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Bacteria employ two-component signal transduction systems (TCS) to sense environmental fluctuations and adjust their cellular functions. The Arc TCS is crucial for facultative anaerobes as it enables adaptation to varying respiratory conditions. The Escherichia coli ArcB detects redox changes through two cysteine amino acid residues within its PAS domain. However, the ArcB homologs from most bacteria belonging to the Pasteurellaceae family, lack the entire PAS domain, and in consequence the two regulatory cysteine amino acid residues. In this study, we show that the PAS-less ArcB of Haemophilus influenzae regulates its activity via a cysteine-independent mechanism, and we provide data suggesting that it responds to metabolic signals rather than redox cues. Thus, these two ArcB orthologs sense distinct signals and their regulatory mechanism rely on different molecular events. Our findings reveal divergent evolutionary trajectories of these ArcB homologs, despite the overall conservation of protein components, providing an example of how evolution has shaped different sensing strategies in bacteria. [ABSTRACT FROM AUTHOR]

Background: Haemophilus influenzae is an opportunistic bacterial pathogen that can cause severe respiratory tract and invasive infections. The emergence of β-lactamase-negative ampicillin-resistant (BLNAR) strains and unclear correlations between genotypic (i.e., gBLNAR) and phenotypic resistance are challenging empirical treatments and patient management. Thus, we sought to revisit molecular resistance mechanisms and to identify new resistance determinants of H. influenzae. Methods: We performed a systematic meta-analysis of H. influenzae isolates (n = 291) to quantify the association of phenotypic ampicillin and cefotaxime resistance with previously defined resistance groups, i.e., specific substitution patterns of the penicillin binding protein PBP3, encoded by ftsI. Using phylogenomics and a genome-wide association study (GWAS), we investigated evolutionary trajectories and novel resistance determinants in a public global cohort (n = 555) and a new clinical cohort from three European centers (n = 298), respectively. Results: Our meta-analysis confirmed that PBP3 group II- and group III-related isolates were significantly associated with phenotypic resistance to ampicillin (p < 0.001), while only group III-related isolates were associated with resistance to cefotaxime (p = 0.02). The vast majority of H. influenzae isolates not classified into a PBP3 resistance group were ampicillin and cefotaxime susceptible. However, particularly group II isolates had low specificities (< 16%) to rule in ampicillin resistance due to clinical breakpoints classifying many of them as phenotypically susceptible. We found indications for positive selection of multiple PBP3 substitutions, which evolved independently and often step-wise in different phylogenetic clades. Beyond ftsI, other possible candidate genes (e.g., oppA, ridA, and ompP2) were moderately associated with ampicillin resistance in the GWAS. The PBP3 substitutions M377I, A502V, N526K, V547I, and N569S were most strongly related to ampicillin resistance and occurred in combination in the most prevalent resistant haplotype H1 in our clinical cohort. Conclusions: Gradient agar diffusion strips and broth microdilution assays do not consistently classify isolates from PBP3 groups as phenotypically resistant. Consequently, when the minimum inhibitory concentration is close to the clinical breakpoints, and genotypic data is available, PBP3 resistance groups should be prioritized over susceptible phenotypic results for ampicillin. The implications on treatment outcome and bacterial fitness of other extended PBP3 substitution patterns and novel candidate genes need to be determined. [ABSTRACT FROM AUTHOR]

The present study evaluates the physicochemical attributes, antibacterial efficacy, and antioxidant capacities of four distinct varieties of honey from the West Bank region of Palestine: Assal Barsem (Medicago sativa) AB, Assal Morar (Centaurea dumulosa Boiss) AM, Assal Horfesh (Silybum) AH, and Assal Sader (Ziziphus spina-christi) AS. The analysis encompassed parameters such as pH, electrical conductivity, Total Flavonoid Content (TFC), and Total Phenolic Content (TPC). Furthermore, the antioxidant potential was gauged through Total Antioxidant Capacity (TAC) determination and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. In addition, the antibacterial effectiveness of the honeys was measured against a spectrum of bacterial strains including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae, and Bacillus subtilis, utilizing minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentrations (MBC). The outcomes of the physicochemical analysis adhered to the quality benchmarks outlined by the European Union Commission and the Codex Alimentarius Commission. The MIC and MBC values exhibited notable variance across the tested honey varieties, with MIC values ranging from 0.024% w/w to 1.56% w/w, and MBC values ranging from 0.048% w/w to 3.15% w/w. Particularly, AH demonstrated superior efficacy against all seven bacterial strains, with MIC values spanning from 0.1 to 0.6% w/w, and MBC values ranging from 0.3% w/w to 0.8% w/w. Staphylococcus aureus and Escherichia coli were notably susceptible to all honey samples. Collectively, our findings underscore the therapeutic potential of Palestinian honey varieties, highlighting their multifaceted health-promoting attributes. Further exploration is warranted to elucidate the mechanistic underpinnings of bioactive constituents and explore their potential applications in healthcare. [ABSTRACT FROM AUTHOR]

Background: Healthcare settings may amplify transmission of respiratory pathogens, however empirical evidence is lacking. We aimed to describe the spectrum and distribution of respiratory pathogens among healthcare workers in eastern China. Methods: Healthcare workers were recruited from October 2020 to November 2021 in Jiangsu province. Participants were interviewed regarding demographic and hospital-based protective measures. Thirty-seven common respiratory pathogens were tested using real-time PCR/RT-PCR (Probe qPCR). The role of demographic and hospital-based protective measures on pathogens colonization using multivariable logistic regression models. Results: Among 316 enrolled healthcare workers, a total of 21 pathogens were detected. In total, 212 (67.1%) healthcare workers had at least one respiratory pathogen; 195 (61.7%) and 70 (22.2%) with a bacterial and viral pathogen. The most commonly detected pathogen was streptococcus pneumoniae (47.5%) followed by Haemophilus influenzae (21.2%). One hundred and five (33.2%) healthcare workers with copathogens had at least two respiratory pathogens. Both bacterial and viral colonization were more common in 2020 compared to 2021. A decreased risk of colonization was seen in participants with infection prevention and control training and suitable hand hygiene. Conclusions: Colonization of respiratory pathogens in healthcare workers from eastern China was high. Differential risk was impacted only by hospital-based protective measures and not demographic factors. [ABSTRACT FROM AUTHOR]

To describe the symptoms, duration, severity, and microbiology of lower respiratory tract infection (LRTI) in outpatients. Prospective cohort study of adults in US primary or urgent care with a chief complaint of cough and symptoms consistent with LRTI. Baseline data included demographics, signs, symptoms, and PCR for 46 viruses and bacteria. The severity of symptoms reported for ≤28 days follow-up via diary and text message. The Bronchitis severity score assessed severity at baseline; overall severity was defined as the area under the symptom severity curve. Of 718 patients with complete baseline data, 618 had valid PCR results, and 443 were followed until symptoms resolved. Of those with valid PCR, 100 (16.2%) had 1+ viruses detected, 211 (34.1%) had 1+ bacteria, and 168 (27.2%) had both. Symptoms more likely with viral or mixed infection included feverishness (36.7–38.4% vs. 18.5%), chills or sweats (36.0–38.1% vs. 17.9%), being generally unwell (78.2–81.3% vs. 64.9%), and myalgias (42.7–48.2% vs. 28.6%). Coloured sputum (42.9% vs. 23.2–29.5%) was more common with a bacterial infection. The mean duration of cough was 14.7 days with viruses (95% CI: 13.2–16.2), 17.3 with bacteria (95% CI: 15.9–18.6), 16.9 with mixed infection (95% CI: 15.2–18.6), and 18.4 with no detection (95% CI: 16.1–20.8). Overall severity of cough was lower for viral infections (20.9 points, 95% CI: 18.6–23.3) than for other groups (range 24.2–26.3). The most common potential bacterial pathogens were Haemophilus influenza (28.0%), Moraxella catarrhalis (16.2%), and Streptococcus pneumoniae (10.2%), whereas the most common viral pathogens were rhinovirus (17.3%), influenza (12.8%), SARS-CoV-2 (11.5%), and seasonal coronaviruses (8.1%). The mean duration of cough was 16.4 days. Consistent with European studies, the type of infection or potential pathogen was not an important predictor of the duration or severity of LRTI. [ABSTRACT FROM AUTHOR]

Rapid identification of causative bacteria in treatment of acute otitis media (AOM) is of paramount importance for appropriate antibiotic use. This prospective observational study was conducted in 15 hospitals and clinics in Japan between 2018 and 2020. A new rapid antigen test kit (AOS-116), which simultaneously detects antigens for Streptococcus pneumoniae (Sp) and Haemophilus influenzae (Hi), was applied for middle ear fluids (MEFs) and nasopharyngeal secretions (NPSs) in patients with moderate to severe AOM. We investigated relationship between the results of rapid test, severity at initial visit, and clinical course. Regarding performance accuracy based on culture results, AOS-116 showed 1) high (>80%) sensitivity, specificity, and negative predictive value (NPV) in MEFs for both antigens, 2) high sensitivity, specificity, and positive predictive value (PPV) in NPSs for Hi antigen, and 3) high specificity, and PPV in NPSs for Sp antigen. Regarding predictive value of nasopharyngeal culture and antigen detection for causative middle ear pathogens, similar results were observed between AOS-116 and culture, which was characterized with high sensitivity and NPV for both pathogens. MEFs/NPSs positive for Hi antigen were significantly associated with eardrum findings, and severity. MEFs/NPSs positive for pneumococcal antigen were significantly associated with severity of otalgia, fever, and otorrhea. Among patients with prior antimicrobial treatment, improvement tended to be slower in cases positive for Hi than in cases negative. The rapid antigen detection test is useful as a decision-making tool for prescribing antimicrobial agents and may play an important role in promoting appropriate antimicrobial use. [ABSTRACT FROM AUTHOR]

