Serum procalcitonin levels in critically ill patients colonized with Candida spp: new clues for the early recognition of invasive candidiasis?

Clinical Utility of Procalcitonin on Antibiotic Stewardship: A Narrative Review

Procalcitonin (PCT) was discovered as a useful marker for bacterial infection. Following its discovery, there have been a substantial number of clinical studies conducted to evaluate the presence of bacterial infections, and to guide antibiotic treatment by the stratified levels of PCT. Clinical evidence suggests that antibiotic treatment by PCT-guided antibiotic stewardship has been associated with a reduction in antibiotic usage without an increase in adverse outcomes. The use of PCT was approved by the Food and Drug Administration in the United States of America in 2017 to guide antibiotic treatment in sepsis and lower respiratory tract infections (LRTIs). In Korea, the use of PCT for sepsis and for pneumonia was approved in 2015 and 2022, respectively. This review will discuss the clinical utility of PCT on antibiotic stewardship in the management of sepsis and LRTIs including pneumonia.

Performance of existing clinical scores and laboratory tests for the diagnosis of invasive candidiasis in critically ill, nonneutropenic, adult patients: a systematic review with qualitative evidence synthesis

BACKGROUND

The Fungal Infections Definitions in Intensive Care Unit (ICU) patients (FUNDICU) project aims to provide standard sets of definitions for invasive fungal diseases in critically ill, adult patients.

OBJECTIVES

To summarize the available evidence on the diagnostic performance of clinical scores and laboratory tests for invasive candidiasis (IC) in nonneutropenic, adult critically ill patients.

METHODS

A systematic review was performed to evaluate studies assessing the diagnostic performance for IC of clinical scores and/or laboratory tests vs. a reference standard or a reference definition in critically ill, nonneutropenic, adult patients in ICU.

RESULTS

Clinical scores, despite the heterogeneity of study populations and IC prevalences, constantly showed a high negative predictive value (NPV) and a low positive predictive value (PPV) for the diagnosis of IC in the target population. Fungal antigen-based biomarkers (with most studies assessing serum beta-D-glucan) retained a high NPV similar to that of clinical scores, with a higher PPV, although the latter showed important heterogeneity across studies, possibly reflecting the targeted or untargeted use of these tests in patients with a consistent clinical picture and risk factors for IC.

CONCLUSIONS

Both clinical scores and laboratory tests showed high NPV for the diagnosis of IC in nonneutropenic critically ill patients. The PPV of laboratory tests varies significantly according to the baseline patients' risk of IC. This qualitative synthesis will provide the FUNDICU panel with baseline evidence to be considered during the development of definitions of IC in critically ill, nonneutropenic adult patients in ICU.

Performance of Procalcitonin to Distinguish Fungal from Bacterial Infections in Patients with Systemic Lupus Erythematosus

Purpose

To evaluate the performance of serum procalcitonin (PCT) concentrations to diagnose fungal infection in patients with systemic lupus erythematosus (SLE).

Patients and Methods

From January 2017 to October 2020, SLE patients hospitalized for serious infection with an identified single bacterial or fungal pathogen, as well as PCT measured within 24h after admission were included. The diagnostic performance of PCT was evaluated independently and in combination with the white blood cell (WBC) count, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR). The analysis included the sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and the crude and adjusted area under the receiver operating characteristic curve (AUROC).

Results

Sixty-nine patients were included; 26 had a fungal infection (38%) and 43 had a bacterial infection (22 gram-positive and 21 gram-negative). Fungal infection patients were mainly distributed in the respiratory group (88.5%), and bacterial infection distribution were more prevalent in respiratory group (44.2%) and abdominal/urinary group (23.3%). The PCT concentration was significantly lower in fungal infections than bacterial infections (fungal: 0.22 ng/mL, interquartile range [IQR], 0.09-0.44 vs bacterial: 0.60 ng/mL, IQR, 0.16-5.74; p = 0.016) and differed significantly between different infection sites (p = 0.022). PCT had better diagnostic performance for predicting fungal infection (AUROC = 0.731) than the WBC count (AUROC = 0.581), the CRP level (AUROC = 0.716), and ESR (AUROC = 0.583). PCT and ESR together had the best diagnostic performance, with 46.2% sensitivity and 88.4% specificity. Further, the AUROC increased compared to PCT alone but was statistically insignificant (p = 0.693).

Conclusion

For SLE patients with serious infection, the PCT concentration had better diagnostic accuracy for predicting fungal infection than the WBC count, the CRP level, and ESR. Combining PCT and ESR obtained the highest AUROC and provided an acceptable discrimination performance.

