Haemophilus influenzae infection of a prosthetic knee joint in a patient with rheumatoid arthritis : A case report

A 60-year-old female was admitted to internal medicine with a painful left knee after a fall and pneumonia. She had undergone a primary cemented left total knee arthroplasty in 2019 and a right cemented total knee arthroplasty in 2021. She had also a history of rheumatoid arthritis treated with steroids and a Janus kinase 1 (JAK1) inhibitor (upadacitinib). On admission intravenous antibiotic therapy was started for the treatment of pneumonia (piperacillin/tazobactam). Because of the persistent left knee pain, a knee puncture was carried out and confirmed a periprosthetic infection. A peripheral blood culture taken on admission day showed Haemophilus influenzae. She underwent a knee arthrotomy with debridement, irrigation, explantation of the knee prosthesis and spacer placement. Intraoperative cultures showed Haemophilus influenzae. The isolate was identified as a nontypeable Haemophilus influenzae strain by the reference laboratory. Haemophilus influenzae strains rarely cause invasive diseases. Rheumatoid arthritis with immunosuppressive therapy may have predisposed this patient to severe invasive disease. The clinical presentation of an infection may differ markedly in patients with rheumatoid arthritis from that in patients without rheumatoid arthritis or immunosuppression.

Reliability of nasopharyngeal PCR for the detection of otopathogens in children with uncomplicated acute otitis media compared to culture

Otopathogens in acute otitis media (AOM) have implications for care because the likelihood of resolution without antibiotics and optimal antibiotic agent varies by microorganism. We aimed to determine the sensitivity, specificity, positive predictive value, and negative predictive value of nasopharyngeal (NP) qualitative polymerase chain reaction (PCR) for common bacterial otopathogens in children with AOM compared to NP culture. NP flocked swabs collected from enrolled children aged 6 to 35 months with uncomplicated AOM in Denver, CO were tested by culture and multiplex PCR. The sensitivity and negative predictive value of PCR using culture as a reference were high (H. influenzae 93.3%, 98.0%; S. pneumoniae 94.2%, 95.1%; M. catarrhalis 92.3%, 86.4%); whereas the specificity and positive predictive value were lower and varied by organism (54.2%-84.1%, 55.1%-69.2%, respectively). PCR detected 1.5 times more organisms than culture. NP PCR has a high predictive value for excluding otopathogens compared to culture and warrants exploration as a diagnostic tool.

Complications to acute bacterial rhinosinusitis in children - a prospective study; bacterial cultures, virus detection, allergy sensitization and immunoglobulins

BACKGROUND

Prospective studies of complications due to acute rhinosinusitis are lacking, bacterial cultures are hard to obtain and the role of airborne allergies, viruses and immunoglobulin levels are unclear. The aim was to investigate the role of bacteria, viruses, allergy and immunoglobulins in children hospitalized due to rhinosinusitis.

METHODOLOGY

A prospective cohort study in Stockholm, Sweden, of children up to 18 years of age, hospitalized due to acute bacterial rhinosinusitis, from April 1st, 2017 to April 1st, 2020.

RESULTS

Of 55 children included, 51% had a positive viral nasopharyngeal PCR and 29% had a positive allergy sensitization test. A higher percentage of middle meatus cultures were positive for bacterial growth compared to nasopharyngeal and displayed a wider array of bacteria. Dominating bacteria were S. milleri in surgical (7/12 cases), S. pyogenes in middle meatus (13/52 cases), and S. pyogenes and H. influenza in nasopharyngeal cultures (8/50 cases respectively). Nasal cultures were negative in 50% of surgical cases. An association was found between S. pyogenes and peak CRP; H. influenzae and peak CRP; S. pneumoniae and peak CRP; and possibly between M. catarrhalis and days of IV antibiotics. Further, an association between influenza A/B and S. pyogenes; a positive viral PCR and lower grade of complication and peak CRP; and a possible association between influenza virus and lower grade of complication. Allergy sensitization was possibly associated with a higher number of days with IV antibiotics. No immunoglobulin deficiencies were found.

CONCLUSIONS

There seem to be differences in the patterns of bacterial growth in nasopharyngeal, middle meatus and surgical cultures in children with complications to acute bacterial rhinosinusitis. Presence of certain viruses and sensitization to airborne allergies seem to play a role in complications to acute bacterial rhinosinusitis in children.

