Repeat blood cultures in children with persistent fever and neutropenia: Diagnostic and clinical implications

Gaps in diagnosing suspected infection in immunocompromised children with cancer: A systematic review

While the survival of children with cancer has improved over time, infection remains a major morbidity and mortality risk. We conducted a systematic literature review to determine the unmet needs in diagnosing infection in immunocompromised children with cancer. The comprehensive search strategy followed the guidelines established by the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 statement, and spanned multiple bibliographic databases and other public sources from January 1, 2012 to June 23, 2022. From 5188 records, 34 unique pediatric-focused studies met inclusion criteria. This review highlights the lack of published data on infectious disease testing in pediatric oncology patients, and the need for well-designed clinical impact and cost-effectiveness studies of both existing and novel diagnostic platforms. Such studies are necessary to optimize diagnostic and antimicrobial stewardship, leading to improvement in patient outcomes.

The Yield, Safety, and Cost-effectiveness of Decreasing Repeat Blood Cultures Beyond 48 Hours in a Pediatric Hematology-Oncology Unit

Clear recommendations are needed on when repeat blood cultures (BCxs) in hospitalized children with cancer should be obtained. We reviewed all BCx obtained on the Hematology-Oncology Unit at Riley Hospital for Children, regardless of reason for patient admission or neutropenia status, between January 2015 and February 2021. Patients with positive BCx within 48 hours of initial cultures, history of stem cell transplant, or admitted to the intensive care unit were excluded. Medical records of patients with new positive BCx drawn >48 hours after initial BCx were reviewed. Seven (1.2%) hospitalization episodes grew new pathogens, or commensals treated as pathogens, on cultures beyond 48 hours. All patients with new, true pathogens were hemodynamically unstable or had recurrent fever when the new positive BCx was obtained. Twenty-three (4.0%) hospitalization episodes had contaminant cultures beyond 48 hours, with 74 (5.4%) of 1362 BCx collected beyond 48 hours being contaminated, resulting in an additional cost of $210,519 from increased length of stay. In conclusion, repeat BCx beyond 48 hours in pediatric hematology-oncology patients with negative initial cultures are low yield and costly. Repeat BCx can be safely and cost-effectively ceased after 48 hours of negative cultures in hemodynamically and clinically stable patients.

From "More is Better" to "Less is More": A Commentary on Antimicrobial Use in Pediatric Oncology

Reducing avoidable antimicrobial exposure to pediatric patients with cancer is achievable and necessary to promote optimal short- and long-term outcomes. Multiple evidence-based practices are already well established but should be more consistently implemented. Important opportunities exist to further improve the evidence to guide selective antimicrobial use in pediatric oncology.

Fever of unknown origin (FUO) in children: a single-centre experience from Beijing, China

OBJECTIVE

To date, there is no standard diagnostic practice to identify the underlying disease-causing mechanism for paediatric patients suffering from chronic fever without any specific diagnosis, which is one of the leading causes of death in paediatric patients. Therefore, we aimed this retrospective study to analyse medical records of paediatric patients with fever of unknown origin (FUO) to provide a preliminary basis for improving the diagnostic categories and facilitate the treatment outcomes.

DESIGN

A retrospective study.

SETTING

Beijing Children's Hospital.

PARTICIPANTS

Clinical data were collected from 1288 children between 1 month and 18 years of age diagnosed with FUO at Beijing Children's Hospital between January 2010 and December 2017.

INTERVENTIONS

According to the aetiological composition, age, duration of fever and laboratory examination results, the diagnostic strategies were analysed and formulated.

PRIMARY AND SECONDARY OUTCOME MEASURES

The statistical analyses were carried out using SPSS V.24.0 platform along with the χ² test and analysis of variance (p<0.05).

RESULTS

The duration of fever ranged from 2 weeks to 2 years, with an average of 6 weeks. There were 656 cases (50.9%) of infectious diseases, 63 cases (4.9%) of non-infectious inflammatory diseases (NIIDs), 86 cases (6.7%) of neoplastic diseases, 343 cases (26.6%) caused by miscellaneous diseases and 140 cases (10.9%) were undiagnosed. With increasing age, the proportion of FUO from infectious diseases gradually decreased from 73.53% to 44.21%. NIID was more common in children over 3 years old, and neoplastic diseases mainly occurred from 1 to 6 years of age. Among miscellaneous diseases, the age distribution was mainly in school-aged children over 6 years. Respiratory tract infection was the most common cause of FUO in children, followed by bloodstream infections. Bacterial infection was the most common cause in children with less than 1 year old, while the virus was the main pathogen in children over 1 year old.

CONCLUSIONS

The diagnosis of neoplastic diseases and miscellaneous diseases-related diseases still depends mainly on invasive examination. According to our clinical experience, the diagnostic process was formulated based on fever duration and the type of disease. This process can provide a guide for the diagnosis and treatment of paediatric FUO in the future.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host: An Update

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere and are only briefly discussed in the context of the immunocompromised host.

