Oropharyngeal flora in asthma and in chronic obstructive pulmonary disease. Indigenous oropharyngeal microorganisms in outpatients with asthma or chronic obstructive pulmonary disease

Delayed acquisition of airway commensals in antibiotic naïve children and its relationship with wheezing in rural Ecuador

Introduction

The hygiene hypothesis identified a relationship between living in rural areas and acquiring protective environmental factors against the development of asthma and atopy. In our previous study, we found a correlation between particular bacterial species and early-onset wheezing in infants from the rural tropics of Ecuador who were corticosteroid-naïve and had limited antibiotic exposure. We now describe a longitudinal study of infants conducted to determine the age-related changes of the microbiome and its relationship with wheezing.

Methods

We performed an amplicon sequencing of the 16S rRNA bacterial gene from the oropharyngeal samples obtained from 110 infants who had a history of recurrent episodic wheezing sampled at different ages (7, 12, and 24 months) and compared it to the sequencing of the oropharyngeal samples from 150 healthy infants sampled at the same time points. Bioinformatic analyses were conducted using QIIME and R.

Results

As expected, the microbiota diversity consistently increased as the infants grew older. Considering age-based microbiota changes, we found that infants with wheeze had significantly lower species richness than the healthy infants at 7 months, but not at 12 or 24 months. Most of the core and accessory organisms increased in abundance and prevalence with age, except for a few which decreased. At 7 months of age, infants with wheeze had notably higher levels of a single Streptococcus operational taxonomic unit and core microbiota member than controls.

Conclusions

In a cohort with limited antibiotic and corticosteroid use, a progressively more complex and diverse respiratory microbial community develops with age. The respiratory microbiota in early life is altered in infants with wheeze, but this does not hold true in older infants.

Allergic rhinitis, rather than asthma, might be associated with dental caries, periodontitis, and other oral diseases in adults

BACKGROUND

The association between asthma (AS), allergic rhinitis (AR) and oral diseases remains inconclusive in adults. AS and AR often coexist. However, studies that investigate AS, AR together and their association with oral diseases are scarce.

METHODS

Data from 22,898 men and 28,541 women, aged 21 to 25 years, were collected from a national database in Taiwan. Five common oral diseases: dental caries, periodontitis, pulpitis, gingivitis, and stomatitis/aphthae were studied. Differences in the incidence of the five oral diseases in AR vs. non-AR, and AS vs. non-AS groups were compared. The incidence of the five oral diseases in men/ women, urban/country citizen, and high/low income groups was studied. The frequencies of clinical visits and impact of topical steroid use between the groups were also studied. The confounding factors included sex, socioeconomic status, urbanization, dentofacial anomalies, disease of salivary flow, diabetes mellitus, and esophageal reflux.

RESULTS

The incidence and the frequencies of clinical visits for all five oral diseases were higher in those with AR than in the non-AR group after adjusting for confounding factors and AS. Similar observation was made for the AS group, without adjusting for AR. However, if AR was included for adjustment, no relationship was found between AS and oral diseases. In the AR group, those with higher incomes, and country residents had a high risk of developing oral disease. Intranasal steroids, rather than inhaled steroids, were also associated with oral diseases.

CONCLUSION

AR, rather than AS, may be associated with oral diseases in young adults.

Oropharyngeal colonization: epidemiology, treatment and ventilator-associated pneumonia prevention

Oropharyngeal (OP) colonization and ventilator-associated pneumonia (VAP) mechanisms are tightly linked. A significant within-population variation in OP colonization has been described, with its composition being dependent from patients' severity. For instance, healthy subjects have a very low rate in Gram-negative bacteria (GNB) colonization, while its rate rises in comorbid patients, reaching high proportions in ICU patients. Various factors can be put forward to explain the modifications of hospital acquired OP. ICU patients might suffer from underlying diseases; the gastric reflux induced by the presence of nasogastric tubes and the patients' position influences OP colonization; salivary composition might influence OP content, as it modulates bacterial adhesion and induces reversible bacterial changes enhancing bacterial binding. The transition from OP colonization to VAP has been shown in numerous studies, with the digestive tract acting as a filter, or as a reservoir. Some therapies have been investigated to modulate OP colonization, in order to reduce the risk for VAP. Among those, mammalian antimicrobial peptides have been shown effective in reducing GNB colonization in healthy subjects, but failed in preventing VAP in ICU patients. The widely used chlorhexidine was tested in numerous trials. Data on its efficacy are conflicting, and meta-analyses yield discordant results. Above all, several drawbacks have aroused: a poor tolerance of concentrated solutions; an increased risk of death in the less severe patients; and a reduced susceptibility towards chlorhexidine of number of VAP pathogens. Proanthocyanidins, used to prevent Escherichia coli adhesion to the urothelium, have been tested in mice model of pneumonia with interesting results. Some complementary data are needed before moving to clinical research. Future research paths should include a reappraisal of OP colonization; finding better formulations for chlorhexidine; define the best populations to target oral decontamination and developing other strategies to prevent and treat OP colonization.

