Role of Nasopharyngeal Bacteria and Respiratory Viruses in Acute Symptoms of Young Children

Exposure to bacterial PAMPs before RSV infection exacerbates innate inflammation and disease via IL-1α and TNF-α

Respiratory syncytial virus (RSV) can cause severe lower respiratory tract infections. Understanding why some individuals get more serious disease may help with diagnosis and treatment. One possible risk factor underlying severe disease is bacterial exposure before RSV infection. Bacterial exposure has been associated with increased respiratory viral-induced disease severity but the mechanism remains unknown. Respiratory bacterial infections or exposure to their pathogen associated molecular patterns (PAMPs) trigger innate immune inflammation, characterised by neutrophil and inflammatory monocyte recruitment and the production of inflammatory cytokines. We hypothesise that these changes to the lung environment alter the immune response and disease severity during subsequent RSV infection. To test this, we intranasally exposed mice to LPS, LTA or Acinetobacter baumannii (an airway bacterial pathogen) before RSV infection and observed an early induction of disease, measured by weight loss, at days 1-3 after infection. Neutrophils or inflammatory monocytes were not responsible for driving this exacerbated weight loss. Instead, exacerbated disease was associated with increased IL-1α and TNF-α, which orchestrated the recruitment of innate immune cells into the lung. This study shows that exposure to bacterial PAMPs prior to RSV infection increases the expression of IL-1α and TNF-α, which dysregulate the immune response resulting in exacerbated disease.

Systematic literature review of the signs and symptoms of respiratory syncytial virus

Respiratory syncytial virus (RSV) is responsible for over 30 million lower respiratory tract infections (LRTIs) and 3 million hospitalizations worldwide each year. Despite the risk RSV poses to young children, older adults, and individuals with comorbidities or suppressed immunity, there is limited understanding of RSV symptom presentation across these at-risk groups, and there is no vaccine for RSV. We conducted two systematic literature reviews (SLRs) of studies that document signs and symptoms (S&S) of RSV in (1) children aged ≤5 years and (2) immunocompromised adolescents and adults, and adults at high risk for severe RSV due to age or comorbidities. Symptom duration and hospital length of stay (LOS) were explored. Electronic database searches were performed following PRISMA guidelines. Studies captured RSV S&S across community and hospital settings. Clinicians and caregivers reported (n = 25 studies) nasal discharge/congestion, cough, shortness of breath, feeding abnormalities, and fever in ≥40% of children across studies and settings. Median hospital stays for children ranged from 2 days in the United States to 7.5 days in China. High-risk adults with RSV (n = 6 studies) commonly (≥40% of adults) reported cough, sputum, dyspnea, and fever/feverishness. Median length of hospital stay in adults ranged from 6 to 15 days across studies. Caregivers and clinicians reported similar RSV S&S in young children, including upper and lower respiratory and systemic symptoms. In high-risk and immunocompromised adults, the most frequent (in multiple publications) and commonly reported RSV S&S were primarily LRTI symptoms. RSV symptoms could last for weeks and are variable based on geography.

Changing Epidemiology of Acute Viral Respiratory Infections in Hospitalized Children: The Post-Lockdown Effect

Several reports highlighted how public health measures aimed at limiting severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) circulation have likely contributed to reducing the circulation of other respiratory viruses, particularly during the first year of the COVID-19 pandemic. We evaluated the epidemiology of acute respiratory infections in a large cohort of hospitalized children during the third year of the pandemic (2021−2022). We retrospectively analyzed data from the health records of children (<14 years) hospitalized for acute respiratory infections between 1 July 2021 and 31 March 2022. A total of 1763 respiratory panels were collected. Overall, 1269 (72%) panels hadpositive results for at least one pathogen. Most positive panels (53.8%) belonged to patients aged 1−12 months. The most detected pathogen was respiratory syncytial virus (RSV) (57.8% of positive panels). The RSV peak occurred in November 2021. Nine hundred and forty-five (74.5%) panels were positive for one pathogen while three hundred and twenty-four (25.5%) showed multiple infections. Patients with multiple infections were significantly older than those with a single infection. The 2021−2022 peak of RSV infection in Italy occurred earlier than in the previous pre-pandemic seasons. A high number of children have been hospitalized because of acute viral infections also due to less aggressive viruses.

