Bacterial colonisation of the respiratory tract in chronic bronchitis

Nanorobotic artificial blood components and its therapeutic applications: A minireview

Numerous scientific and medical domains have been revolutionized by nanotechnology, opening up unprecedented opportunities for healthcare applications. Among these developments, the creation of nanorobots for artificial blood components is a novel field of research that seeks to overcome the constraints of conventional pharmacological therapy. This review article provides a comprehensive overview of the nanorobotic artificial blood components and their therapeutic uses. The article begins by outlining the core concepts of nanotechnology and nanorobotic systems, emphasizing their design and control methods. It then delves into various types of nanorobotic artificial blood components, such as oxygen transporters (artificial RBCs), clotting agents (artificial platelets), and immune modulators (artificial WBCs). It goes into detail about their properties, functioning, and capabilities, which allow them to replicate the physiological activities of actual blood components. The article also assesses the clinical uses of artificial blood components in a variety of medical circumstances. It highlights their potential value in the management of certain blood-related diseases.

The Common Mucosal System Fifty Years on: From Cell Traffic in the Rabbit to Immune Resilience to SARS-CoV-2 Infection by Shifting Risk within Normal and Disease Populations

The idea of a common mucosal immune system (CMS) is 50 years old. Its relevance to immune protection at mucosal sites and its potential to modulate the impact of vaccination-induced protection against infection of the airway has been poorly understood. The consequent failure of the current SARS-CoV-2 vaccination to satisfy expectations with respect to prevention of infection, viral transmission, duration of protection, and pattern of clinical protection, led to public health and medical decisions now under review. This review summarises knowledge of the CMS in man, including the powerful role it plays in immune protection and lessons with respect to what can and cannot be achieved by systemic and mucosal vaccination for the prevention of airway infection. The powerful impact in both health and disease of optimising delivery of immune protection using selected isolates from the respiratory microbiome is demonstrated through a review of randomised controlled trials (RCTs) in subjects with chronic airway disease, and in otherwise healthy individuals with risk factors, in whom the idea of mucosal immune resilience is introduced. This review is dedicated to two giants of mucosal immunology: Professors John Bienenstock and Allan Cripps. Their recent deaths are keenly felt by their colleagues and students.

Exploring factors associated with acquisition and chronicity of infection in bronchiectasis: A population-based study

INTRODUCTION

Chronic infection is associated with adverse outcomes among people with bronchiectasis. However, it is not known which factors are associated with a bacterial infection, and with persistence of an infection after the first episode. We aimed to determine factors associated with a new infection and with chronicity of Pseudomonas aeruginosa (PA) and H. influenzae (HI), the most common organisms in bronchiectasis infection.

METHODS

Using an Israeli population database, we identified individuals diagnosed with bronchiectasis. Cox proportional hazard models were used to assess risk factors for first isolation and Logistic regression for chronicity of infection after a first isolation of PA and HI.

RESULTS

We included 1305 people with a median of 5 respiratory samples per individual. PA was initially isolated in 297 people, of whom 97 (33%) developed chronic PA infection. HI was newly identified in 169 people, of whom 39 (23%) developed chronic infection (p = 0.029). Factors associated with increased risk of a new infection with PA were COPD (HR 1.87 [1.52-2.28], previous isolation of HI (HR 1.38 [1.07-1.78]), and alcohol abuse (HR 2.22 [1.13-4.3]). Younger age was associated with increased risk of HI infection, while COPD was associated with a lower risk of HI infection. Prescription of an anti- PA antibiotic was associated with chronic PA after a new infection (OR = 1.8 [1.09-2.9], p = 0.02). A landmark analysis showed that survival was worse in people with chronic PA infection vs. single or intermittent infection (Log rank: p = 0.034) CONCLUSIONS: Younger age and presence of PCD are associated with a new isolation of HI. A new infection with PA is associated with previous HI infection, PCD, COPD, and alcohol abuse. Unexpectedly, treatment with appropriate anti-PA antimicrobials was not associated with a reduced risk of chronicity.

The DNABII family of proteins is comprised of the only nucleoid associated proteins required for nontypeable Haemophilus influenzae biofilm structure

Biofilms play a central role in the pathobiology of otitis media (OM), bronchitis, sinusitis, conjunctivitis, and pneumonia caused by nontypeable Haemophilus influenzae (NTHI). Our previous studies show that extracellular DNA (eDNA) and DNABII proteins are essential components of biofilms formed by NTHI. The DNABII protein family includes integration host factor (IHF) and the histone‐like protein HU and plays a central role in NTHI biofilm structural integrity. We demonstrated that immunological targeting of these proteins during NTHI‐induced experimental OM in a chinchilla model caused rapid clearance of biofilms from the middle ear. Given the essential role of DNABII proteins in maintaining the structure of an NTHI biofilm, we investigated whether any of the other nucleoid associated proteins (NAPs) expressed by NTHI might play a similar role, thereby serving as additional target(s) for intervention. We demonstrated that although several NAPs including H‐NS, CbpA, HfQ and Dps are present within the biofilm extracellular matrix, only the DNABII family of proteins is critical for the structural integrity of the biofilms formed by NTHI. We have also demonstrated that IHF and HU are located at distinct regions within the extracellular matrix of NTHI biofilms formed in vitro, indicative of independent functions of these two proteins.

Haemophilus influenzae oral vaccination for preventing acute exacerbations of chronic bronchitis and chronic obstructive pulmonary disease

BACKGROUND

Chronic bronchitis and chronic obstructive pulmonary disease (COPD) are serious conditions in which patients are predisposed to viral and bacterial infections resulting in potentially fatal acute exacerbations. Chronic obstructive pulmonary disease is defined as a lung disease characterised by obstruction to lung airflow that interferes with normal breathing. Antibiotic therapy has not been particularly useful in eradicating bacteria such as non-typeable Haemophilus influenzae (NTHi) because they are naturally occurring flora of the upper respiratory tract in many people. However, they can cause opportunistic infection. An oral NTHi vaccine has been developed to protect against recurrent infective acute exacerbations in chronic bronchitis.

