gradient in patients infected with non-biofilm-forming strains vs. low/medium and high-level biofilm-forming strains (25.0%, 66.7% and 82.3%, respectively, p = 0.049). In treated patients, a high level of biofilm formation was associated with increased mortality (HR, 3.92; 95% p = 0.022), and this association persisted after adjusting for age, comorbidities, and hospital emergency admission (HR, 6.59; CI: 1.87-23.24, p = 0.003).

CONCLUSIONS

The association between candidemia with in vitro biofilm formation and an increased risk of death consistently observed both in patients with and without treatment, provides another level of evidence for a possible causal association. The presence of comorbidities and the origin of the hospital emergency, which reflect the fragile clinical condition of the patients, and increasing age above 15 years were associated with a higher risk of death.

Navigating the New Reality: A Review of the Epidemiological, Clinical, and Microbiological Characteristics of Candida auris, with a Focus on Children

During the past decade, Candida auris emerged across the world, causing nosocomial outbreaks in both pediatric and adult populations, particularly in intensive care settings. We reviewed the epidemiological trends and the clinical and microbiological characteristics of C. auris infection, focusing on the pediatric population. The review is based on 22 studies, which included about 250 pediatric patients with C. auris infection, across multiple countries; neonates and premature babies were the predominant pediatric patient group affected. The most common type of infection reported was bloodstream infection, which was associated with exceptionally high mortality rates. Antifungal treatment varied widely between the patients; this signifies a serious knowledge gap that should be addressed in future research. Advances in molecular diagnostic methods for rapid and accurate identification and for detection of resistance may prove especially valuable in future outbreak situations, as well as the development of investigational antifungals. However, the new reality of a highly resistant and difficult-to-treat pathogen calls for preparedness of all aspects of patient care. This spans from laboratory readiness, to raising awareness among epidemiologists and clinicians for global collaborative efforts to improve patient care and limit the spread of C. auris.

A Survival Analysis of Invasive Fungal Diseases in Children with Cancer

Objective This study aimed to determine the survival in a retrospective cohort of 152 patients treated for invasive fungal diseases (IFD) (133 proven and 19 probable) in 9 years.

Methods Our study included patients aged 0 to 18 years diagnosed with cancer at our institution and with proven or probable IFD, treated from 2011 to 2019. Weibull distribution was used for hazard ratios and accelerated failure time models for the outcome “death attributed to IFD.”

Results Our median age was 97 months. The most frequent diagnosis was leukemia (39, 25.7%). A total of 37 patients received prophylaxis with fluconazole (24.3%). Among 133 fungal isolates, the most frequent were Candida species in blood 81 (53.2%). Moreover, 43 deaths were attributed to IFD (28.3%). Survival probabilities were lower for pulmonary IFD (46.9%, p = 0.0017), leukemia (62.5%, p = 0.004), and neutropenia <500 cells/mm3 (55.4%, p < 0.0001). For Candida fungemia, survival probabilities were 76.6% (p = 0.043). In Weibull models, the diagnosis of leukemia shortened survival times by a factor of 0.006, relapse of disease by 0.05, lymphoma by 0.04, pulmonary IFD by 0.04, and neutropenia by 0.015. Hematopoietic stem cell transplantation did not affect the survival times as well as prophylaxis with fluconazole.

Conclusion Host factors, such as neutropenia, relapse of disease, and hematologic malignancies, are determinants in the survival times of children with IFD as well as pulmonary involvement.

Candidemia in Children: A 16-year Longitudinal Epidemiologic Study

BACKGROUND

Candida species are the most common cause of systemic fungal infections in children. Risk factors for candidemia vary in different patient populations, posing challenges for clinical prediction of infection. We describe the epidemiology and clinical disease of candidemia in children admitted to a tertiary pediatric hospital.

METHODS

Retrospective audit of children ≤18 years of age with candidemia at a tertiary pediatric hospital over a 16-year period.

