Early bacteriologic, immunologic, and clinical courses of young infants with cystic fibrosis identified by neonatal screening

Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Respiratory tract infections with Pseudomonas aeruginosa occur in most people with cystic fibrosis (CF). Established chronic P aeruginosa infection is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate. This is an updated review.

OBJECTIVES

Does giving antibiotics for P aeruginosa infection in people with CF at the time of new isolation improve clinical outcomes (e.g. mortality, quality of life and morbidity), eradicate P aeruginosa infection, and delay the onset of chronic infection, but without adverse effects, compared to usual treatment or an alternative antibiotic regimen? We also assessed cost-effectiveness.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and conference proceedings. Latest search: 24 March 2022. We searched ongoing trials registries. Latest search: 6 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of people with CF, in whom P aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous (IV) antibiotics with placebo, usual treatment or other antibiotic combinations. We excluded non-randomised trials and cross-over trials.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, assessed risk of bias and extracted data. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 11 trials (1449 participants) lasting between 28 days and 27 months; some had few participants and most had relatively short follow-up periods. Antibiotics in this review are: oral - ciprofloxacin and azithromycin; inhaled - tobramycin nebuliser solution for inhalation (TNS), aztreonam lysine (AZLI) and colistin; IV - ceftazidime and tobramycin. There was generally a low risk of bias from missing data. In most trials it was difficult to blind participants and clinicians to treatment. Two trials were supported by the manufacturers of the antibiotic used. TNS versus placebo TNS may improve eradication; fewer participants were still positive for P aeruginosa at one month (odds ratio (OR) 0.06, 95% confidence interval (CI) 0.02 to 0.18; 3 trials, 89 participants; low-certainty evidence) and two months (OR 0.15, 95% CI 0.03 to 0.65; 2 trials, 38 participants). We are uncertain whether the odds of a positive culture decrease at 12 months (OR 0.02, 95% CI 0.00 to 0.67; 1 trial, 12 participants). TNS (28 days) versus TNS (56 days) One trial (88 participants) comparing 28 days to 56 days TNS treatment found duration of treatment may make little or no difference in time to next isolation (hazard ratio (HR) 0.81, 95% CI 0.37 to 1.76; low-certainty evidence). Cycled TNS versus culture-based TNS One trial (304 children, one to 12 years old) compared cycled TNS to culture-based therapy and also ciprofloxacin to placebo. We found moderate-certainty evidence of an effect favouring cycled TNS therapy (OR 0.51, 95% CI 0.31 to 0.82), although the trial publication reported age-adjusted OR and no difference between groups. Ciprofloxacin versus placebo added to cycled and culture-based TNS therapy One trial (296 participants) examined the effect of adding ciprofloxacin versus placebo to cycled and culture-based TNS therapy. There is probably no difference between ciprofloxacin and placebo in eradicating P aeruginosa (OR 0.89, 95% CI 0.55 to 1.44; moderate-certainty evidence). Ciprofloxacin and colistin versus TNS We are uncertain whether there is any difference between groups in eradication of P aeruginosa at up to six months (OR 0.43, 95% CI 0.15 to 1.23; 1 trial, 58 participants) or up to 24 months (OR 0.76, 95% CI 0.24 to 2.42; 1 trial, 47 participants); there was a low rate of short-term eradication in both groups. Ciprofloxacin plus colistin versus ciprofloxacin plus TNS One trial (223 participants) found there may be no difference in positive respiratory cultures at 16 months between ciprofloxacin with colistin versus TNS with ciprofloxacin (OR 1.28, 95% CI 0.72 to 2.29; low-certainty evidence). TNS plus azithromycin compared to TNS plus oral placebo Adding azithromycin may make no difference to the number of participants eradicating P aeruginosa after a three-month treatment phase (risk ratio (RR) 1.01, 95% CI 0.75 to 1.35; 1 trial, 91 participants; low-certainty evidence); there was also no evidence of any difference in the time to recurrence. Ciprofloxacin and colistin versus no treatment A single trial only reported one of our planned outcomes; there were no adverse effects in either group. AZLI for 14 days plus placebo for 14 days compared to AZLI for 28 days We are uncertain whether giving 14 or 28 days of AZLI makes any difference to the proportion of participants having a negative respiratory culture at 28 days (mean difference (MD) -7.50, 95% CI -24.80 to 9.80; 1 trial, 139 participants; very low-certainty evidence). Ceftazidime with IV tobramycin compared with ciprofloxacin (both regimens in conjunction with three months colistin) IV ceftazidime with tobramycin compared with ciprofloxacin may make little or no difference to eradication of P aeruginosa at three months, sustained to 15 months, provided that inhaled antibiotics are also used (RR 0.84, 95 % CI 0.65 to 1.09; P = 0.18; 1 trial, 255 participants; high-certainty evidence). The results do not support using IV antibiotics over oral therapy to eradicate P aeruginosa, based on both eradication rate and financial cost.