OBJECTIVES

To assess the effectiveness of an oral, whole-cell NTHi vaccine in protecting against recurrent episodes of acute exacerbations of chronic bronchitis and COPD in adults. To assess the effectiveness of NTHi vaccine in reducing NTHi colonising the respiratory tract during recurrent episodes of acute exacerbations of COPD.

SEARCH METHODS

We searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (2017, Issue 1), MEDLINE (1946 to January 2017), Embase (1974 to January 2017), CINAHL (1981 to January 2017), LILACS (1985 to January 2017), and Web of Science (1955 to January 2017). We also searched trials registries and contacted authors of trials requesting unpublished data.

SELECTION CRITERIA

We included randomised controlled trials comparing the effects of an oral monobacterial NTHi vaccine in adults with recurrent acute exacerbations of chronic bronchitis or COPD when there was overt matching of the vaccine and placebo groups on clinical grounds. The selection criteria considered populations aged less than 65 years and those older than 65 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data from original records and publications for incidence and severity of bronchitis episodes and carriage rate of NTHi measured in the upper respiratory tract, as well as data relevant to other primary and secondary outcomes.

MAIN RESULTS

We identified six placebo-controlled randomised controlled trials with a total of 557 participants. These trials investigated the efficacy of enteric-coated, killed preparations of H influenzae in populations prone to recurrent acute exacerbations of chronic bronchitis or COPD. The vaccine preparation and immunisation regimen in all trials consisted of at least three courses of formalin-killed H influenzae in enteric-coated tablets taken at intervals (e.g. days 0, 28, and 56). Each course generally consisted of two tablets taken after breakfast over three consecutive days. In all cases the placebo groups took enteric-coated tablets containing glucose. Risk of bias was moderate across the studies, namely due to the lack of information provided about methods and inadequate presentation of results.Meta-analysis of the oral NTHi vaccine showed a small, non-statistically significant reduction in the incidence of acute exacerbations of chronic bronchitis or COPD (risk ratio (RR) 0.79, 95% confidence interval (CI) 0.57 to 1.10; P = 0.16). There was no significant difference in mortality rate between the vaccine and placebo groups (odds ratio (OR) 1.62, 95% CI 0.63 to 4.12; P = 0.31).We were unable to meta-analyse the carriage levels of NTHi in participants as each trial reported this result using different units and tools of measurement. Four trials showed no significant difference in carriage levels, while two trials showed a significant decrease in carriage levels in the vaccinated group compared with the placebo group.Four trials assessed severity of exacerbations measured by requirement for antibiotics. Three of these trials were comparable and when meta-analysed showed a statistically significant 80% increase in antibiotic courses per person in the placebo group (RR 1.81, 95% CI 1.35 to 2.44; P < 0.001). There was no significant difference between the groups with regard to hospital admission rates (OR 0.96, 95% CI 0.13 to 7.04; P = 0.97). Adverse events were reported in five trials but were not necessarily related to the vaccine; a point estimate is suggestive that they occurred more frequently in the vaccine group, however this result was not statistically significant (RR 1.43, 95% CI 0.70 to 2.92; P = 0.87). Quality of life was not meta-analysed but was reported in two trials, with results at six months showing an improvement in quality of life in the vaccinated group (scoring at least two points better than placebo).

AUTHORS' CONCLUSIONS

Analyses demonstrate that NTHi oral vaccination of people with recurrent exacerbations of chronic bronchitis or COPD does not yield a significant reduction in the number and severity of exacerbations. Evidence was mixed, and the individual trials that showed a significant benefit of the vaccine are too small to advocate widespread oral vaccination of people with COPD.

Nontypeable Haemophilus influenzae and chronic obstructive pulmonary disease: a review for clinicians

Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of morbidity and mortality worldwide. In the lower airways of COPD patients, bacterial infection is a common phenomenon and Haemophilus influenzae is the most commonly identified bacteria. Haemophilus influenzae is divided into typeable and nontypeable (NTHi) strains based on the presence or absence of a polysaccharide capsule. While NTHi is a common commensal in the human nasopharynx, it is associated with considerable inflammation when it is present in the lower airways of COPD patients, resulting in morbidity due to worsening symptoms and increased frequency of COPD exacerbations. Treatment of lower airway NTHi infection with antibiotics, though successful in the short term, does not offer long-term protection against reinfection, nor does it change the course of the disease. Hence, there has been much interest in the development of an effective NTHi vaccine. This review will summarize the current literature concerning the role of NTHi infections in COPD patients and the consequences of using prophylactic antibiotics in patients with COPD. There is particular focus on the rationale, findings of clinical studies and possible future directions of NTHi vaccines in patients with COPD.

Protracted Bacterial Bronchitis in Children: Natural History and Risk Factors for Bronchiectasis

BACKGROUND

Protracted bacterial bronchitis (PBB) and bronchiectasis are distinct diagnostic entities that share common clinical and laboratory features. It is postulated, but remains unproved, that PBB precedes a diagnosis of bronchiectasis in a subgroup of children. In a cohort of children with PBB, our objectives were to (1) determine the medium-term risk of bronchiectasis and (2) identify risk factors for bronchiectasis and recurrent episodes of PBB.

METHODS

One hundred sixty-one children with PBB and 25 control subjects were prospectively recruited to this cohort study. A subset of 106 children was followed for 2 years. Flexible bronchoscopy, BAL, and basic immune function tests were performed. Chest CT was undertaken if clinical features were suggestive of bronchiectasis.

RESULTS

Of 161 children with PBB (66% boys), 13 were diagnosed with bronchiectasis over the study period (8.1%). Almost one-half with PBB (43.5%) had recurrent episodes (> 3/y). Major risk factors for bronchiectasis included lower airway infection with Haemophilus influenzae (recovered in BAL fluid) (P = .013) and recurrent episodes of PBB (P = .003). H influenzae infection conferred a more than seven times higher risk of bronchiectasis (hazard ratio, 7.55; 95% CI, 1.66-34.28; P = .009) compared with no H influenzae infection. The majority of isolates (82%) were nontypeable H influenzae. No risk factors for recurrent PBB were identified.