RESULTS

There were 139 episodes of candidemia in 124 children. A central venous catheter was present in 94% of episodes, prior antibiotic exposure in 86% and parenteral nutrition in 43%. During the study period, the proportion of candidemia due to non-albicans Candida spp. increased primarily due to a rise in C. krusei. Colonization with Candida spp. in the 30 days before developing candidemia was identified in 40% of episodes and the species was concordant in 60%. Infection at other sites was rare, including pulmonary dissemination (9/38, 24%), renal fungal disease (9/114, 8%), fungal endophthalmitis (8/102, 8%) and hepatosplenic nodules (5/92, 5%). Overall, 8/127 (6%) isolates were fluconazole-resistant (7 C. krusei and 1 C. glabrata) and 7/127 (6%) had intermediate susceptibility to fluconazole. The overall 30-day mortality was 12% and significant risk factors for mortality on multivariate analysis were male sex, liver disease and mucositis.

CONCLUSIONS

Our study outlines low rates of disseminated candidiasis and low mortality associated with candidemia at our institution. Additionally, it suggests that prior colonization may be an important risk factor, however, this should be validated in large prospective controlled studies.

The Profile of Microorganisms Responsible for Port-Related Bacteremia in Pediatric Hemato-Oncological Patients

Patients with pediatric cancer face an increased risk of infections. In most cases, these infections are associated with the use of a long-term central venous catheter. This study describes the epidemiology of a port-associated bacteremia as well as a profile of microorganisms responsible for port-associated bloodstream infections (PABSIs) in pediatric patients with cancer treated in a single center. The retrospective analysis included patients with cancer who had implanted a port, hospitalized between 2010 and 2015 at the Department of Pediatric Oncology, Hematology and Bone Marrow Transplantation, Poznan University of Medical Sciences. The medical records of patients were reviewed for demographic characteristics, diagnosis, port-related complications, and their management. Data were collected from patients' electronic medical records containing complete information on medical examinations and supplementary tests, diagnosis, timing, and type of port-associated complications. In a study period, 277 ports were inserted to 241 patients. A total of 183 094 catheter days were analyzed. Sixteen patients had more than 1 insertion of a port. The commonest observed complication was PABSI (40.07%) and the incidence density was 0.6 per 1000 port-days. Staphylococcus was the most commonly isolated organisms from patients with PABSI. From all port-associated complications, bloodstream infections and mechanical complications were the most often observed complications. The commonest pathogens responsible for PABSI were coagulase-negative staphylococci. Pathogens resistant to standard antibiotic treatment play an important role in PABSI, with methicillin-resistant Staphylococcus epidermidis being the predominant pathogen. Port-associated bloodstream infections are a common reason for preterm removal of a port.

Candidemia in Patients with Acute Leukemia: Analysis of 7 Years' Experience at a Single Center in China

The study of candidemia in Chinese leukemia patients has been limited. This retrospective study aims to investigate the characteristics and prognostic factors of candidemia among leukemia patients. From 2009 to 2015, 30 isolates of candidemia were detected in 19 patients with acute leukemia after chemotherapy. The overall incidence of candidemia was 2.12 episodes per 1000 admissions. Candida tropicalis was the most common Candida species (n = 17; 89.5%). The vast majority of candidal infections are endogeneous. The overall 30-day crude mortality rate was 31.6%. Neutrophil recovery (P = 0.000) and initiation of empiric antifugal treatment before first positive blood culture (P = 0.041) were associated with a significant improvement in overall survival. Early diagnosis, followed by rapid antifungal treatment remains the cornerstone of successful management. The widespread use of newer antifungal agents as prophylaxis among patients with acute leukemia may result in a decreased candidemia incidence.

Presence of O-glycosidically linked oligosaccharides in the cell wall mannan of Candida krusei purified with Benanomicin A

Cell wall mannan of the pathogenic yeast Candida krusei was prepared using the antibiotic Benanomicin A, which has a lectin-like function. The chemical structure of this molecule was found to be similar to that of mannan prepared from the same yeast by the conventional method using Fehling reagent. Only a few degradation products were detected when the mannan prepared using Fehling reagent was subjected to alkali treatment (β-elimination), but multiple α-1,2-linked oligosaccharides were detected when the mannan purified with Benanomicin A was treated with alkali. These results indicate that most of the O-linked sugar chains in mannan were lost under conventional conditions when exposed to the strongly alkaline Fehling reagent. In contrast, the O-glycosidic bond in mannan was not cleaved and the O-linked sugar chains were maintained and almost intact following treatment with the mild novel preparation method using Benanomicin A. Therefore, we argue that the new mannan preparation method using Benanomicin A is superior to conventional methods. In addition, our study suggests that some yeast mannans, whose overall structure has already been reported, may contain more O-linked sugar chains than previously recognized.