Haemophilus influenzae serotype a (Hia) has recently emerged as an important cause of invasive disease in the North American Arctic and Sub-Arctic regions, mainly affecting young Indigenous children. In this study, we addressed the question of whether the prevalence of Hia and all H. influenzae in the nasopharynx differed between paediatric populations from regions with high versus low incidence of invasive Hia disease. Nasopharyngeal specimens from children with acute respiratory tract infections (ARTI) collected for routine diagnostic detection of respiratory viruses were analysed with molecular-genetic methods to identify and serotype H. influenzae. In Nunavut, a region with a high incidence of invasive Hia disease, all H. influenzae and particularly Hia were found in the nasopharynx of 60.6% and 3.0% children. In Southern Ontario (Hamilton region), where Hia invasive disease is rare, the frequencies of all H. influenzae and Hia detection were 38.5% and 0.6%, respectively. In both cohorts, non-typeable H. influenzae was prevalent (57.0% and 37.9%, respectively). Considering that Hia is an important cause of severe invasive disease in Nunavut children, 3% prevalence of Hia among children with ARTI can reflect continuing circulation of the pathogen in the Northern communities that may result in invasive disease outbreaks. [ABSTRACT FROM AUTHOR]

The triple combination elexacaftor-tezacaftor-ivacaftor (ETI) has provided unprecedented clinical benefits for people with cystic fibrosis (pwCF) and drastically transformed the outcome of this disease. We aimed to describe the evolution of lung bacterial colonization in 198 French adult pwCF taking into account the use of concomitantly respiratory treatment. We collected sputum cultures produced during the entire follow-up period starting 3 years before and ending 1 year after ETI initiation. All sputum cultures were centralized and analyzed at our bacteriological laboratory. Clinical data included pulmonary function, respiratory treatments, physiotherapy, number of IV antibiotics treatment, as well as inpatient stays. We observed a significant decrease in colonization prevalence by any CF pathogen after one year of treatment with ETI (p < 0.001). This decrease was confirmed for Pseudomonas aeruginosa, MRSA and MSSA, Stenotrophomonas maltophilia, Achromobacter spp. and nontuberculous mycobacteria (NTM). The maximal density of bacteria documented in sputum cultures decreased from 2.107 CFU/ml to 1.106 CFU/ml after one year of ETI. We also found a decrease in prevalence of Pseudomonas aeruginosa chronic colonization and in the density of Pseudomonas aeruginosa after one year of ETI. These results confirm the decrease in prevalence and bacterial density of lung colonisation for most of the CF pathogens, including Achromobacter spp, Stenotrophomonas maltophilia concomitantly to the clinical improvement. Further studies are needed to better understand the underlying mechanisms of these microbiological changes. [ABSTRACT FROM AUTHOR]

Nucleic acid amplification tests (NAATs) greatly enhance the capacity to identify the etiology of pediatric complicated pneumonia. However, the use of pneumococcal conjugate vaccines could reduce the importance of Streptococcus pneumoniae in pediatric complicated pneumonia with the potential emergence of other bacterial agents. Using an expanded NAAT in culture negative pleural fluid or empyema samples collected in 2010–2024 (n = 554) in Portugal, we show that S. pneumoniae remains the most frequent agent despite decades of pneumococcal conjugate vaccine use and the COVID-19 pandemic. A rebound in pediatric complicated pneumonia occurred post-pandemic, including a rise in cases by Streptococcus pyogenes and Haemophilus influenzae. Empiric therapy of pediatric complicated pneumonia should still consider S. pneumoniae as the most likely cause, even in countries where the pneumococcal conjugate vaccine is in the national immunization program with a high uptake. [ABSTRACT FROM AUTHOR]

The tripartite ATP-independent periplasmic (TRAP) transporters enable Vibrio cholerae and Haemophilus influenzae to acquire sialic acid, aiding their colonization of human hosts. This process depends on SiaP, a substrate-binding protein (SBP) that captures and delivers sialic acid to the transporter. We identified 11 nanobodies that bind specifically to the SiaP proteins from H. influenzae (HiSiaP) and V. cholerae (VcSiaP). Two nanobodies inhibited sialic acid binding. Detailed structural and biophysical studies of one nanobody-SBP complex revealed an allosteric inhibition mechanism, preventing ligand binding and releasing pre-bound sialic acid. A hydrophobic surface pocket of the SBP is crucial for the allosteric mechanism and for the conformational rearrangement that occurs upon binding of sialic acid to the SBP. Our findings provide new clues regarding the mechanism of TRAP transporters, as well as potential starting points for novel drug design approaches to starve these human pathogens of important host-derived molecules. Biophysical and structural characterization of the TRAP transporter SBP SiaP in complex with a nanobody provides insights into an allosteric mechanism of inhibition. [ABSTRACT FROM AUTHOR]

Background: Haemophilus influenzae causes life-threatening invasive diseases such as septicaemia and meningitis. Reports on circulating H. influenzae causing invasive disease in lower-middle income settings, including Indonesia, are lacking. This study describes the serotype distributions and whole-genome sequence (WGS) data of H. influenzae isolated from hospitalized patients at Soetomo Hospital, Surabaya, Indonesia. Methods: H. influenzae isolates were isolated from blood and pleural fluid specimens and identified using culture-based and molecular methods, followed by serotyping and WGS using RT‒PCR and Illumina MiSeq, respectively. Sequencing reads were assembled, and further analyses were undertaken to determine the genomic content and reconstruct the phylogeny. A second dataset consisting of publicly available H. influenzae genomes was curated to conduct phylogenetic analyses of isolates in this study in the context of globally circulating isolates. Results: Ten H. influenzae isolates from hospitalized patients were collected, and septicaemia was the most common diagnosis (n=8). RT‒PCR and WGS were performed to determine whether all the isolates were nontypeable H. influenzae (NTHi). There were four newly identified STs distributed across the two main clusters. A total of 91 out of 126 virulence factor (VF)-related genes in Haemophilus sp. were detected in at least one isolate. Further evaluation incorporating a global collection of H. influenzae genomes confirmed the diverse population structure of NTHi in this study. Conclusion: This study showed that all H. influenzae recovered from invasive disease patients were nonvaccine-preventable NTHi isolates. The inclusion of WGS revealed four novel STs and the possession of key VF-associated genes. [ABSTRACT FROM AUTHOR]

Over the past decade, there have been many improvements in the field of metagenomics, including sequencing technologies, advances in bioinformatics and the development of reference databases, but a one-size-fits-all sequencing and bioinformatics pipeline does not yet seem achievable. In this study, we address the bioinformatics part of the analysis by combining three methods into a three-step workflow that increases the sensitivity and specificity of clinical metagenomics and improves pathogen detection. The individual tools are combined into a user-friendly workflow suitable for analysing short paired-end (PE) and long reads from metagenomics datasets—MetaAll. To demonstrate the applicability of the developed workflow, four complicated clinical cases with different disease presentations and multiple samples collected from different biological sites as well as the CAMI Clinical pathogen detection challenge dataset were used. MetaAll was able to identify putative pathogens in all but one case. In this case, however, traditional microbiological diagnostics were also unsuccessful. In addition, co-infection with Haemophilus influenzae and Human rhinovirus C54 was detected in case 1 and co-infection with SARS-Cov-2 and Influenza A virus (FluA) subtype H3N2 was detected in case 3. In case 2, in which conventional diagnostics could not find a pathogen, mNGS pointed to Klebsiella pneumoniae as the suspected pathogen. Finally, this study demonstrated the importance of combining read classification, contig validation and targeted reference mapping for more reliable detection of infectious agents in clinical metagenome samples. [ABSTRACT FROM AUTHOR]