CONCLUSIONS

PBB is associated with a future diagnosis of bronchiectasis in a subgroup of children. Lower airway infection with H influenzae and recurrent PBB are significant predictors. Clinicians should be cognizant of the relationship between PBB and bronchiectasis, and appropriate follow-up measures should be taken in those with risk factors.

Haemophilus influenzae oral vaccination for preventing acute exacerbations of chronic bronchitis and chronic obstructive pulmonary disease

BACKGROUND

Chronic bronchitis and chronic obstructive pulmonary disease (COPD) are serious conditions in which patients are predisposed to viral and bacterial infections resulting in potentially fatal acute exacerbations. COPD is defined as a lung disease characterised by obstruction to lung airflow that interferes with normal breathing. Antibiotic therapy has not been particularly useful in eradicating bacteria such as non-typeable Haemophilus influenzae (NTHi) because they are naturally occurring flora of the upper respiratory tract in many people. However, they can cause opportunistic infection. An oral NTHi vaccine has been developed to protect against recurrent infective acute exacerbations in chronic bronchitis.

OBJECTIVES

To assess the effectiveness of an oral, whole-cell, non-typeable H. influenzae (NTHi) vaccine in protecting against recurrent episodes of acute exacerbations of chronic bronchitis and COPD in adults. To assess the effectiveness of NTHi vaccine in reducing NTHi colonising the respiratory tract during recurrent episodes of acute exacerbations of COPD.

SEARCH METHODS

We searched the following databases: CENTRAL (2014, Issue 6), MEDLINE (1946 to July week 3, 2014), EMBASE (1974 to July 2014), CINAHL (1981 to July 2014), LILACS (1982 to July 2014) and Web of Science (1955 to July 2014). We also searched trials registries and contacted authors of trials requesting unpublished data.

SELECTION CRITERIA

We included randomised controlled trials comparing the effects of an oral monobacterial NTHi vaccine in adults with recurrent acute exacerbations of chronic bronchitis or COPD when there was overt matching of the vaccine and placebo groups on clinical grounds. The selection criteria considered populations aged less than 65 years and those older than 65 years.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data from original records and publications for incidence and severity of bronchitis episodes and carriage rate of NTHi measured in the upper respiratory tract, as well as data relevant to other primary and secondary outcomes.

MAIN RESULTS

We identified six placebo-controlled randomised controlled trials with a total of 557 participants. They investigated the efficacy of enteric-coated, killed preparations of H. influenzae in populations prone to recurrent acute exacerbations of chronic bronchitis or COPD. The vaccine preparation and immunisation regime in all trials consisted of at least three courses of formalin-killed H. influenzae in enteric-coated tablets taken at intervals (for example, days 0, 28 and 56). Each course generally consisted of two tablets taken after breakfast over three consecutive days. In all cases the placebo groups took enteric-coated tablets containing glucose. Risk of bias was moderate across the studies, namely due to the lack of information provided about methods and inadequate presentation of results.Meta-analysis of the oral NTHi vaccine showed a small, non-statistically significant reduction in the incidence of acute exacerbations of chronic bronchitis or COPD by 2.048% (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.84 to 1.12, P value = 0.68). There was no significant difference in mortality rate between the vaccine and placebo groups (odds ratio (OR) 1.62, 95% CI 0.63 to 4.12, P value = 0.31).We were unable to meta-analyse the carriage levels of NTHi in participants as each trial reported this result using different units and tools of measurement. Four trials showed no significant difference in carriage levels, while two trials showed a significant decrease in carriage levels in the vaccinated group compared with placebo.Four trials assessed severity of exacerbations measured by requirement for antibiotics. Three of these trials were comparable and when meta-analysed showed a statistically significant 80% increase in antibiotic courses per person in the placebo group (RR 1.81, 95% CI 1.35 to 2.44, P value < 0.0001). There was no significant difference between the groups with regards to hospital admission rates (OR 0.96, 95% CI 0.13 to 7.04, P value = 0.97). Adverse events were reported in all six trials with a point estimate suggestive that they occurred more frequently in the vaccine group, however, this result was not statistically significant (RR 1.43, 95% CI 0.70 to 2.92, P value = 0.87). Quality of life was not meta-analysed but was reported in two trials, with results at six months showing an improvement in quality of life in the vaccinated group (scoring at least two points better than placebo).

AUTHORS' CONCLUSIONS

Analyses demonstrate that NTHi oral vaccination of patients with recurrent exacerbations of chronic bronchitis or COPD does not yield a significant reduction in the number and severity of exacerbations. Evidence is mixed and the individual trials that show a significant benefit of the vaccine are too small to advocate widespread oral vaccination of people with COPD.

Non-typeable Haemophilus influenzae, an under-recognised pathogen

Non-typeable Haemophilus influenzae (NTHi) is a major cause of mucosal infections such as otitis media, sinusitis, conjunctivitis, and exacerbations of chronic obstructive pulmonary disease. In some regions, a strong causal relation links this pathogen with infections of the lower respiratory tract. In the past 20 years, a steady but constant increase has occurred in invasive NTHi worldwide, with perinatal infants, young children, and elderly people most at risk. Individuals with underlying comorbidities are most susceptible and infection is associated with high mortality. β-lactamase production is the predominant mechanism of resistance. However, the emergence and spread of β-lactamase-negative ampicillin-resistant strains in many regions of the world is of substantial concern, potentially necessitating changes to antibiotic treatment guidelines for community-acquired infections of the upper and lower respiratory tract and potentially increasing morbidity associated with invasive NTHi infections. Standardised surveillance protocols and typing methodologies to monitor this emerging pathogen should be implemented. International scientific organisations need to raise the profile of NTHi and to document the pathobiology of this microbe.

