Comparative Fecal Microbiota Analysis of Infants With Acute Bronchiolitis Caused or Not Caused by Respiratory Syncytial Virus.

Bronchiolitis due to respiratory syncytial virus (RSV) or non-RSV agents is a health-menacing lower respiratory tract (LRT) disease of infants. Whereas RSV causes more severe disease than other viral agents may, genus-dominant fecal microbiota profiles have been identified in US hospitalized infants with bronchiolitis. We investigated the fecal microbiota composition of infants admitted to an Italian hospital with acute RSV (25/37 [67.6%]; group I) or non-RSV (12/37 [32.4%]; group II) bronchiolitis, and the relationship of fecal microbiota characteristics with the clinical characteristics of infants. Group I and group II infants differed significantly (24/25 [96.0%] versus 5/12 [41.7%]; P = 0.001) regarding 90% oxygen saturation (SpO2), which is an increased respiratory effort hallmark. Accordingly, impaired feeding in infants from group I was significantly more frequent than in infants from group II (19/25 [76.0%] versus 4/12 [33.3%]; P = 0.04). Conversely, the median (IQR) length of stay was not significantly different between the two groups (seven [3-14] for group I versus five [5-10] for group II; P = 0.11). The 16S ribosomal RNA V3-V4 region amplification of infants' fecal samples resulted in 299 annotated amplicon sequence variants. Based on alpha- and beta-diversity microbiota downstream analyses, group I and group II infants had similar bacterial communities in their samples. Additionally, comparing infants having <90% SpO2 (n = 29) with infants having ≥90% SpO2 (n = 8) showed that well-known dominant genera (Bacteroides, Bifidobacterium, Escherichia/Shigella, and Enterobacter/Veillonella) were differently, but not significantly (P = 0.44, P = 0.71, P = 0.98, and P = 0.41, respectively) abundant between the two subgroups. Overall, we showed that, regardless of RSV or non-RSV bronchiolitis etiology, no fecal microbiota-composing bacteria could be associated with the severity of acute bronchiolitis in infants. Larger and longitudinally conducted studies will be necessary to confirm these findings.

Analysis of Risk Factors of Bronchiolitis Obliterans in Children with Mycoplasma pneumoniae Bronchiolitis.

OBJECTIVE: To investigate the related risk factors for bronchiolitis obliterans (BO) in children with mycoplasma pneumonia (MP) bronchiolitis. METHOD: The clinical data of 227 children with MP bronchiolitis who were admitted to the II Department of Respiratory of Children's Hospital of Hebei Province from January 2018 to June 2020 were retrospectively analyzed. According to the sequelae of BO, they were divided into 32 cases in the BO group and 195 cases in the non-BO group. The univariate analysis was performed on the clinical and laboratory parameters of the two groups, and the multifactor logistic regression was performed further to determine the independent risk factors for the occurrence of BO in MP bronchiolitis, and then, the cut-off value with the maximum diagnostic value of indicators was found through the ROC curve analysis. RESULTS: The results of univariate and multivariate logistic regression analysis showed that the independent risk factors for the occurrence of BO in MP bronchioles were longer duration of moist rales (OR = 1.203, P = 0.003), higher levels of serum lactate dehydrogenase (LDH) (OR = 1.005, P = 0.036), hypoxemia (OR = 7.442, P = 0.035), and pleural effusion (OR = 4.437, P = 0.004). The area under the ROC curve was 78.2%, 72.0%, 68.2%, and 71.0%, respectively (P < 0.001). The cut-off value of duration of moist rales and levels of serum LDH are 7.5 d and 330 U/L, respectively. CONCLUSION: Children with MP bronchiolitis with high serum LDH level (≥330 U/L), combined with hypoxemia, pleural effusion, and lung wet rale duration (≥7.5 d), may be more prone to BO, in which lung wet rale duration prediction value is the largest. Among them, duration of pulmonary moist rales has the highest predictive value.

Isolation of Mycobacterium talmoniae from a patient with diffuse panbronchiolitis: a case report.