Candidemia in children: Epidemiology, prevention and management

Candidemia is the leading cause of invasive fungal infections in hospitalised children. The highest rates of candidemia have been recorded in neonates and infants <1 year of age. Candidemia is more frequent in neonates and young infants than in adults, and is associated with better clinical outcomes, but higher inpatient costs. Over the last 10 years, a declining trend has been noted in the incidence of paediatric candidemia in the US and elsewhere due to the hospital-wide implementation of central-line insertion and maintenance bundles that emphasise full sterile barrier precautions, chlorhexidine skin preparation during line insertion, meticulous site and tubing care, and daily discussion of catheter necessity. Additional interventions aiming at reducing gut-associated candidemia are required in immunocompromised and critically ill children.

Creation and Assessment of a Clinical Predictive Calculator and Mortality Associated With Candida krusei Bloodstream Infections

Background

Candida krusei bloodstream infection (CK BSI) is associated with high mortality, but whether this is due to underlying comorbidities in affected patients or the organism itself is unknown. Identifying patient characteristics that are associated with CK BSI is crucial for clinical decision-making and prognosis.

Methods

We conducted a retrospective analysis of hospitalized patients with Candida BSI at our institution between 2002 and 2015. Data were collected on demographics, comorbidities, medications, procedures, central lines, vital signs, and laboratory values. Multivariable logistic and Cox regression were used to identify risk factors associated with CK and mortality, respectively.

Results

We identified 1873 individual patients who developed Candida BSI within the study period, 59 of whom had CK BSI. CK BSI was predicted by hematologic malignancy, gastric malignancy, neutropenia, and the use of prophylactic azole antifungals, monoclonal antibodies, and β-lactam/β-lactamase inhibitor combinations. The C-statistic was 0.86 (95% confidence interval, 0.81–0.91). The crude mortality rates were 64.4% for CK BSI and 41.4% for non-CK BSI. Although CK was associated with higher mortality in univariable Cox regression, this relationship was no longer significant with the addition of the following confounders: lymphoma, neutropenia, glucocorticoid use, chronic liver disease, and elevated creatinine.

Conclusions

Six patient comorbidities predicted the development of CK BSI with high accuracy. Although patients with CK BSI have higher crude mortality rates than patients with non-CK BSI, this difference is not significant when accounting for other patient characteristics.

Antifungal susceptibility patterns of colonized Candida species isolates from immunocompromised pediatric patients in five university hospitals

BACKGROUND AND OBJECTIVES

Colonization of Candida species is common in pediatric patients admitted to hematology-oncology wards. The aim of this study was to identify colonized Candida species and their susceptibility patterns in hematologic pediatric patients.

MATERIALS AND METHODS

Samples were collected from mouth, nose, urine and stool of the patients admitted to five university hospitals and cultured on sabouraud dextrose agar. The isolates were identified by API 20 C AUX system and their susceptibility patterns were evaluated by CLSI M27-A3 and S4.

RESULTS

From 650 patients, 320 (49.2%) were colonized with 387 Candida species. Candida albicans was the most prevalent isolated species, followed by Candida glabrata, Candida tropicalis, Candida famata, Candida kefyr and Candida kuresi. The epidemiological cut off value (ECV) for all Candida species to amphotericin B was ≤0.25 μg except C. krusei (4 μg). The resistance rate to fluconazole in this study in C. albicans was 4.9% with ECV 8 μg/ml, followed by C. tropicalis 8.8% with ECV 0.5 μg/ml. Voriconazole and posaconazole were effective antifungal agents for all Candida isolates. The ECV of C. albicans, Candida parapsilosis, C. tropicalis, C. glabrata and C. krusei for itraconazole were 0.5, 0.25, 0.5, 1 and 2 μg, respectively. The resistant and intermediate rates of Candida species to caspofungin in this study were 2.9%, 5.9%, 18.8%, 47.9%, 0.0% and 16.7% in C. tropicalis, C. glabrata and C. parapsilosis respectively.

CONCLUSION

C. albicans was the most prevalent species in pediatric colonized patients. New azole agents like voriconazole and posaconazole are effective against non-albicans Candida species. Increase in intermediate species is alarming to future emerging resistant species.