Boron-doped diamond nanosheet volume-enriched screen-printed carbon electrodes: a platform for electroanalytical and impedimetric biosensor applications

This paper focuses on the development of a novel electrode based on boron-doped diamond nanosheet full-volume-enriched screen-printed carbon electrodes (BDDPE) for use as an impedimetric biosensor. Impedimetric biosensors offer high sensitivity and selectivity for virus detection, but their use as point-of-care devices is limited by the complexity of nanomaterials' architecture and the receptor immobilisation procedures. The study presents a two-step modification process involving the electroreduction of diazonium salt at the BDDPE and the immobilisation of antibodies using zero-length cross-linkers for a selective impedimetric biosensor of Haemophilus influenzae (Hi). The incorporation of diamond nanosheets into BDDPE leads to enhanced charge transfer and electrochemical behaviour, demonstrating greatly improved electrochemically active surface area compared with unmodified screen-printed electrodes (by 44% and 10% on average for [Ru(NH3)6]Cl2 and K3[Fe(CN)6], respectively). The presented sensing system shows high specificity towards protein D in Hi bacteria, as confirmed by negative controls against potential interference from other pathogens, with an estimated tolerance limit for interference under 12%. The Hi limit of detection by electrochemical impedance spectroscopy was 1 CFU/mL (measured at - 0.13 V vs BDDPE pseudo-reference), which was achieved in under 10 min, including 5 min sample incubation in the presence of the analyte.

Molecular basis for bacterial N-glycosylation by a soluble HMW1C-like N-glycosyltransferase

Soluble HMW1C-like N-glycosyltransferases (NGTs) catalyze the glycosylation of Asn residues in proteins, a process fundamental for bacterial autoaggregation, adhesion and pathogenicity. However, our understanding of their molecular mechanisms is hindered by the lack of structures of enzymatic complexes. Here, we report structures of binary and ternary NGT complexes of Aggregatibacter aphrophilus NGT (AaNGT), revealing an essential dyad of basic/acidic residues located in the N-terminal all α-domain (AAD) that intimately recognizes the Thr residue within the conserved motif Asn0-X+1-Ser/Thr+2. Poor substrates and inhibitors such as UDP-galactose and UDP-glucose mimetics adopt non-productive conformations, decreasing or impeding catalysis. QM/MM simulations rationalize these results, showing that AaNGT follows a SN2 reaction mechanism in which the acceptor asparagine uses its imidic form for catalysis and the UDP-glucose phosphate group acts as a general base. These findings provide key insights into the mechanism of NGTs and will facilitate the design of structure-based inhibitors to treat diseases caused by non-typeable H. influenzae or other Gram-negative bacteria.

Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium

BACKGROUND

The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic.

METHODS

For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere.

FINDINGS

Overall, 116 841 cases were analysed: 76 481 in 2018-19, before the pandemic, and 40 360 in 2020-21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40-0·55), H influenzae (0·51; 0·40-0·66) and N meningitidis (0·26; 0·21-0·31), while no significant changes were observed for S agalactiae (1·02; 0·75-1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145-55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories.

INTERPRETATION

COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies.

FUNDING

Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization.

Changes in antimicrobial resistance in acute otitis media and otitis externa

OBJECTIVES

Acute otitis media (AOM) and otitis externa (OE) are common ear infections which may warrant antibiotic therapy. For many infections, there is a rise in antimicrobial resistance, which is associated with treatment failure, morbidity, prolonged hospitalisation and mortality. This study aimed to identify longitudinal changes in microbiology and antimicrobial resistance in aural swabs taken from patients with AOM or OE.

DESIGN

Retrospective observational analysis.

SETTING

Aural samples processed at Manchester Medical Microbiology Partnership Laboratories between January 2008 and December 2018 were analysed to record organism isolated and antimicrobial sensitivity.

PARTICIPANTS

Individual aural swabs from 7200 patients.

MAIN OUTCOME MEASURES

Changes in the incidence of organisms and antimicrobial resistance between two time periods (2008-2012 and 2013-2018) were compared using the chi-squared test (alpha = 0.05).

RESULTS

From 7200 swabs, 2879 (40%) were from children. The most frequently isolated organisms were Staphylococcus aureus (25%), Pseudomonas aeruginosa (24.4%), yeast (9.1%), mixed anaerobes (7.9%) and Haemophilus influenzae (6.1%). In children aged 0-4 years, H. influenzae had particularly high incidence (25%). Overall, the incidence of P. aeruginosa decreased significantly with time (p = 0.05). Isolates displaying resistance to one or more antimicrobial agents increased significantly in number in the second time period for P. aeruginosa (p = 0.04) and H. influenzae (p =  0.03). There was increased resistance to amoxicillin for P. aeruginosa (p = 0.01) and to erythromycin for H. influenzae (p < 0.01).