Introduction: Allergic fungal rhinosinusitis (AFRS) is a severe phenotype of chronic rhinosinusitis with nasal polyposis (CRSwNP), characterised by localised and exaggerated type 2 inflammation. While fungal antigenic stimulation of unregulated Th2‐mediated inflammation is the core pathophysiological mechanism, the direct and synergistic role of bacteria in disease modification is a pervasive hypothesis. We set out to define the microenvironment of AFRS to elucidate virulent organisms that may be implicated in the pathophysiology of AFRS. Methodology: We undertook a cross‐sectional study of AFRS patients and non‐fungal CRSwNP patients. Demographics, disease severity, culture and microbiome sequences were analysed. Multimodality microbiome sequencing included short‐read next‐generation sequencing (NGS) on the Illumina Miseq (16S rRNA and ITS) and full‐length 16S rRNA sequencing on the Oxford Nanopore Technologies GridION (ONT). Results: Thirty‐two AFRS and 29 non‐fungal CRSwNP patients (NF) were included in this study. Staphylococcus aureus was the dominant organism cultured and sequenced in both AFRS and NF groups (AFRS 27.54%; NF 18.04%; p =.07). Streptococcus pneumoniae (AFRS 12.31%; NF 0.98%; p =.03) and Haemophilus influenzae (AFRS 15.03%; NF 0.24%; p =.005) were significantly more abundant in AFRS. Bacterial diversity (Shannon's index) was considerably lower in AFRS relative to NF (AFRS 0.6; NF 1.0, p =.008). Aspergillus was the most cultured fungus in AFRS (10/32, 31.3%). The AFRS sequenced mycobiome was predominantly represented by Malassezia (43.6%), Curvularia (18.5%) and Aspergillus (16.8%), while the NF mycobiome was nearly exclusively Malassezia (84.2%) with an absence of Aspergillus or dematiaceous fungi. Conclusion: A low diversity, dysbiotic microenvironment dominated by Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae characterised the bacterial microbiome of AFRS, with a mycobiome abundant in Malassezia, Aspergillus and Curvularia. While Staphylococcus aureus has been previously implicated in AFRS through enterotoxin superantigen potential, Streptococcus pneumoniae and Haemophilus influenzae are novel findings that may represent alternate cross‐kingdom pathophysiological mechanisms. [ABSTRACT FROM AUTHOR]

Purpose: Haemophilus influenzae (HINF), primarily non-typeable H. influenzae: (NTHi), is an important cause of neonatal sepsis and meningitis. The goal of this study was to investigate the point prevalence of HINF vaginal-rectal carriage in pregnant women, which could impact neonatal health. Methods: Simulated vaginal-rectal swabs were cultured and tested to establish optimal recovery methods for HINF. These methods were then applied to vaginal-rectal swabs from a prospective cohort of pregnant women (n = 300) undergoing routine Group B Streptococcus: (GBS) screening. Both culture and PCR were used for detection of HINF. Subject demographics, reproductive history, and genitourinary test results were documented. A retrospective surveillance study was conducted to determine incidence of invasive neonatal HINF infections from 7/1/2017-6/30/2023. Results: HINF was recovered from 42/42 (100%) simulated vaginal-rectal swabs at 2–45 CFU/plate via direct plating onto chocolate and chocolate + bacitracin agar. HINF was rarely recovered following LIM broth enrichment at 0–75 CFU/plate in 1/42 (2.4%) simulated swabs, but was recovered from BHI/Fildes broth enrichment in 22/42 (52%) specimens at high abundance (> 100 CFU/plate). Among pregnant women prospectively screened for HINF, the median age was 29 (IQR, 24–33) years and gestational age was 36 (IQR, 34–36) weeks. HINF was recovered in 1 of 300 prospective specimens by culture but 0/100 by PCR. A six-year retrospective analysis showed there were seven total cases of neonatal sepsis and majority of HINF was isolated from respiratory specimens followed by blood/CSF overall. Conclusion: This study established a sensitive culture method for recovering HINF from vaginal-rectal swab specimens and demonstrated low prevalence of HINF carriage rate in pregnant women. These findings highlight the need for further research to pinpoint the source for transmission of HINF to neonates. [ABSTRACT FROM AUTHOR]

Although most countries recommend amoxicillin for paediatric pneumonia, there is a long tradition of treatment with penicillin V (PcV) in Sweden, thus not empirically covering Haemophilus influenzae. There are, however, large regional differences in treatment practice. The aim was to compare clinical outcomes (treatment failure and severe complications), in children aged 1–59 months treated with PcV vs. amoxicillin for pneumonia. This population-based emulated target trial included all children born in Sweden between 2001 and 2021, using national health, sociodemographic, and population registers. All pneumonia cases from hospitals and paediatric outpatient clinics in children aged 1–59 months treated as outpatients with PcV or amoxicillin between July 2005 and December 2021, were identified. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for treatment failure (newly dispensed antibiotic prescription or pneumonia-associated hospitalization day 1–14) and severe complications (lung complications, an invasive bacterial disease, admission to intensive care unit or death day 1–28) were calculated with logistic regression analysis. PcV was prescribed in 14 766 cases and amoxicillin in 10 566. Treatment failure occurred in 7.7% with PcV vs. 4.7% with amoxicillin, aOR 1.76 (95% CI: 1.54–2.00). Severe complications were rare, with no significant difference between PcV and amoxicillin (0.3% vs. 0.2%, aOR 0.96, 95% CI: 0.53–1.73). Sensitivity and interaction analyses showed consistent results. PcV treatment compared with amoxicillin, was associated with an increased risk for treatment failure but not for severe complications. The absolute risks for adverse outcomes were low in both groups suggesting a minor role of H. influenzae in paediatric pneumonia. [ABSTRACT FROM AUTHOR]

Background: Inadequate production of immunoglobulin G (IgG) antibodies renders patients with primary immunodeficiency susceptible to infection by numerous pathogens, some of which can lead to severe asthma exacerbation and possible death. These patients who are immunocompromised are often reliant on intravenous immunoglobulin (IVIG) therapies, which provide passive antibodies against various respiratory pathogens, including measles virus and encapsulated bacteria. Objective: We conducted a subanalysis of data from a multicenter, multinational, phase III, open-label bioequivalence study to compare protective concentrations oflgG antibodies provided by a 5% and a 10% IVIG product in patients with primary immunodeficiency. Methods: Patients on stable 21- or 28-day regimens of previous IVIG products were assigned to receive study treatment (adults: 5% IVIG and 10% IVIG; children: 10% IVIG) at doses of 300-800 mg/kg per infusion. Trough concentrations of total IgG, IgG subclasses, measles-neutralizing antibodies, and IgG against Haemophilus influenzae type b and Streptococcus pneumoniae serotypes were evaluated. Results: A total of 48 patients (33 adidts ages 16-55 years; 15 children ages 2-15 years) were enrolled and received treatment. No statistically significant differences in trough concentrations of total IgG, IgG subclasses, measles-neutralizing antibodies, or IgG directed at encapsulated bacteria were observed between the 5% and 10% formulations in analyses by age (adidt or pediatric) or infusion schedule (every 21 or 28 days). All evaluated patients had trough IgG concentrations above accepted thresholds for protection against disease. Conclusion: These findings support the conclusion that, at dose levels and infusion schedules prescribed in clinical practice, this 5% and 10% IVIG product provided consistent, predictable, and bioequivalent IgG concentrations for adult and pediatric patients with primary immunodeficiency disease. Both formulations delivered trough antibody concentrations of total IgG, measles-neutralizing antibodies, and antibodies against encapsulated bacteria that are above thresholds accepted as protective. [ABSTRACT FROM AUTHOR]

Background: Netherton syndrome (NS) is a rare, severe genetic skin disorder, currently classified as an inborn error of immunity (IEI) due to previously reported immune dysregulation. We recently reported the results of an immunological evaluation showing no evidence for a relevant B- and/or T-cell mediated immunodeficiency, but immune responses after vaccination were not evaluated in that study. Therefore, we evaluated immune responses to three vaccine platforms in adult NS patients to further investigate the presence of a clinically relevant B- and/or T-cell immunodeficiency. Methods: Vaccination responses in eight adult NS patients were assessed in a cross-sectional study performed between January and August 2022. Clinical patient data were retrospectively retrieved from electronic patient files. Immune responses to a polysaccharide Streptococcus pneumoniae vaccine (PPV23) and conjugate Haemophilus influenzae type b vaccine (ActHiB) were measured. SARS-CoV-2-specific (functional) antibody and T-cell responses following booster vaccination with an mRNA-based COVID-19 vaccine were compared to controls. Results: None of the included patients suffered from recurrent and/or severe infections that could be attributed to a B- and/or T-cell immunodeficiency. ActHiB induced immune responses were normal in 7/7 NS patients. PPV23 induced responses were absent in 1/7, diminished in 2/7, and normal in 4/7 patients. Levels of SARS-CoV-2-specific binding and neutralizing antibodies after mRNA-based COVID-19 booster vaccination in NS patients were comparable to controls. SARS-CoV-2-specific CD4 + T-cell responses were detectable in all NS patients. In contrast, SARS-CoV-2-specific CD8 + T-cell responses were detectable in only 2/6 NS patients. T-cell responses to a positive control antigen pool were comparable to controls. Conclusions: Vaccine-induced immune responses were detectable after polysaccharide, conjugate and mRNA-based vaccination in our cohort of NS patients. A spectrum of responsiveness to vaccine challenges was found, with the ranges of vaccine responses overlapping those demonstrated in healthy control populations. [ABSTRACT FROM AUTHOR]