Oral microbial colonization in patients with systemic lupus erythematous: correlation with treatment and disease activity

Treating patients with systemic lupus erythematosus (SLE) with steroids and immunosuppressive drugs may interfere in the presence of potentially opportunistic microorganisms in the oral cavity. The aim of this study was to evaluate the presence of Candida spp., Staphylococcus spp., Enterobacteria and Pseudomonas spp. in the oral cavity of SLE patients, compared with healthy controls. A group of 40 patients who had received therapy for at least 60 days was selected (19-53 years). For the control group, 40 healthy individuals matched for age, gender and use of partial prosthesis were selected. Oral rinse samples were collected and plated on specific culture media. After incubation, the number of colony forming units (CFU) was obtained and the isolates were identified at species level. Microbial counts were compared between SLE and control by analysis of variance (ANOVA) and Mann-Whitney (p < 0.05 significant). Microorganism counts in patients with and without immunosuppressive drugs, as well with active and inactive disease (according to SLEDAI score) were also compared. No significant differences in CFU/mL between SLE and control patients were observed (yeasts, p = 0.55; Staphylococci, p = 0.24; Enterobacteria/Pseudomonas spp., p = 0.26). No differences in microbial counts were observed regarding clinical parameters tested. The most frequent species isolated in the SLE group were Candida albicans, Staphylococcus epidermidis and Klebsiella oxytoca. In conclusion, no differences in frequency and microorganism levels were found between SLE patients and healthy individuals.

Effectiveness of oral hygiene interventions against oral and oropharyngeal reservoirs of aerobic and facultatively anaerobic gram-negative bacilli

BACKGROUND

Aerobic and facultatively anaerobic gram-negative bacilli (AGNB) are opportunistic pathogens and continue to cause a large number of hospital-acquired infections. AGNB residing in the oral cavity and oropharynx have been linked to nosocomial pneumonia and septicemia. Although AGNB are not considered members of the normal oral and oropharyngeal flora, medically compromised patients have been demonstrated to be susceptible to AGNB colonization.

METHODS

A literature search was conducted to retrieve articles that evaluated the effectiveness of oral hygiene interventions in reducing the oral and oropharyngeal carriage of AGNB in medically compromised patients.

RESULTS

Few studies have documented the use of mechanical oral hygiene interventions alone against AGNB. Although a number of studies have employed oral hygiene interventions complemented by antiseptic agents such as chlorhexidine and povidone iodine, there appears to be a discrepancy between their in vitro and in vivo effectiveness.

CONCLUSION

With the recognition of the oral cavity and oropharynx as a reservoir of AGNB and the recent emergence of multidrug and pandrug resistance in hospital settings, there is a pressing need for additional high-quality randomized controlled trials to determine which oral hygiene interventions or combination of interventions are most effective in eliminating or reducing AGNB carriage.

Haemophilus influenzae and smoking-related obstructive airways disease

Background

Intralumenal bacteria play a critical role in the pathogenesis of acute infective episodes and airway inflammation. Antigens from colonizing bacteria such as nontypeable Haemophilus influenzae (NTHi) may contribute to chronic lung disease through an immediate hypersensitivity response. The objective of this study was to determine the presence of specific NTHi-IgE antibodies in subjects with chronic bronchitis (CB) and COPD who had smoked.

Methods

Serum, sputum, and saliva samples were collected from subjects with CB and moderate–severe COPD and healthy aged-matched controls. Total IgE and specific NTHi IgE were measured by enzyme linked immmunosorbent assay. Throat swabs were examined for the presence of NTHi.

Results

The results demonstrate that: i) specific NTHi IgE antibodies occur at a low level in healthy subjects; ii) those with both CB and moderate–severe COPD have elevated specific NTHi IgE antibody compared with healthy controls, with higher levels in those with most severe disease; iii) IgE levels are greater in those with moderate–severe COPD than in those with CB. They demonstrate specific NTHi IgE antibody is regularly found at higher than normal levels in COPD.

Conclusion

The detection of IgE antibody to colonizing bacteria in all subjects with CB or moderate–severe COPD identifies a possible mechanism of bronchospasm in these subjects amenable to specific intervention therapy.

Acute exacerbations in COPD and their control with oral immunization with non-typeable haemophilus influenzae

Chronic obstructive pulmonary disease (COPD) a term based on the demonstration of irreversible airways obstruction, introduced to unify a range of chronic progressive diseases of the airways consequent upon inhalation of toxins. While disease is initiated and progressed by inhaled toxins, an additional pathway of damage has emerged, with particular relevance to acute exacerbations. Exacerbations of disease due to an increase in the level of intrabronchial inflammation have taken on a new significance as their role in determining both acute and chronic outcomes is better understood. This “second pathway” of disease is a consequence of bacterial colonization of damaged airways. Although bacteria have been linked to acute episodes in COPD over 50 years, only recently has quality data on antibiotic usage and the detection of “exacerbation isolates” of non-typeable Haemophilus influenzae (NTHi) provided strong argument in support of a pathogenic role. Yet a poor correlation between detection of colonizing bacteria and clinical status remained a concern in attempts to explain a role for bacteria in a classical infection model. This presentation discusses a hypothesis that acute exacerbations reflect a T cell-dependent hypersensitivity response to colonizing bacteria, with IL-17 dependent accumulation of neutrophils within the bronchus, as the main outcome measure. Critical protection against exacerbations following oral administration of NTHi, an immunotherapy that drives a TH17 T cell response from Peyer’s patches, reduces the load of intrabronchial bacteria while preventing access of inhaled bacteria into small airways. Immunotherapy augments a physiological “loop” based on aspiration of bronchus content into the gut. A second “hypersensitivity” mechanism may cause bronchospasm – in both COPD and treatment-resistant asthma – due to specific IgE antibody directed against colonizing bacteria, as oral NTHi abrogates wheeze in subjects with recurrent “wheezy bronchitis.”