CONCLUSION

Variations in type and frequency of organisms with increasing age likely result from differences in the preponderance of AOM compared to OE in children versus adults. We found increasing antimicrobial resistance for two organisms commonly isolated from AOM and OE infections, suggesting that aspects of current UK treatment practices and national recommendations may need to be revised.

The bacterial profile and antibiotic susceptibility pattern in respiratory tract samples from art-experienced HIV-positive adults in Uganda

INTRODUCTION

Microbial infections are a major cause of morbidity and mortality among people living with HIV (PLWH). Respiratory tract infections (RTIs) are responsible for approximately 70% of illnesses among PLWH. Drug resistant bacteria are highly prevalent among PLWH and this is a public health concern.

METHODS

This is a retrospective analysis of data collected during the COSTOP trial between 2011 and 2013. Sputum collected on spot from participants presenting with a productive cough was examined using Gram, Ziehl-Neelsen stains and cultured on suitable bacteriological media. Antimicrobial sensitivity testing was done on isolated pathogens, by disc diffusion technique.

RESULTS

We included 687 participants with mean age 41.3 (SD 8.2) years of whom 76.4% were female. Two hundred one sputum samples grew bacteria; Moraxella species (27.4%), Streptococcus pneumoniae(25.4%), Haemophilus influenza(22.4%), Mycobacterium species(4.5%), Pseudomonas species(4.0%), Staphylococcus aureus(4.0%), Escherichia coli (1.0%), Klebsiella species (1.0%), other bacteria (10.4%). A higher monthly income greater than or equal to 30$ (aOR = 0.63, 95%CI: 0.40-0.99) and longer duration since HIV diagnosis (aOR = 1.06, 95%CI: 1.0-1.11) were found to be independently associated with a positive bacterial culture. Moraxella sp, H. influenza and Pseudomonas had zero sensitivity towards cotrimoxazole. Sensitivity to erythromycin was low among Moraxella sp (28.6%), H. influenza (31.6%) and S. aureus(42.9%) and other bacteria (42.9%). Most isolates were sensitive to Amoxicillin + Clavulanic acid and ceftriaxone.

CONCLUSION

There is a very low sensitivity of isolated bacteria to commonly prescribed antibiotics that are more available through the national supply chain, which is of public health concern. Urgent steps to tackle the high antimicrobial resistance among PLWH is required.

Comparative Genomic Analysis Reveals Genetic Diversity and Pathogenic Potential of Haemophilus seminalis and Emended Description of Haemophilus seminalis

Haemophilus seminalis is a newly proposed species that is phylogenetically related to Haemophilus haemolyticus. The distribution of H. seminalis in the human population, its genomic diversity, and its pathogenic potential are still unclear. This study reports the finding of our comparative genomic analyses of four newly isolated Haemophilus strains (SZY H8, SZY H35, SZY H36, and SZY H68) from human sputum specimens (Guangzhou, China) along with the publicly available genomes of other phylogenetically related Haemophilus species. Based on pairwise comparisons of the 16S rRNA gene sequences, the four isolates showed <98.65% sequence identity to the type strains of all known Haemophilus species but were identified as belonging to H. seminalis, based on comparable phenotypic and genotypic features. Additionally, the four isolates showed high genome-genome relatedness indices (>95% ANI values) with 17 strains that were previously identified as either "Haemophilus intermedius" or hemin (X-factor)-independent H. haemolyticus and therefore required a more detailed classification study. Phylogenetically, these isolates, along with the two previously described H. seminalis isolates (a total of 23 isolates), shared a highly homologous lineage that is distinct from the clades of the main H. haemolyticus and Haemophilus influenzae strains. These isolates present an open pangenome with multiple virulence genes. Notably, all 23 isolates have a functional heme biosynthesis pathway that is similar to that of Haemophilus parainfluenzae. The phenotype of hemin (X-factor) independence and the analysis of the ispD, pepG, and moeA genes can be used to distinguish these isolates from H. haemolyticus and H. influenzae. Based on the above findings, we propose a reclassification for all "H. intermedius" and two H. haemolyticus isolates belonging to H. seminalis with an emended description of H. seminalis. This study provides a more accurate identification of Haemophilus isolates for use in the clinical laboratory and a better understanding of the clinical significance and genetic diversity in human environments. IMPORTANCE As a versatile opportunistic pathogen, the accurate identification of Haemophilus species is a challenge in clinical practice. In this study, we characterized the phenotypic and genotypic features of four H. seminalis strains that were isolated from human sputum specimens and propose the "H. intermedius" and hemin (X-factor)-independent H. haemolyticus isolates as belonging to H. seminalis. The prediction of virulence-related genes indicates that H. seminalis isolates carry several virulence genes that are likely to play an important role in its pathogenicity. In addition, we depict that the genes ispD, pepG, and moeA can be used as biomarkers for distinguishing H. seminalis from H. haemolyticus and H. influenzae. Our findings provide some insights into the identification, epidemiology, genetic diversity, pathogenic potential, and antimicrobial resistance of the newly proposed H. seminalis.