Background: Haemophilus influenzae is prevalent within the airways of persons with cystic fibrosis (pwCF). H. influenzae is often associated with pulmonary exacerbations (PEx) in pediatric cohorts, but in adults, studies have yielded conflicting reports around the impact(s) on clinical outcomes such as lung function decline. Accordingly, we sought to discern the prevalence, natural history, and clinical impact of H. influenzae in adult pwCF. Methods: This single-centre retrospective cohort study reviewed all adult pwCF with H. influenzae sputum cultures between 2002 and 2016. From this cohort, persistently infected subjects (defined as: ≥2 samples with the same pulsotype and > 50% sputum culture-positive for H. influenzae in each year) were matched (1:2) to controls without H. influenzae. Demographic and clinical status (baseline health or during periods of PEx) were obtained at each visit that H. influenzae was cultured. Yearly biobank isolates were typed using pulsed-field gel electrophoresis (PFGE) to assess relatedness. Results: Over the study period, 30% (n = 70/240) of pwCF were culture positive for H. influenzae, of which 38 (54%) were culture-positive on multiple occasions and 12 (17%) had persistent infection. One hundred and thirty-seven isolates underwent PFGE, with 94 unique pulsotypes identified. Two (1.5%) were serotype f with the rest non-typeable (98.5%). H. influenzae isolation was associated with an increased risk of PEx (RR = 1.61 [1.14–2.27], p = 0.006), however, this association was lost when we excluded those who irregularly produced sputum (i.e. only during a PEx). Annual lung function decline did not differ across cohorts. Conclusions: Isolation of H. influenzae was common amongst adult pwCF but often transient. H. influenzae infection was not associated with acute PEx or chronic lung function decline. [ABSTRACT FROM AUTHOR]

This research comprehensively investigates the epidemiological features and pathogen profile of acute respiratory infections (ARI) in Shihezi City, Xinjiang. A pivotal aspect of this study is the construction of a Bayes discriminant function for principal pathogen infections. This innovative methodology aims to furnish a robust scientific basis for the prevention and clinical management of ARI, potentially guiding more effective strategies in both public health and clinical settings. We compiled and examined data from January 2020 to June 2023, pertaining to patients admitted with acute respiratory infections at the First Affiliated Hospital of Shihezi University. This investigation focused on discerning patterns in epidemiology and pathogen etiology. Among 2110 cases of acute respiratory infections (ARI), 1736 underwent pathogenetic testing. Of these, 595 cases tested positive for at least one pathogen, marking a positivity rate of 34.27%. Viral detections, at a rate of 27.47%, were notably higher than bacterial detections, which stood at 6.51%. The most prevalent viruses identified were Human respiratory syncytial virus (hRSV), Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2), and Human adenovirus (HAdV), while the dominant bacterial pathogens included Klebsiella pneumoniae, Haemophilus influenzae, and Staphylococcus aureus. Co‐infections were observed in 76 cases, accounting for 12.77% of positive diagnoses, predominantly involving hRSV in conjunction with other pathogens. In cases of acute bronchiolitis, hRSV was the most frequent pathogen, contributing to 23.10% of such cases. Similarly, in severe pneumonia cases, SARS‐CoV‐2 was predominant, accounting for 25.4% of these infections. The group with bacterial positivity exhibited elevated levels of C‐reactive protein (CRP, 19.17 mg/L) and neutrophilic granulocyte percentage (NE%, 54.7%). The Bayes discriminant function demonstrated an initial validation accuracy of 74.9% and a cross‐validation accuracy of 63.7%. The study underscores that hRSV, SARS‐CoV‐2, and HAdV are the primary pathogens in acute respiratory infections in the Shihezi region. Pathogen susceptibility exhibits variation across different age groups, with a higher pathogen detection rate in children compared to adults. The Bayes discriminant function shows significant promise in the classification and diagnosis of major pathogenic infections. [ABSTRACT FROM AUTHOR]

Background: Community-acquired pneumonia (CAP) is associated with high morbidity and hospitalization rate. In infectious diseases, host genetics plays a critical role in susceptibility and immune response, and the immune pathways involved are highly dependent on the microorganism and its route of infection. Here we aimed to identify genetic risk loci for CAP using a case-control genome-wide association study (GWAS). Methods: We performed a GWAS on 3,765 Spanish individuals, including 257 adult patients hospitalized with CAP and 3,508 population controls. Pneumococcal CAP was documented in 30% of patients; the remaining 70% were selected among patients with unidentified microbiological etiology. We tested 7,6 million imputed genotypes using logistic regressions. UK Biobank GWAS of bacterial pneumonia were used for results validation. Subsequently, we prioritized genes and likely causal variants based on Bayesian fine mapping and functional evidence. Imputation and association of classical HLA alleles and amino acids were also conducted. Results: Six independent sentinel variants reached the genome-wide significance (p < 5 × 10-8), three on chromosome 6p21.32, and one for each of the chromosomes 4q28.2, 11p12, and 20q11.22. Only one variant at 6p21.32 was validated in independent GWAS of bacterial and pneumococcal pneumonia. Our analyses prioritized C4orf33 on 4q28.2, TAPBP on 6p21.32, and ZNF341 on 20q11.22. Interestingly, genetic defects of TAPBP and ZNF341 are previously known inborn errors of immunity predisposing to bacterial pneumonia, including pneumococcus and Haemophilus influenzae. Associations were all non-significant for the classical HLA alleles. Conclusions: We completed a GWAS of CAP and identified four novel risk loci involved in CAP susceptibility. [ABSTRACT FROM AUTHOR]

Aim: To examine how reduced iron content and added bovine lactoferrin in infant formula affect the antibody response following routine immunisation. Methods: In this randomised controlled trial, 180 Swedish formula‐fed infants received, from 6 weeks to 6 months of age, a 2 mg/L iron formula with (n = 72) or without (n = 72) bovine lactoferrin, or a control formula with 8 mg/L iron and no lactoferrin (n = 36). Another 72 infants were recruited as a breastfed reference. Serum immunoglobulin G (IgG) levels against Haemophilus influenzae type b (Hib), diphtheria and tetanus were assessed at four, six and 12 months of age. Results: With an equal gender distribution, 180 + 72 term infants were included with a mean age of 7.0 ± 0.7 weeks. At 12 months, infants fed low iron formula showed a significantly higher geometric mean Hib IgG (1.40 μg/mL [1.07–1.83]) compared to the control formula infants (0.67 μg/mL [0.42–1.07]). For all three vaccines, breastfed infants had significantly lower IgG levels at six and 12 months of age. Conclusion: Except for higher Hib IgG levels at 12 months in infants fed low iron formula, the interventions did not affect vaccine IgG response. Unexpectedly, breastfed infants had significantly lower vaccine IgG levels compared to formula‐fed infants. [ABSTRACT FROM AUTHOR]

Background/Objectives: The diagnosis of encephalitis is a challenging problem due to the heterogeneity of clinical presentations. The objective was to determine the etiology, clinical features, laboratory parameters, radiological findings, and in-hospital outcome of acute encephalitis syndrome (AES) cases in Myanmar. Methods: A prospective descriptive study was conducted at the Neuromedical Ward of Yangon General Hospital from March to August 2023. Eighty-one AES cases were enrolled, and cerebrospinal fluid (CSF) samples were collected. A Qiastat ME Panel was used to detect viral, bacterial, and fungal pathogens. Results: Seventeen out of eighty-one (21%) cases were non-encephalitis with alternative definite diagnosis. Among the remaining 64 encephalitis cases, the exact infectious and immune etiologies were identified in 31 of 64 cases (48.4%); 26 of these (83.9%) were due to infectious causes and 5 (16.1%) were immune encephalitis. Among the infectious causes, six Herpes Simplex Virus-1-, one bacteriologically confirmed and seven probable Mycobacterium tuberculosis-, three Haemophilus influenzae-, two Streptococcus pneumoniae-, one Streptococcus pyogenes-, one Varicella-Zoster Virus (Ramsay Hunt Syndrome with meningoencephalitis)-, and two Cryptococcus neoformans-infected patients and rare causes such as Listeria monocytogenes, Burkholdelria cepacia, Sphingomonas paucimobilis, and Aspergillus were identified. One case was a dual infection with Haemophilus influenzae and Cryptococcus neformans. Abnormal protein levels and CSF pleocytosis were significantly higher among bacterial causes (p < 0.05). In total, 6.45% (2/31) of encephalitis patients with identified causes and 12.12% (4/33) of those without an identified organism had poor outcome. Conclusions: Herpes encephalitis and tuberculous meningoencepalitis were the commonest. This study highlighted that molecular testing with a multidisciplinary approach is required to ensure the right treatment on time. [ABSTRACT FROM AUTHOR]