AUTHORS' CONCLUSIONS

We found that nebulised antibiotics, alone or with oral antibiotics, were better than no treatment for early infection with P aeruginosa. Eradication may be sustained in the short term. There is insufficient evidence to determine whether these antibiotic strategies decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials comparing two active treatments have failed to show differences in rates of eradication of P aeruginosa. One large trial showed that intravenous ceftazidime with tobramycin is not superior to oral ciprofloxacin when inhaled antibiotics are also used. There is still insufficient evidence to state which antibiotic strategy should be used for the eradication of early P aeruginosa infection in CF, but there is now evidence that intravenous therapy is not superior to oral antibiotics.

The potential of volatile organic compound analysis for pathogen detection and disease monitoring in patients with cystic fibrosis

INTRODUCTION

Airway infection with pathogens and its associated pulmonary exacerbations (PEX) are the major causes of morbidity and premature death in cystic fibrosis (CF). Preventing or postponing chronic infections requires early diagnosis. However, limitations of conventional microbiology-based methods can hamper identification of exacerbations and specific pathogen detection. Analyzing volatile organic compounds (VOCs) in breath samples may be an interesting tool in this regard, as VOC-biomarkers can characterize specific airway infections in CF.

AREAS COVERED

We address the current achievements in VOC-analysis and discuss studies assessing VOC-biomarkers and fingerprints, i.e. a combination of multiple VOCs, in breath samples aiming at pathogen and PEX detection in people with CF (pwCF). We aim to provide bases for further research in this interesting field.

EXPERT OPINION

Overall, VOC-based analysis is a promising tool for diagnosis of infection and inflammation with potential to monitor disease progression in pwCF. Advantages over conventional diagnostic methods, including easy and non-invasive sampling procedures, may help to drive prompt, suitable therapeutic approaches in the future. Our review shall encourage further research, including validation of VOC-based methods. Specifically, longitudinal validation under standardized conditions is of interest in order to ensure repeatability and enable inclusion in CF diagnostic routine.

Staphylococcus aureus and its Effects on the Prognosis of Bronchiectasis

Bronchiectasis, which is an abnormal and irreversible dilation of one or several bronchial segments, causes significant morbidity and impaired quality of life to patients, mainly as the result of recurrent and chronic respiratory infections. Staphylococcus aureus is a microorganism known for its high infectious potential related to the production of molecules with great pathogenic power, such as enzymes, toxins, adhesins, and biofilm, which determine the degree of severity of systemic symptoms and can induce exacerbated immune response. This review highlighted the clinical significance of S. aureus colonization/infection in bronchiectasis patients, since little is known about it, despite its increasing frequency of isolation and potential serious morbidity.

Elucidating the Interaction of CF Airway Epithelial Cells and Rhinovirus: Using the Host-Pathogen Relationship to Identify Future Therapeutic Strategies

Chronic lung disease remains the primary cause of mortality in cystic fibrosis (CF). Growing evidence suggests respiratory viral infections are often more severe in CF compared to healthy peers and contributes to pulmonary exacerbations (PEx) and deterioration of lung function. Rhinovirus is the most prevalent respiratory virus detected, particularly during exacerbations in children with CF <5 years old. However, even though rhinoviral infections are likely to be one of the factors initiating the onset of CF lung disease, there is no effective targeted treatment. A better understanding of the innate immune responses by CF airway epithelial cells, the primary site of infection for viruses, is needed to identify why viral infections are more severe in CF. The aim of this review is to present the clinical impact of virus infection in both young children and adults with CF, focusing on rhinovirus infection. Previous in vitro and in vivo investigations looking at the mechanisms behind virus infection will also be summarized. The review will finish on the potential of transcriptomics to elucidate the host-pathogen responses by CF airway cells to viral infection and identify novel therapeutic targets.

