Background/Objectives: Carbapenem-resistant Klebsiella pneumoniae has become endemic in Europe, including in Italy, where its prevalence has risen dramatically, primarily due to epidemic clones harboring metallo-enzymes. This study aims to investigate the dissemination of K. pneumoniae strains co-producing OXA-48 and NDM-1 between two hospitals in southern Italy using molecular analyses. Methods: A total of 49 K. pneumoniae strains, predominantly co-producing OXA-48 and NDM-1, were collected between March and December 2023. Antibiotic susceptibility testing was conducted following EUCAST guidelines. Whole-genome sequencing (Illumina MiSeq) and bioinformatics tools (CARD, CLC Genomics Workbench) were used to identify resistance and virulence genes, capsule loci, and phylogenetic relationships. Results: All isolates exhibited multidrug-resistant or extensively drug-resistant profiles, including resistance to ceftazidime/avibactam and meropenem/vaborbactam. Genomic analysis revealed diverse resistance genes such as bla_OXA-48, bla_NDM-1, bla_CTX-M-15, and bla_SHV variants. Virulence genes associated with capsules, fimbriae, and siderophores were widespread. Most strains were classified as ST147 by MLST and contained various plasmids known to carry antimicrobial resistance. Phylogenetic analysis confirmed their clonal relatedness, highlighting the intra-hospital dissemination of high-risk clones. Conclusions: High-risk K. pneumoniae clones, particularly ST147, pose significant challenges in healthcare settings due to the extensive antimicrobial resistance driven by plasmid-borne resistance genes, including those that co-produce carbapenemases, like bla_NDM-1 and bla_OXA-48. Molecular monitoring of these clones is essential for improving targeted infection control strategies, mitigating the spread of multidrug-resistant pathogens, and managing their clinical impact effectively.

SARS-CoV-2 is constantly evolving, leading to new variants. We analysed data from 4400 SARS-CoV-2-positive samples in order to pursue epidemiological variant surveillance and to evaluate their impact on public health in Italy in the period of April–December 2021. The main circulating strain (76.2%) was the Delta variant, followed by the Alpha (13.3%), the Omicron (5.3%), and the Gamma variants (2.9%). The B.1.1 lineages, Eta, Beta, Iota, Mu, and Kappa variants, represented around 1% of cases. There were 48.2% of subjects who had not been vaccinated, and they had a lower median age compared to the vaccinated subjects (47 vs. 61 years). An increasing number of infections in the vaccinated subjects were observed over time, with the highest proportion in November (85.2%). The variants correlated with clinical status; the largest proportion of symptomatic patients (59.6%) was observed with the Delta variant, while subjects harbouring the Gamma variant showed the highest proportion of asymptomatic infection (21.6%), albeit also deaths (5.4%). The Omicron variant was only found in the vaccinated subjects, of which 47% had been hospitalised. The diffusivity and pathogenicity associated with the different SARS-CoV-2 variants are likely to have relevant public health implications, both at the national and international levels. Our study provides data on the rapid changes in the epidemiological landscape of the SARS-CoV-2 variants in Italy.

Background: Sepsis remains a major cause of morbidity and mortality in both developed and limited-resource countries. Despite over a century of research, accurate biomarkers for reliable diagnosis and prognosis in critically ill patients have yet to be established. Methods: This multicenter retrospective observational study aims to evaluate serum levels of Calprotectin, Azurocidin, cytokines, chemokines, procalcitonin (PCT) and C-Reactive Protein (CRP) in 15 healthy volunteers (controls), 15 non-infectious SIRS patients, 92 alive septic patients (Sepsis_A) and 29 dead septic patients (Sepsis_D). Results: Most biomarkers showed significantly higher serum concentrations in septic patients compared with controls, with IL-4 being increased only in the Sepsis_D group. In addition, several markers, including Calprotectin, Azurocidin, IL-6, IL-8, IL-10, TNF-α, and IL-35, were progressively elevated from SIRS to Sepsis_A and Sepsis_D cohorts, reflecting disease severity. All biomarkers showed good diagnostic performance for predicting Gram-negative bacteremia, although their accuracy in discriminating survivors from non-survivors was relatively low. Conclusions: In conclusion, calprotectin, azurocidin, IL-8, TNF-α, and IL-35 may assist clinicians in identifying Gram-negative bacteremia in septic patients; however, their prognostic value appears to be limited.