BACKGROUND: Mycobacterium (M) talmoniae isolated from a patient with cystic fibrosis was first described in 2017, and cases of M. talmoniae remain exceedingly rare. CASE PRESENTATION: A 51-year-old woman had respiratory symptoms for 10 years. Diffuse panbronchiolitis (DPB) was detected at the first visit at our hospital. A cavity lesion in the apex of the left lung was found, and sputum and bronchoalveolar lavage fluid were acid-fast bacillus (AFB) smear- and culture-positive besides Pseudomonas aeruginosa. M. talmoniae was finally identified, and the standard combination therapy for non-tuberculous mycobacteria (NTM) was administered for 2 y referring to the drug-susceptibility test. Thereafter, the AFB culture was negative, the wall thickness of the lung cavity was ameliorated, and oxygen saturation improved. CONCLUSIONS: We encountered a rare case of M. talmoniae with DPB, for which standard combination therapy was effective. M. talmoniae may be considered a potential pathogen of lung disease, especially in patients with bronchiectatic lesions.

Utilidad de la vigilancia microbiológica del virus respiratorio sincitial en Galicia (España): 2008-2017 / Usefulness of the microbiological surveillance of respiratory syncytial virus in Galicia (Spain): 2008-2017

OBJETIVO: Describir si la información microbiológica del virus respiratorio sincitial (VRS) facilitada semanalmente por cuatro hospitales captura adecuadamente la estacionalidad del VRS en toda la comunidad. MÉTODO: Estudio descriptivo retrospectivo. Se compararon las detecciones de VRS en muestras respiratorias de pacientes (ingresados y no), de todos los grupos de edad, de los cuatro hospitales que forman parte del sistema de vigilancia microbiológica (SVM), con datos del Conjunto Mínimo Básico de Datos de hospitalización por bronquiolitis causada por VRS u otro microorganismo infeccioso, en pacientes menores de 5 años ingresados en cualquier hospital público de Galicia (temporadas 2008/2009 a 2016/2017). Se consideró como periodo de onda epidémica cuando la positividad de detecciones de VRS en el total de muestras respiratorias del SVM superó el 10%. Se calculó la sensibilidad del SVM como el porcentaje de ingresos ocurridos en la onda epidémica. RESULTADOS: La sensibilidad del SVM fue del 92% (86-96%) para los ingresos por bronquiolitis por VRS en cada temporada y del 79% (75-84%) para los ingresos por bronquiolitis totales. CONCLUSIONES: El SVM del VRS, basado en información de solo cuatro hospitales, mostró muy buena sensibilidad para predecir el inicio y el final de la onda anual de VRS en toda la comunidad autónoma. Estos resultados respaldan la utilización de esta información para alertar a todo el sistema sanitario del inicio de la onda

OBJECTIVE: To describe whether the microbiological information of the respiratory syncytial virus (RSV), provided by four hospitals on a weekly basis, adequately captures the seasonality of the RSV in the entire community. METHOD: Retrospective descriptive study. We compared the detection of RSV in respiratory samples of patients (hospitalized and not) from all age groups, from the 4 hospitals that are part of the microbiological surveillance system (MSS), with data from the Minimum Basic Data Set of hospitalization for bronchiolitis by RSV or another infectious organism, in patients under 5 years of age, admitted to any public hospital in Galicia (seasons 2008/2009 to 2016/2017). An epidemic wave period was considered when the positivity of RSV detections in the total respiratory samples of the SVM exceeded 10%. The sensitivity of the MSS was calculated as a percentage of admissions occurring in the epidemic wave. RESULTS: MSS sensitivity was 92% (86%-96%) for RSV bronchiolitis admissions in each season and 79% (75%-84%) for total bronchiolitis admissions. CONCLUSIONS: The RSV microbiological surveillance system, based on data from only 4 hospitals, showed very good sensitivity to predict the start and end of the annual RSV wave throughout the Galician region. These results support the use of this information to alert the entire health system of the onset of the wave

Increased Moraxella and Streptococcus species abundance after severe bronchiolitis is associated with recurrent wheezing.