Cough and sputum production as risk factors for poor outcomes in patients with COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality in developed countries, and its prevalence is projected to increase over the coming decades. According to the World Health Organization, COPD will become the third leading cause of death worldwide by 2020. COPD has a chronic and progressive course, and is often aggravated by exacerbations, which typically arise as a result of bronchial infection. Exacerbations are characterised by periods of increasing acute symptoms, particularly cough, dyspnoea and production of sputum, which worsen airflow obstruction, further impair quality of life and generally require a change in regular medication. Exacerbations are the most common cause of medical visits, hospital admissions and death in patients with COPD, and frequent exacerbations worsen health status and may cause a permanent decline in lung function. Chronic cough and sputum production are common in the general population, but significantly more prevalent in patients with respiratory disorders; these symptoms have been suggested as a risk factor for exacerbations of COPD. This article will review the consequences of chronic cough and sputum production in patients with COPD and analyse whether these risk factors may be useful for identifying a specific phenotype of patient that requires different management to reduce the occurrence of exacerbations.

Oral non-typable Haemophilus influenzae enhances physiological mechanism of airways protection

Oral immunotherapy with inactivated non-typeable Haemophilus influenzae (NTHi) prevents exacerbations of chronic obstructive pulmonary disease, but the mechanism is unclear. The aim of this study was to determine the mechanism of protection. This was a placebo versus active prospective study over 3 months in 64 smokers. The active treatment was three courses of oral NTHi given at monthly intervals, followed by measurement of bacteriological and immunological parameters. The results can be summarized: (i) NTHi-specific T cells increased in the placebo treatment group over time (P<0.05); (ii) the T cell response in the oral NTHi group started earlier than that in the placebo group (P<0.05); and (iii) serum NTHi-specific immunoglobulin (Ig)G had significantly greater variation in the placebo group (P<0.0001). The increase in antibody in placebos over time correlated with exposure to live H. influenzae (P<0.05) determined from culture of gargles; (iv) reduction in saliva lysozyme over time (P<0.05) was detected only in the oral NTHi treatment group. These data are consistent with T cell priming of gut lymphoid tissue by aspiration of bronchus content into the gut, with oral immunotherapy augmenting this process leading to enhanced bronchus protection. The evidence for protection was a stable IgG antibody level through the study in the oral NTHi treatment group, contrasting with an increase in antibody correlating with exposure of the airways to H. influenzae in the placebo group. Saliva lysozyme was a useful biomarker of mucosal inflammation, falling after oral NTHi consistent with a reduction in the level of intralumenal inflammation.

Oral immunotherapy with inactivated nontypeable Haemophilus influenzae reduces severity of acute exacerbations in severe COPD

BACKGROUND

Acute exacerbations of COPD reflect in part an inappropriate host response to abnormal bacterial colonization. Orally administered inactivated nontypeable Haemophilus influenzae (NTHi) can drive a specific T-cell response that by promoting intrabronchial phagocytosis down-regulates bronchus inflammation.

METHODS

Subjects with recurrent exacerbations of COPD were studied in a randomized, multicenter, double-blind, placebo-controlled trial, to test efficacy of an NTHi oral immunotherapeutic (HI-164OV). This report describes the outcome in 38 subjects with severe COPD defined as having an FEV(1) < or = 50% of predicted normal.

RESULTS

Exacerbations defined as an increase in volume and purulence of sputum were reduced by 16% (not significant) in the active group. However, moderate-to-severe exacerbations (defined as requiring corticosteroid therapy) were reduced by 63% (P = .05). The proportion with any acute exacerbation was little changed with treatment, but the proportion with episodes requiring corticosteroid therapy was reduced by 56% (P = .07). The mean duration of episodes was reduced by 37% (P = .01) and prescribed courses of antibiotics were reduced by 56% (P = .03) following therapy. Exacerbations requiring admission into hospital were reduced by 90% (P = .04) in the active group. No specific adverse effect was detected.

CONCLUSIONS

Treatment of severe COPD with frequent exacerbations with HI-164OV was safe and effective, especially with respect to reduction in parameters of severity.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, www.anzctr.org.au; identifier: ACTRN012606000074594.

Inhaled endotoxin in healthy human subjects: A dose-related study on systemic effects and peripheral CD4+ and CD8+ T cells

BACKGROUND

Inhaled endotoxin or lipopolysaccharide (LPS) is implicated in the pathogenesis of pulmonary diseases. We investigated the inhalation effects of two different doses of LPS in healthy human subjects.

METHODS

Eighteen healthy non-atopic human subjects inhaled either 15 microg (n=10) or 50 microg (n=8)Escherichia coli LPS in an open study. As control, each subject had isotonic saline inhalation 1 week before (baseline) and after LPS inhalation. Data collected included those of clinical parameter, induced sputum and peripheral blood CD4+ and CD8+ T cells.

RESULTS

Acute flu-like symptoms and pyrexia were significantly greater in the 50 microg than 15 microg LPS group. Similarly, the increase in sputum and blood total cell and neutrophil counts at 6h following inhaled LPS were greater in the 50 microg group. Myeloperoxidase, human neutrophil elastase and interleukin-8 in sputum sol, but not blood, showed a trend towards greater increase following 50 microg LPS. All these changes were resolved at one week. In the 50 microg dose group alone, there was a reduction in the proportion of peripheral blood interferon (IFN)-gamma-producing CD4+ and CD8+ T cells at 6h followed by an increase at 1 week after inhaled LPS.

CONCLUSIONS

The airway and systemic effects of inhaled LPS are dose-related and predominantly neutrophilic. The changes in the proportions of circulating CD4+ and CD8+ T cells suggests preferential recruitment of IFN-gamma-producing T cells into tissue from inhaled 50 microg LPS, followed by reappearance of these cells in blood 1 week later.

Mucosal immunity in the lung and upper airway

The mucosal surfaces of the lungs and upper airways are common sites for infection. Extensive studies of the mechanisms associated with immune responses in the respiratory tract have found that understanding the system is challenging and involves many complex interactions to prevent and eliminate infection. Immune protection against diseases transmitted through the respiratory tract requires an understanding of the important aspects associated with beneficial, detrimental or ineffective immune responses. Two critical aspects of an immune response against a pathogen are that of the inductive stage, either induced by vaccination or primary infection, and the effector stage, the ability to recognise, respond to and eliminate the infection without detriment to the host. An immunisation strategy must not only have a measure of the induced antigen specific response, but this response must also be protective.