The VP1 unique region of human parvovirus B19 and human bocavirus induce lung injury in naïve Balb/c mice

Both human parvovirus B19 (B19V) and human bocavirus (HBoV) are known to be important human pathogens of the Parvoviridae family. Our earlier investigation demonstrated that both B19V-VP1u and HBoV-VP1u have a significantly disruptive effect on tight junctions (TJs) in A549 cells, implying the essential role of parvovirus in airway infection and lung injury. However, no direct evidence that B19V-VP1u and HBoV-VP1u induce lung injury exists. The present study further investigates the induction of lung injury by B19V-VP1u and HBoV-VP1u in naïve Balb/c mice following subcutaneous injection of PBS, recombinant B19V-VP1u or HBoV-VP1u. The experimental results reveal significantly increased activity, protein expression and ratio of matrix metalloproteinase-9 (MMP-9) to MMP-2 in Balb/c mice that received B19V-VP1u or HBoV-VP1u compared to those that received PBS. Significantly higher levels of inflammatory cytokines, including IL-6 and IL-1β, and greater lymphocyte infiltration in lung tissue sections were detected in mice that received B19V-VP1u or HBoV-VP1u. Additionally, significantly increased levels of phosphorylated p65 (NF-κB) and MAPK signaling proteins were observed in lung tissue of mice that received B19V-VP1u or HBoV-VP1u compared to those of mice that received PBS. These findings demonstrate for the first time that B19V-VP1u and HBoV-VP1u proteins induce lung inflammatory reactions through p65 (NF-κB) and MAPK signaling.

Early childhood lung function is a stronger predictor of adolescent lung function in cystic fibrosis than early Pseudomonas aeruginosa infection

OBJECTIVE

Pseudomonas aeruginosa has been suggested as a major determinant of poor pulmonary outcomes in cystic fibrosis (CF), although other factors play a role. Our objective was to investigate the association of early childhood Pseudomonas infection on differences in lung function in adolescence with CF.

METHODS

Two populations of subjects with CF were studied: from the Gene Modifier Study (GMS), 346 F508del homozygotes with severe vs. mild adolescent lung disease, and from the Colorado Newborn Screen Study (NBS) 172 subjects diagnosed with CF by newborn screening. Associations of Pseudomonas infection and lung function in early childhood with lung function in adolescence were investigated using multivariate linear regression analyses.

RESULTS

Among GMS subjects, those with severe adolescent lung disease had worse lung function in childhood (FEV1 25 percentage points lower) compared to subjects with mild adolescent lung disease, regardless of early childhood Pseudomonas status. Among NBS subjects, those with lowest adolescent lung function had significantly lower early childhood lung function and faster rate of decline in FEV1 than subjects with highest adolescent lung function; early Pseudomonas infection was not associated with rate of FEV1 decline. The strongest predictor of adolescent lung function was early childhood lung function. Subjects with a higher percentage of cultures positive for Pseudomonas before age 6 or a lower BMI at 2-4 years old also had lower adolescent lung function, though these associations were not as strong as with early childhood lung function.

CONCLUSIONS

In separate analyses of two distinct populations of subjects with CF, we found a strong correlation between lower lung function in early childhood and adolescence, regardless of early childhood Pseudomonas status. Factors in addition to early Pseudomonas infection have a strong impact on lung function in early childhood in CF. Further exploration may identify novel underlying genetic or environmental factors that predispose children with CF to early loss of lung function.

Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis. Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.This is an update of a Cochrane review first published in 2003, and previously updated in 2006, 2009 and 2014.

OBJECTIVES

To determine whether antibiotic treatment of early Pseudomonas aeruginosa infection in children and adults with cystic fibrosis eradicates the organism, delays the onset of chronic infection, and results in clinical improvement. To evaluate whether there is evidence that a particular antibiotic strategy is superior to or more cost-effective than other strategies and to compare the adverse effects of different antibiotic strategies (including respiratory infection with other micro-organisms).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 10 October 2016.

SELECTION CRITERIA

We included randomised controlled trials of people with cystic fibrosis, in whom Pseudomonas aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo, usual treatment or other combinations of inhaled, oral or intravenous antibiotics. We excluded non-randomised trials, cross-over trials, and those utilising historical controls.