BACKGROUND: The role of the airway microbiome in the development of recurrent wheezing and asthma remains uncertain, particularly in the high-risk group of infants hospitalized for bronchiolitis. OBJECTIVE: We sought to examine the relation of the nasal microbiota at bronchiolitis-related hospitalization and 3 later points to the risk of recurrent wheezing by age 3 years. METHODS: In 17 US centers researchers collected clinical data and nasal swabs from infants hospitalized for bronchiolitis. Trained parents collected nasal swabs 3 weeks after hospitalization and, when healthy, during the summer and 1 year after hospitalization. We applied 16S rRNA gene sequencing to all nasal swabs. We used joint modeling to examine the relation of longitudinal nasal microbiota abundances to the risk of recurrent wheezing. RESULTS: Among 842 infants hospitalized for bronchiolitis, there was 88% follow-up at 3 years, and 31% had recurrent wheezing. The median age at enrollment was 3.2 months (interquartile range, 1.7-5.8 months). In joint modeling analyses adjusting for 16 covariates, including viral cause, a 10% increase in relative abundance of Moraxella or Streptococcus species 3 weeks after day 1 of hospitalization was associated with an increased risk of recurrent wheezing (hazard ratio [HR] of 1.38 and 95% high-density interval [HDI] of 1.11-1.85 and HR of 1.76 and 95% HDI of 1.13-3.19, respectively). Increased Streptococcus species abundance the summer after hospitalization was also associated with a greater risk of recurrent wheezing (HR, 1.76; 95% HDI, 1.15-3.27). CONCLUSIONS: Enrichment of Moraxella or Streptococcus species after bronchiolitis hospitalization was associated with recurrent wheezing by age 3 years, possibly providing new avenues to ameliorate the long-term respiratory outcomes of infants with severe bronchiolitis.

Airway microbiome, host immune response and recurrent wheezing in infants with severe respiratory syncytial virus bronchiolitis.

BACKGROUND: Early interactions between respiratory viruses and microbiota might modulate host immune responses and subsequently contribute to later development of recurrent wheezing and asthma in childhood. We aimed to study the possible association between respiratory microbiome, host immune response, and the development of recurrent wheezing in infants with severe respiratory syncytial virus (RSV) bronchiolitis. METHODS: Seventy-four infants who were hospitalized at Beijing Children's Hospital during an initial episode of severe RSV bronchiolitis at 6 months of age or less were included and followed up until the age of 3 years. Sputum samples were collected, and their microbiota profiles, LPS, and cytokines were analyzed by 16S rRNA-based sequencing, ELISA, and multiplex immunoassay, respectively. RESULTS: Twenty-six (35.1%) infants developed recurrent wheezing by the age of 3 years, and 48 (64.9%) did not. The relative abundance of Haemophilus, Moraxella, and Klebsiella was higher in infants who later developed recurrent wheezing than in those who did not (LDA score >3.5). Airway levels of LPS (P = .003), CXCL8 (P = .004), CCL5 (P = .029), IL-6 (P = .004), and IL-13 (P < .001) were significantly higher in infants who later developed recurrent wheezing than in those who did not. Moreover, high airway abundance of Haemophilus was associated with CXCL8 (r = 0.246, P = .037) level, and that of Moraxella was associated with IL-6 level (r = 0.236, P = .046) and IL-10 level (r = 0.266, P = .024). CONCLUSION: Our study suggests that higher abundance of Haemophilus and Moraxella in airway microbiome might modulate airway inflammation during severe RSV bronchiolitis in infancy, potentially contributing to the development of subsequent recurrent wheezing in later childhood.

Effects of macrolides on airway microbiome and cytokine of children with bronchiolitis: A systematic review and meta-analysis of randomized controlled trials.