Community-Based Antibiotic Prescribing Attributable to Respiratory Syncytial Virus and Other Common Respiratory Viruses in Young Children: A Population-Based Time-series Study of Scottish Children

BACKGROUND

Inappropriate antibiotic prescribing, such as for viral illness, remains common in primary care. The objective of this study was to estimate the proportion of community-prescribed antibiotics to children aged less than 5 years attributable to common respiratory viruses.

METHODS

We fitted time-series negative binomial models to predict weekly antibiotic prescribing rates from positive viral pathogen tests for the period 1 April 2009 through 27 December 2017 using comprehensive, population-based administrative data for all children (<5 years) living in Scotland. Multiple respiratory viral pathogens were considered, including respiratory syncytial virus (RSV), influenza, human metapneumovirus (HMPV), rhinovirus, and human parainfluenza (HPIV) types 1-4. We estimated the proportion of antibiotic prescriptions explained by virus circulation according to type of virus, by age group, presence of high-risk chronic conditions, and antibiotic class.

RESULTS

We included data on 6 066 492 antibiotic prescriptions among 452 877 children. The antibiotic-prescribing rate among all Scottish children (<5 years) was 609.7 per 1000 child-years. Our final model included RSV, influenza, HMPV, HPIV-1, and HPIV-3. An estimated 6.9% (95% confidence interval, 5.6-8.3%), 2.4% (1.7-3.1%), and 2.3% (.8-3.9%) of antibiotics were attributable to RSV, influenza, and HMPV, respectively. RSV was consistently associated with the highest proportion of prescribed antibiotics, particularly among children without chronic conditions and for amoxicillin and macrolide prescriptions.

CONCLUSIONS

Nearly 14% of antibiotics prescribed to children in this study were estimated to be attributable to common viruses for which antibiotics are not recommended. A future RSV vaccine could substantially reduce unnecessary antibiotic prescribing among children.

The clinical application of Filmarray respiratory panel in children especially with severe respiratory tract infections

BACKGROUND

Respiratory tract infections (RTIs) are the common diseases in children and the routine detection methods frequently fail to identify the infectious pathogens especially for viruses. The Filmarray respiratory panel (FARP) can reliably and rapidly identify viruses and bacteria pathogens. This study is to evaluate the performance and clinical significance of FARP in children.

METHODS

Children diagnosed with RTIs in pediatric intensive care unit (PICU) were enrolled in this study. Nasopharyngeal secretion (NPS) samples of these children were collected and the FARP assay for 17 pathogens and routine microbiological methods were performed. Clinical data of all patients was also collected and evaluated.

RESULTS

A total of 90 children were enrolled into this study and 58 patients (64.4%) were positive for 13 pathogens by FARP, with 18 being detected positive with multiple-virus (31.3%, 18/58). Human rhinovirus/enterovirus (21.0%%, 17/58) were the predominant pathogen, followed by adenovirus (18.5%). Higher proportions of various pathogens were identified in the infant and toddler (0-2 years) groups with human rhinovirus/enterovirus being mostly virus. Adenovirus were common in the group aged 3-5 years, but only three pathogens including M.pneumoniae, respiratory syncytial virus, and adenovirus were also found in age group (6-14 years). Among 58 FARP positive patients, significant differences were found in antibiotic prescription and use of glucocorticoid between the single-organism-positive group and the multi-organism-positive group (P < 0.05). Furthermore, there was significant difference in use of anti-virus and usage of glucocorticoid between severe respiratory infections group and non severe respiratory infections group (P < 0.05).

CONCLUSIONS

This study demonstrated that FARP can provide the rapid detection of respiratory virus and atypical bacteria for children, especially with severe respiratory tract infections.

Panel 4: Recent advances in understanding the natural history of the otitis media microbiome and its response to environmental pressures

OBJECTIVE

To perform a comprehensive review of otitis media microbiome literature published between 1^st July 2015 and 30th June 2019.

DATA SOURCES

PubMed database, National Library of Medicine.

REVIEW METHODS

Key topics were assigned to each panel member for detailed review. Draft reviews were collated and circulated for discussion when the panel met at the 20th International Symposium on Recent Advances in Otitis Media in June 2019. The final draft was prepared with input from all panel members.