DATA COLLECTION AND ANALYSIS

Both authors independently selected trials, assessed risk of bias and extracted data.

MAIN RESULTS

The search identified 60 trials; seven trials (744 participants) with a duration between 28 days and 27 months were eligible for inclusion. Three of the trials are over 10 years old and their results may be less applicable today given the changes in standard treatment. Some of the trials had low numbers of participants and most had relatively short follow-up periods; however, there was generally a low risk of bias from missing data. In most trials it was difficult to blind participants and clinicians to treatment given the interventions and comparators used. Two trials were supported by the manufacturers of the antibiotic used.Evidence from two trials (38 participants) at the two-month time-point showed treatment of early Pseudomonas aeruginosa infection with inhaled tobramycin results in microbiological eradication of the organism from respiratory secretions more often than placebo, odds ratio 0.15 (95% confidence interval (CI) 0.03 to 0.65) and data from one of these trials, with longer follow up, suggested that this effect may persist for up to 12 months.One randomised controlled trial (26 participants) compared oral ciprofloxacin and nebulised colistin versus usual treatment. Results after two years suggested treatment of early infection results in microbiological eradication of Pseudomonas aeruginosa more often than no anti-pseudomonal treatment, odds ratio 0.12 (95% CI 0.02 to 0.79).One trial comparing 28 days to 56 days treatment with nebulised tobramycin solution for inhalation in 88 participants showed that both treatments were effective and well-tolerated, with no notable additional improvement with longer over shorter duration of therapy. However, this trial was not powered to detect non-inferiority or equivalence .A trial of oral ciprofloxacin with inhaled colistin versus nebulised tobramycin solution for inhalation alone (223 participants) failed to show a difference between the two strategies, although it was underpowered to show this. A further trial of inhaled colistin with oral ciprofloxacin versus nebulised tobramycin solution for inhalation with oral ciprofloxacin also showed no superiority of the former, with increased isolation of Stenotrophomonas maltophilia in both groups.A recent, large trial in 306 children aged between one and 12 years compared cycled nebulised tobramycin solution for inhalation to culture-based therapy and also ciprofloxacin to placebo. The primary analysis showed no difference in time to pulmonary exacerbation or proportion of Pseudomonas aeruginosa positive cultures. An analysis performed in this review (not adjusted for age) showed fewer participants in the cycled therapy group with one or more isolates of Pseudomonas aeruginosa, odds ratio 0.51 (95% CI 0.31 to 0.28). Using GRADE, the quality of evidence for outcomes was downgraded to moderate to very low. Downgrading decisions for Pseudomonas aeruginosa eradication and lung function were based on applicability (participants mostly children) and limitations in study design, with imprecision an additional limitation for lung function, growth parameters and adverse effects.

AUTHORS' CONCLUSIONS

We found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained for up to two years. There is insufficient evidence to determine whether antibiotic strategies for the eradication of early Pseudomonas aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials comparing two active treatments have failed to show differences in rates of eradication of Pseudomonas aeruginosa. There have been no published randomised controlled trials that investigate the efficacy of intravenous antibiotics to eradicate Pseudomonas aeruginosa in cystic fibrosis. Overall, there is still insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in cystic fibrosis.

Cystic Fibrosis Diagnosis and Newborn Screening

The diagnosis of cystic fibrosis (CF) has evolved over the past decade as newborn screening has become universal in the United States and elsewhere. The heterogeneity of phenotypes associated with CF transmembrane conductance regulator (CFTR) dysfunction and mutations in the CFTR gene has become clearer, ranging from classic pancreatic-insufficient CF to manifestations in only 1 organ system to indeterminate diagnoses identified by newborn screening. The tools available for diagnosis have also expanded. This article reviews the newest diagnostic criteria for CF, newborn screening, prenatal screening and diagnosis, and indeterminate diagnoses in newborn-screened infants and symptomatic adults.

The nasal microbiota in infants with cystic fibrosis in the first year of life: a prospective cohort study

BACKGROUND

Respiratory tract infections and subsequent airway inflammation occur early in the life of infants with cystic fibrosis. However, detailed information about the microbial composition of the respiratory tract in infants with this disorder is scarce. We aimed to undertake longitudinal in-depth characterisation of the upper respiratory tract microbiota in infants with cystic fibrosis during the first year of life.