Optimized blood culture strategy to document febrile neutropenia

BACKGROUND

Poor and delayed microbiological documentation of episodes of febrile neutropenia (EFN) deserves improvement. We assessed the impact of a new blood culture (BC) sampling protocol to optimize the diagnosis of bloodstream infection during EFN, compared with standard of care protocol.

METHODS

This pre/post intervention included patients who presented an EFN in a pediatric hematology-oncology center. Data were compared between 1-year periods P1 (110 EFN, 53 patients) and P2 (124 EFN, 53 patients). Pre-intervention settings were 1-2 mL of blood cultured per BC set and several samplings over days (multisampling strategy) during period P1 vs. one unique early sampling of a large volume of blood (0.5-60 mL) depending on patient weight during period P2 (single-sampling weight-adapted strategy). Microbial detection and time-to-diagnosis were evaluated.

RESULTS

Seventeen EFNs were microbiologically documented in P1 (15.5%) and 26 in P2 (21%). The rate of positive BC sets increased during P2 (10.4% vs. 5.8%). All cases of bacteremia were documented by BC drawn during the first 4 days of fever, and during P2 by samples obtained on the first day of fever.

CONCLUSIONS

Bacteremia detection was improved. This proof-of-concept study shows benefits of combining the single-sampling strategy with large weight-adapted blood sampling strategy during EFN.

IMPACT

Combination of single-sampling and weight-adapted blood culture strategies showed benefits in the documentation of bloodstream infections during febrile neutropenia. Bacteremia detection was improved in this preliminary study and this warrants further evaluation in the overall pediatric population. We observed no adverse effects associated with the new strategy while overall blood sparing was improved and handling of intravascular devices was reduced. The good tolerance of the blood sampling suggests that the recommended 1% volume limitation in children could be reconsidered. A similar evaluation is justified in the overall pediatric population suspected for bloodstream infection.

Diagnostic Yield of Initial and Consecutive Blood Cultures in Children With Cancer and Febrile Neutropenia

BACKGROUND

The timing and necessity of repeated blood cultures (BCs) in children with cancer and febrile neutropenia (FN) are unknown. We evaluated the diagnostic yield of BCs collected pre- and post-empiric FN antibiotics.

METHODS

Data collected prospectively from the Australian Predicting Infectious ComplicatioNs in Children with Cancer (PICNICC) study were used. Diagnostic yield was calculated as the number of FN episodes with a true bloodstream infection (BSI) detected divided by the number of FN episodes that had a BC taken.

RESULTS

A BSI was identified in 13% of 858 FN episodes. The diagnostic yield of pre-antibiotic BCs was higher than of post-antibiotic cultures (12.3% vs 4.4%, P < .001). Two-thirds of the post-antibiotic BSIs were associated with a new episode of fever or clinical instability, and only 2 new BSIs were identified after 48 hours of empiric antibiotics and persistent fever. A contaminated BC was identified more frequently in post-antibiotic cultures.

CONCLUSIONS

In the absence of new fever or clinical instability, BCs beyond 48 hours of persistent fever have limited yield. Opportunity exists to optimize BC collection in this population and reduce the burden of unnecessary tests on patients, healthcare workers, and hospitals.

Timing of Blood Cultures in the Setting of Febrile Neutropenia: An Australian Institutional Experience

Objective

Febrile neutropenia (FN) is a hematological emergency requiring urgent investigations to exclude infection and treatment with broad-spectrum antibiotics. Despite frequent blood cultures (BCs) being taking during episodes of FN, in the current literature BC positivity rates remain low in FN. This study aims to determine the BC positivity rate in FN hematology patients and determine the utility of collecting BCs beyond 24 h of commencing broad-spectrum antibiotics.

Materials and Methods

BC results between 2014 and 2016 from all FN hematology patients were analyzed. Patient episodes of FN (PEFNs) were defined as a continuous period of FN where the interval between BC samples was a maximum of two days. In total from 2014 to 2016, 379 patients experienced 914 PEFNs and had 4267 BCs collected.

Results

Overall BC positivity rates and BC-positive PEFN rates were 8.16% and 13.35%, respectively. Within the first 24 h, the positivity rate of the first BCs was 3.49%, while subsequent BC positivity within the first 24 h was 11.96%. BC positivity rates declined after 24 h to 2.18%.

Conclusion

It is likely that BCs beyond 24 h of commencing broad-spectrum antibiotics will rarely identify relevant microorganisms. Not collecting BCs after 24 h would likely reduce laboratory test costs, patient discomfort, and iatrogenic anemia.