Staphylococcus aureus Nasal Colonization and Asthma in Adults: Systematic Review and Meta-Analysis

BACKGROUND

Staphylococcus aureus (SA) is a frequent colonizer in humans, and it is known to be associated with chronic allergic diseases including asthma. Recent individual studies suggested that nasal SA colonization may be positively associated with asthma.

OBJECTIVE

To examine relationships between nasal SA colonization and asthma prevalence and activity in adults.

METHODS

Electronic databases were searched for studies published until June 2018. Studies that reported nasal SA colonization prevalence and asthma outcome (prevalence and disease activity) in general adult populations or patients with chronic rhinosinusitis (CRS) were included. Random effects meta-analyses were performed to calculate pooled odds ratio (OR) of the relationships. Subgroup analysis was conducted for the presence of nasal polyps within CRS populations.

RESULTS

A total of 21 cross-sectional studies were identified, and the data from 16 studies using culture methods for SA detection were meta-analyzed (5 general population-based studies and 11 studies of patients with CRS). In studies of general populations, nasal SA colonization had significant relationships with asthma prevalence (OR 1.19; 95% confidence interval [CI] 1.06-1.34; I² = 1%). In studies of patients with CRS, positive associations were also found but had a considerable heterogeneity (OR 1.87; 95% CI 1.18-2.97; I² = 72%). However, the results were comparable between CRS with and without nasal polyps.

CONCLUSIONS

This study demonstrated modest but significant relationships between nasal SA colonization and asthma, supporting potential roles of SA in adult patients with asthma. Further longitudinal cohort and intervention studies are warranted to identify host determinants and to clarify causality of the relationships.

Association of COPD exacerbation frequency with gene expression of pattern recognition receptors in inflammatory cells in induced sputum

BACKGROUND

Bacteria and viruses are major causes of chronic obstructive pulmonary disease (COPD) exacerbations. Molecular components of these pathogens are recognized by pattern-recognition receptors (PRRs) expressed by various cells in the airway, which leads to initiation of inflammatory processes. Expression levels of PRRs in airway inflammatory cells are expected to affect susceptibility to COPD exacerbation.

AIMS

This prospective observational study was conducted to detect any association between exacerbation and PRR expression.

METHODS

Thirty-one male COPD patients were recruited. At baseline, clinical history, lung function measurements, peripheral blood samples and induced sputum were obtained. Using sputum samples, we performed gene expression analysis of TLR2, TLR3, TLR4, NOD1, NOD2, RIG-I and MDA-5 by quantitative reverse transcription-polymerase chain reaction in addition to quantitative bacterial culture. COPD exacerbations were assessed based on Anthonisen's criteria using symptom diaries for the following 1-year period.

RESULTS

During 1-year follow-up period, 13 patients experienced at least one exacerbation, but 18 patients did not. Those with exacerbations tended to be more severe COPD and showed larger neutrophil fraction in their induced sputum. Among PRRs, only TLR3 gene expression was increased in COPD patients with exacerbation compared with those without exacerbations. Multivariate logistic regression analysis including neutrophil fraction and TLR3 gene expression as predictor variables demonstrated that only an increase of neutrophil fraction, but not TLR3 gene expression, was a significant predictor for COPD exacerbation.

CONCLUSION

TLR3 expression in inflammatory cells might affect the susceptibility to COPD exacerbation.

Effect of inhaled budesonide on oropharyngeal, Gram-negative bacilli colonization in asthma patients

BACKGROUND AND OBJECTIVE

The effect of inhaled budesonide on oropharyngeal Gram-negative bacilli colonization (OGNBC) in asthmatic patients was investigated.

METHODS

Oropharyngeal cultures were obtained from asthmatic patients attending the hospital respiratory outpatient clinic, at baseline and 1 month after treatment with 800 microg/day of inhaled budesonide. Cultures were evaluated for OGNBC and compared with those of healthy controls.