Macrolides may attenuate airway inflammation of bronchiolitis with anti-inflammatory and antiviral effects. However, the potential mechanisms of action underlying the efficiency of macrolides in treating bronchiolitis are limited. Therefore, we performed a meta-analysis to assess the effects of macrolides on airway microbiome and cytokine of children with bronchiolitis. PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched until May 2018. The reference lists of included studies and pertinent reviews were investigated for supplementing our search. Randomized controlled trials (RCTs) that compared macrolides with placebo assessing the change of microbiome in airway and cytokine were included. A total of four RCTs were included in this review. Data analysis showed no significant reduction of viruses at 48 hr after azithromycin treatment (p = 0.41). There were significant reductions in Streptococcus pneumoniae (risk ratio [RR] 0.28, 95% confidence interval (CI) 0.14 to 0.6, p < 0.01), Haemophilus influenza (RR 0.35, 95% CI 0.2 to 0.62, p < 0.01), and Moraxella catarrhalis (RR 0.29, 95% CI 0.17 to 0.5, p < 0.01), but no significant reduction of Staphylococcus aureus (p = 0.28) following treatment with macrolides. There was a significant decrease in the serum interleukin-8(IL-8), interleukin-4(IL-4), and eotaxin levels following 3 weeks of clarithromycin therapy. There was no significant difference in the serum IL-8 level at Day 15 after the intervention between the azithromycin and control groups; however, a significant reduction of nasal lavage IL-8 level was found. The macrolides may reduce the IL-8 levels in the airway and plasma, but failed to demonstrate an antiviral effect in children with bronchiolitis.

Impact of Rhinovirus Infections in Children.

Rhinovirus (RV) is an RNA virus that causes more than 50% of upper respiratory tract infections in humans worldwide. Together with Respiratory Syncytial Virus, RV is one of the leading causes of viral bronchiolitis in infants and the most common virus associated with wheezing in children aged between one and two years. Because of its tremendous genetic diversity (>150 serotypes), the recurrence of RV infections each year is quite typical. Furthermore, because of its broad clinical spectrum, the clinical variability as well as the pathogenesis of RV infection are nowadays the subjects of an in-depth examination and have been the subject of several studies in the literature. In fact, the virus is responsible for direct cell cytotoxicity in only a small way, and it is now clearer than ever that it may act indirectly by triggering the release of active mediators by structural and inflammatory airway cells, causing the onset and/or the acute exacerbation of asthmatic events in predisposed children. In the present review, we aim to summarize the RV infection's epidemiology, pathogenetic hypotheses, and available treatment options as well as its correlation with respiratory morbidity and mortality in the pediatric population.

Serum Metabolome Is Associated With the Nasopharyngeal Microbiota and Disease Severity Among Infants With Bronchiolitis.

BACKGROUND: Emerging evidence suggests relationships between the nasopharyngeal metabolome and both the microbiota and severity of bronchiolitis. However, the influence of host systemic metabolism on disease pathobiology remains unclear. We aimed to examine metabolome profiles and their association with more-severe disease, defined by use of positive pressure ventilation (PPV), in infants hospitalized for bronchiolitis. METHODS: In 140 infants with bronchiolitis, metabolomic profiling was performed on serum; samples from 70 were in a training data set, and samples from 70 were in an independent test data set. We also profiled the nasopharyngeal airway microbiota and examined its association with the serum metabolites. RESULTS: Serum metabolome profiles differed by bronchiolitis severity (P < .001). In total, 20 metabolites in the training data set were significantly associated with the risk of PPV, of which 18 remained significant following adjustment for confounders (false-discovery rate [FDR], < 0.10). Phosphatidylcholine metabolites were associated with higher risks of PPV use, while metabolites from the plasmalogen subpathway were associated with lower risks. The test data set validated these findings (FDR < 0.05). Streptococcus abundance was positively associated with metabolites that are associated with higher risks of PPV. CONCLUSIONS: Serum metabolomic signatures were associated with both the nasopharyngeal microbiota and the severity of bronchiolitis. Our findings advance research into the complex interrelations between the airway microbiome, host systemic response, and pathobiology of bronchiolitis.

Haemophilus-Dominant Nasopharyngeal Microbiota Is Associated With Delayed Clearance of Respiratory Syncytial Virus in Infants Hospitalized for Bronchiolitis.