Is there a role for a mucosal influenza vaccine in the elderly?

Influenza infection is an acute respiratory disease with a high morbidity and significant mortality, particularly among the elderly and individuals with chronic diseases. The majority of countries now recommend annual influenza vaccination for all people aged 65 years or older, and for those with high risk conditions. Most commercially available influenza vaccines are administered systemically and while these are effective in children and young adults, efficacy levels in elderly individuals have been reported to be much lower. Mucosal vaccines may offer an improved vaccine strategy for protection of the elderly. As the influenza virus causes a respiratory infection, it is potentially more beneficial to administer a vaccine that will boost protection in the mucosal surfaces of the upper and lower respiratory tract. Mucosal influenza vaccines are aimed at stimulating protective immunity in the respiratory tract via oral or intranasal immunisation. This review examines our present knowledge of mucosal immunity and current strategies for mucosal vaccination. It also stresses that the use of serum antibody levels as a 'surrogate marker' for protection against influenza is potentially misleading; serum antibody, for example, may be a quite inappropriate marker to assess a mucosal vaccine. This marker does not reflect other immune responses to vaccination that are crucial for protection.

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.

Induction of phagocyte-stimulating cytokines by in vitro stimulation of human peripheral blood mononuclear cells with Haemophilus influenzae

The aim of this study was to analyse the in vitro response of human peripheral blood mononuclear cells to stimulation with killed Haemophilus influenzae strains of different capsular types, isolation sites and from cases with different forms of infections. The mean stimulatory index using 10(6) bacteria/well was 10, and 80 when 10(8) bacteria/well were used for stimulation. The mean+/-SD level was 13+/-4 ng/ml for interleukin (IL)-1beta, 128+/-73 ng/ml for IL-6, 203+/-122 ng/ml for IL-8, 3160+/-1220 pg/ml for IL-10, 29+/-40 pg/ml for IL-12, 2800+/-1790 pg/ml for tumour necrosis factor (TNF)-alpha and 4+/-7 ng/ml for interferon (IFN)-gamma, when stimulating cells with the lower dose of 10(6) bacteria/well. Using the higher bacterial dose, the levels of IL-1beta, TNF-alpha and IL-12 remained similar, whereas the IL-6, IL-8 and IL-10 levels were significantly lower, and IFN-gamma levels were significantly higher. Strains isolated from the bronchial tree induced significantly higher levels of IFN-gamma and significantly lower levels of IL-6, IL-8 and IL-10 than strains from other isolation sites. In conclusion, H. influenzae generated phagocyte-activating cytokines and an IL-10/IL-12 ratio that was 1090 times that described previously for Streptococcus pneumoniae.

Nontypeable Haemophilus influenzae: pathogenesis and prevention

In this paper, we describe the ability of nontypeable Haemophilus influenzae (NTHi) to coexist with the human host and the devastating results associated with disruption of the delicate state of balanced pathogenesis, resulting in both acute and chronic respiratory tract infections. It has been seen that the strains of NTHi causing disease show a marked genetic and phenotypic diversity but that changes in the lipooligosaccharide (LOS) and protein size and antigenicity in chronically infected individuals indicate that individual strains of NTHi can remain and adapt themselves to avoid expulsion from their infective niche. The lack of reliance of NTHi on a single mechanism of attachment and its ability to interact with the host with rapid responses to its environment confirmed the success of this organism as both a colonizer and a pathogen. In vitro experiments on cell and organ cultures, combined with otitis media and pulmonary models in chinchillas, rats, and mice, have allowed investigations into individual interactions between NTHi and the mammalian host. The host-organism interaction appears to be a two-way process, with NTHi using cell surface structures to directly interact with the mammalian host and using secreted proteins and LOS to change the mammalian host in order to pave the way for colonization and invasion. Many experiments have also noted that immune system evasion through antigenic variation, secretion of enzymes and epithelial cell invasion allowed NTHi to survive for longer periods despite a specific immune response being mounted to infection. Several outer membrane proteins and LOS derivatives are discussed in relation to their efficacy in preventing pulmonary infections and otitis media in animals. General host responses with respect to age, genetic makeup, and vaccine delivery routes are considered, and a mucosal vaccine strategy is suggested.

In vitro susceptibility patterns of nonserotypable Haemophilus influenzae from patients with chronic bronchitis

The antimicrobial susceptibility patterns of 76 nonserotypable Haemophilus influenzae (biotypes I-IV) from patients with chronic bronchitis were compared against ten orally administered antimicrobial agents. In addition the sputum ampicillin concentrations one hour after standard therapy were determined in five patients with chronic bronchitis. Ampicillin resistance was demonstrated in one strain (biotype IV) which produced beta-lactamase and two strains (biotype II) with innate resistance (MIC = 4 mg/l). Resistance to trimethoprim, chloramphenicol, ciprofloxacin and cefaclor was not detected. The incidence of resistance to tetracycline was 0.5% and cephalexin 13.2%. A high incidence of resistance to erythromycin (95%) was noted. There was no association between resistance and biotype of nonserotypable H. influenzae. The sputum ampicillin concentrations from four out of five patients given standard antibiotic doses were shown to be sufficient to inhibit the growth of the majority of nonserotypable H. influenzae strains one hour after treatment. This study shows that the incidence of nonserotypable H. influenzae resistant to ampicillin is low in this community but that resistance levels to erythromycin, commonly prescribed for the management of acute bronchitis, are high. Regular sensitivity screens are important in monitoring the value of various antibiotic regimens in the management of acute bronchitis.