RESULTS

A total of 148 cultures (74 from asthma patients, 74 from healthy controls) were evaluated. Six cultures (8.1%) from healthy controls, eight cultures (10.8%) from asthma patients obtained before treatment and 20 cultures (27.0%) obtained after treatment were positive for OGNBC (P < 0.05). Gender, age, presence of atopy and the degree of illness were not found to be related to the presence of OGNBC in and healthy control cultures. In the cultures obtained from the patients after treatment, OGNBC was higher in patients >50 years and in those with FEV1 < 70% (P < 0.05). Nine (18.8%) of 48 patients <50 years compare with 11 (42.3%) of the 26 patients >50 revealed OGNBC (P < 0.05). OGNBC were observed in 18.9% of the patients with FEV1 = 70% and in 47.6% of those with FEV1 < 70% (P < 0.05).

CONCLUSIONS

The increased rate of OGNBC in asthma patients treated with inhaled budesonide was found to be related to increased age and lower level of FEV1. Further studies with larger numbers of patients are required for the interpretation of this colonization in the course of lower respiratory infections in these patients.

Clinical items not helpful in differentiating viral from bacterial lower respiratory tract infections in general practice

OBJECTIVE

Incorrect and unnecessary antibiotic prescribing enhancing bacterial resistance rates might be reduced if viral and bacterial lower respiratory tract infections (LRTI) could be differentiated clinically. Whether this is possible is often doubted but has rarely been studied in general practice.

STUDY DESIGN AND SETTING

This was an observational cohort study in 15 general practice surgeries in the Netherlands.

RESULTS

Etiologic diagnoses were obtained in 112 of 234 patients with complete data (48%). Viral pathogens were found as often as bacterial pathogens. Haemophilus (para-) influenzae was most frequently found. None of the symptoms and signs correlated statistically significantly with viral or bacterial LRTI. Erythrocyte sedimentation rate >50 (odds ratio [OR] 2.3-3.3) and C-reactive protein (CRP) >20 (OR 2.1-4.6) were independent predictors for viral LRTI and bacterial LRTI when compared with microbiologically unexplained LRTI.

CONCLUSION

Extensive history-taking and physical examination did not provide items that predict viral or bacterial LRTI in adult patients in daily general practice. We could not confirm CRP to differentiate between viral and bacterial LRTI.

Relationship between group A beta-hemolytic streptococcal tonsillopharyngitis and asthma

Increasing morbidity due to asthma in children and antimicrobial resistance among human pathogens are both major public-health concerns. Frequent use of antibiotics during childhood might be a factor underlying the rising severity and prevalence of asthma and other allergic disorders. The objective of the study was to determine if pediatric patients with asthma or allergic rhinitis have an altered rate of group A beta hemolytic streptococcal (GABHS) tonsillopharyngeal infection which might support any change in guidelines for antibiotic prescription. A prospective analysis of all patients presenting a clinical feature of GABHS pharyngitis with a sore throat in two pediatric clinics located in Detroit, MI, USA and San Antonio de Areco, Buenos Aires, Argentina. Eligible patients aged between 2 and 18 years were screened for the presence of asthma and/or allergic rhinitis and administered a test (rapid strep test) and throat culture to determine GABHS infection. At the Redford Medical Center, Detroit, 500 patients met the eligibility criteria, with 168 (33.6%) having a positive strep test. At the San Antonio de Areco's Hospital, in a rural area 100 km away from Buenos Aires, 188 patients met the eligibility criteria, with 41 (21.8%) having a positive strep test or GABHS throat cultures. In both the Detroit [odds ratio (OR) = 1.36; 95% confidence interval (CI) 0.72-2.57] and Buenos Aires clinics (OR = 0.50; 95% CI 0.23-1.07), patients with asthma or allergic rhinitis were not at an increased risk for true GABHS tonsillopharyngeal infections when compared with the general pediatric population. These results suggest that children with asthma do not differ from the normal population in their risk of developing GABHS tonsillopharyngeal infection and should not be liberally prescribed antibiotics.