Microbiologically Documented Bloodstream Infection in Children With Malignancies: A Single-center Experience

BACKGROUND

Bloodstream infection (BSI) remains a considerable cause of morbidity and mortality for cancer patients. With a better understanding of it, better methods can be used. The primary objective of this study was to describe the characteristics of BSIs in our institution, and the second was to determine the possible risk factors associated with them.

MATERIALS AND METHODS

Data of cancer patients from 2009 to 2015 at our institution were included. Medical information and blood cultures were analyzed to determine the BSI rate. The χ and Fisher exact tests were used for categorical data and to determine risk factors associated with BSIs and pathogens.

RESULTS

A total of 565 (8.6%) events were diagnosed with BSIs. Although Gram-negative bacteria (52.6%) were the most commonly isolated pathogens, Gram-positive microorganisms (45.0%) were also prevalent. Oral and gastrointestinal organisms were common. Pathogens were more likely to be identified in patients with central venous catheters and in patients with prolonged neutropenia (P<0.05).

CONCLUSIONS

This study provides updated epidemiology in BSIs and helps with the prevention and management of suspected BSIs in vulnerable patients. Better anti-infection therapy could be provided to these patients based on the isolated pathogens.

Cotransplantation of haploidentical hematopoietic stem cells and allogeneic bone marrow-derived mesenchymal stromal cells as a first-line treatment in very severe aplastic anemia patients with refractory infections

OBJECTIVES

In patients with very severe aplastic anemia (VSAA), neutropenia is prolonged and persistent, resulting in refractory overwhelming infections. Hematopoiesis recovery is urgently needed.

METHODS

Six patients with de novo VSAA lacking HLA-identical sibling donors and those who experienced refractory infections underwent haploidentical related donor (HRD) hematopoietic stem cell transplantation (HSCT) as a first-line therapy. The conditioning regimen consisted of busulfan, cyclophosphamide, and rabbit antithymocyte globulin. Culture-expanded allogeneic bone marrow-derived mesenchymal stromal cells were infused on day 0 and day +14.

RESULTS

From diagnosis to HSCT, 6 patients experienced a total of 28 episodes of persistent fever, and the median number was 4 (range, 3-7). All cases developed major bacterial infections and invasive pulmonary fungal infection pre-HSCT. The median time from diagnosis to HSCT was 2 months (range, 1-3.5 months). All patients achieved sustained, full donor chimerism, and the median time of myeloid recovery and platelet engraftment was 13 days (range, 9-19 days) and 15.5 days (range, 10-23 days), respectively. One patient died of aGVHD, and 5 patients are alive after a median follow-up of 21 months (range 17-40.5).

CONCLUSIONS

Upfront HRD-HSCT may be a safe and promising choice for patients with VSAA in critical situations without suitably matched donors.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere, and are only briefly discussed in the context of the immunocompromised host.

Repeated Blood Cultures in Pediatric Febrile Neutropenia: Would Following the Guidelines Alter the Outcome?

BACKGROUND

The Infectious Diseases Society of America (IDSA) guidelines recommend collecting blood cultures for the first 3 days of febrile neutropenia (FN) in the clinically stable oncology patient with persistent fevers. Nonetheless, many physicians send daily blood cultures beyond 3 days, and the impact of that practice is uncertain.

PROCEDURE

We reviewed pediatric FN episodes from July 2009 to May 2014 at University of Chicago Comer Children's Hospital. For each positive culture, we determined if it was a pathogen or a contaminant. We reviewed episode and patient demographics to identify risk factors for subsequent positive blood cultures in the setting of an initially negative culture.

RESULTS

We identified 381 episodes of FN in 162 patients. Of those, 87 had a positive blood culture on day 1 (21.0% incidence of bacteremia). Of 294 episodes with a negative blood culture on day 1, six (2.04%, 95% confidence interval [CI] 0.42-3.67) had a positive culture after day 3. Of those, three were pathogens (1.02%, 95%CI -0.14 to 2.18), and only one was found in a hemodynamically stable patient (0.34%, 95%CI -0.33 to 1.01) with new mucositis. In the other two patients, Escherichia coli was isolated from blood cultures after day 10 in the setting of significant hemodynamic changes. Risk factor analysis performed in stable patients yielded nonsignificant results.

CONCLUSIONS

Of 294 FN episodes with an initial negative blood culture, only one episode of bacteremia occurred without hemodynamic changes past day 3, supporting the IDSA guidelines to discontinue blood cultures in stable FN patients after day 3.

Diagnosis of Bloodstream Infections in Children

Identification of bloodstream infections is among the most critical tasks performed by the clinical microbiology laboratory. While the criteria for achieving an adequate blood culture specimen in adults have been well described, there is much more ambiguity in pediatric populations. This minireview focuses on the available pediatric literature pertaining to the collection of an optimal blood culture specimen, including timing, volume, and bottle selection, as well as rapid diagnostic approaches and their role in the management of pediatric bloodstream infections.