The relation of nasopharyngeal microbiota to the clearance of respiratory syncytial virus (RSV) in infants hospitalized for bronchiolitis is not known. In a multicenter cohort, we found that 106 of 557 infants (19%) hospitalized with RSV bronchiolitis had the same RSV subtype 3 weeks later (ie, delayed clearance of RSV). Using 16S ribosomal RNA gene sequencing and a clustering approach, infants with a Haemophilus-dominant microbiota profile at hospitalization were more likely than those with a mixed profile to have delayed clearance, after adjustment for 11 factors, including viral load. Nasopharyngeal microbiota composition is associated with delayed RSV clearance.

A low abundance of Bifidobacterium but not Lactobacillius in the feces of Chinese children with wheezing diseases.

BACKGROUND: The intestinal microbiota is linked with allergic reaction diseases. However, the difference in the fecal microbiota composition between sensitized wheezy and nonsensitized subjects in Chinese children remains unknown. The aim of this study was to quantitate the amounts of fecal microbiota in wheezy children, and to explore the correlation between fecal microbiota and serum Th1/Th2/Th17-type cytokines and total IgE in these patients. METHODS: The amounts of Bifidobacterium and Lactobacillus were determined using a 16S-RNA real-time polymerase chain reaction (PCR) method in wheezy children (cases) and nonwheezy controls. Serum Th1/Th2/Th17-type cytokines levels were measured using flow a cytometric bead array assay. In addition, the concentrations of total serum IgE was also determined. RESULTS: In comparison with that in the healthy control (HC), significantly lower abundance of Bifidobacterium and lower levels of Th1 cytokines (IFN-γ and TNF-α), but higher levels of Th2-type cytokines (IL-4, IL-5) and Th17-type (IL-17A) cytokine were detected in children with bronchiolitis and asthma. But there was no significant difference in the amounts of Lactobacillus. Interestingly, the amounts of fecal Bifidobacterium were correlated positively with serum Th1 cytokines IFN-γ, and correlated negatively with serum Th17 cytokines IL-17A, Th2 cytokines IL-4 and serum total IgE in these patients. CONCLUSIONS: Our findings demonstrated that lower quantity of Bifidobacterium, but not Lactobacillus, may be correlated with asthma and bronchiolitis in chinese children. These results also may provide guidance in choosing the proper probiotics for wheezing children.

A 2-year-old girl with chronic crackles after respiratory syncytial virus infection: a case report.

BACKGROUND: Respiratory syncytial virus is the most common cause of lower respiratory tract infections in infants and young children. While the majority of infants display only mild upper respiratory tract infection or occasionally otitis media, around one-third will develop an infection of the lower respiratory tract, usually bronchiolitis. There is now convincing evidence from a number of cohorts that respiratory syncytial virus is a significant, independent risk factor for later wheezing, at least within the first decade of life. The wide variation in response to respiratory syncytial virus infection suggests that susceptibility and disease are influenced by multiple host-intrinsic factors. CASE PRESENTATION: A 2-year-old white girl presented to our Pediatric Allergy Clinic with recurrent crackles in addition to cough, fevers, and labored breathing since her first respiratory syncytial virus infection at the age of 7 months. She had been under the care of pulmonologists, who suspected childhood interstitial lung disease. She was hospitalized eight times due to exacerbation of symptoms and prescribed systemic and inhaled steroids, short-acting ß2-mimetics, and antileukotriene. There was no short-term clinical improvement at that time between hospitalizations. During her hospital stay at the Pneumonology and Cystic Fibrosis Department in Rabka a bronchoscopy with bronchoalveolar lavage was performed. Laboratory bacteriological tests found high colony count of Moraxella catarrhalis (ß-lactamase positive), sensitive to amoxicillin-clavulanate, in bronchial secretions and swabs from her nose. After this, infections were treated with antibiotics; she remained in good condition without symptoms. Crackles and wheezing recurred only during symptoms of infections. Therefore, we hypothesize that respiratory syncytial virus infection at an early age might cause severe damage of the lung epithelium and prolonged clinical symptoms, mainly crackles and wheezing, each time the child has a respiratory infection. CONCLUSIONS: This case illustrates the importance of respiratory syncytial virus infection in an immunocompetent child. Pediatricians need to have a high index of suspicion and knowledge of recurrent symptoms associated with severe damage of the lung epithelium to establish the correct diagnosis.