CONCLUSIONS

Much has been learned about the different types of bacteria (including commensals) present in the upper respiratory microbiome, but little is known about the virome and mycobiome. A small number of studies have investigated the middle ear microbiome; however, current data are often limited by small sample sizes and methodological heterogeneity between studies. Furthermore, limited reporting of sample collection methods mean that it is often difficult to determine whether bacteria detected in middle ear fluid specimens originated from the middle ear or the external auditory canal. Recent in vitro studies suggest that bacterial interactions in the nasal/nasopharyngeal microbiome may affect otitis media pathogenesis by modifying otopathogen behaviours. Impacts of environmental pressures (e.g. smoke, nutrition) and clinical interventions (e.g. vaccination, antibiotics) on the upper respiratory and middle ear microbiomes remain poorly understood as there are few data.

IMPLICATIONS FOR PRACTICE

Advances in understanding bacterial dynamics in the upper airway microbiome are driving development of microbiota-modifying therapies to prevent or treat disease (e.g. probiotics). Further advances in otitis media microbiomics will likely require technological improvements that overcome the current limitations of OMICs technologies when applied to low volume and low biomass specimens that potentially contain high numbers of host cells. Improved laboratory models are needed to elucidate mechanistic interactions among the upper respiratory and middle ear microbiomes. Minimum reporting standards are critically needed to improve inter-study comparisons and enable future meta-analyses.

The Suppressive Role of Streptococcus pneumoniae Colonization in Acute Exacerbations of Childhood Bronchial Asthma

INTRODUCTION

Little is known about the association between bacterial infections and exacerbations of bronchial asthma.

OBJECTIVE

To elucidate the effect of bacterial infections on bronchial asthma, we examined pharyngeal bacterial colonization, duration of wheezing, and serum levels of cytokines and chemokines during acute exacerbations of asthma in children.

METHODS

Potential bacterial pathogens were investigated in pharyngeal samples and viruses obtained from nasal secretions of 111 children who were outpatients and/or in patients with acute exacerbations of asthma (mean/median age: 2.8/2.6, respectively). We also measured serum levels of 27 different cytokines/chemokines.

RESULTS

Pharyngeal bacterial cultures were positive in 110 of 111 children. The 3 major bacterial pathogens were Streptococcus pneumoniae (29.7%), Moraxella catarrhalis (11.7%), and Haemophilus influenzae (10.8%). M. catarrhalis was detected more frequently in patients with pneumonia. Furthermore, patients with S. pneumoniae colonization had significantly shorter wheezing episodes than those without it. In contrast, the duration of wheezing did not differ significantly among cases with other bacteria such as M. catarrhalis and H. influenzae. Furthermore, the length of wheezing episode in patients with S. pneumoniae colonization showed significant inverse correlation with peripheral white blood cell count, neutrophil count, and C-reactive protein, while there was no significant correlation between duration of wheezing and these 3 parameters among patients with M. catarrhalis or H. influenza. Among the 27 cytokines/chemokines, only serum tumor necrosis factor (TNF)-α was significantly lower in patients with S. pneumoniae colonization than in those without it.

CONCLUSIONS

These results suggested that pharyngeal S. pneumoniae colonization plays a suppressive role on the pathophysiology during acute exacerbations of asthma.

Adaptation of pain scales for parent observation: are pain scales and symptoms useful in detecting pain of young children with the suspicion of acute otitis media?

Background

The assessment of ear pain is challenging in young, mostly preverbal children. Our aim was to investigate whether pain scales are useful tools for parents to detect pain in their young children with the suspicion of acute otitis media (AOM), and to assess associations between 16 symptoms and the severity of pain.

Methods

This cross-sectional study included 426 children (6–35 months) with symptoms suggestive of AOM. We surveyed symptoms and pain via parental interview. As part of the interview, parents assessed their child’s pain by using two pain scales: The Faces Pain Scale-Revised (FPS-R) and the Face, Legs, Activity, Cry, Consolability (FLACC) Scale. The outcome of interest was moderate/severe pain. We used the χ² test or Fisher’s test as applicable to compare the severity of pain between three parental pain assessment methods (the parental interview, the FPS-R and the FLACC Scale). We also used multivariable logistic regression models to study the association between the severity of pain and AOM and to study the association between symptoms and the severity of pain.