Association Between Nasopharyngeal Colonization and Clinical Outcome in Children With Acute Otitis Media

BACKGROUND

Young children with acute otitis media (AOM) frequently exhibit nasopharyngeal colonization with either Streptococcus pneumoniae, Haemophilus influenzae or both pathogens. We aimed to determine if antibiotics could be spared or shortened in those without nasopharyngeal colonization with either pathogen.

METHODS

In 2 separate randomized clinical trials in children aged 6-23 months with stringently-diagnosed AOM, we performed bacterial cultures on nasopharyngeal specimens collected at the time of diagnosis. In the first trial, we compared the efficacy of amoxicillin/clavulanate (amox/clav) administered for 10 days vs. that of placebo, and in the second trial, we compared the efficacy of amox/clav administered for 10 days vs. 5 days. In each trial, we classified children as being colonized with both S. pneumoniae and H. influenzae, S. pneumoniae alone, H. influenzae alone, or neither pathogen, and as experiencing either clinical success or clinical failure at the end-of-therapy visit, based on previously reported a priori criteria.

RESULTS

We evaluated 796 children. Among children randomized to amox/clav, those colonized with either S. pneumoniae or H. influenzae or both were approximately twice as likely to experience clinical failure as children not colonized with either pathogen (odds ratio: 1.8; confidence intervals: 1.2-2.9). In contrast, among children randomized to placebo, clinical failure at the end-of-therapy visit was not associated with nasopharyngeal culture results at the time of diagnosis.

CONCLUSIONS

Children colonized with either S. pneumoniae or H. influenzae or both have a greater chance of treatment failure than children colonized with neither pathogen.

Haemophilus Influenzae Empyema in a Two-Month-Old Infant

Empyema can rarely complicate pneumonia in neonates; it has a high morbidity and mortality in this population. We report a two-month-old healthy term male neonate who presented with fever, mild shortness of breath and reduced feeding to a tertiary care hospital in Muscat, Oman, in 2021. Investigations revealed the presence of Haemophilus influenzae empyema. He was managed with video-assisted thoracoscopic surgery and prolonged course of antibiotics. A follow-up at the end of the antibiotic course revealed complete symptom resolution with a repeated chest x-ray showing significant right chest opacity improvement. A baseline immune work-up was done and was reported to be within normal ranges.

Epithelial immune activation and intracellular invasion by non-typeable Haemophilus influenzae

Type-2 low asthma affects 30-50% of people with severe asthma and includes a phenotype characterized by sputum neutrophilia and resistance to corticosteroids. Airways inflammation in type-2 low asthma or COPD is potentially driven by persistent bacterial colonization of the lower airways by bacteria such as non-encapsulated Haemophilus influenzae (NTHi). Although pathogenic in the lower airways, NTHi is a commensal of the upper airways. It is not known to what extent these strains can invade airway epithelial cells, persist intracellularly and activate epithelial cell production of proinflammatory cytokines, and how this differs between the upper and lower airways. We studied NTHi infection of primary human bronchial epithelial cells (PBECs), primary nasal epithelial cells (NECs) and epithelial cell lines from upper and lower airways. NTHi strains differed in propensity for intracellular and paracellular invasion. We found NTHi was internalized within PBECs at 6 h, but live intracellular infection did not persist at 24 h. Confocal microscopy and flow cytometry showed NTHi infected secretory, ciliated and basal PBECs. Infection of PBECs led to induction of CXCL8, interleukin (IL)-1β, IL-6 and TNF. The magnitude of cytokine induction was independent of the degree of intracellular invasion, either by differing strains or by cytochalasin D inhibition of endocytosis, with the exception of the inflammasome-induced mediator IL-1β. NTHi-induced activation of TLR2/4, NOD1/2 and NLR inflammasome pathways was significantly stronger in NECs than in PBECs. These data suggest that NTHi is internalized transiently by airway epithelial cells and has capacity to drive inflammation in airway epithelial cells.