METHODS

We did this prospective cohort study at seven cystic fibrosis centres in Switzerland. Between Feb 1, 2011, and May 31, 2014, we enrolled 30 infants with a diagnosis of cystic fibrosis. Microbiota characterisation was done with 16S rRNA gene pyrosequencing and oligotyping of nasal swabs collected every 2 weeks from the infants with cystic fibrosis. We compared these data with data for an age-matched cohort of 47 healthy infants. We additionally investigated the effect of antibiotic treatment on the microbiota of infants with cystic fibrosis. Statistical methods included regression analyses with a multivariable multilevel linear model with random effects to correct for clustering on the individual level.

FINDINGS

We analysed 461 nasal swabs taken from the infants with cystic fibrosis; the cohort of healthy infants comprised 872 samples. The microbiota of infants with cystic fibrosis differed compositionally from that of healthy infants (p=0·001). This difference was also found in exclusively antibiotic-naive samples (p=0·001). The disordering was mainly, but not solely, due to an overall increase in the mean relative abundance of Staphylococcaceae in infants with cystic fibrosis compared with healthy infants (multivariable linear regression model stratified by age and adjusted for season; second month: coefficient 16·2 [95% CI 0·6-31·9]; p=0·04; third month: 17·9 [3·3-32·5]; p=0·02; fourth month: 21·1 [7·8-34·3]; p=0·002). Oligotyping analysis enabled differentiation between Staphylococcus aureus and coagulase-negative Staphylococci. Whereas the analysis showed a decrease in S aureus at and after antibiotic treatment, coagulase-negative Staphylococci increased.

INTERPRETATION

Our study describes compositional differences in the microbiota of infants with cystic fibrosis compared with healthy controls, and disordering of the microbiota on antibiotic administration. Besides S aureus, coagulase-negative Staphylococci also contributed to the disordering identified in these infants. These findings are clinically important in view of the crucial role that bacterial pathogens have in the disease progression of cystic fibrosis in early life. Our findings could be used to inform future studies of the effect of antibiotic treatment on the microbiota in infants with cystic fibrosis, and could assist in the prevention of early disease progression in infants with this disorder.

FUNDING

Swiss National Science Foundation, Fondation Botnar, the Swiss Society for Cystic Fibrosis, and the Swiss Lung Association Bern.

NETs and CF Lung Disease: Current Status and Future Prospects

Cystic Fibrosis (CF) is the most common fatal monogenic disease among Caucasians. While CF affects multiple organ systems, the principle morbidity arises from progressive destruction of lung architecture due to chronic bacterial infection and inflammation. It is characterized by an innate immune defect that results in colonization of the airways with bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa from an early age. Within the airway microenvironment the innate immune cells including epithelial cells, neutrophils, and macrophages have all been implicated in the host defense defect. The neutrophil, however, is the principal effector cell facilitating bacterial killing, but also participates in lung damage. This is evidenced by a disproportionately elevated neutrophil burden in the airways and increased neutrophil products capable of tissue degradation, such as neutrophil elastase. The CF airways also contain an abundance of nuclear material that may be originating from neutrophils. Neutrophil extracellular traps (NETs) are the product of a novel neutrophil death process that involves the expulsion of nuclear material embedded with histones, proteases, and antimicrobial proteins and peptides. NETs have been postulated to contribute to the bacterial killing capacity of neutrophils, however they also function as a source of proteases and other neutrophil products that may contribute to lung injury. Targeting nuclear material with inhaled DNase therapy improves lung function and reduces exacerbations in CF and some of these effects may be due to the degradation of NETs. We critically discuss the evidence for an antimicrobial function of NETs and their potential to cause lung damage and inflammation. We propose that CF animal models that recapitulate the human CF phenotype such as the CFTR(-/-) pig may be useful in further elucidating a role for NETs.

Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis. Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.This is an update of a Cochrane review first published in 2003, and previously updated in 2006 and 2009.

OBJECTIVES

To determine whether antibiotic treatment of early Pseudomonas aeruginosa infection in children and adults with cystic fibrosis eradicates the organism, delays the onset of chronic infection, and results in clinical improvement. To evaluate whether there is evidence that a particular antibiotic strategy is superior to or more cost-effective than other strategies and to compare the adverse effects of different antibiotic strategies (including respiratory infection with other micro-organisms).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 08 September 2014.