OBJECTIVES: American Indian and Alaska Native (AI/AN) infants historically experienced a disproportionate burden of invasive Haemophilus influenzae type b (Hib) disease, especially early in life. PedvaxHIB vaccine is preferentially recommended for AI/AN infants because it elicits protective antibody levels postdose 1. Vaxelis, a hexavalent vaccine that contains the same Hib conjugate as PedvaxHIB but at lower concentration, is recommended for US children, but postdose 1 Hib immunogenicity data are needed to inform whether a preferential recommendation should be made for AI/AN infants. METHODS: We conducted a phase IV randomized, open-label, noninferiority trial comparing postdose 1 immunogenicity of Vaxelis to PedvaxHIB in AI/AN infants. Participants were randomized to receive a primary series of PedvaxHIB or Vaxelis. Serum samples collected 30 days postdose 1 were tested for anti-Hib immunoglobulin G antibody by enzyme-linked immunosorbent assay. The anti-Hib immunoglobulin G geometric mean concentration (GMC) ratio (Vaxelis/PedvaxHIB) was estimated by constrained longitudinal data analysis. Noninferiority was defined a priori as the lower bound of the 95% confidence interval (CI) of the GMC ratio ≥0.67. RESULTS: A total of 327 of the 333 infants enrolled in the study were included in the per-protocol analysis. The postdose 1 anti-Hib GMC was 0.41 µg/mL (95% CI 0.33-0.52) in the Vaxelis group (n = 152) and 0.39 µg/mL (95% CI 0.31-0.50) in the PedvaxHIB group (n = 146). The constrained longitudinal data analysis GMC ratio was 1.03 (95% CI 0.76-1.39). CONCLUSIONS: Postdose 1 immunogenicity of Vaxelis was noninferior to PedvaxHIB. Our findings support the use of Vaxelis in AI/AN children, a population with elevated risk of Hib disease. [ABSTRACT FROM AUTHOR]

Evidence on serological responses to vaccination in children exposed to ustekinumab (UST) or vedolizumab (VDZ) in utero is lacking. This multicentre prospective study aimed to assess the impact of prenatal exposure to UST or VDZ due to maternal inflammatory bowel disease (IBD) on serological responses to vaccination and other immunological parameters in exposed children. Children aged ≥ 1 year who were exposed in utero to UST or VDZ and completed at least 1-year of mandatory vaccination were included. We assessed the serological response to vaccination (non-live: tetanus, diphtheria, and Haemophilus influenzae B; live: mumps, rubella, and measles), whole blood count, and immunoglobulin levels. The control group comprised unexposed children born to mothers without IBD. A total of 23 children (median age, 25 months) exposed to UST (n = 13) or VDZ (n = 10) and 10 controls (median age, 37 months) were included. The serological response to vaccination was comparable between the UST and VDZ groups and controls, with an adequate serological response rate of ≥ 80%. Only children exposed to UST showed a slightly reduced serological response to mumps (67% vs. 86% in controls), whereas all children exposed to VDZ showed an adequate response. The majority of the exposed children had normal levels of individual immunoglobulin classes, similar to the controls. No severe pathology was observed in any of the children. Conclusion: Despite the limited sample size, our findings suggest that in utero exposure to VDZ or UST does not significantly impair the vaccine response or broader immunological parameters in exposed children. What is known: • Treatment with anti-TNF inhibitors during pregnancy does not appear to affect serologic response to vaccination in exposed children. • Evidence on the efficacy of vaccination in children exposed to ustekinumab or vedolizumab in utero is almost lacking. What is new: • Our findings suggest that in utero exposure to ustekinumab or vedolizumab does not significantly affect the serological responses to common childhood non-live (tetanus, Haemophilus influenzae B, diphtheria) and live vaccines (measles, mumps, rubella). • No major adverse effects on overall immunological health were observed in children exposed in utero to ustekinumab or vedolizumab. [ABSTRACT FROM AUTHOR]

Introduction: H. influenzae carriage may evolve into respiratory or systemic infections. However, no surveillancesystem is in place in Belgium to monitor carriage strains. Material and Methods: This study provides a detailed description of H. influenzae strains isolated from both carriage and lower respiratory infections, collected during a six-month national surveillance. Subsequently, a comparison is conducted with invasive isolates collected during the same period at the National Reference Centre (NRC). Results and discussion: From November 2021 to April 2022, 39 clinical laboratories collected 142 and 210 strains of H. influenzae from carriage and infection, respectively, and 56 strains of blood were submitted to the NRC. In each group, the biotype II comprised more than 40%, followed by biotypes III and I. The majority of strains were non-typeable H. influenzae, with a notable increase in the number of encapsulated strains in the invasive group (14.3% vs. 1–2%). A beta-lactamase was identified in 18.5% and 12.5% of surveillance and invasive strains, respectively. Resistance to the amoxicillin-clavulanic acid combination accounted for 7% in the surveillance strains and 10.7% in invasive strains. The overall resistance to third-generation cephalosporins at 1.2% is consistent with rates observed in other European countries. Of particular significance is the identification of mutations in the ftsI gene in both carriage and infected strains, which are associated with high-level beta-lactam resistance. Conclusion: NRC must engage in regular and systematic monitoring of beta-lactam susceptibility of H. influenzae to guarantee safe empiric therapy in severe cases and identify potential transitions from low-level to high-level resistance in the future. [ABSTRACT FROM AUTHOR]

Background: Mixed infections can worsen disease symptoms. This study investigated the impact of mixed infections with viral and bacterial pathogens in patients positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Using the in-house multiplex PCR method, we tested 337 SARS-CoV-2 positive samples for co-infections with three bacterial and 14 other viral pathogens. Results: Between August 2021 and May 2022, 8% of 337 SARS-CoV-2-positive patients had bacterial co-infections, 5.6% had viral co-infections, and 1.4% had triple mixed infections. The most common causes of mixed infections were Haemophilus influenzae (5.93%) and respiratory syncytial virus (RSV) (1.18%). Children < 5 years old had more frequent co-infections than adults < 65 years old (20.8% vs. 16.4%), while adults showed a more severe clinical picture with a higher C-reactive protein (CRP) level (78.1 vs.16.2 mg/L; p = 0.033), a lower oxygen saturation (SpO2) (89.5 vs. 93.2%), and a longer hospital stay (8.1 vs. 3.1 days; p = 0.025) (mean levels). The risk of a fatal outcome was 41% in unvaccinated patients (p = 0.713), which increased by 2.66% with co-infection with two pathogens (p = 0.342) and by 26% with three pathogens (p = 0.005). Additionally, 50% of intensive care unit (ICU) patients had a triple infection, compared with only 1.3% in the inpatient unit (p = 0.0029). The risk of death and/or ICU admission was 12 times higher (p = 0.042) with an additional pathogen and increased by 95% (p = 0.003) with a third concomitant pathogen. Conclusions: Regular multiplex testing is important for prompt treatment and targeted antibiotic use. [ABSTRACT FROM AUTHOR]

Abstract Background Haemophilus influenzae is an opportunistic bacterial pathogen that can cause severe respiratory tract and invasive infections. The emergence of β-lactamase-negative ampicillin-resistant (BLNAR) strains and unclear correlations between genotypic (i.e., gBLNAR) and phenotypic resistance are challenging empirical treatments and patient management. Thus, we sought to revisit molecular resistance mechanisms and to identify new resistance determinants of H. influenzae. Methods We performed a systematic meta-analysis of H. influenzae isolates (n = 291) to quantify the association of phenotypic ampicillin and cefotaxime resistance with previously defined resistance groups, i.e., specific substitution patterns of the penicillin binding protein PBP3, encoded by ftsI. Using phylogenomics and a genome-wide association study (GWAS), we investigated evolutionary trajectories and novel resistance determinants in a public global cohort (n = 555) and a new clinical cohort from three European centers (n = 298), respectively. Results Our meta-analysis confirmed that PBP3 group II- and group III-related isolates were significantly associated with phenotypic resistance to ampicillin (p

Abstract The triple combination elexacaftor-tezacaftor-ivacaftor (ETI) has provided unprecedented clinical benefits for people with cystic fibrosis (pwCF) and drastically transformed the outcome of this disease. We aimed to describe the evolution of lung bacterial colonization in 198 French adult pwCF taking into account the use of concomitantly respiratory treatment. We collected sputum cultures produced during the entire follow-up period starting 3 years before and ending 1 year after ETI initiation. All sputum cultures were centralized and analyzed at our bacteriological laboratory. Clinical data included pulmonary function, respiratory treatments, physiotherapy, number of IV antibiotics treatment, as well as inpatient stays. We observed a significant decrease in colonization prevalence by any CF pathogen after one year of treatment with ETI (p

Abstract Background Haemophilus influenzae is prevalent within the airways of persons with cystic fibrosis (pwCF). H. influenzae is often associated with pulmonary exacerbations (PEx) in pediatric cohorts, but in adults, studies have yielded conflicting reports around the impact(s) on clinical outcomes such as lung function decline. Accordingly, we sought to discern the prevalence, natural history, and clinical impact of H. influenzae in adult pwCF. Methods This single-centre retrospective cohort study reviewed all adult pwCF with H. influenzae sputum cultures between 2002 and 2016. From this cohort, persistently infected subjects (defined as: ≥2 samples with the same pulsotype and > 50% sputum culture-positive for H. influenzae in each year) were matched (1:2) to controls without H. influenzae. Demographic and clinical status (baseline health or during periods of PEx) were obtained at each visit that H. influenzae was cultured. Yearly biobank isolates were typed using pulsed-field gel electrophoresis (PFGE) to assess relatedness. Results Over the study period, 30% (n = 70/240) of pwCF were culture positive for H. influenzae, of which 38 (54%) were culture-positive on multiple occasions and 12 (17%) had persistent infection. One hundred and thirty-seven isolates underwent PFGE, with 94 unique pulsotypes identified. Two (1.5%) were serotype f with the rest non-typeable (98.5%). H. influenzae isolation was associated with an increased risk of PEx (RR = 1.61 [1.14–2.27], p = 0.006), however, this association was lost when we excluded those who irregularly produced sputum (i.e. only during a PEx). Annual lung function decline did not differ across cohorts. Conclusions Isolation of H. influenzae was common amongst adult pwCF but often transient. H. influenzae infection was not associated with acute PEx or chronic lung function decline.

