Bacterial infections in pediatric oncology patients- a single center experience.

Patients with neoplasms have a high predisposition to bacterial infections, due to the implemented treatment that impairs immunity and numerous risk factors. Numerous research studies have been published on this problem but epidemiological studies are insufficient, and existing data are difficult to generalize on different populations. The aim of the study was to assess the epidemiology of bacterial and fungal bloodstream infections and contaminations in cancer patients hospitalized between 2011 and 2021, with a focus on identifying predominant pathogens, resistance mechanisms, and evaluating the effectiveness of infection prophylaxis. We collected data of blood contaminations and infections epidemiology with cooperation with the Department of Clinical Microbiology UCH. Between 2011 and 2021, 7,667 blood samples were collected and 32,610 tests were performed on 1,914 patients. The analysed cultures were divided into 3 groups depending on the substrate specific for a given group of microorganisms. The number positive test result was 5.5%. The highest detection was noticed in 2021. Differences in the distribution of patients with positive and negative results in individual years were not statistically significant. The most common pathogen detected was Staphylococcus epidermidis, which was also the leader among Gram-positive microorganisms. There were not dominant species among the isolated Gram-negative microorganisms. Detection of anaerobic organisms was rare (only 4 different anaerobic organisms were isolated in single patients). The same was among the fungal observed. Mechanisms of resistance were included in the analysis of all identified strains- the most common was methicillin-resistant Staphylococcus epidermidis (MRSE). Our results confirmed that bacterial infections are still a problem and may indicate the effectiveness of prophylaxis. Most of our results are consistent with the current literature, however we were able to highlight data unique to our patient population. Our findings can be helpful for clinical practice and be base for further research.