SELECTION CRITERIA

We included randomised controlled trials of people with cystic fibrosis, in whom Pseudomonas aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo, usual treatment or other combinations of inhaled, oral or intravenous antibiotics. We excluded non-randomised trials, cross-over trials, and those utilising historical controls.

DATA COLLECTION AND ANALYSIS

Both authors independently selected trials, assessed risk of bias and extracted data.

MAIN RESULTS

The search identified 49 trials; seven trials (744 participants) with a duration between 28 days and 27 months were eligible for inclusion. Three of the trials are over 10 years old and their results may be less applicable today given the changes in standard treatment. Some of the trials had low numbers of participants and most had relatively short follow-up periods; however, there was generally a low risk of bias from missing data. In most trials it was difficult to blind participants and clinicians to treatment given the interventions and comparators used. Two trials were supported by the manufacturers of the antibiotic used.Evidence from two trials (38 participants) at the two-month time-point showed treatment of early Pseudomonas aeruginosa infection with inhaled tobramycin results in microbiological eradication of the organism from respiratory secretions more often than placebo, odds ratio 0.15 (95% confidence interval 0.03 to 0.65) and data from one of these trials, with longer follow up, suggested that this effect may persist for up to 12 months.One randomised controlled trial (26 participants) compared oral ciprofloxacin and nebulised colistin versus usual treatment. Results after two years suggested treatment of early infection results in microbiological eradication of Pseudomonas aeruginosa more often than no anti-pseudomonal treatment, odds ratio 0.12 (95% confidence interval 0.02 to 0.79).One trial comparing 28 days to 56 days treatment with nebulised tobramycin solution for inhalation in 88 participants showed that both treatments were effective and well-tolerated, with no notable additional improvement with longer over shorter duration of therapy. However, this trial was not powered to detect non-inferiority or equivalence .A trial of oral ciprofloxacin with inhaled colistin versus nebulised tobramycin solution for inhalation alone (223 participants) failed to show a difference between the two strategies, although it was underpowered to show this. A further trial of inhaled colistin with oral ciprofloxacin versus nebulised tobramycin solution for inhalation with oral ciprofloxacin also showed no superiority of the former, with increased isolation of Stenotrophomonas maltophilia in both groups.A recent, large trial in 306 children aged between one and 12 years compared cycled nebulised tobramycin solution for inhalation to culture-based therapy and also ciprofloxacin to placebo. The primary analysis showed no difference in time to pulmonary exacerbation or proportion of Pseudomonas aeruginosa positive cultures. An analysis performed in this review (not adjusted for age) showed fewer participants in the cycled therapy group with one or more isolates of Pseudomonas aeruginosa, odds ratio 0.51 (95% CI 0.31 to 0.28).

AUTHORS' CONCLUSIONS

We found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained for up to two years. There is insufficient evidence to determine whether antibiotic strategies for the eradication of early Pseudomonas aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials of two active treatments have failed to show differences in rates of eradication of Pseudomonas aeruginosa. There have been no published randomised controlled trials that investigate the efficacy of intravenous antibiotics to eradicate Pseudomonas aeruginosa in cystic fibrosis. Overall, there is still insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in cystic fibrosis.

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.

Staphylococcus aureus in early cystic fibrosis lung disease

Staphylococcus aureus: is a common bacterial organism infecting children with cystic fibrosis (CF). Emerging evidence suggests early lower airway infection with this organism in young children with CF results in the deterioration of lung function, poorer nutrition parameters and heightens the airway inflammatory response. Despite contributing significantly to the burden of early lung disease among this group, there are ongoing controversies in the management of S. aureus infection, and gaps in our understanding of exactly how this organism causes lung disease. To reduce the morbidity and mortality of early infection ongoing research is needed to: (i) understand the early host immune response that enables this pathogen to reside within the CF lung; (ii) determine if there are organism specific factors that are associated with CF lung disease; and (iii) clarify the utility of anti-staphylococcal antibiotic prophylaxis and/or eradication in the treatment of this patient population.

Targeting bacterial integration host factor to disrupt biofilms associated with cystic fibrosis

BACKGROUND

This study aims to identify whether the bacterial protein, Integration Host Factor (IHF), is present within sputum solids collected from cystic fibrosis (CF) patients and thus might contribute to the structural stability of biofilms within the lungs.