Severe pneumonia due to infection with Candida krusei in a case of suspected Middle East respiratory syndrome: A case report and literature review

Candida krusei (C. krusei) pneumonia is a rare infection that is frequently associated with a poor outcome. The present study reports an unusual case of C. krusei pneumonia that was initially suspected to be a Middle East respiratory syndrome (MERS) case. A 64-year-old Saudi Arabian male patient was admitted to our hospital with complaints of cough and dyspnea that persisted for 6 days. The patient presented fever (oral temperature, 38.5°C) and slight tachypnea (25 respirations/min). A chest computerized tomography demonstrated unclear lung fields, diffuse pathological changes in the two lungs and multiple lymphadenectasis in the retrocaval and para-aortic arch area. The patient received 95-98% oxygen (6 l/min) for 24 h, as well as sulbactam sodium/cefoperazone sodium (1:1) injection (3.0 g) every 12 h, oral oseltamivir capsules (75 mg/time) twice a day, medaron injection (80 mg/time) and 750 ml fluid infusion; however, he succumbed to the disease on day 2 after admission. The infection was diagnosed by sputum smear and culture subsequent to patient mortality. A sputum smear showed a large fungal infection and sputum culture revealed the presence of C. krusei infection. Serum procalcitonin concentrations were 4.73 µg/l and 7.23 µg/l on days 2 and 3 after admission, respectively. In conclusion, the diagnosis of Candida pneumonia should be strongly considered in the presence of growth of Candida from a sputum culture and based on a suggestive computed tomography image. Tumescent diaphragmatic lymph nodes may also be an important symptom of Candida pneumonia. Treatment should be initiated immediately to improve tissue oxygenation, restore cardiovascular function and improve other organ functions.

Evolution of procalcitonin, C-reactive protein and fibrinogen levels in neutropenic leukaemia patients with invasive pulmonary aspergillosis or mucormycosis

Unlike bacterial infections, the value of procalcitonin (PCT) in detecting fungal infections in leukaemia patients is not clear. To determine whether the monitoring of PCT coupled with C-reactive protein (CRP) and fibrinogen (Fib) could be helpful in the management of pulmonary aspergillosis (IPA) or mucormycosis (PM), we retrospectively analysed the evolution of PCT, CRP and Fib levels in 94 leukaemia patients with proven/probable IPA (n = 77) or PM (n = 17) from D-12 to D12 relative to IFI onset defined as D0. Overall, 2140 assays were performed. From D-12 to D0, 12%, 5% and 1.4% of patients had PCT >0.5, 1 and 1.5 μg l(-1) , respectively, while CRP was >50, 75 and 100 mg l(-1) in 84%, 70% and 57% and Fib was >4, 5 and 6 g l(-1) in 96%, 80% and 61% of cases respectively (P < 10(-7) ). The same trends were observed from D1 to D12. Overall, between D-12 and D12, only 6.4% of patients had PCT >1.5 μg l(-1) , while CRP >100 mg l(-1) and Fib >6 g l(-1) were observed in 80% and 75% of cases respectively (P < 10(-7) ). In leukaemia patients, IPA or PM was accompanied by a significant increase in CRP and Fib while PCT remained low.

Fungal "colonisation" is associated with increased mortality in medical intensive care unit patients with liver cirrhosis

OBJECTIVES

Patients with liver cirrhosis are at increased risk for fungal infections. However, distinction of fungal colonisation (FC) and invasive mycoses is difficult. Aim of this study was to analyse the impact of FC on mortality of cirrhotic ICU-patients.

METHODS

Retrospective mortality analysis of a prospectively maintained database on 120 cirrhotic patients with and without FC. Comparison to 120 noncirrhotic controls matched for APACHE-II (24.9 ± 3.7 vs. 25.0 ± 2.6; p = 0.263).

RESULTS

About 69/120 (58%) of patients with cirrhosis had FC. These patients had significantly higher APACHE-II score and mortality compared to cirrhotic patients without FC (27 ± 3 vs. 23 ± 4, p < 0.001; 78 vs. 35%, p < 0.001). In multivariate analysis, FC was independently (p = 0.047) associated to mortality. Mortality of noncirrhotic patients with FC (14/31; 45.2%) was not different to noncirrhotic controls without FC [28/89 (31.2%; p = 0.168)]. Similarly, in multivariate analysis of noncirrhotics, APACHE-II (p < 0.001), but not FC, was independently associated to mortality. Multiple regression analysis of all 240 cirrhotic and noncirrhotic patients demonstrated that APACHE-II (p < 0.001), cirrhosis (p = 0.001) and FC (p = 0.049) were independently associated with mortality.

CONCLUSION

Fungal "colonisation" is independently associated to mortality in cirrhotic ICU-patients. Early antimycotic therapy should be considered in critically ill cirrhotic patients with FC.

