Knowledge of epidemiology is essential for guiding correct antibiotic prescription, reducing bacteremia-associated mortality, and implementing targeted infection control programs. However, only a few studies have reported on the epidemiology of bloodstream infections (BSIs) in pediatrics. We performed a retrospective analysis of all BSIs (excluding those caused by common skin contaminants) diagnosed from 2006 to 2022 in patients younger than 18 years who were treated at an Italian pediatric tertiary care hospital. Overall, 2395 BSIs were recorded, including 2207 (92.15%) due to bacteria and 188 (7.85%) due to fungi. The incidence rate (BSIs/10,000 hospital discharges, IR) of bacterial BSIs significantly increased during the study period. In particular, BSIs caused by S. aureus (including MRSA), Enterobacterales (including ESBL and AmpC producers), Enterococcus spp., and P. aeruginosa became more common. The frequency of carbapenem-resistant strains was <1% and stable over time. Conversely, there was a significant reduction in the incidence of BSIs due to S. pneumoniae. The BSIs were stratified by patient age, and S. aureus was the most frequent cause of BSIs in all age groups, while E. coli was the most frequent in the Enterobacterales family. S. agalactiae was the third most frequent cause of neonatal early-onset BSIs. The prevalence of Enterococcus spp. increased in the subgroups from 8 days to 5 years of age, while P. aeruginosa became more prevalent in children over 5 years of age. S. aureus was also the most frequent isolate in both community- and hospital-onset BSIs, followed by E. coli. The prevalence of multidrug-resistant (MDR) pathogens was very low. It was <5% for both Gram-positive (i.e., MRSA and VRE) and Gram-negative (ESBL, AmpC, and carbapenem-resistant) pathogens, and MDR pathogens were almost exclusively detected in hospital-onset BSIs. Fungi accounted for just under 8% of BSIs. C. albicans was the most frequently isolated strain, followed by C. parapsilosis. Notably, the IR of fungemia did not change significantly during the study period, in spite of an increase in the absolute number of events. The continuous monitoring of local epidemiology is essential to identify changes in the IRs of pathogens and antibiotic susceptibility and to guide antibiotic treatments, especially in the phase when antibiograms are not yet available.

Background/Objectives: Meropenem is a broad-spectrum antibiotic essential for treating resistant Gram-negative infections in pediatric patients. Current dosing recommendations may not consistently achieve optimal pharmacokinetic (PK) targets, especially in critically ill children. Methods: We conducted a retrospective cohort study at IRCCS Istituto Giannina Gaslini, analyzing 97 plasma levels from 86 pediatric patients (<18 years) hospitalized between January 2020 and December 2023 in the neonatal and pediatric intensive care unit. Patients receiving meropenem for proven or suspected infections were included. Demographic, clinical, and PK parameters were assessed, with a focus on trough concentrations (C_trough). Results: The median age was 25 months, with neonates representing 15.5% of cases. The median C_trough was 2.8 mg/L and was significantly higher in neonates (8.9 mg/L) compared to older patients (2.2 mg/L, p < 0.001). Only 27.8% of patients achieved the target C_trough of >8 mg/L, with estimated glomerular filtration rate (eGFR) being the primary factor influencing these levels. Patients with C_trough > 8 mg/L had a significantly lower eGFR (61 mL/min/1.73 m²) compared to those below this threshold (131 mL/min/1.73 m², p = 0.001). Conclusions: The current meropenem dosing regimen may not reliably meet PK targets in critically ill pediatric patients, particularly those with augmented renal clearance or when treating pathogens with increased meropenem MIC. Our findings suggest that increased dosages and prolonged infusion times may be necessary to optimize therapeutic efficacy against resistant Gram-negative bacteria in this vulnerable population. Further studies are needed to refine dosing strategies and improve patient outcomes.

Background: Urinary tract infections (UTIs) are among the most common bacterial infections in children, and the antibiotic susceptibility in the youngest patients remains poorly understood. This study aimed to describe the distribution of uropathogens and their antibiotic susceptibility, focusing on oral formulations. Methods: Data from the first microbiological isolation, between January 2007 and December 2023, at Istituto Gaslini, in young infants (aged <6 months), were analyzed. Results: We isolated 2473 infants’ first pathogen, with a median age in the sample of 2.8 months and 62.6% male. A total of 2498 bacterial isolates were identified, of which 88.8% were Gram-negative and 11.2% were Gram-positive. Escherichia coli (53%) was the most frequent isolate, followed by Klebsiella pneumoniae (12.3%) and Enterococcus spp. (9.6%). No significant differences were observed between males and females, but infants younger than 3 months exhibited a significantly different pathogen distribution compared to older infants. The pathogen distribution showed significant changes before and after 2015, with a marked increase in Klebsiella pneumoniae isolates post-2015. Escherichia coli showed increases in resistance to amoxicillin-clavulanate and ciprofloxacin after 2015. Conclusions: Escherichia coli remains the most common uropathogen; however, Klebsiella pneumoniae has not only shown a high prevalence but also significant resistance, particularly in recent years.

Manual thrombus aspiration and local drug delivery of abciximab have been proposed as a strategy to reduce thrombus burden during percutaneous coronary intervention in patients with ST elevation myocardial infarction; however, the effectiveness of these approaches, is uncertain. In this COCTAIL II substudy, we compared the effect of these strategies on prestenting and poststenting thrombus burden assessed by optical coherence tomography. COCTAIL II trial enrolled patients with ST elevation myocardial infarction randomized to intralesion (IL, by the ClearWay catheter) versus intracoronary (IC, by the guide catheter) abciximab bolus with or without aspiration thrombectomy (AT). The following parameters were used to quantify atherothrombotic burden: thrombus volume (TVol), maximum thrombus area (TA), and thrombus burden (TB). Primary endpoint was the comparison of prestenting TVol after the use of local drug delivery (group IL+IL abciximab plus AT) versus nonlocal drug delivery (group IC abciximab plus AT+IC). The final population consisted of 59 patients undergoing both prestenting and poststenting optical coherence tomography assessment. The amount of thrombus was not significantly different in the groups with local drug delivery of abciximab versus nonlocal drug delivery in both prestenting (TVol: 18.87±26.70 vs. 19.02±18.45; TB: 26.73±12.8 vs. 25.18±13.25; and maximum TA: 59.25±18.84 vs. 53.34±19.30) and poststenting (TVol: 8.46±9.15 vs. 8.05±6.81; TB: 6.68±3.54 vs. 6.24±3.66; and maximum TA: 15.47±7.61 vs. 16.52±11.55) evaluations. A good correlation between thrombus measurements after thrombus removal techniques and intrastent thrombus was observed. Either local drug delivery of abciximab or manual thrombus aspiration showed comparable results in terms of prestenting and poststenting thrombus burden removal.