The oral prevalence of aerobic and facultatively anaerobic gram-negative rods and yeasts in semi-recluse human vegetarians

Limited data exist on the oral ecology of vegetarians. Hence the dental and periodontal status, and the oral prevalence of aerobic and facultatively anaerobic Gram-negative rods (AGNR) and yeasts, were studied in 36 semi-recluse, vegetarian, Buddhist monks and nuns in Hong Kong. The oral prevalence of AGNR and yeasts was 61.1% and 33.3%. There was no correlation between the prevalence of AGNR and/or yeasts and the incidence of carious or filled teeth and the health status of the periodontium. Rather, the results of this study combined with those of previous studies suggest that increasing age and the consumption of food prepared in communal kitchens might be more important contributory factors in the oral prevalence of AGNR than the nature of the diet itself or the health of the dentition and periodontium.

A possible role for lysozyme in determining acute exacerbation in chronic bronchitis

The aggregation of non-serotypable Haemophilus influenzae (NTHI) by whole saliva from patients with chronic obstructive lung disease (COLD) was investigated. Significant differences were observed between salivary aggregating activity of a control and COLD population (P < 0.001). Saliva from patients less prone to acute exacerbations had a greater capacity to aggregate bacteria compared with saliva from patients with a predilection to infection. The mechanism of saliva-mediated aggregation of NTHI was investigated and shown to be related to lysozyme content. Lysozyme activity in saliva was measured by the turbidimetric technique and results showed that patients with chronic bronchitis had increased levels of salivary lysozyme, with a subpopulation within the non-infection-prone group having greater amounts. A significant difference was observed in salivary lysozyme between controls and non-infection-prone (P < 0.005) and infection-prone (P < 0.05) patients, respectively: the non-infection-prone patients having significantly (P < 0.005) more than the infection-prone patients. There was significant correlation (r = 0.742, P < 0.001) between salivary aggregation of NTHI and lysozyme activity. Chromatographically purified human lysozyme had a similar aggregation profile to that of saliva. There was no difference in serum and saliva lactoferrin concentrations between groups, but there was a significant increase (P < 0.05) in serum lysozyme concentration in the non-infection-prone group. This study suggests that the level of salivary lysozyme derived from macrophages may play an important role in determining resistance or susceptibility to acute bronchitis.

Acute on chronic bronchitis: A model of mucosal immunology

Acute bronchitis has been studied as a model of disturbed mucosal immunoregulation. A new hypothesis relating to the pathogenesis of acute bronchitis has been developed, based on altered host response as the prime mover. Infection-prone subjects had low levels of lysozyme. Effective oral immunization, especially if early, reduced levels of bacterial colonization. Future attention focuses on intra bronchial inflammation and its link to the host-parasite relationship.

Simple method for quantifying viable bacterial numbers in sputum

AIMS

To establish a simple method of quantitative culture for determining the viable bacterial numbers present in expectorated sputum samples.

METHODS

Sputum samples were homogenised with dithiothreitol, sterile saline or glass beads to determine which method recovered the greatest number of viable bacteria. Culture broths were also incubated with dithiothreitol and sampled over time to determine its effect on bacterial viability. Sputum samples homogenised with dithiothreitol were diluted in sterile saline and sampled using either standard bacteriological loops or a precision pipette to determine which method resulted in the least variation.

RESULTS

Homogenisation of sputum using dithiothreitol increased the recovery of viable bacteria compared with sterile glass beads and/or saline, with no apparent effect on bacterial viability when incubated with culture broths. By inoculating agar plates with 10(-3), 10(-4) and 10(-5) dilutions of the homogenised sputum sample, all potential pathogens could easily be identified. A 10 microliter sample volume dispensed by precision pipette and spread with a "hockey stick" resulted in the least variation between plates (less than 16%) and an even distribution of bacterial colonies. Numbers of viable bacteria recovered from different aliquots of individual sputum samples were generally of the same order of magnitude.

CONCLUSIONS

This method represents a relatively quick and simple technique for accurately quantifying viable bacteria present in sputum samples. The use of a small portion appears to be representative of the sample as a whole.

The oral prevalence of aerobic and facultatively anaerobic gram-negative rods and yeasts in Hong Kong Chinese

Saline oral rinse samples were obtained from 300 community-dwelling Hong Kong Chinese attending an outpatient dental clinic to determine the oral prevalence of aerobic and facultatively anaerobic Gram-negative rods (AGNR) and yeasts. The oral prevalence of AGNR was 41.7%. Enterobacteriaceae species comprised 73% of all AGNR isolated, with an overall prevalence of 32%. There was no difference in prevalence between females (n = 190) and males (n = 110). Morning samples (n = 154) yielded a significantly higher prevalence of AGNR (54.5%) and Enterobacteriaceae (42.2%) than afternoon samples (n = 146) (28.1 and 21.2%, respectively; p < 0.01, p < 0.01). Subjects over 50 yr had a significantly higher prevalence of AGNR than those aged 30-49 yr (p < 0.01). The most commonly isolated AGNR species were Enterobacter cloacae and Klebsiella pneumoniae pneumoniae. The oral prevalence of yeasts was 24%, with Candida albicans forming 77% of all yeasts isolated. Subjects taking medication (n = 38) or wearing dentures (n = 38) had a significantly higher oral yeast prevalence of 36.8 (p < 0.05) and 44.7% (p < 0.01), respectively. Yeast prevalence was significantly higher in subjects over 50 yr than those aged 30-49 yr (p < 0.05) and 15-29 yr (p < 0.05). Comparisons with previous studies suggest that the oral prevalence of AGNR in Chinese may be higher in Hong Kong than in other parts of the world.