Neonatal meningitis and sepsis were diagnosed in a 32-day-old preterm-born infant. Streptococcus (S.) suis was isolated from cerebrospinal fluid and blood. Next-generation sequencing revealed that the strain was serotype 2 sequence type 1, and contained the ermB and tet(W) genes, which are responsible for resistance to macrolides and tetracycline, along with several pilus-associated genes and 20 virulence factors. High homology was observed with previously identified human and swine strains in the same area. S. suis meningitis and sepsis are mainly reported in adults, related to direct contact with pigs or contaminated pork meat consumption, while it is rarely reported in children. Herein, we describe the first case of S. suis in a newborn associated with meningitis and antimicrobial resistance. The rates of resistance to tetracyclines, lincosamides, and macrolides for this bacterium are increasing and are creating concern worldwide. Altogether, our findings highlight the importance of investigating S. suis in cases of neonatal meningitis, as well as the necessity of assessing the antimicrobial profile to obtain useful information for developing targeted therapies.

West Nile virus lineage 2 (WNV-2) is a growing public health concern in Europe causing West Nile fever or West Nile neuroinvasive disease (WNND) with substantial morbidity and mortality; however, genomic data from southern Italy are limited despite recent expansion of autochthonous transmission. The aim of the study was to characterize the phylogenetic and molecular features of the WNV-2 strain responsible for the first autochthonous human infection reported in Calabria (2023), and two more additional WNND cases detected in 2024. Full WNV-2 genomes were generated from the three cases. Phylogenetic analysis was performed using all publicly available WNV sequences up to September 2025. Amino acid changes in the polyprotein were compared with known WNV-2 lineage and sub-lineage signatures. The three sequences formed a monophyletic group within sub-lineage WNV-2a, clustering with strains circulating in Central-South-Eastern Europe and showing closest affinity to Hungarian sequences. Non-synonymous substitutions characteristic of the Hungary 578/10 strain (NS2B-119I, NS4B-14G, NS4B-49A, and NS5-298A) were identified and were absent from Central-Northern-Western European and previously reported Italian sequences. Additional substitutions (E-159T, E-399R, and NS3-249P) corresponded to signatures from a fatal WNV-2 infection in a Great Grey Owl in Slovakia. Our study provides the first report of Central-South-Eastern European WNV-2 circulation outside Eastern Europe, supporting its likely spread through the Balkans into Italy by 2022. These findings underscore the rapid spread of WNV-2 in newly affected areas and highlight the critical need for sustained molecular surveillance.

This study, for the first time in Italy, analyses by WGS a Streptococcus agalactiae strain isolated from a non-pregnant adult affected by Meningitis and without common risk factors. The S. agalactiae strain was classified as a serotype II (SS2), sequence type ST569. Molecular characterization evidenced the presence of resistance genes to tetracycline and macrolide (tet(M) and mre(A)) and several virulence genes coding for adhesion and immune evasion factors (bca, cps family, neu family, scpB, gbs family, pil family and hylB), toxins (cfa/cfb, cyl family), pro-inflammatory factors (lepA), and two homologous genes that contributed to bacterial escape from the host immune system (lmb, luxS). SNP analysis showed 18 different alleles, with 9 missense SNP mutations related to genes involved in cellular metabolism (dhaS, ftsE, ligA, nrdD and secA), virulence (bgrR and galE) and antimicrobial resistance (glpK and mutL). SNPs in glpK and mutL genes might reduce susceptibility to drugs. The SNP analysis highlighted the presence of mutations conferring pathogenicity to the strain. The evidence in this study could explain the development of Meningitis in a healthy patient. This case highlights the importance of using molecular methods to characterize the complete genome of a bacterial species that could seriously affect human health.