Secondary Cases of Invasive Disease Caused by Encapsulated and Nontypeable Haemophilus influenzae - 10 U.S. Jurisdictions, 2011-2018

Haemophilus influenzae (Hi) can cause meningitis and other serious invasive disease. Encapsulated Hi is classified into six serotypes (a-f) based on chemical composition of the polysaccharide capsule; unencapsulated strains are termed nontypeable Hi (NTHi). Hi serotype b (Hib) was the most common cause of bacterial meningitis in children in the pre-Hib vaccine era, and secondary transmission of Hi among children (e.g., to household contacts and in child care facilities) (1,2) led to the Advisory Committee on Immunization Practices (ACIP) recommendation for antibiotic chemoprophylaxis to prevent Hib disease in certain circumstances.* High Hib vaccination coverage since the 1990s has substantially reduced Hib disease, and other serotypes now account for most Hi-associated invasive disease in the United States (3). Nevertheless, CDC does not currently recommend chemoprophylaxis for contacts of persons with invasive disease caused by serotypes other than Hib and by NTHi (non-b Hi). Given this changing epidemiology, U.S. surveillance data were reviewed to investigate secondary cases of invasive disease caused by Hi. The estimated prevalence of secondary transmission was 0.32% among persons with encapsulated Hi disease (≤60 days of one another) and 0.12% among persons with NTHi disease (≤14 days of one another). Isolates from all Hi case pairs were genetically closely related, and all patients with potential secondary infection had underlying medical conditions. These results strongly suggest that secondary transmission of non-b Hi occurs. Expansion of Hi chemoprophylaxis recommendations might be warranted to control invasive Hi disease in certain populations in the United States, but further analysis is needed to evaluate the potential benefits against the risks, such as increased antibiotic use.

Changes in the Incidence of Invasive Bacterial Disease During the COVID-19 Pandemic in the United States, 2014-2020

BACKGROUND

Descriptions of changes in invasive bacterial disease (IBD) epidemiology during the coronavirus disease 2019 (COVID-19) pandemic in the United States are limited.

METHODS

We investigated changes in the incidence of IBD due to Streptococcus pneumoniae, Haemophilus influenzae, group A Streptococcus (GAS), and group B Streptococcus (GBS). We defined the COVID-19 pandemic period as 1 March to 31 December 2020. We compared observed IBD incidences during the pandemic to expected incidences, consistent with January 2014 to February 2020 trends. We conducted secondary analysis of a health care database to assess changes in testing by blood and cerebrospinal fluid (CSF) culture during the pandemic.

RESULTS

Compared with expected incidences, the observed incidences of IBD due to S. pneumoniae, H. influenzae, GAS, and GBS were 58%, 60%, 28%, and 12% lower during the pandemic period of 2020, respectively. Declines from expected incidences corresponded closely with implementation of COVID-19-associated nonpharmaceutical interventions (NPIs). Significant declines were observed across all age and race groups, and surveillance sites for S. pneumoniae and H. influenzae. Blood and CSF culture testing rates during the pandemic were comparable to previous years.

CONCLUSIONS

NPIs likely contributed to the decline in IBD incidence in the United States in 2020; observed declines were unlikely to be driven by reductions in testing.

Neonatal Early-Onset Sepsis Due to Haemophilus Influenzae in Utah

Haemophilus influenzae causes serious invasive disease in children and is described as an infrequent cause of neonatal early-onset sepsis (EOS). Here we present the clinical and microbiologic features of 10 cases of EOS due to H. influenzae in Utah.

Genetic Adaptation and Acquisition of Macrolide Resistance in Haemophilus spp. during Persistent Respiratory Tract Colonization in Chronic Obstructive Pulmonary Disease (COPD) Patients Receiving Long-Term Azithromycin Treatment

