Bacterial infections caused by multidrug-resistant (MDR) Gram-negatives are of great concern worldwide, as they are frequently associated with high mortality and morbidity rates. To date, two cases of VIM-2 metallo-β-lactamase (MBL)-producing Pseudomonas putida bacteremia have been ever reported in France and Spain between 2004 and 2010. Here, we present the first case of VIM-1-like-producing P. putida isolated in blood culture collected from an oncohematological pediatric patient admitted to Bambino Gesù Children’s Hospital (IRCCS) in Rome, Italy.

Invasive group A streptococci infections are increasing worldwide, mainly due to the emm1 lineage M1_UK emergence. Although this variant has recently been described in adult Italian patients, its circulation in children has not yet been established. Characterizing by whole genome sequencing 6 invasive group A streptococci strains isolated between 2022 and 2023, we highlighted M1_UK lineage circulation in pediatric patients in Italy.

Candida viswanathii has been sporadically reported in Asia and South America but not in Europe. This study reports the first European outbreak of C. viswanathii in a paediatric hospital, outlining diagnostic challenges and containment measures. Fifteen C. viswanathii isolates were recovered from blood cultures of consecutive pediatric patients admitted to intensive care units between April and August 2025. Identification was performed using MALDI-TOF MS, chromogenic media, Fourier-transform infrared (FT-IR) spectroscopy, and whole-genome sequencing (WGS). Antifungal susceptibility testing was performed by broth microdilution. All isolates were initially misidentified as C. tropicalis by MALDI-TOF MS and undetected by the FilmArray BCID2 panel. WGS confirmed C. viswanathii, and FT-IR analysis revealed clonally related strains, indicating an outbreak. Colonies displayed a distinct deep-blue color on chromogenic CHROMagar™ medium. Elevated fluconazole minimum inhibitory concentrations were observed, while isolates remained susceptible to echinocandins and amphotericin B. A multidisciplinary infection-control response halted transmission within four weeks. This investigation documents the first C. viswanathii outbreak in Europe, highlighting diagnostic limitations of current commercial tools and the need for updated databases. Integration of FT-IR spectroscopy and WGS facilitated outbreak detection and containment, underscoring the importance of advanced diagnostics and surveillance for emerging fungal pathogens.

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.

Streptococcus pyogenes meningitis is a rare invasive disease, accounting for less than 2% of bacterial meningitis. We presented two case reports and conducted a systematic review using PUBMED, covering the database from its inception up to 31 December 2024, of pediatric cases of Streptococcus pyogenes meningitis. Only case reports and case series were included. Differences in clinical and laboratory parameters were compared between uneventful course and complicated admissions. A total of 57 cases were included. The median age at diagnosis was 4 years. A primary infection focus outside the brain was identified in 61.39% of cases. S. pyogenes was identified from cerebrospinal fluid in 66.66% of cases and from blood in 15.79%. Septic shock occurred in 24.56% of cases, and 36.84% had brain anatomical anomalies. All patients received broad-spectrum empiric antibiotics, while protein-synthesis inhibitors were administered in 26.31% of cases. A total of 17% of patients died, and 28.07% experienced sequelae. The identification of S. pyogenes from blood and a Phoenix Sepsis Score ≥ 2 were significantly associated with a complicated clinical course. Our findings may offer useful insights for the clinical management of Streptococcus pyogenes meningitis.

(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.