Temporal Shifts in Pathogen Profiles Due to the COVID-19 Pandemic in a Romanian Pediatric Tertiary Hospital

<b>Background</b>: The COVID-19 pandemic disrupted pediatric healthcare systems globally, altering infection dynamics, hospital admissions, and antimicrobial practices. This study aimed to evaluate temporal shifts in patient demographics, clinical aspects, and microbial pathogen profiles in a tertiary pediatric hospital in Western Romania, spanning pre-pandemic (2019), pandemic (2021), and post-pandemic (2023) periods. <b>Methods</b>: A retrospective observational study was conducted at the "Louis Țurcanu" Emergency Children's Hospital, Timișoara. Pediatric patients (<18 years) with laboratory-confirmed bacterial infections were included. Data on demographics, hospital wards, sample types, and pathogen distribution were analyzed using Χ² tests, incidence rate ratios (IRR), and non-parametric statistical methods. <b>Results</b>: A total of 3530 patients and 6885 samples were analyzed. Pediatric admissions declined by nearly 50% during the pandemic. The Outpatient and Emergency department observed a decrease in cases, while the ICU and surgical ward cases increased proportionally. Nasal and pharyngeal samples declined during the pandemic, while catheter, blood, and conjunctival samples rose. The study identified a significant shift in pathogen prevalence, with <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> as the most frequent isolates. ICU patients showed increased rates of <i>Pseudomonas aeruginosa</i>, <i>Candida albicans</i>, and <i>Klebsiella pneumoniae</i>. Group A <i>Streptococcus</i> resurged post-pandemic after a decline in 2021. <b>Conclusions</b>: The pandemic significantly impacted pediatric infection profiles, hospital service utilization, and sample collection patterns. Strengthening infection surveillance, ensuring consistent reporting standards, and adapting pediatric care to future crises are critical for improving child health outcomes.