An alteration in the host-parasite relationship in subjects with chronic bronchitis prone to recurrent episodes of acute bronchitis

Acute episodes of bronchitis have been shown to be unequally distributed within a population of subjects with chronic bronchitis. Two groups were identified based on incidence of acute bronchitis--subjects who were 'infection-prone' (2-5 infections per year) and those who were 'non-infection-prone' (0-1 infections per year). Minor differences in clinical parameters existed, except for smoking experience. The non-infection-prone group included more current smokers, and the total smoking experience (in 'pack years') was significantly greater in this group. Between-year analysis demonstrated a stability of classification, established after a minimum of two years' prospective observation. Parameters of the host-parasite relationship were assessed in both groups. A significantly greater polybacterial colonization of the oropharynx was observed for chronic bronchitics, both infection-prone (P < 0.0001) and non-infection-prone (P < 0.001), compared with control subjects. Infection-prone chronic bronchitics had significantly greater total bacteria cultured from the oropharynx compared to the non-infection-prone group (P < 0.05); adherence of indigenous microflora to buccal epithelial cells, in particular Gram-positive cocci (P < 0.01) and in vitro adherence of non-serotypable Haemophilus influenzae to buccal cells (P < 0.05) compared with the control and non-infection-prone groups. These studies suggest that an important variation in subjects with chronic bronchitis is the binding capacity of epithelial cells for bacteria, which when increased enhances susceptibility to colonization and clinical infection.

Oral and oropharyngeal prevalence of Enterobacteriaceae in humans: a review

Members of the Enterobacteriaceae family are widely distributed in nature and exhibit substantial diversity in ecology, host range and pathogenic potential for man. While wide discrepancies in methodology exist between epidemiological studies, the available data indicate an increased prevalence of oral and/or oropharyngeal Enterobacteriaceae carriage in patients with illnesses of varying severity compared with healthy subjects. This paper reviews the prevalence of Enterobacteriaceae in the oral and oropharyngeal region of healthy human subjects and those affected by different disease entities, and discusses the complexities associated with collating and interpreting such data. The effect of antimicrobials and antiseptics on oral and oropharyngeal Enterobacteriaceae has also been reviewed, while highlighting the gaps in knowledge and future research directions.

The course of nosocomial oropharyngeal colonization in patients recovering from acute respiratory failure

We sought to determine the duration of nosocomially acquired Gram-negative bacilli (GNB) oropharyngeal colonization following hospitalization for acute respiratory failure (ARF). We selected 24 inpatients recovering from ARF who had positive oropharyngeal cultures for GNB. Follow-up cultures were obtained at the time of hospital discharge, and 2 and 4 weeks afterwards. The prevalence of GNB colonization in these patients was 14/21 (67 percent) at the time of hospital discharge and 14/23 (60 percent) 2 weeks afterwards. Both rates were greater than the control population's 7/30 (23 percent, p < 0.02 and < 0.05, respectively). Four weeks after hospital discharge, the prevalence of colonization had fallen to 7/19 (37 percent) which was not significantly different from that of controls. Five of 24 subjects were rehospitalized during the follow-up period. Pneumonia was diagnosed in only two of the five and both proved to be due to pathogens other than GNB. We conclude that the prevalence of GNB oropharyngeal colonization following ARF approaches control levels within four weeks of hospital discharge. We speculate that a post-ARF patient's risk for GNB pneumonia similarly declines.

Microbial flora of the trachea during intubation of patients undergoing upper abdominal surgery

BACKGROUND

The presence of Haemophilus influenzae in the oropharynx is correlated with the subsequent development of chest infection. The importance of colonisation of the trachea by bacteria at the time of surgery is uncertain. This study investigated the tracheal flora at the time of intubation in 24 patients undergoing elective upper abdominal surgery.

METHODS

The bacterial flora of the trachea was sampled in all 24 patients immediately after intubation and immediately before extubation. Patients were assessed postoperatively for the development of chest infection.

RESULTS

Bacteria, including H influenzae in five cases, were isolated from the post-intubation brushings of the trachea of 15 patients. The pre-extubation brushings from only four patients yielded growth. Three of five patients developing a chest infection were colonised by H influenzae according to the postintubation brush, compared with two of 19 without chest infections. Before extubation two of five developing chest infections had H influenzae in the trachea but none of 19 without infection. All but one of the patients from whom H influenzae was isolated were smokers.

CONCLUSIONS

These results suggest that the increased risk of postoperative chest infection in cigarette smokers may be due in part to colonisation of the trachea by H influenzae at the time of operation.

Reduction in the incidence of acute bronchitis by an oral Haemophilus influenzae vaccine in patients with chronic bronchitis in the highlands of Papua New Guinea

Following the administration of a standardized questionnaire, 62 adult patients with chronic bronchitis were enrolled into a double-blind controlled trial of an oral killed Haemophilus influenzae vaccine in the highlands of Papua New Guinea. A 3-day course of vaccine or placebo was given monthly for 3 consecutive months. Participants were monitored weekly over 12 months for acute exacerbations; early morning sputum specimens were collected monthly and during acute exacerbations. Density of colonization by H. influenzae and H. parainfluenzae was determined by standard quantitative and semiquantitative techniques, and the latter method (quadrant score) was used to determine the density of growth of pneumococci. A total of 30 patients received vaccine and 32 placebo. The incidence rate of acute bronchitis in the vaccine group (0.011 episodes/person-weeks) was significantly lower than that in the placebo group (0.021 episodes/person-weeks), but there was no difference between the two groups in the incidence rates of more severe disease. Vaccine efficacy was maximal at times of peak incidence of disease. There was no evidence of a decline in vaccine efficacy for acute bronchitis over the 12-month follow-up period. The number of viable H. influenzae in the sputum declined in both vaccine and placebo groups over the 12-month follow-up period. The average concentration of H. influenzae in the vaccine group fell below that in the placebo group within 1 to 2 months after first immunization and remained so for 12 months, although the difference between the two groups narrowed during the follow-up period.(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled trial of a killed Haemophilus influenzae vaccine for prevention of acute exacerbations of chronic bronchitis

Sixty-four patients with chronic bronchitis with a history of recurrent respiratory tract infections were admitted to a double-blind randomised controlled study in which the efficacy of an oral vaccine containing killed Haemophilus influenzae in preventing acute exacerbations of chronic bronchitis was compared with placebo. Patients given vaccine developed fewer acute infective episodes. Although the numbers of patients who required antibiotic therapy in the two groups were not significantly different, the number of antibiotic prescriptions given to the vaccinated group of patients was significantly less than that required by the control group. A reduction in colonisation with Haemophilus influenzae occurred in the active group, which was maximal 14 weeks after the onset of the study.