Relationship Between Clinical Features and Computed Tomographic Findings in Hospitalized Adult Patients With Community-Acquired Pneumonia.

BACKGROUND: Data on the relationship between the clinical and microbiological features of community-acquired pneumonia (CAP) and its computed tomography (CT) findings are limited. The aim of the present study was to investigate the clinic-microbiological features of patients with CAP presenting with ground-glass opacity (GGO) and centrilobular nodules or tree-in-bud pattern on CT images. METHODS: Patients with CAP who underwent a CT scan at presentation were retrospectively classified using CT findings into consolidation, GGO and bronchiolitis groups. These 3 groups were compared in terms of clinical parameters and microbiological data. RESULTS: A total of 40 patients (2.4%) were allocated to the bronchiolitis group and 46 (2.8%) to the GGO group. The most common pathogen in the bronchiolitis group was Mycoplasma pneumoniae, which was significantly more frequently isolated in this group. The bronchiolitis group was characterized by a higher percentage of cough, a lower percentage of chest pain and lower blood levels of inflammatory markers. Common pathogens in the GGO group were not significantly different from those in the other 2 groups. Unlike that observed in the consolidation group, complicated parapneumonic effusion or empyema was not observed in the bronchiolitis or GGO group. Outcome variables were similar in the 3 groups. CONCLUSIONS: The bronchiolitis group was characterized by a higher frequency of M. pneumoniae and a less severe form of CAP. The GGO and consolidation groups was similar with respect to causative microorganisms and the clinical features of CAP. No patient in the bronchiolitis or GGO group exhibited complicated parapneumonic effusion or empyema.

Detection of immunoglobulin M and immunoglobulin G antibodies to Mycoplasma pneumoniae in children with community-acquired lower respiratory tract infections.

CONTEXT: Mycoplasma pneumoniae (M. pneumoniae) causes up to 40% of community-acquired pneumonia in children. It is impossible to identify M. pneumoniae infection on the basis of clinical signs, symptoms, and radiological features. Therefore, correct etiological diagnosis strongly depends on laboratory diagnosis. AIMS: This study aims to investigate the role of M. pneumonia e in pediatric lower respiratory tract infections (LRTIs) employing enzyme-linked immunosorbent assays (ELISA) and particle agglutination (PA) test. SETTINGS AND DESIGN: Two hundred and eighty children, age 6 months to 12 years with community-acquired LRTIs were investigated for M. pneumoniae etiology. MATERIALS AND METHODS: We investigated 280 children hospitalized for community-acquired LRTIs, using ELISA and PA test for detecting M. pneumoniae immunoglobulin M (IgM) and immunoglobulin G antibodies. STATISTICAL ANALYSIS USED: The difference of proportion between the qualitative variables was tested using the Chi-square test and Fischer exact test. P ≤ 0.05 was considered as statistically significant. Kappa value was used to assess agreement between ELISA and PA test. RESULTS: M. pneumoniae was positive in 51 (23.2%) <5 years and 33 (54.0%) children in ≥5 years of age group, and this difference was statistically significant (P < 0.001). Clinical and radiological findings in M. pneumoniae positive and negative groups were comparable. ELISA detected M. pneumoniae in 78 (27.8%) and PA test 39 (13.9%) patients; 33 (84.6%) ELISA positive and 6 (15.4%) ELISA negative. ELISA/PA test together detected M. pneumoniae infection in 84 (30%) children. CONCLUSIONS: Our data underline that M. pneumoniae plays an important role in children with community-acquired LRTIs and more particularly in children >5 years of age.

CD64 on monocytes and granulocytes in severe acute bronchiolitis: Pilot study on its usefulness as a bacterial infection biomarker.