Patients with chronic obstructive pulmonary disease (COPD) benefit from the immunomodulatory effect of azithromycin, but long-term administration may alter colonizing bacteria. Our goal was to identify changes in Haemophilus influenzae and Haemophilus parainfluenzae during azithromycin treatment. Fifteen patients were followed while receiving prolonged azithromycin treatment (Hospital Universitari de Bellvitge, Spain). Four patients (P02, P08, P11, and P13) were persistently colonized by H. influenzae for at least 3 months and two (P04 and P11) by H. parainfluenzae. Isolates from these patients (53 H. influenzae and 18 H. parainfluenzae) were included to identify, by whole-genome sequencing, antimicrobial resistance changes and genetic variation accumulated during persistent colonization. All persistent lineages isolated before treatment were azithromycin-susceptible but developed resistance within the first months, apart from those belonging to P02, who discontinued the treatment. H. influenzae isolates from P08-ST107 acquired mutations in 23S rRNA, and those from P11-ST2480 and P13-ST165 had changes in L4 and L22. In H. parainfluenzae, P04 persistent isolates acquired changes in rlmC, and P11 carried genes encoding MefE/MsrD efflux pumps in an integrative conjugative element, which was also identified in H. influenzae P11-ST147. Other genetic variation occurred in genes associated with cell wall and inorganic ion metabolism. Persistent H. influenzae strains all showed changes in licA and hgpB genes. Other genes (lex1, lic3A, hgpC, and fadL) had variation in multiple lineages. Furthermore, persistent strains showed loss, acquisition, or genetic changes in prophage-associated regions. Long-term azithromycin therapy results in macrolide resistance, as well as genetic changes that likely favor bacterial adaptation during persistent respiratory colonization. IMPORTANCE The immunomodulatory properties of azithromycin reduce the frequency of exacerbations and improve the quality of life of COPD patients. However, long-term administration may alter the respiratory microbiota, such as Haemophilus influenzae, an opportunistic respiratory colonizing bacteria that play an important role in exacerbations. This study contributes to a better understanding of COPD progression by characterizing the clinical evolution of H. influenzae in a cohort of patients with prolonged azithromycin treatment. The emergence of macrolide resistance during the first months, combined with the role of Haemophilus parainfluenzae as a reservoir and source of resistance dissemination, is a cause for concern that may lead to therapeutic failure. Furthermore, genetic variations in cell wall and inorganic ion metabolism coding genes likely favor bacterial adaptation to host selective pressures. Therefore, the bacterial pathoadaptive evolution in these severe COPD patients raise our awareness of the possible spread of macrolide resistance and selection of host-adapted clones.

Pathogens associated with hospitalization due to acute lower respiratory tract infections in children in rural Ghana: a case-control study

Respiratory infections are one of the most common causes of death among children under the age of five years. Data on prevalence and relevance of specific organisms in African children are still lacking. This case-control-study investigated prevalence and relevance of specific organisms in Ghanaian children admitted to hospital with symptoms of lower respiratory tract infection (LRTI). Pharyngeal swabs were taken and tested by PCR for 19 respiratory isolates. Adjusted odds ratios (aORs) were calculated to estimate associations between isolates and admission with LRTI. Population attributable fractions (PAFs) were calculated to assess the proportion of LRTI cases due to a particular pathogen. The study included 327 cases and 562 controls. We found associations between detection and admission for LRTI for influenza (aOR 98.6; 95% confidence interval (CI) 20.0-1789.6), respiratory syncytial virus (aOR 40.2; 95% CI 7.2-758.6), H. influenzae (aOR 4.1; 95% CI 2.2-7.9) and S. pneumoniae (aOR 2.4; 95% CI 1.7-3.4). PAFs ≥ 10% were observed for S. pneumoniae (30%; 95% CI 26-42), H. influenzae (10%; 95% CI 2-19) and influenza (10%; 95% CI 2-18). This study highlights the need for heightened surveillance and development of effective vaccines for respiratory pathogens other than SARS-CoV-2 in the future.

A cascade nanozyme with antimicrobial effects against nontypeable Haemophilus influenzae

Otitis media (OM) is the main cause of pediatric antibiotic prescriptions. Nontypeable Haemophilus influenzae (NTHi) is a major OM pathogen, which forms a biofilm that resists conventional antimicrobials and immune clearance. Thus, novel treatments that are effective against NTHi and its biofilm are urgently required. Nanozymes (often inorganic nanoparticles) mimic natural enzymes' catalytic activities to generate strong antimicrobials at the site of infection, and thus represent one of the emerging solutions to the crisis of antimicrobial resistance. They mimic natural enzymes' activities, such as generating strong antimicrobials catalytically at the site of infection, to minimize overexposure. However, that in situ generation often relies on Reactive Oxygen Species (ROS) as precursors, a prerequisite that limits the broad deployment of nanozymes. To address this challenge, we designed a cascade nanozyme that generates an antiseptic, HOBr, from a ubiquitous non-ROS, i.e., O₂, which successfully eradicates NTHi. The cascade nanozyme simultaneously exhibits glucose oxidase (GOx)-like activity from gold nanoparticles (AuNPs) and haloperoxidase (HPO)-mimicking activity from vanadium pentoxide nanowires (V₂O₅ NWs) connected using dopamine (DPA). The cascade nanozyme demonstrated strong antimicrobial efficacy against NTHi and its biofilm, while showing improved biocompatibility compared to the nanozyme of V₂O₅ NWs alone. The cascade nanozyme thus points to a material-oriented infectious disease treatment strategy, where small-molecule antimicrobials are generated in real time at the site of infection for the benefit of autonomous dosing. This strategy potentially mitigates the development of antimicrobial resistance and reduces side effects.