Abstract Background Haemophilus influenzae causes life-threatening invasive diseases such as septicaemia and meningitis. Reports on circulating H. influenzae causing invasive disease in lower-middle income settings, including Indonesia, are lacking. This study describes the serotype distributions and whole-genome sequence (WGS) data of H. influenzae isolated from hospitalized patients at Soetomo Hospital, Surabaya, Indonesia. Methods H. influenzae isolates were isolated from blood and pleural fluid specimens and identified using culture-based and molecular methods, followed by serotyping and WGS using RT‒PCR and Illumina MiSeq, respectively. Sequencing reads were assembled, and further analyses were undertaken to determine the genomic content and reconstruct the phylogeny. A second dataset consisting of publicly available H. influenzae genomes was curated to conduct phylogenetic analyses of isolates in this study in the context of globally circulating isolates. Results Ten H. influenzae isolates from hospitalized patients were collected, and septicaemia was the most common diagnosis (n=8). RT‒PCR and WGS were performed to determine whether all the isolates were nontypeable H. influenzae (NTHi). There were four newly identified STs distributed across the two main clusters. A total of 91 out of 126 virulence factor (VF)-related genes in Haemophilus sp. were detected in at least one isolate. Further evaluation incorporating a global collection of H. influenzae genomes confirmed the diverse population structure of NTHi in this study. Conclusion This study showed that all H. influenzae recovered from invasive disease patients were nonvaccine-preventable NTHi isolates. The inclusion of WGS revealed four novel STs and the possession of key VF-associated genes.

Abstract Background Haemophilus influenzae community-acquired pneumonia (CAP) is common, and it is equally common to Streptococcus pneumoniae in some settings. The purpose of this study was to provide additional data on patients affected by H. influenzae CAP and their outcomes. Methods Streptococcus pneumoniae-caused CAP (111 cases) was compared to CAP with H. influenzae (53 cases). Patients were adults (≥ 18 years) from the prospective study “Etiology of community acquired pneumonia in Sweden” (ECAPS), which was established during the years 2016–2018. Results Cases with H. influenzae CAP were significantly older compared to S. pneumoniae CAP (median 77 vs 70 years, p = 0.037) albeit similar comorbidities. Haemophilus influenzae was generally absent in the bloodstream compared to S. pneumoniae (18% vs 2%, p = 0.01) but clinical presentations were comparable. Only a minority of patients, 34% with H. influenzae and 41% with S. pneumoniae CAP had underlying lung disease. Conclusion In the light of childhood immunization campaigns against S. pneumoniae and the increasing numbers of pneumococcal vaccinations among the elderly, coupled with an aging population, the incidence of CAP caused by H. influenzae may increase. Further research is needed to understand the impact of H. influenzae CAP and to a development of a vaccine against this emerging microbe.

We recently characterized the competitive inhibition of cyclic AMP (cAMP) on three periplasmic acid phosphatases, AphAHi, NadNHi, and eP4 (HelHi), in Haemophilus influenzae Rd KW20. This inhibitory effect is vital for orchestrating the nutritional growth and competence development in KW20. Initially discovered in Escherichia coli, the function of AphA remains however obscure. This study investigates the regulation of E. coli aphA expression under nutrient starvation conditions. Using transcriptional reporters with truncated aphA promoter sequences, we found that starvations of carbon and phosphate, but not amino acid, stimulated aphA expression through distinct promoter regions. Deletions of crp or cyaA abolished aphA expression, confirming their crucial roles. Conversely, CytR deletion increased aphA expression, suggesting CytR's role as a repressor of aphA expression. Additionally, we extended the study of three other second messengers, i.e., cyclic GMP, cyclic UMP, and cyclic CMP, each sharing structural similarities with cAMP. Notably, cGMP competitively inhibits AphAHi's acid phosphatase activity akin to cAMP. In contrast, both cUMP and cCMP stimulate AphAHi's phosphatase activity in a concentration dependent manner. Collectively, these data imply a complicated connection between nucleotide metabolism, AphA, cyclic purine and pyrimidine nucleotides in bacterial nutrient uptake and natural competence.

Introduction: Bacterial meningitis is a major cause of death, with an approximate case fatality rate of 37% across all age groups in South Africa. This study aimed to describe the demographic and pathogen characteristics of incident meningitis in children aged <1 year in South Africa from 2014 through 2018, during a period when Haemophilus influenzae type b vaccine and pneumococcal conjugate vaccines (PCV) were both included in the expanded program on immunization (EPI). Methods: We conducted a cohort study of routine laboratory data in the National Health Laboratory Service Corporate Data Warehouse, which covers approximately 80% of the South African population. We defined a case of laboratory-confirmed bacterial meningitis as any person aged <1 year with meningitis diagnosed by culture and identification of a pathogen documented as being a common cause of meningitis in CSF. The cause-specific incidence risks were calculated by dividing the number of positive specimens in each age group and year by the corresponding mid-year population for children under 1 year old and those in the post-neonatal period (≥ 28 days to 365 days old). For children under 28 days old, the annual numbers of registered livebirths were used. We used Poisson regression to compare the incidence of meningitis by year. Results: We identified 3575 (1.5%) cases of culture-confirmed bacterial meningitis from the 232,016 cerebrospinal fluid (CSF) specimens tested from 2014–2018. The highest number of cases were recorded in children aged <28 days (1873, 52.4%), male children (1800, 50.4%) as well as in the Gauteng Province (2014, 56.3%). Acinetobacter baumannii (14.9%), followed by Klebsiella pneumoniae (13.5%), and group B streptococcus (GBS) (10.7%), were the most common pathogens detected. Overall, A. baumannii had the highest incidence risk, occurring at 9.8 per 100,000 persons in children aged <1 year in 2018. Among neonates, A. baumannii peaked at 14.9 per 100,000 livebirths in 2018, while Streptococcus pneumoniae was most common in the post-neonatal period (≥ 28 days to 365 days old), peaking at 9.8 per 100,000 persons in 2014. There was an increase in the annual incidence of most pathogens over the study period. Conclusion: There was an increasing trend in the annual incidence of bacterial meningitis in infants caused by most pathogens, particularly A. baumannii, K. pneumoniae and GBS. In addition to increased uptake of vaccination, prevention measures to reduce nosocomial and mother-to-child transmission of bacteria could include antenatal screening for GBS in pregnant women, rigorous hygiene in the hospital environment as well as rational antibiotic use. [ABSTRACT FROM AUTHOR]

Invasive Haemophilus influenzae type b (Hib) disease is a serious bacterial infection that disproportionally affects American Indian and Alaska Native (AI/AN) populations. Hib vaccination with a monovalent Hib conjugate vaccine consisting of Hib capsular polysaccharide (polyribosylribitol phosphate [PRP]) conjugated to outer membrane protein complex of Neisseria meningitidis serogroup B, PRP-OMP (PedvaxHIB, Merck and Co., Inc.) has historically been preferred for AI/AN infants, who are at increased risk for invasive Hib disease, because it provides substantial protection after the first dose. On June 26, 2024, CDC's Advisory Committee on Immunization Practices (ACIP) recommended that a hexavalent, combined diphtheria and tetanus toxoids and acellular pertussis (DTaP), inactivated poliovirus (IPV), Hib conjugate, and hepatitis B (HepB) vaccine, DTaP-IPV-Hib-HepB (Vaxelis, MSP Vaccine Company) should be included with monovalent PRP-OMP in the preferential recommendation for AI/AN infants because of the PRP-OMP Hib component. A primary Hib vaccination series consisting of either 1) monovalent PRP-OMP (2-dose series at ages 2 and 4 months) or 2) DTaP-IPV-Hib-HepB (3-dose series at ages 2, 4, and 6 months) is preferred for AI/AN infants. DTaP-IPV-Hib-HepB is only indicated for use in infants at ages 2, 4, and 6 months and should not be used for the booster doses of Hib, DTaP, or IPV vaccines. For the booster dose of Hib vaccine, no vaccine formulation is preferred for AI/AN children; any Hib vaccine (except DTaP-IPV-Hib-HepB) should be used. This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of Hib-containing vaccines among AI/AN infants and children. [ABSTRACT FROM AUTHOR]