Candida colonization index and subsequent infection in critically ill surgical patients: 20 years later

Introduction

For decades, clinicians dealing with immunocompromised and critically ill patients have perceived a link between Candida colonization and subsequent infection. However, the pathophysiological progression from colonization to infection was clearly established only through the formal description of the colonization index (CI) in critically ill patients. Unfortunately, the literature reflects intense confusion about the pathophysiology of invasive candidiasis and specific associated risk factors.

Methods

We review the contribution of the CI in the field of Candida infection and its development in the 20 years following its original description in 1994. The development of the CI enabled an improved understanding of the pathogenesis of invasive candidiasis and the use of targeted empirical antifungal therapy in subgroups of patients at increased risk for infection.

Results

The recognition of specific characteristics among underlying conditions, such as neutropenia, solid organ transplantation, and surgical and nonsurgical critical illness, has enabled the description of distinct epidemiological patterns in the development of invasive candidiasis.

Conclusions

Despite its limited bedside practicality and before confirmation of potentially more accurate predictors, such as specific biomarkers, the CI remains an important way to characterize the dynamics of colonization, which increases early in patients who develop invasive candidiasis.

An Italian consensus for invasive candidiasis management (ITALIC)

INTRODUCTION

Invasive candidiasis (IC) has primarily been studied in intensive care unit (ICU) patients, although, in reality, a vast majority of these infections occur outside of the ICU. The recent publication of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines also deal with the non-ICU population, but many uncertainties remain on the management of IC, particularly in non-critically ill patients.

METHODS

The Italian Society of Antimicrobial Therapy, Società Italiana di Terapia Antimicrobica (SITA), produced practical, hospital-wide recommendations on the management of Candida infection in non-immunocompromised patients in the hospital ward.

RESULTS AND DISCUSSION

Our focus is on patient stratification in terms of risk factors for IC and of clinical severity, emphasising a high index of suspicion to ensure early diagnosis, early treatment and de-escalation when a patient is clinically stable, in order to optimise resource allocation.

The role of procalcitonin in the identification of invasive fungal infection-a systemic review and meta-analysis

We aimed to summarize evidence on the accuracy of procalcitonin (PCT) test in differentiating fungal infection from other causes of infection. We searched electronic database for original researches that reported diagnostic performance of PCT alone or compare with other biomarkers to diagnose invasive fungal infection (IFI). We included 8 qualifying studies studying 474 episodes of suspected fungal infection with 155 (32.7%) probable or proven IFIs. Four studies compared IFI to bacterial sepsis, in which the pooled positive likelihood ratios and negative likelihood ratios were 4.65 (95% confidence interval [CI], 2.46-8.79) and 0.15 (95% CI, 0.05-0.41), respectively. Another 4 studies compared IFI to uninfected individuals, in which the pooled positive likelihood ratios and negative likelihood ratios were 4.01 (95% CI, 2.04-7.88) and 0.23 (0.07-0.77), respectively. The existing literature suggests good diagnostic accuracy for the PCT test for discrimination between IFIs and bacterial infection or noninfectious conditions. Given the high heterogeneity, medical decisions should be based on both PCT test results and clinical findings.

Value of β-D-glucan and Candida albicans germ tube antibody for discriminating between Candida colonization and invasive candidiasis in patients with severe abdominal conditions

PURPOSE

To assess the value of (1→3)-β-D: -glucan (BDG), Candida albicans germ tube antibody (CAGTA), C-reactive protein (CRP), and procalcitonin (PCT) levels for the diagnosis of invasive candidiasis (IC) and for differentiating Candida spp. colonization from infection in ICU patients with severe abdominal conditions (SAC).

METHODS

Prospective study of 176 non-neutropenic patients, with SAC at ICU admission, and expected to stay at least 7 days. Surveillance cultures and BDG, CAGTA, CRP, and PCT levels were performed on the third day of ICU stay and twice a week for four consecutive weeks. Patients were grouped into invasive candidiasis (IC), Candida colonization, and neither colonized/nor infected. The classification and regression tree (CART) analysis was used to predict IC in colonized patients. The discriminatory ability of the obtained prediction rule was assessed by the area under the ROC curve (AUC).

RESULTS

The probabilities of IC were 59.3 % for the terminal node of BDG greater than 259 pg/mL and 30.8 % for BDG less than 259 pg/mL and CAGTA positivity, whereas there was a 93.9 % probability in predicting the absence of IC for BDG less than 259 pg/mL and negative CAGTA. Using a cutoff of 30 % for IC probability, the prediction rule showed 90.3 % sensitivity, 54.8 % specificity, 42.4 % positive predictive value, and 93.9 % negative predictive value with an AUC of 0.78 (95 % confidence interval 0.76-0.81). Significant differences in CRP (p = 0.411) and PCT (p = 0.179) among the studied groups were not found.