Results

In children with AOM (n = 201), pain was assessed by parents as moderate/severe in 65% via interview; 90% with the FPS-R; and 91% with the FLACC Scale (P < 0.001). In children without AOM (n = 225), the percentages were 56, 83 and 88%, respectively (P < 0.001). Between children with and without AOM, the occurrence of moderate/severe pain did not differ with any of the pain evaluation methods. Of symptoms, ear pain reported by child and restless sleep were significantly associated with moderate/severe pain, regardless of the pain evaluation method.

Conclusions

It seems that nearly all the children with respiratory tract infection, either with or without AOM, might suffer from moderate/severe pain. Without pain scales, parents may underestimate their child’s pain. Of symptoms, ear pain reported by child and restless sleep might indicate pain in children with respiratory tract infection. We suggest that the adaptation of pain scales for parent observation is a possibility in children with respiratory tract infection which, however, requires further studies.

Trial registration

www.clinicaltrials.gov, identifier NCT00299455. Date of registration: March 3, 2006.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1361-y) contains supplementary material, which is available to authorized users.

In situ Immune Signatures and Microbial Load at the Nasopharyngeal Interface in Children With Acute Respiratory Infection

Acute respiratory infection (ARI) is the most frequent cause for hospitalization in infants and young children. Using multiplexed nCounter technology to digitally quantify 600 human mRNAs in parallel with 14 virus- and 5 bacterium-specific RNAs, we characterized viral and bacterial presence in nasopharyngeal aspirates (NPA) of 58 children with ARI and determined the corresponding in situ immune profiles. NPA contained different groups of organisms and these were classified into bacterial (n = 27), viral (n = 5), codetection [containing both viral and bacterial transcripts (n = 21), or indeterminate intermediate where microbial load is below threshold (n = 5)]. We then identified differentially expressed immune transcripts (DEITs) comparing NPAs from symptomatic children vs. healthy controls, and comparing children presenting NPAs with detectable microbial load vs. indeterminate. We observed a strong innate immune response in NPAs, due to the presence of evolutionarily conserved type I Interferon (IFN)-stimulated genes (ISG), which was correlated with total bacterial and/or viral load. In comparison with indeterminate NPAs, adaptive immunity transcripts discriminated among viral, bacterial, and codetected microbial profiles. In viral NPAs, B cell transcripts were significantly enriched among DEITs, while only type III IFN was correlated with viral load. In bacterial NPAs, myeloid cells and coinhibitory transcripts were enriched and significantly correlated with bacterial load. In conclusion, digital nCounter transcriptomics provide a microbial and immunological in situ “snapshot” of the nasopharyngeal interface in children with ARI. This enabled discrimination among viral, bacterial, codetection, and indeterminate transcripts in the samples using non-invasive sampling.

Effect of Antimicrobial Treatment on the Resolution of Middle-Ear Effusion After Acute Otitis Media

BACKGROUND

Acute otitis media (AOM) induces middle-ear effusion (MEE), which affects hearing. The effect of antimicrobial treatment on the resolution of MEE is controversial, and the factors that affect resolution are unknown.

METHODS

We studied the effect of antimicrobial treatment on the time to the resolution of MEE as a secondary objective in our randomized double-blind placebo-controlled trial. Children aged 6 to 35 months with stringently diagnosed AOM were allocated to receive amoxicillin-clavulanate (161 patients) or placebo (158 patients) for 7 days and closely followed for 3 months. This study was registered at ClinicalTrials.gov (identifier NCT00299455).

RESULTS

The median times to resolution of MEE were 20 days (95% confidence interval [CI], 16-24 days) and 29 days (95% CI, 26-32 days) in the amoxicillin-clavulanate and placebo groups, respectively (P = .10). The resolution of MEE was confirmed in 138 (86%) of 161 and 132 (84%) of 158 patients in the amoxicillin-clavulanate and placebo groups, respectively (P = .59). In multivariable analysis, the resolution of MEE was prolonged most significantly by at least 1 recurrence of AOM during follow-up. MEE resolved in 65 (65%) of 100 patients with a recurrence of AOM during follow-up and in 205 (94%) of 219 of those without a recurrence (P < .001) (median times to resolution, 67 vs 15 days, respectively; P < .001).