Background: Severe asthma (SA) encompasses several clinical phenotypes with a heterogeneous airway microbiome. We determined the phenotypes associated with a low α‐diversity microbiome. Methods: Metagenomic sequencing was performed on sputum samples from SA participants. A threshold of 2 standard deviations below the mean of α‐diversity of mild‐moderate asthma and healthy control subjects was used to define those with an abnormal abundance threshold as relative dominant species (RDS). Findings: Fifty‐one out of 97 SA samples were classified as RDSs with Haemophilus influenzae RDS being most common (n = 16), followed by Actinobacillus unclassified (n = 10), Veillonella unclassified (n = 9), Haemophilus aegyptius (n = 9), Streptococcus pseudopneumoniae (n = 7), Propionibacterium acnes (n = 5), Moraxella catarrhalis (n = 5) and Tropheryma whipplei (n = 5). Haemophilus influenzae RDS had the highest duration of disease, more exacerbations in previous year and greatest number on daily oral corticosteroids. Hierarchical clustering of RDSs revealed a C2 cluster (n = 9) of highest relative abundance of exclusively Haemophilus influenzae RDSs with longer duration of disease and higher sputum neutrophil counts associated with enrichment pathways of MAPK, NF‐κB, TNF, mTOR and necroptosis, compared to the only other cluster, C1, which consisted of 7 Haemophilus influenzae RDSs out of 42. Sputum transcriptomics of C2 cluster compared to C1 RDSs revealed higher expression of neutrophil extracellular trap pathway (NETosis), IL6‐transignalling signature and neutrophil activation. Conclusion: We describe a Haemophilus influenzae cluster of the highest relative abundance associated with neutrophilic inflammation and NETosis indicating a host response to the bacteria. This phenotype of severe asthma may respond to specific antibiotics. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to evaluate respiratory syncytial virus (RSV) infections in cases followed in the pediatric intensive care unit (PICU). Materials and Methods: The study was designed as a prospective cohort in 6 PICUs. There were 3 groups: only RSV (+), RSV (v+) who were positive for another viral agent(s) in addition to RSV, and RSV (b+) who were positive for a bacterial agent(s) in addition to RSV. Results: A total of 119 cases were included in the study, 67 (56.3%) of whom were male. The RSV (+) group had a lower pH compared to the other groups and a higher rate of acute bronc hiolitis/bronchitis diagnoses compared to the RSV (v+) group. The RSV (v+) group had higher bicarbonate levels, higher creatinine levels, longer hospital stays, and higher Pediatric Risk of Mortality-3 scores (PRISM-3) compared to the RSV (+) group. Cases with RSV (b+) were younger and also had lower body weight compared to the other groups. Furthermore, the RSV (b+) group had higher C-reactive protein and Procalcitonin (PCT) levels and higher rates of High Flow Nasal Cannula-Oxygen Therapy (HFNC-OT) use. Multiple linear regression analysis revealed that PRISM-3 score, PCT levels, Pediatric Acute Respiratory Distress Syndrome diagnoses, inhaled steroid use, chronic illness status, and heart rate on admission were associated with the length of stay in the PICU. Conclusion: High flow nasal cannula-oxygen therapy continues to be the most frequently preferred respiratory support method in RSV infections. Viral infections accompanying RSV can increase the severity of the disease. [ABSTRACT FROM AUTHOR]

Community‐acquired necrotizing pneumonia is a rare but potentially fatal infection, mainly caused by specific pathogens such as Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa. Escherichia coli is extremely rare as a pathogen for community‐acquired necrotizing pneumonia, typically accompanied with bloodstream infection. Here, we report an unusual case of a 60‐year‐old man with uncontrolled diabetes mellitus and no bloodstream infections, who had severe necrotizing E. coli pneumonia leading to massive hemoptysis and death. Clinicians should be aware of this pathogen in respiratory infections, as it requires immediate pathogen detection and usually aggressive antibiotic treatment. [ABSTRACT FROM AUTHOR]

Objectives This study aimed to explore the prevalence of macrolide resistance and the underlying resistance mechanisms in Haemophilus influenzae (n  = 2556) and Haemophilus parainfluenzae (n  = 510) collected between 2018 and 2021 from Bellvitge University Hospital, Spain. Methods Antimicrobial susceptibility was tested by microdilution. Whole-genome sequencing was performed using Illumina MiSeq and Oxford Nanopore technologies, and sequences were examined for macrolide resistance determinants and mobile genetic structures. Results Macrolide resistance was detected in 67 H. influenzae (2.6%) and 52 (10.2%) H. parainfluenzae strains and associated with resistance to other antimicrobials (co-trimoxazole, chloramphenicol, tetracycline). Differences in macrolide resistance existed between the two species. Acquired resistance genes were more prevalent in H. parainfluenzae (35/52; 67.3%) than in H. influenzae (12/67; 17.9%). Gene mutations and amino acid substitutions were more common in H. influenzae (57/67; 85%) than in H. parainfluenzae (16/52; 30.8%). Substitutions in L22 and in 23S rRNA were only detected in H. influenzae (34.3% and 29.0%, respectively), while substitutions in L4 and AcrAB/AcrR were observed in both species. The MEGA element was identified in 35 (67.3%) H. parainfluenzae strains, five located in an integrative and conjugative element (ICE); by contrast, 11 (16.4%) H. influenzae strains contained the MEGA element (all in an ICE). A new ICE HpaHUB8 was described in H. parainfluenzae. Conclusions Macrolide resistance was higher in H. parainfluenzae than in H. influenzae , with differences in the underlying mechanisms. H. parainfluenzae exhibits co-resistance to other antimicrobials, often leading to an extensively drug-resistant phenotype. This highlights the importance of conducting antimicrobial resistance surveillance. [ABSTRACT FROM AUTHOR]

Objective: In a previous study we have shown that, in the presence of interleukin (IL)-33, repeated, per-nasal challenge of murine airways with Streptococcus pneumoniae (S. pneumoniae) organisms induces human asthma-like airways inflammation. It is not clear, however, whether this effect is unique or manifest in response to other common respiratory pathogens.Methods: To explore this, airways of BALB/c mice were repeatedly challenged per-nasally with formaldehyde-inactivated bacterial bodies in the presence or absence of murine recombinant IL-33. Serum concentrations of S.pneumoniae, Moraxella catarrhalis (M.catarrhalis) and Haemophilus influenzae (H.influenzae) lysates-specific IgE were measured in patients with asthma and control subjects.Results: We showed that in the presence of IL-33, repeated, per-nasal airways exposure to the bodies of these bacteria induced airways hyperresponsiveness (AHR) in the experimental mice. This was accompanied by cellular infiltration into bronchoalveolar lavage fluid (BALF), eosinophilic infiltration and mucous hypertrophy of the lung tissue, with elevated local expression of some type 2 cytokines and elevated, specific IgG and IgE in the serum. The precise characteristics of the inflammation evoked by exposure to each bacterial species were distinguishable.Conclusions: These results suggest that in the certain circumstances, inhaled or commensal bacterial body antigens of both Gram-positive (S. pneumoniae) and Gram-negative (M. catarrhalis and H. influenzae) respiratory tract bacteria may initiate type 2 inflammation typical of asthma in the airways. In addition, we demonstrated that human asthmatic patients manifest elevated serum concentrations of M.catarrhalis- and H.influenzae-specific IgE. [ABSTRACT FROM AUTHOR]

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Influenza-like illness (ILI) patients co-detected with respiratory pathogens exhibit poorer health outcomes than those with single infections. To address the paucity of knowledge concerning the incidence of concurrent respiratory pathogens, their relationships, and the clinical differences between patients detected with single and multiple pathogens, we performed an in-depth characterization of the oropharyngeal samples of primary care patients collected in Genoa (Northwest Italy), during winter seasons 2018/19–2019/20. The apriori algorithm was employed to evaluate the incidence of viral, bacterial, and viral-bacterial pairs during the study period. The grade of correlation between pathogens was investigated using the Phi coefficient. Factors associated with viral, bacterial or viral-bacterial co-detection were assessed using logistic regression. The most frequently identified pathogens included influenza A, rhinovirus, Haemophilus influenzae and Streptococcus pneumoniae. The highest correlations were found between bacterial-bacterial and viral-bacterial pairs, such as Haemophilus influenzae-Streptococcus pneumoniae, adenovirus-Haemophilus influenzae, adenovirus-Streptococcus pneumoniae, RSV-A-Bordetella pertussis, and influenza B Victoria-Bordetella parapertussis. Viruses were detected together at significantly lower rates. Notably, rhinovirus, influenza, and RSV exhibited significant negative correlations with each other. Co-detection was more prevalent in children aged < 4, and cough was shown to be a reliable indicator of viral co-detection. Given the evolving epidemiological landscape following the COVID-19 pandemic, future research utilizing the methodology described here, while considering the circulation of SARS-CoV-2, could further enrich the understanding of concurrent respiratory pathogens. [ABSTRACT FROM AUTHOR]

Glycoconjugate vaccines are based on chemical conjugation of pathogen‐associated carbohydrates with immunogenic carrier proteins and are considered a very cost‐effective way to prevent infections. Most of the licensed glycoconjugate vaccines are composed of saccharide antigens extracted from bacterial sources. However, synthetic oligosaccharide antigens have become a promising alternative to natural polysaccharides with the advantage of being well‐defined structures providing homogeneous conjugates. Haemophilus influenzae (Hi) is responsible for a number of severe diseases. In recent years, an increasing rate of invasive infections caused by Hi serotype a (Hia) raised some concern, because no vaccine targeting Hia is currently available. The capsular polysaccharide (CPS) of Hia is constituted by phosphodiester‐linked 4‐β‐d‐glucose‐(1→4)‐d‐ribitol‐5‐(PO4→) repeating units and is the antigen for protein‐conjugated polysaccharide vaccines. To investigate the antigenic potential of the CPS from Hia, we synthesized related saccharide fragments containing up to five repeating units. Following the synthetic optimization of the needed disaccharide building blocks, they were assembled using the phosphoramidite approach for the installation of the phosphodiester linkages. The resulting CPS‐based Hia oligomers were conjugated to CRM197 carrier protein and evaluated in vivo for their immunogenic potential, showing that all glycoconjugates were capable of raising antibodies recognizing Hia synthetic fragments. [ABSTRACT FROM AUTHOR]