Impact of IL-17-producing γδ T cells on chronic otitis media induced by nontypeable Haemophilus influenzae in a mouse model

Nontypeable Haemophilus influenzae (NTHi) is considered a major pathogen underlying middle ear infection. This study aimed to investigate the impact of IL-17 on chronic otitis media (COM) induced by NTHi in mice. NTHi was inoculated into the tympanic bulla with eustachian tubal obstruction. Middle ear effusions (MEEs) and tissues were collected on days 3, 14, and at 1, 2, and 6 months after injection. The expression of interleukin-17A (IL-17A) in MEEs was significantly elevated compared to that in the control group at the translational and transcriptional levels during the experiments. The quantities of IL-17-producing γδ T cells were significantly increased compared to that in the control group during COM, but that of Th17 cells did not. Depletion of γδ T cells by anti-γδ T-cell receptor (TCR) monoclonal antibody (mAb) administration significantly decreased the bacteria counts and the concentrations of IL-1β, IL-6, IL-17A, TNF-α, and IL-10 in MEEs. Our results suggest that IL-17 may play an important role in prolonging the inflammation in the middle ear in COM and that IL-17-producing γδ T cells may contribute to the exacerbated inflammatory response in the middle ear. In this study, anti-γδ TCR mAb administration was found to improve chronic middle ear inflammatory conditions.

Non-immunization associated with increased risk of sudden unexpected death in infancy: A national case-control study

OBJECTIVE

In the context of vaccine scepticism, our study aimed to analyse the association between immunization status and the occurrence of sudden unexpected death in infancy (SUDI).

STUDY DESIGN

A multi-centre case-control study was conducted between May 2015 and June 2017 with data from the French national SUDI registry (OMIN) for 35 French regional SUDI centres. Cases were infants under age 1 year who died from SUDI and who were registered in OMIN. Controls, matched to cases by age and sex at a 2:1 ratio, were infants admitted to Nantes University Hospital. All immunization data for diphtheria (D), tetanus (T), acellular pertussis (aP), inactivated poliovirus (IPV), Haemophilus influenzae b (Hib), hepatitis B (HB) and 13-valent pneumococcal conjugate vaccine (PCV13) were collected by a physician. Cases and controls were considered immunized if at least one dose of vaccine was administered.

RESULTS

A total of 91 cases and 182 controls were included. The median age was 131 days (interquartile range 98-200.0) and the sex ratio (M/F) was about 1.1. For all vaccines combined (D-T-aP-IPV-Hib and PCV13), 22 % of SUDI cases versus 12 % of controls were non-immunized, which was significantly associated with SUDI after adjustment for potential adjustment factors (adjusted odds ratio 2.01 [95 % confidence interval 1.01-3.98, p = 0,047]).

CONCLUSIONS

Non-immunization for D-T-aP-IPV-Hib-HB and PCV13 was associated with increased risk of SUDI. This result can be used to inform the general public and health professionals about this risk of SUDI in case of vaccine hesitancy.

An Isolate of Streptococcus mitis Displayed In Vitro Antimicrobial Activity and Deleterious Effect in a Preclinical Model of Lung Infection

Microbiota studies have dramatically increased over these last two decades, and the repertoire of microorganisms with potential health benefits has been considerably enlarged. The development of next generation probiotics from new bacterial candidates is a long-term strategy that may be more efficient and rapid with discriminative in vitro tests. Streptococcus strains have received attention regarding their antimicrobial potential against pathogens of the upper and, more recently, the lower respiratory tracts. Pathogenic bacterial strains, such as non-typable Haemophilus influenzae (NTHi), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus), are commonly associated with acute and chronic respiratory diseases, and it could be interesting to fight against pathogens with probiotics. In this study, we show that a Streptococcus mitis (S. mitis) EM-371 strain, isolated from the buccal cavity of a human newborn and previously selected for promising anti-inflammatory effects, displayed in vitro antimicrobial activity against NTHi, P. aeruginosa or S. aureus. However, the anti-pathogenic in vitro activity was not sufficient to predict an efficient protective effect in a preclinical model. Two weeks of treatment with S. mitis EM-371 did not protect against, and even exacerbated, NTHi lung infection.

