# Infections with Staphylococcus spp. in Children Undergoing Anticancer Therapy or Haematopoietic Cell Transplantation: A Nationwide Multicentre Study

## TL;DR

This study analyzed staphylococcal infections in children undergoing cancer treatment or transplants in Poland, finding higher risks and mortality in transplant patients.

## Contribution

The study provides a nationwide, multicenter analysis of staphylococcal infection incidence, risk factors, and outcomes in pediatric oncology and transplant patients.

## Key findings

- HCT patients had higher cumulative infection incidence and mortality compared to PHO patients.
- Methicillin-resistant coagulase-negative Staphylococci were the main pathogens in fatal cases.
- Undergoing HCT and prolonged treatment were independent risk factors for mortality.

## Abstract

Staphylococcal infections (SIs) are among the most frequent contributors to morbidity and mortality in paediatric oncology (PHO) and haematopoietic cell transplantation (HCT) patients. This study, performed over 12 years across 17 centres in Poland, evaluated the incidence, risk factors, and outcomes of SI in 1725 paediatric patients. The cumulative incidence of infection was significantly higher in HCT recipients compared to PHO patients, with recurrent infections being more prevalent in the former group. The first episode of infection occurred much earlier in HCT patients. Infection-related mortality was higher in the HCT cohort, and methicillin-resistant coagulase-negative Staphylococci (MRCNS) were the predominant pathogen in fatal cases. The multivariate analysis revealed that undergoing HCT or requiring extended treatment were independent risk factors for mortality. These findings underscore the need for enhanced infection prevention strategies and early, tailored antimicrobial therapy in this vulnerable paediatric population.

Background: Staphylococcus spp. represent the most prevalent Gram-positive organisms in children with malignancies or undergoing haematopoietic cell transplantation (HCT), contributing to significant morbidity and mortality. This study aimed to assess the epidemiology, risk factors, treatment strategies, and outcomes of staphylococcal infections (SIs) in paediatric haemato-oncology (PHO) and HCT patients in Poland over a 12-year period. Methods: A retrospective, multicentre study was conducted across 17 paediatric oncology centres in Poland. The clinical and microbiological data of patients under the age of 18, diagnosed with malignancies or post-HCT, were analysed for confirmed SI between 2012 and 2023. The variables assessed included demographics, underlying conditions, infection type and source, antimicrobial susceptibility, treatment, and 30-day infection-free survival. Results: Among 1725 patients with SI, 1433 were PHO and 292 were HCT patients. The cumulative incidence of SI was 12.7% in PHO and 14.3% in HCT patients (p = 0.008). The 30-day survival rate was significantly higher in PHO compared to HCT patients (98.4% vs. 93.2%, p < 0.001). Most deaths were caused by S. epidermidis, S. haemolyticus, and S. hominis, predominantly involving methicillin-resistant coagulase-negative Staphylococci (MRCNS). Multivariate Cox regression identified undergoing HCT (HR = 3.0, 95% CI: 1.6–5.6, p < 0.001) and treatment of infection > 10 days (HR = 2.0, 95% CI: 1.1–3.6, p = 0.019) as independent risk factors for mortality. Conclusions: Staphylococcal infections pose a significant challenge in paediatric oncology and transplant populations. Optimising prevention, diagnostics, and antimicrobial therapy is crucial for improving outcomes in these high-risk groups.