Background: Haemophilus influenzae community-acquired pneumonia (CAP) is common, and it is equally common to Streptococcus pneumoniae in some settings. The purpose of this study was to provide additional data on patients affected by H. influenzae CAP and their outcomes. Methods: Streptococcus pneumoniae-caused CAP (111 cases) was compared to CAP with H. influenzae (53 cases). Patients were adults (≥ 18 years) from the prospective study "Etiology of community acquired pneumonia in Sweden" (ECAPS), which was established during the years 2016–2018. Results: Cases with H. influenzae CAP were significantly older compared to S. pneumoniae CAP (median 77 vs 70 years, p = 0.037) albeit similar comorbidities. Haemophilus influenzae was generally absent in the bloodstream compared to S. pneumoniae (18% vs 2%, p = 0.01) but clinical presentations were comparable. Only a minority of patients, 34% with H. influenzae and 41% with S. pneumoniae CAP had underlying lung disease. Conclusion: In the light of childhood immunization campaigns against S. pneumoniae and the increasing numbers of pneumococcal vaccinations among the elderly, coupled with an aging population, the incidence of CAP caused by H. influenzae may increase. Further research is needed to understand the impact of H. influenzae CAP and to a development of a vaccine against this emerging microbe. [ABSTRACT FROM AUTHOR]

In May 2023, the Detroit Health Department was notified of four cases of invasive nontypeable Haemophilus influenzae (Hi) disease among students attending the same elementary school and grade, all with illness onsets within 7 days. Three patients were hospitalized, and one died. Most U.S. cases of invasive Hi disease are caused by nontypeable strains. No vaccines against nontypeable or non-type b Hi strains are currently available. Chemoprophylaxis is not typically recommended in response to nontypeable Hi cases; however, because of the high attack rate (four cases among 46 students; 8.7%), rifampin prophylaxis was recommended for household contacts of patients with confirmed cases and for all students and staff members in the school wing where confirmed cases occurred. Only 10.8% of students for whom chemoprophylaxis was recommended took it, highlighting gaps in understanding among caregivers and health care providers about persons for whom chemoprophylaxis was recommended. Public health authorities subsequently enhanced communication and education to the school community, improved coordination with health care partners, and established mass prophylaxis clinics at the school. This outbreak highlights the potential for nontypeable Hi to cause serious illness and outbreaks and the need for chemoprophylaxis guidance for nontypeable Hi disease. Achieving high chemoprophylaxis coverage requires education, communication, and coordination with community and health care partners. [ABSTRACT FROM AUTHOR]

Background Despite vaccination, influenza and otitis media (OM) remain leading causes of illness. We previously found that the human respiratory commensal Haemophilus haemolyticus prevents bacterial infection in vitro and that the related murine commensal Muribacter muris delays OM development in mice. The observation that M muris pretreatment reduced lung influenza titer and inflammation suggests that these bacteria could be exploited for protection against influenza/OM. Methods Safety and efficacy of intranasal H haemolyticus at 5 × 107 colony-forming units (CFU) was tested in female BALB/cARC mice using an influenza model and influenza-driven nontypeable Haemophilus influenzae (NTHi) OM model. Weight, symptoms, viral/bacterial levels, and immune responses were measured. Results Intranasal delivery of H haemolyticus was safe and reduced severity of influenza, with quicker recovery, reduced inflammation, and lower lung influenza virus titers (up to 8-fold decrease vs placebo; P ≤.01). Haemophilus haemolyticus reduced NTHi colonization density (day 5 median NTHi CFU/mL = 1.79 × 103 in treatment group vs 4.04 × 104 in placebo, P =.041; day 7 median NTHi CFU/mL = 28.18 vs 1.03 × 104; P =.028) and prevented OM (17% OM in treatment group, 83% in placebo group; P =.015). Conclusions Haemophilus haemolyticus has potential as a live biotherapeutic for prevention or early treatment of influenza and influenza-driven NTHi OM. Additional studies will deem whether these findings translate to humans and other respiratory infections. [ABSTRACT FROM AUTHOR]

Neutrophilic asthma, as corticosteroid resistant asthma, is clinically more severe than eosinophilic asthma. Therefore, the treatment of neutrophilic asthma has been a challenging. Reactive oxygen species (ROS) play a key role in the neutrophilic asthma. However, the direct use of antioxidant enzymes, such as catalase (CAT), is challenging due to the poor stability, short plasma half‐life, and the lack of effective drug delivery systems to pulmonary systems. In this work, a novel kind of nanogels for delivering CAT (CAT‐NGs) is synthesized, incorporating CAT with an antibacterial "protective film", as a modality for the treatment of neutrophilic asthma. Compared with free CAT, CAT‐NGs demonstrated superior enzyme activity and trypsin resistance, and exhibited outstanding anti‐inflammatory and antioxidant activities in vitro. Furthermore, CAT‐NGs showed significant inhibitory effects on nontypeable Haemophilus influenzae (NTHi), Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Additionally, nebulized inhalation of CAT‐NGs alleviated pulmonary inflammation in neutrophilic asthma mice. Mechanistically, the alleviation of neutrophilic asthma symptoms by CAT‐NGs is possibly associated with the clearance of ROS in the lung and the inhibition of the NLRP3 and NF‐κB pathways. Hence, the work have demonstrated the therapeutic potential of CAT‐NGs, offering new insights into the clinical treatment of neutrophilic asthma. [ABSTRACT FROM AUTHOR]

Background and Objective: COPD and bronchiectasis are common causes of morbidity, particularly around exacerbation. Colonisation with respiratory pathogens can increase the frequency and severity of exacerbations. However, bacterial and viral presence at exacerbation in people with airway colonisation has not been well studied. Methods: A 6‐month cohort study of participants (n = 30) with chronic bronchitis due to bronchiectasis (n = 26) and/or COPD (n = 13) and colonisation with Pseudomonas aeruginosa or Haemophilus influenzae was proven on two sputum cultures at exacerbation in the previous 12 months. Participants were provided self‐management education and collected sputum samples daily. Sputum samples at baseline (at least 14 days before or after an exacerbation) and at each exacerbation were examined for a panel of 34 respiratory pathogens using commercially available RT‐PCR kits and compared to results obtained using culture methods for the detection of bacteria. Results: Participants provided 29 baseline samples and 71 samples at exacerbation. In 17/29 baseline samples, RT‐PCR analysis confirmed the organism demonstrated by culture, while 12 samples showed a discrepancy from culture results. Most exacerbations (57.7%) were not associated with acquiring new bacteria or viruses, while 19.8% showed new bacteria, 15.7% new viruses and 7% both new viruses and bacteria. Conclusion: Over half of exacerbations were not associated with new organisms in this cohort of participants with chronic bronchitis and colonisation. However, 26.8% demonstrated a new bacterial species in sputum, which is relevant for antibiotic therapy. Baseline RT‐PCR and culture results were discordant in one‐third of participants. [ABSTRACT FROM AUTHOR]

Acute bacterial meningitis (ABM) is associated with severe morbidity and mortality. The most prevalent pathogens in community-acquired ABM are Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. Other pathogens may affect specific patient groups, such as newborns, older patients, or immunocompromised patients. It is well established that ABM is associated with elevated intracranial pressure (ICP). However, the role of ICP monitoring and management in the treatment of ABM has been poorly described.An electronic search was performed in four electronic databases: PubMed, Web of Science, Embase, and the Cochrane Library. The search strategy chosen for this review used the following terms: Intracranial Pressure AND (management OR monitoring) AND bacterial meningitis. The search yielded a total of 403 studies, of which 18 were selected for inclusion. Eighteen studies were finally included in this review. Only one study was a randomized controlled trial. All studies employed invasive ICP monitoring techniques, whereas some also relied on assessment of ICP-based on clinical and/or radiological observations. The most commonly used invasive tools were external ventricular drains, which were used both to monitor and treat elevated ICP. Results from the included studies revealed a clear association between elevated ICP and mortality, and possibly improved outcomes when invasive ICP monitoring and management were used. Finally, the review highlights the absence of clear standardized protocols for the monitoring and management of ICP in patients with ABM. This review provides an insight into the role of invasive ICP monitoring and ICP-based management in the treatment of ABM. Despite weak evidence certainty, the present literature points toward enhanced patient outcomes in ABM with the use of treatment strategies aiming to normalize ICP using continuous invasive monitoring and cerebrospinal fluid diversion techniques. Continued research is needed to define when and how to employ these strategies to best improve outcomes in ABM. [ABSTRACT FROM AUTHOR]