CONCLUSIONS

Immediate antimicrobial treatment of AOM does not significantly affect the resolution of MEE in young children. Subsequent recurrences of AOM are a major reason for the persistence of MEE.

A Moraxella catarrhalis vaccine to protect against otitis media and exacerbations of COPD: An update on current progress and challenges

Moraxella catarrhalis is a major cause of morbidity and mortality worldwide, especially causing otitis media in young children and exacerbations of chronic obstructive pulmonary disease in adults. This pathogen uses several virulence mechanisms to colonize and survive in its host, including adherence and invasion of host cells, formation of polymicrobial biofilms with other bacterial pathogens, and production of β-lactamase. Given the global impact of otitis media and COPD, an effective vaccine to prevent M. catarrhalis infection would have a huge impact on the quality of life in both patient populations by preventing disease, thus reducing morbidity and health care costs. A number of promising vaccine antigens have been identified for M. catarrhalis. The development of improved animal models of M. catarrhalis disease and identification of a correlate of protection are needed to accelerate vaccine development. This review will discuss the current state of M. catarrhalis vaccine development, and the challenges that must be addressed to succeed.

Airway Microbiota and the Implications of Dysbiosis in Asthma

The mucosal surfaces of the human body are typically colonized by polymicrobial communities seeded in infancy and are continuously shaped by environmental exposures. These communities interact with the mucosal immune system to maintain homeostasis in health, but perturbations in their composition and function are associated with lower airway diseases, including asthma, a developmental and heterogeneous chronic disease with various degrees and types of airway inflammation. This review will summarize recent studies examining airway microbiota dysbioses associated with asthma and their relationship with the pathophysiology of this disease.

Upper airway viruses and bacteria in urban Aboriginal and Torres Strait Islander children in Brisbane, Australia: a cross-sectional study

BACKGROUND

Respiratory morbidity in Australian Indigenous children is higher than their non-Indigenous counterparts, irrespective of urban or remote residence. There are limited studies addressing acute respiratory illness (ARI) in urban Indigenous children, particularly those that address the upper airway microbiome and its relationship to disease. We aimed to describe the prevalence of upper airway viruses and bacteria in symptomatic and asymptomatic urban-based Australian Indigenous children aged less than 5 years.

METHODS

A cross-sectional analysis of data collected at baseline in an ongoing prospective cohort study of urban Aboriginal and Torres Strait Islander children registered with a primary health care service in the northern suburbs of Brisbane, Australia. Clinical, demographic and epidemiological data and bilateral anterior nasal swabs were collected on enrolment. Polymerase chain reaction was performed on nasal swabs to detect 17 respiratory viruses and 7 bacteria. The primary outcome was the prevalence of these microbes at enrolment. Logistic regression was performed to investigate differences in microbe prevalence between children with and without acute respiratory illness with cough as a symptom (ARIwC) at time of specimen collection.

RESULTS

Between February 2013 and October 2015, 164 children were enrolled. The median age at enrolment was 18.0 months (IQR 7.2-34.3), 49.4% were boys and 56 children (34.2%) had ARIwC. Overall, 133/164 (81%) nasal swabs were positive for at least one organism; 131 (79.9%) for any bacteria, 59 (36.2%) for any virus and 57 (34.8%) for both viruses and bacteria. Co-detection of viruses and bacteria was more common in females than males (61.4% vs 38.6%, p = 0.044). No microbes, alone or in combination, were significantly associated with the presence of ARIwC.

CONCLUSIONS

The prevalence of upper airways microbes in asymptomatic children is similar to non-Indigenous children with ARIwC from the same region. Determining the aetiology of ARIwC in this community is complicated by the high prevalence of multiple respiratory pathogens in the upper airways.

STUDY REGISTRATION

Australia New Zealand Clinical Trial Registry Registration Number: 12,614,001,214,628. Retrospectively registered.