Beta-haemolytic streptococci isolated from acute sore-throat patients: cause or coincidence? A case-control study in general practice

As beta-haemolytic streptococci can be cultured in people with and in those without a sore throat, a case-control study was set up in 43 family practices in The Netherlands. The association was tested between the number of colony counts, specific T/M types and exotoxin genes and an acute sore throat. Duplicate throat swabs were taken from 663 sore-throat patients, selected by clinical criteria, and from 694 healthy controls. They were cultured for beta-haemolytic streptococci by combining several updated laboratory methods. Approximately 40% of the controls and 80% of the patients had beta-haemolytic streptococci-positive cultures. When focusing on cultures with high colony counts, not only group A (46%), but also non-group A streptococci (20%), predominated significantly in adult patients compared with controls. No T/M or exotoxin gene type was significantly more prevalent in patients than in controls. Thus, semiquantitative analysis, but not T/M and exotoxin gene typing, showed an association between beta-haemolytic streptococci and active disease. Groups A, C and G streptococci were found to be potentially pathogenic in adult sore-throat patients, and should be included in the discussion on the use of rapid antigen detection tests and penicillin treatment in primary care.

Oropharyngeal gram-negative bacillary carriage in chronic obstructive pulmonary disease: relation to severity of disease

The prolonged presence of aerobic Gram-negative bacilli (AGNB) in the oropharynx is termed 'carriage'. AGNB carriage rates are low in populations of healthy individuals. Previously, severity of underlying disease has been positively correlated with oropharyngeal AGNB carriage rate. Overgrowth of AGNB at the oropharynx poses a significant risk of endogenous infection in end-stage chronic obstructive pulmonary disease (COPD) patients. The aims of this study were to undertake an epidemiological survey of the oropharyngeal flora of COPD patients and to correlate oropharyngeal carriage of AGNB with severity of disease. Two oral rinses were obtained, within a 2-day interval, from 40 COPD patients comprising three disease severity groups: 1. mild, 2. moderate and 3. severe. Eighty oral rinses were quantitatively (1:10 dilution series) cultured for AGNB and yeasts using broth enrichment. The mean AGNB carriage rate was 15%. AGNB carriage rates of 0, 7.7 and 29.4% were observed within the mild, moderate and severe disease groups, respectively. The mean yeast carriage rate was 33.3%. Yeast carriage rates of 33.3, 15.4 and 64.7% were observed within the mild, moderate and severe disease groups, respectively. Carriage of Staphylococcus aureus was 5%. Rates of oropharyngeal carriage of AGNB (1/23 vs. 5/17) and yeasts (5/23 vs. 11/17) were significantly higher within the severe disease group than in non-severe disease groups. Oropharyngeal carriage of AGNB in end-stage COPD patients (forced expiratory volume in 1 sec, FEV1 < 50% predicted) presents a potential source of Gram-negative endogenous pneumonia. This outcome may be promoted by intubation and some flora-suppressing antibiotic therapies.

Oropharyngeal Gram-negative bacillary carriage: a survey of 120 healthy individuals

BACKGROUND

The presence of aerobic Gram-negative bacilli (AGNB) in the oropharynx can be either temporary or persistent. Prolonged colonization (ie, carriage) is distinguished from transient presence (ie, acquisition), which often occurs in healthy individuals but less frequently in those with underlying disease. Prevalence rates of up to 61.1% quoted previously for healthy individuals were obtained by using single sample surveys, which fail to differentiate acquisition from carriage.

STUDY OBJECTIVES

To illustrate the need to distinguish carriage from acquisition in a healthy population at risk of acquisition of AGNB, and to show that although differing groups of healthy individuals may acquire oropharyngeal AGNB at differing frequencies, carriage is rare in healthy individuals.

PARTICIPANTS

Two oral rinses were obtained within a 2-day interval from 120 healthy individuals comprising 40 nurses, 40 students, and 40 laboratory-associated persons.

DESIGN

Two hundred forty oral rinses were quantitatively (1:10 dilution series) cultured for AGNB by using broth enrichment.

MEASUREMENTS AND RESULTS

The rate of AGNB carriage based on two consecutive samples positive for the same AGNB was 6.6%; the rate of AGNB acquisition based on one positive sample was 35.8%. The concentrations of all carried and acquired AGNB were < or = 103 cfu/mL. AGNB acquisition was significantly higher in students (52.5%) compared to nurses (32.5%) and laboratory-associated persons (22.5%; p < 0.05).

CONCLUSION

Healthy individuals rarely carry oropharyngeal AGNB, suggesting effective oropharyngeal clearance in a healthy population predisposed to acquisition. Apparently, the oropharyngeal mucosa in healthy individuals is not receptive to adhesins of AGNB, resulting in rapid elimination of these bacteria.

