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Cystic fibrosis (CF) is a life-threatening genetic disease characterised by chronic lung infections sustained by opportunistic pathogens such as Pseudomonas aeruginosa. During the chronic long-lasting lung infections, P. aeruginosa adapts to the host environment. Hypermutability, mainly due to defects in the DNA repair system, resulting in an increased spontaneous mutation rate, represents a way to boost the rapid adaptation frequently encountered in CF P. aeruginosa isolates. We selected 609 isolates from 51 patients with CF chronically colonised by P. aeruginosa to study, by full-length genome sequencing, the longitudinal evolution of the bacterium. We recovered at least one hypermutable (mutator) isolate in 57% of patients. By combining genomic information and phenotypic analyses, we followed the evolutionary pathways of the P. aeruginosa mutator strains, identifying their contribution to multi-drug resistance and the emergence of new sub-lineages. By implementing patient clinical data, we observed that mutators preferentially follow a specific evolutionary trajectory in patients with a negative clinical outcome and that maintenance antibiotic polytherapy, based on alternating molecules, apparently reduces the occurrence of hypermutability. Finally, we draw attention to the possibility that modulator-induced changes in the pulmonary environment may be associated with the onset of hypermutability. [ABSTRACT FROM AUTHOR]

(1) Background: The literature reports a low risk of serious bacterial infections (SBIs) in febrile infants presenting with bronchiolitis or respiratory syncytial virus infection, but current microbiological techniques have a higher accuracy. (2) Methods: We assessed the risk of SBIs in neonates and infants with bronchiolitis from 2021 to 2023. We also evaluated C-reactive protein, procalcitonin, and leukocyte values. (3) Results: We included 242 infants. Blood cultures (BCs) were performed in 66/242 patients, with a positivity rate of 9.1% (including one BC with Staphylococcus hominis, considered as a contaminant). The cerebrospinal fluid culture was performed in 6/242 patients, and the results were all negative. Infection markers did not discriminate infants with positive BCs from those with negative ones. (4) Conclusions: Blood cultures should be performed in neonates and young infants with bronchiolitis fever, as the sepsis risk is not negligible. Conversely, our proposed algorithm is to wait for the respiratory panel results before decision-making for a lumbar puncture. Further studies are needed to understand lumbar puncture requirements. [ABSTRACT FROM AUTHOR]

This article reports a rapid and unexpected spread of colonization cases of NDM-1 carbapenemase-producing Klebsiella pneumoniae and Escherichia coli in a neonatal surgical unit (NSU) at Bambino Gesù Children's Hospital in Rome, Italy. Between the 16th of November 2020 and the 18th of January 2021, a total of 20 NDM-1 carbapenemase-producing K. pneumoniae (n = 8) and E. coli (n = 12) were isolated from 17 out of 230 stool samples collected from neonates admitted in the aforementioned ward and time period by an active surveillance culture program routinely in place to monitor the prevalence of colonization/infection with multidrug-resistant Gram-negative microorganisms. All strains were characterized by antimicrobial susceptibility testing, detection of resistance determinants, PCR-based replicon typing (PBRT) and multilocus-sequence typing (MLST). All isolates were highly resistant to most of the tested antibiotics, and molecular characterization revealed that all of them harbored the blaNDM-1 gene. Overall, IncA/C was the most common Inc group (n = 20/20), followed by IncFIA (n = 17/20), IncFIIK (n = 14/20) and IncFII (n = 11/20). MLST analysis was performed on all 20 carbapenemase-producing Enterobacterales (CPE) strains, revealing three different Sequence Types (STs) among E. coli isolates, with the prevalence of ST131 (n = 10/12; 83%). Additionally, among the 8 K. pneumoniae strains we found 2 STs with the prevalence of ST37 (n = 7/8; 87.5%). Although patient results were positive for CPE colonization during their hospital stay, infection control interventions prevented their dissemination in the ward and no cases of infection were recorded in the same time period. [ABSTRACT FROM AUTHOR]

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Objectives: Blood level of pancreatic stone protein (PSP) is a promising biomarker of sepsis both in adults and children. The aim of our study was to investigate the diagnostic accuracy of PSP in children with suspected sepsis and to compare diagnostic performance with other sepsis biomarkers approved for clinical use, that is, procalcitonin (PCT) and C-reactive protein (CRP)., Design: Prospective study., Setting: PICU and pediatric emergency department., Intervention: Blood levels of PSP were measured using a nanofluidic point-of-care immunoassay (abioSCOPE, Abionic SA, Switzerland) within 24 hours of admission., Measurements and Main Results: We studied 99 children aged between older than 1 month and younger than 18 years with signs and symptoms of systemic inflammatory response syndrome (irrespective of associated organ dysfunction). The prevalence of sepsis was 35 of 99 (35.4%). Patients with sepsis had higher PSP levels ( p < 0.001) than patients with systemic inflammation of noninfectious cause. In this analysis, the optimal cutoff for the diagnosis of sepsis using PSP was 123 ng/mL, which resulted in a sensitivity of 0.63 (95% CI, 0.43-0.80), specificity of 0.89 (95% CI, 0.77-0.95). The PSP test area under the receiver operating characteristic curve (AUROC) was 0.82 (95% CI, 0.73-0.91) and, by comparison, procalcitonin and CRP AUROC were 0.70 (95% CI, 0.58-0.82) and 0.72 (95% CI, 0.60-0.84), respectively. Overall, the pretest to posttest probability of sepsis with a positive test changed from 0.35 to 0.73., Conclusions: In this single-center prospective pediatric cohort, admitted to the high intensive care and to the PICU, our findings suggested the potential use of PSP as a sepsis biomarker. However, because of the clinical diagnostic uncertainty with a positive result, further investigation is needed particularly in combination with other biomarkers., Competing Interests: Dr. Cecchetti received support for article research from the National Institutes of Health; he disclosed government work. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.)