Meningitis and encephalitis in Poland in 2021

Introduction

Meningitis meningitis and/or encephalitis regardless of etiology are subject to monitoring in Poland as part of routine epidemiological surveillance. In this paper, meningitis and/or encephalitis in 2021 caused by Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and tick-borne encephalitis virus are discussed in detail. In Poland, immunoprophylaxis in the form of mandatory or recommended vaccinations is used to prevent diseases caused by the aforementioned etiological agents.

Aim of the study

The aim of this study was to assess the epidemiological incidence of meningoencephalitis and encephalitis in Poland, in 2021 including analysis of the impact of the COVID-19 pandemic.

Material and methods

To analyse the epidemiological situation of neuroinfections in Poland, we used data sent to NIPH NIH - NRI by Voivodeship Sanitary and Epidemiological Stations and published in the annual bulletin: "Infectious diseases and poisonings in Poland in 2021" and "Protective vaccination in Poland in 2021" as well as individual epidemiological interviews recorded in the EpiBase system.

Results

In 2021, a total of 973 cases of meningitis and/or encephalitis were registered in Poland. This is a 16.1% increase in the number of cases compared to 2020, but still a 57% decrease in the number of cases compared to 2019 when 2,249 cases were recorded. For infections of bacterial etiology, including cases of neuroborreliosis, the number of cases increased by 38.3% (from 376 to 520, incidence from 0.96 to 1.76 per 100,000). Compared to 2020 and 2019, the incidence of meningitis and/or encephalitis of N. meningitidis decreased by 10.7% (from 0.13 to 0.15) and 47.4% (from 0.25 to 0.13), respectively, and for H. influenzae by 75% (from 0.01 to 0.03) and 70% (from 0.01 to 0.03). For S. pneumoniae, we can speak of an increase in incidence against 2020 of 57.1% (121 vs 77 cases, incidence 0.32 vs 0.20) and a decrease against 2019. (121 vs 190, incidence 0.32 vs 0.47). Infections of viral etiology accounted for 47% of all registered cases. There was a slight decrease in their number, by 2% (from 462 to 453 cases). In addition, there was an increase in cases of tick-borne encephalitis, from 158 in 2020 to 210 in 2021 (an increase of 32.9%), and a decrease in cases from 265 in 2019 (a decrease of 20.8%).

Summary and conclusions

2021 showed an overall upward trend in the number of recorded cases of bacterial meningitis and/or encephalitis, and a slight decrease in the number of viral meningitis and/or encephalitis cases compared to 2020. Still, the observed number of meningitis and/or encephalitis cases in 2021, both bacterial and viral incidences, remains below the levels observed in the pre-pandemic COVID-19 period (2019). As a result of the SARS-CoV-2 outbreak, the introduction of measures to limit the transmission of the SARS-CoV-2 virus has been observed to reduce the spread of other droplet- and airborne pathogens, thus also pathogens such as S. pneumoniae, H.influenzae and N. menningitidis.

Haemophilus influenzae Protein D antibody suppression in a multi-component vaccine formulation

Nontypeable Haemophilus influenzae (NTHi) has emerged as a dominant mucosal pathogen causing acute otitis media (AOM) in children, acute sinusitis in children and adults, and acute exacerbations of chronic bronchitis in adults. Consequently, there is an urgent need to develop a vaccine to protect against NTHi infection. A multi-component vaccine will be desirable to avoid emergence of strains expressing modified proteins allowing vaccine escape. Protein D (PD), outer membrane protein (OMP) 26, and Protein 6 (P6) are leading protein vaccine candidates against NTHi. In pre-clinical research using mouse models, we found that recombinantly expressed PD, OMP26, and P6 induce robust antibody responses after vaccination as individual vaccines, but when PD and OMP26 were combined into a single vaccine formulation, PD antibody levels were significantly lower. We postulated that PD and OMP26 physiochemically interacted to mask PD antigenic epitopes resulting in the observed effect on antibody response. However, column chromatography and mass spectrometry analysis did not support our hypothesis. We postulated that the effect might be in vivo through the mechanism of protein vaccine immunologic antigenic competition. We found when PD and OMP26 were injected into the same leg or separate legs of mice, so that antigens were immunologically processed at the same or different regional lymph nodes, respectively, antibody levels to PD were significantly lower with same leg vaccination. Different leg vaccination produced PD antibody levels quantitatively similar to vaccination with PD alone. We conclude that mixing PD and OMP26 into a single vaccine formulation requires further formulation studies.