The CD64 receptor has been described as a biomarker of bacterial infection. We speculated that CD64 surface expression on monocytes and granulocytes of children with severe acute bronchiolitis (SAB) could be altered in cases of probable bacterial infection (PBI) determined using classical biomarkers (procalcitonin and C-reactive protein, leukocyte count, and radiographic findings). A prospective observational pilot study was conducted from October 2015 to February 2016 in children admitted for pediatric critical care. A blood sample was taken in the first 24 hours of admission, and CD64 was measured by flow cytometry. The values obtained were analyzed and correlated with traditional biomarkers of PBI. Thirty-two children were included; a correlation was found between CD64 expression and the PBI criteria. CD64 surface expression was higher in children with PBI (area under the receiver operating characteristic curve of 0.73; P = 0.042) and the percentage of CD64+ granulocytes was higher in children with PBI. This is the first study to describe CD64 surface expression on monocytes and granulocytes in SAB, finding CD64 values to be higher in children with PBI. Larger clinical studies are needed to elucidate the real accuracy of CD64 as a biomarker of bacterial infection.

The association between anterior nares and nasopharyngeal microbiota in infants hospitalized for bronchiolitis.

BACKGROUND: The airway microbiome is a subject of great interest for the study of respiratory disease. Anterior nare samples are more accessible than samples from deeper within the nasopharynx. However, the correlation between the microbiota found in the anterior nares and the microbiota found within the nasopharynx is unknown. We assessed the anterior nares and nasopharyngeal microbiota to determine (1) the relation of the microbiota from these two upper airway sites and (2) if associations were maintained between the microbiota from these two sites and two bronchiolitis severity outcomes. RESULTS: Among 815 infants hospitalized at 17 US centers for bronchiolitis with optimal 16S rRNA gene sequence reads from both nasal swab and nasopharyngeal aspirate samples, there were strong intra-individual correlations in the microbial communities between the two sample types, especially relating to Haemophilus and Moraxella genera. By contrast, we found a high abundance of Staphylococcus genus in the nasal swabs-a pattern not found in the nasopharyngeal samples and not informative when predicting the dominant nasopharyngeal genera. While these disparities may have been due to sample processing differences (i.e., nasal swabs were mailed at ambient temperature to emulate processing of future parent collected swabs while nasopharyngeal aspirates were mailed on dry ice), a previously reported association between Haemophilus-dominant nasopharyngeal microbiota and the increased severity of bronchiolitis was replicated utilizing the nasal swab microbiota and the same outcome measures: intensive care use (adjusted OR 6.43; 95% CI 2.25-20.51; P < 0.001) and hospital length-of-stay (adjusted OR 4.31; 95% CI, 1.73-11.11; P = 0.002). Additionally, Moraxella-dominant nasopharyngeal microbiota was previously identified as protective against intensive care use, a result that was replicated when analyzing the nasal swab microbiota (adjusted OR 0.30; 95% CI, 0.11-0.64; P = 0.01). CONCLUSIONS: While the microbiota of the anterior nares and the nasopharynx are distinct, there is considerable overlap between the bacterial community compositions from these two anatomic sites. Despite processing differences between the samples, these results indicate that microbiota severity associations from the nasopharynx are recapitulated in the anterior nares, suggesting that nasal swab samples not only are effective sample types, but also can be used to detect microbial risk markers.

Dynamic oropharyngeal and faecal microbiota during treatment in infants hospitalized for bronchiolitis compared with age-matched healthy subjects.

Bronchiolitis is one of the most severe diseases affecting infants worldwide. An imbalanced oropharynx (OP) microbiota has been reported in infants hospitalized with bronchiolitis; however, the microbiota dynamics in the OP and faeces during therapy remain unexplored. In total, 27 infants who were hospitalized with bronchiolitis were selected for this study, and sampling was conducted before therapy and after clinical recovery. We also recruited 22 age-matched healthy infants for this study. The faecal and OP microbiota diversity in the patients was lower than that in the healthy children. The faecal microbiota (FM) in the diseased children significantly differed from that in the healthy subjects and contained accumulated Bacteroides and Streptococcus. The OP microbiota in both the healthy and diseased infants was dominated by Streptococcus. After the treatment, the FM and OP microbiota in the patients was comparable to that before the treatment. This study may serve as an additional reference for future bronchiolitis studies, and the "risk microbiota model" of clinically recovered infants suggests an increased susceptibility to pathogen intrusion.