Infective exacerbations of chronic bronchitis: relation between bacteriologic etiology and lung function

STUDY OBJECTIVE

In patients with severe COPD, acute infective exacerbations are frequent. Streptococcus pneumoniae and Haemophilus influenzae are the most commonly isolated bacteria in sputum cultures from these patients. We hypothesized that in patients with advanced disease, Gram-negative bacteria other than H influenzae play at least an equally important role.

METHODS

We evaluated clinical data and sputum culture results from 211 unselected COPD patients admitted to our hospital with an acute infective exacerbation of COPD. One hundred twelve patients fulfilled our protocol criteria of reliable microbiologic results and reproducible lung function tests; the patients were categorized according to the recently published three stages of severity.

RESULTS

Lung function tests revealed an FEV1 of > or =50% of the predicted value in 30 patients (stage I), an FEV1 of 35% to <50% of the predicted value in 30 patients (stage II), and an FEV1 of < or =35% of the predicted value in 34 patients (stage III). Bacteria were classified into three groups: group 1 contained S pneumoniae and other Gram-positive cocci; group 2, H influenzae and Moraxella catarrhalis; and group 3, Enterobacteriaceae and Pseudomonas spp. For all patients together, the most frequently isolated bacteria were group 3 organisms (Enterobacteriaceae and Pseudomonas spp, 48.2%), followed by group 1 organisms (S pneumoniae and other Gram-positive cocci, 30.4%), and group 2 organisms (H influenzae and M catarrhalis, 21.4%). In stage I patients, 14 of 30 had bacteria from group 1, seven of 30 had group 2, and nine of 30 had group 3. In stage II patients, eight of 30 had group 1 bacteria, 10 of 30 had group 2, and 12 of 30 had group 3. In stage III patients, 12 of 52 had group 1 bacteria, seven of 52 had group 2, and 22 of 52 had group 3. The three groups of bacteria causing infective exacerbations were unevenly distributed among the three severity stages of lung function (p=0.016).

CONCLUSION

There is a correlation between deterioration of lung function and the bacteria isolated from patients with infective exacerbations of COPD. In acute infective exacerbations, Enterobacteriaceae and Pseudomonas spp are the predominant bacteria in patients with an FEV1 < or =35% of the predicted value.

Changes in symptoms, peak expiratory flow, and sputum flora during treatment with antibiotics of exacerbations in patients with chronic obstructive pulmonary disease in general practice

BACKGROUND

Bacterial infections of the lower airways during an exacerbation in patients with asthma or chronic obstructive pulmonary disease (COPD) may be the cause of an exacerbation or the consequence of a viral infection or an increase in airways limitation. To determine whether bacterial infection is an important component in the pathogenesis of an exacerbation, the effects of antimicrobial treatment must be studied.

METHODS

Patients with asthma or COPD seen in general practice were studied in a double blind randomised manner to investigate whether the antimicrobial drugs amoxicillin (500 mg three times daily), cotrimoxazole (960 mg twice daily), or a placebo, each when added to a short course of oral corticosteroids, can accelerate recovery from exacerbations. Patients were instructed to contact their own physician early in the morning when complaints of increased shortness of breath, wheezing, or exacerbations of cough with or without sputum production occurred. Treatment effects were evaluated over the next 14 days by studying symptom scores (wheeze, dyspnoea, cough with and without mucus production, and awakening with dyspnoea), peak expiratory flow values (PEF, expressed as % predicted), and sublingual temperature. Bacteriological study of the sputum was made at the onset of an exacerbation and 7, 21 and 35 days afterwards.

RESULTS

Of 195 patients enrolled 71 (36%) contacted their physician for symptoms of an exacerbation. Symptoms improved in all three groups, improvements ranging from 0.54 to 0.75 points per day on a four point scale. PEF% predicted showed improvements in the three groups after the exacerbation, ranging from 0.34% to 0.78% predicted per day, finally returning to baseline values. Sublingual temperature did not change. Six of 71 patients consulted their physician because of a relapse between four and 24 days after the start of treatment. In only two of the 50 sputum samples, collected during an exacerbation, and which contained > or = 10(5) bacteria in culture sensitive to the chosen antibiotic given, did any benefit from antimicrobial treatment occur. During the recovery period sputum purulence improved irrespective of antibiotic treatment.

CONCLUSIONS

Antibiotics given with a short course of oral prednisolone during an exacerbation do not accelerate recovery as measured by changes in peak flow and symptom scores in ambulatory patients with mild to moderate asthma or COPD when treated by their general practitioners. Moreover, antibiotics do not reduce the number of relapses after treating an exacerbation.