Background Allergic rhinitis (AR) is one of the most common allergic diseases affecting children. Objective assessment of nasal obstruction is possible through active anterior rhinomanometry (AAR). Several factors, such as passive smoke exposure (PSE), are triggers for worsening nasal obstruction and chronic inflammation. PSE affects bacterial eubiosis in the upper respiratory tract. This study evaluates the influence of PSE and cotinine levels on both nasal obstruction and local microbiome composition in children with AR. Methods Fifty patients (aged between 6 and 16 years) with AR monosensitized grass pollen were enrolled. They underwent skin prick tests, a nasal swab to evaluate the microbial composition of the anterior nostrils, a basal AAR, a post‐decongestion AAR, and spirometry. Serum cotinine levels were assessed to evaluate PSE. Results A significantly lower percentage of mean nasal flow (mNF%) was observed before and after hydrazine administration in subjects exposed to passive smoke (Exp group) compared with the non‐exposed group. In contrast, higher cotinine levels were observed in the Exp group than in the controls. PSE has been associated with a decrease in biodiversity and a change in the nasal microbiome composition; instead, although to a different extent, the abundance of specific taxa resulted in being correlated to cotinine levels and nasal flow. Conclusion Children with AR exposed to passive smoke with positive serum cotinine could represent a risk factor for developing nasal obstruction and microbial dysbiosis, suggesting their possible role in pathophysiological processes.

In recent decades, Acinetobacter baumannii emerged as a major infective menace in healthcare settings due to scarce therapeutic options to treat infections. Therefore, undertaking genome comparison analyses of multi-resistant A. baumannii strains could aid the identification of key bacterial determinants to develop innovative anti-virulence approaches. Following genome sequencing, we performed a molecular characterization of key genes and genomic comparison of two A. baumannii strains, #36 and #150, with selected reference genomes. Despite a different antibiotic resistance gene content, the analyzed strains showed a very similar antibiogram profile. Interestingly, the lack of some important virulence determinants (i.e., bap, ata and omp33–36) did not abrogate their adhesive abilities to abiotic and biotic surfaces, as reported before; indeed, strains retained these capacities, although to a different extent, suggesting the presence of distinct vicarious genes. Conversely, secretion systems, lipopolysaccharide (LPS), capsule and iron acquisition systems were highly similar to A. baumannii reference strains. Overall, our analyses increased our knowledge on A. baumannii genomic content and organization as well as the genomic events occurring in nosocomial isolates to better fit into changing healthcare environments.

BackgroundAtopic dermatitis (AD) is a chronic inflammatory skin condition whose pathogenesis involves genetic predisposition, epidermal barrier dysfunction, alterations in the immune responses and microbial dysbiosis. Clinical studies have shown a link between Staphylococcus aureus and the pathogenesis of AD, although the origins and genetic diversity of S. aureus colonizing patients with AD is poorly understood. The aim of the study was to investigate if specific clones might be associated with the disease. MethodsWGS analyses were performed on 38 S. aureus strains, deriving from AD patients and healthy carriers. Genotypes (i.e. MLST, spa-, agr- and SCCmec-typing), genomic content (e.g. virulome and resistome), and the pan-genome structure of strains have been investigated. Phenotypic analyses were performed to determine the antibiotic susceptibility, the biofilm production and the invasiveness within the investigated S. aureus population. ResultsStrains isolated from AD patients revealed a high degree of genetic heterogeneity and a shared set of virulence factors and antimicrobial resistance genes, suggesting that no genotype and genomic content are uniquely associated with AD. The same strains were characterized by a lower variability in terms of gene content, indicating that the inflammatory conditions could exert a selective pressure leading to the optimization of the gene repertoire. Furthermore, genes related to specific mechanisms, like post-translational modification, protein turnover and chaperones as well as intracellular trafficking, secretion and vesicular transport, were significantly more enriched in AD strains. Phenotypic analysis revealed that all of our AD strains were strong or moderate biofilm producers, while less than half showed invasive capabilities.ConclusionsWe conclude that in AD skin, the functional role played by S. aureus may depend on differential gene expression patterns and/or on post-translational modification mechanisms rather than being associated with peculiar genetic features.