Search

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. [ABSTRACT FROM AUTHOR]

Erythromycin resistance in Streptococcus pyogenes has been studied using a prospective study of acute pharyngitis in children in Italy. S. pyogenes was eradicated in 12 of 19 of patients who had erythromycin-resistant S. pyogenes who were treated with clarithromycin. It was also eradicated in 22 of 25 with erythromycin-susceptible strains. The constitutive-resistant phenotype was in correlation with failure of macrolide treatment., In a prospective study of acute pharyngitis in Italian children, 69 (38.3%) of 180 isolates of Streptococcus pyogenes were resistant to macrolides. S. pyogenes was eradicated in 12 (63.1%) of [...]

Gut microbiota plays a role in human health and autoimmunity. Among environmental factor linked to type 1 diabetes (T1DM) pathogenesis, gut microbiota impairment seems to be involved. We evaluated gut microbial fingerprinting in 31 pediatric patients with new-onset T1DM and 25 healthy children using multiple polymorphic region of the 16S rRNA. We performed machine learning and metagenome functional analyses to identify significant taxa and metabolic pathways and correlate with clinical and metabolic parameters. Inclusion criteria were living in Northern Italy, born from Caucasian parents, singleton birth, personal history negative for acute/chronic gastrointestinal diseases and/or antibiotic or probiotics administration. Different Bacteroidetes species i.e., B.stercoris (q=1,473E-4), B.intestinalis (q=0.010), B.fragilis (q=0.0452) were significantly more frequent in patients as well as B.bifidum, Gammaproteobacteria, Holdemania, Synergistetes and their descendants. Abundance of the Synergistetes (q=0.001), Synergistia (q=4.798E-5), Synergistales (q=2.64E-4) and Synergistaceae (q=0.0017) was reported. Among Deltaproteobacteria descendants, the Desulfovibrionales (q=0.0016), Desulfovibrionaceae (q=0.016) and the Bilophila genus (q=0.036) were significantly lower in patients as well as B.vulgatus, Deltaproteobacteria, Parasutterella and Lactobacillus, Turicibacter genera. BMI-SDS, insulin autoantibodies, glycemia, HbA1c, Tanner and age were the most significant positively or negatively parameters related to specific clusters of taxa. The supervised analyses confirmed the importance of B. stercoris in T1DM patients and a relevant role of Synergistetes and its descendants. The robustness and coherence of our results underline the relevance of studying microbioma using multiple polymorphic regions, different types of analysis and approaches within each analysis. Disclosure: G. d'Annunzio: Consultant; Self; Sandoz. R. Biassoni: None. M. Squillario: None. E. Ugolotti: None. A. Barla: None. G. Piccolo: None. N. Minuto: None. M. Maghnie: None. [ABSTRACT FROM AUTHOR]

HLA-C expression is associated with a differential ability to control HIV-1 infection. Higher HLA-C levels may lead to better control of HIV-1 infection through both a higher efficiency of antigen presentation to cytotoxic T lymphocytes and the triggering of activating killer immunoglobulin-like receptors on NK cells, whereas lower levels may provide poor HIV-1 control and rapid progression to AIDS. We characterized the relative amounts of HLA-C heterotrimers (heavy chain/β 2 microglobulin [β 2 m]/peptide) and HLA-C free heavy chains on peripheral blood mononuclear cells (PBMCs) from healthy blood donors harboring both alleles with stable or unstable binding to β 2 m/peptide. We analyzed the stability of HLA-C heterotrimers of different allotypes and the infectivity of HIV-1 virions produced by PBMCs with various allotypes. We observed significant differences in HLA-C heterotrimer stability and in expression levels. We found that R5 HIV-1 virions produced by PBMCs harboring unstable HLA-C alleles were more infectious than those produced by PBMCs carrying the stable variants. We propose that HIV-1 infectivity might depend both on the amounts of HLA-C molecules and on their stability as trimeric complex. According to this model, individuals with low-expression HLA-C alleles and unstable binding to β 2 m/peptide might have worse control of HIV-1 infection and an intrinsically higher capacity to support viral replication. IMPORTANCE Following HIV-1 infection, some people advance rapidly to AIDS while others have slow disease progression. HLA-C, a molecule involved in immunity, is a key determinant of HIV-1 control. Here we reveal how HLA-C variants contribute to the modulation of viral infectivity. HLA-C is present on the cell surface in two different conformations. The immunologically active conformation is part of a complex that includes β 2 microglobulin/peptide; the other conformation is not bound to β 2 microglobulin/peptide and can associate with HIV-1, increasing its infectivity. Individuals with HLA-C variants with a predominance of immunologically active conformations would display stronger immunity to HIV-1, reduced viral infectivity and effective control of HIV-1 infection, while subjects with HLA-C variants that easily dissociate from β 2 microglobulin/peptide would have a reduced immunological response to HIV-1 and produce more infectious virions. This study provides new information that could be useful in the design of novel vaccine strategies and therapeutic approaches to HIV-1., (Copyright © 2017 Parolini et al.)