CONCLUSIONS

BDG with a positive test for CAGTA accurately differentiated Candida colonization from IC in patients with SAC, whereas CRP and PCT did not.

The role of procalcitonin in neonatal intensive care unit patients with candidemia

Candidemia is a major infectious complication in neonatal patients. The isolation of yeasts from blood is still the “gold standard” for its diagnosis, but other laboratory markers (i.e., circulating antigens) have been studied with varying specificities and sensitivities. The aim of this study was to evaluate the role of procalcitonin for the diagnosis of candidemia in neonatal patients at high risk. To verify if the use of different commercial methods can highlight dissimilar results of sensitivity and/or specificity, the determination of procalcitonin serum levels was estimated by two systems. Overall, 90 patients from a Neonatal Intensive Care Units were enrolled, of whom six developed Candida bloodstream infection. Four of six infants with candidemia had slight increase of procalcitonin values (0.5–1 ng/mL). Only one baby showed very high levels but he had fungal and bacterial sepsis at the same time, while no elevation was observed in the sixth patient. No statistically significant difference was observed between two different methods at the time of monitoring (p > 0.643). Both methods showed a sensitivity of 83.3 % at diagnosis, while the specificity was 73.8 and 63.1 % by methods A and B, respectively. In the light of the low sensibility and specificity of this assay, we can assume that the determination of procalcitonin would not seem to play a significant role in the diagnosis of fungal infection in neonatal patients.

Invasive fungal infections in patients with cancer in the Intensive Care Unit

Invasive fungal infections (IFIs) have emerged as a major cause of morbidity and mortality amongst critically ill patients. Cancer patients admitted to the Intensive Care Unit (ICU) have multiple risk factors for IFIs. The vast majority of IFIs in the ICU are due to Candida spp. The incidence of invasive candidiasis (IC) has increased over recent decades, especially in the ICU. A shift in the distribution of Candida spp. from Candida albicans to non-albicans Candida spp. has been observed both in ICUs and oncology units in the last two decades. Timely diagnosis of IC remains a challenge despite the introduction of new microbiology techniques. Delayed initiation of antifungal therapy is associated with increased mortality. Therefore, prediction rules have been developed and validated prospectively in order to identify those ICU patients at high risk for IC and likely to benefit from early treatment. These rules, however, have not been validated in cancer patients. Similarly, major clinical studies on the efficacy of newer antifungals typically do not include cancer patients. Despite the introduction of more potent and less toxic antifungals, mortality from IFIs amongst cancer patients remains high. In recent years, aspergillosis and mucormycosis have also emerged as significant causes of morbidity and mortality amongst ICU patients with haematological cancer.

Anidulafungin for the treatment of invasive candidiasis

Candidaemia/invasive candidiasis (C/IC) is the most frequently occurring invasive fungal infection worldwide, with a particularly strong impact and high incidence in the intensive-care unit, where there is a need for new treatment options and strategies. The echinocandin anidulafungin has broad in vitro activity against a wide range of Candida species, along with favourable pharmacokinetics that allow administration in hepatic and renal impairment and with any comedication without the need for dose adjustments. The efficacy and safety of anidulafungin for the treatment of C/IC were demonstrated in a number of clinical studies and by some limited data from clinical practice. In a randomized comparative trial for the treatment of C/IC in adults, 76% of patients receiving anidulafungin and 60% of those given fluconazole were treated successfully (95% CI for difference: 4-27; p 0.01). Post hoc analyses suggest that anidulafungin is significantly more effective than standard-dose fluconazole for the treatment of candidaemia in critically ill patients. Anidulafungin is generally well tolerated, with commonly reported side effects including headache, hypokalaemia, gastrointestinal symptoms, abnormal liver function test results, and rash. In pharmaco-economic analyses, anidulafungin compared favourably with fluconazole (in terms of overall costs and hospital resource use) as well as with other echinocandins. Echinocandins, including anidulafungin, are now generally recommended as first-line therapy in moderately to severely ill patients, those with prior azole exposure, and patients with C/IC caused by Candida glabrata or Candida krusei.

Early treatment of candidemia in adults: a review

Invasive candidiasis is associated with high mortality, particularly in adults. Retrospective studies show that shorter times to treatment are correlated with a lower risk of death. A number of factors can be used to predict which patients would benefit from antifungal prophylaxis or early (pre-emptive or empirical) therapy. Detection of the fungal cell wall component (1→3)-β-D-glucan (BDG) shows promise as an early biomarker of invasive fungal infection and may be useful in identifying patients who would benefit from early antifungal treatment. To date, no consistent early treatment strategy has evolved. Proof-of-concept studies are needed to assess the role of pre-emptive and empirical therapy in ICU patients and the relevance of BDG as an early marker of infection.