Upper airway viruses and bacteria and clinical outcomes in children with cough

BACKGROUND

Cough is symptomatic of a broad range of acute and chronic pediatric respiratory illnesses. No studies in children have tested for an extended panel of upper airway respiratory viruses and bacteria to identify whether they predict cough outcomes, irrespective of clinical diagnosis at the time of acute respiratory illness (ARI). We therefore determined whether upper airway microbes independently predicted hospitalization and persistent cough 28-days later in children presenting with an ARI, including cough as a symptom.

METHODS

A cohort study of children aged <15-years were followed for 28-days after presenting to a pediatric emergency department with an ARI where cough was also a symptom. Socio-demographic factors, presenting clinical features and a bilateral anterior nasal swab were collected at enrolment. Polymerase chain reaction assays tested for seven respiratory bacteria and 17 viruses. Predictors of hospitalization and persistent cough at day-28 were evaluated in logistic regression models.

RESULTS

Eight hundred and seventeen children were included in the analysis; median age 27.7-months. 116 (14.2%, 95%CI 11.8, 16.6) children were hospitalized and 163 (20.0%, 95%CI 17.2, 22.7) had persistent cough at day-28. Hospitalized children were more likely to have RSV A or B detected on nasal swab than those not admitted (adjusted relative risk (aRR) 1.8, 95%CI 1.0, 3.3). M. catarrhalis was the only microbial difference between children with and without cough persistence (aRR for those with cough at day 28: 2.1, 95%CI 1.3, 3.1).

DISCUSSION

An etiologic role for M. catarrhalis in the pathogenesis of persistent cough post-ARI is worth exploring, especially given the burden of chronic cough in children and its relationship with chronic lung disease. Pediatr Pulmonol. 2017;52:373-381. © 2016 Wiley Periodicals, Inc.

Potential impact of a Moraxella catarrhalis vaccine in COPD

Moraxella catarrhalis is the second most common cause of exacerbations in adults with COPD, resulting in enormous morbidity and mortality in this clinical setting. Vaccine development for M. catarrhalis has lagged behind the other two important causes of exacerbations in COPD, nontypeable Haemophilus influenzae and Streptococcus pneumoniae. While no licensed vaccine is currently available for M. catarrhalis, several promising candidate vaccine antigens have been identified and characterized and are close to entering clinical trials. Key steps that are required to advance vaccines for M. catarrhalis along the translational pipeline include standardization of assay systems to assess candidate antigens, identification of a reliable correlate of protection and expansion of partnerships between industry, academia and government to overcome regulatory hurdles. A vaccine to prevent M. catarrhalis infections in COPD would have a major impact in reducing morbidity, mortality and healthcare costs in COPD.

Acute Otitis Media and Other Complications of Viral Respiratory Infection

BACKGROUND

Viral upper and lower respiratory tract infections (URI, LRI) are common in infants. We determined the prevalence of viral URI and its complications, including acute otitis media (AOM) and LRI, and assessed the effect of bacterial-viral interactions, and genetic and environmental risks on AOM development.

METHODS

Healthy infants were enrolled from near birth and followed to the first episode of AOM up to 12 months of age. Nasopharyngeal specimens were collected at monthly intervals (months 1-6, 9) and during viral URI episodes for bacterial culture and viral polymerase chain reaction studies. Subjects were followed closely for AOM development.

RESULTS

A total of 367 infants were followed for 286 child-years; 887 URI (305 infants) and 180 AOM episodes (143 infants) were documented. Prevalence of URI, LRI, and AOM in the first year was 3.2, 0.25, and 0.67 per child-year, respectively. Cumulative AOM incidence by ages 3, 6, and 12 months was 6%, 23%, and 46%. Infants with and without AOM had 4.7 and 2.3 URI episodes per child-year, respectively (P < .002). Pathogenic bacterial colonization rates by month were significantly higher in infants with AOM (P < .005). Breastfeeding reduced both URI and AOM risks (P < .05). Significant bacterial-viral interactions occurred with Moraxella catarrhalis and a variety of respiratory viruses and altered URI and AOM risks.

CONCLUSIONS

Almost half of infants experienced AOM by age 1. Important AOM risk factors included frequent viral URI, pathogenic bacterial colonization, and lack of breastfeeding. Bacterial-viral interactions may play a significant role in AOM pathogenesis and deserve further investigation.