METHODS

The presence of IHF in sputum was determined by immunohistochemistry. The role of IHF in stabilizing biofilms within sputum was tested in vitro wherein anti-IHF was used to attempt to dissolve sputum solids.

RESULTS

Thirty-seven of 44 sputum samples (84%) were positive for anti-IHF staining. Treatment with anti-IHF or DNase of 6 representative samples, dissolved sputum solids significantly better than treatment with normal saline in vitro, and strong synergism was observed when these agents were used in combination.

CONCLUSIONS

IHF was detected in the majority of sputum samples from patients with CF and in vitro treatment with anti-IHF induced dissolution of sputum solids. These data support further investigation of IHF as a potential therapeutic target for patients with CF.

Spectrum of viral infections in patients with cystic fibrosis

This review explores the extensive influence of viral infections leading to chronic deterioration of lung function in patients with cystic fibrosis (CF). The mechanisms how viral agents affect the pathogenesis as well as the inflammatory and immune response of CF are discussed. Viral infections of the upper and lower respiratory tract due to viruses in CF patients and methods for diagnosis of respiratory viruses are described in detail. The importance of respiratory and non-respiratory viral agents for the pathogenesis, especially for the exacerbation of bacterial lower respiratory tract infections and course of CF, is stressed, especially emphasizing respiratory syncytial virus, influenza virus, rhinovirus, and human herpes viruses. Possible harmful effects of further viruses like adenovirus, bocavirus, coronavirus, metapneumovirus, parainfluenzavirus on the lung function of CF patients are discussed. The potential use of adenovirus-based vectors for somatic gene therapy is mentioned.

Newborn screening for cystic fibrosis

PURPOSE OF REVIEW

Newborn screening for cystic fibrosis (CF) is now universal in the US and many other countries. The rapid expansion of screening has resulted in numerous publications identifying new challenges for healthcare providers. This review provides an overview of these publications and includes ideas on managing these challenges.

RECENT FINDINGS

Most CF newborn screening algorithms involve DNA mutation analysis. As screening has expanded, new challenges have been identified related to carrier detection and inconclusive diagnoses. Early descriptions of infants with CF-related metabolic syndrome (CRMS) indicate that the natural history of this condition cannot be predicted. Early identification has also provided an opportunity to better understand the pathophysiology of CF. However, few studies have been conducted in infants with CF to determine optimal therapy and recommendations are largely anecdotal.

SUMMARY

Newborn screening provides an opportunity to identify and begin treatment early in individuals with CF. Whereas a single, optimal approach to screening does not exist, all programs can benefit from new findings regarding sweat testing, carrier detection, early pathophysiology, and clinical outcomes.

Respiratory viruses in children with cystic fibrosis: viral detection and clinical findings

BACKGROUND

Viral detection from different respiratory sample types in children with cystic fibrosis (CF) is facilitated by available molecular methods, but optimum sampling strategies have not been identified. In addition, associations between viral detection and respiratory symptoms are not well described.

OBJECTIVES

Study goals were to compare molecular detection of viruses from concurrent upper airway and sputum samples in children with CF and to describe relative frequency of respiratory viral infections and identify potential clinical associations.

METHODS

We conducted a 2-year prospective surveillance study in 44 children with CF aged 6-18 years. Upper airway and sputum samples were collected quarterly and during pulmonary exacerbations and tested for respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses types 1-4, human metapneumovirus, coronaviruses, rhinoviruses, and adenoviruses. Physical exams and symptom surveys were used to identify respiratory signs and symptoms.

RESULTS

Upper airway samples were collected at 359 visits; concordance of PCR-based viral detection was examined in a subset of paired upper airway and sputum samples from 21 participants at 92 visits. Rhinovirus was the most commonly detected virus (23·1% overall), and rhinovirus detection was the same for both sample types (21·7% each). Sensitivity and specificity for the detection of rhinovirus in sputum relative to upper airway sampling were 70% and 91·7%, respectively. Respiratory symptoms associated with rhinovirus detection included increased cough, increased nasal congestion, increased sputum production, and wheezing.

CONCLUSIONS

A relatively high frequency of rhinovirus detection was observed by either upper airway or sputum samples, and clinical findings suggest a significant-associated symptom burden.

Clinical significance of microbial infection and adaptation in cystic fibrosis

A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.

Baseline characteristics and factors associated with nutritional and pulmonary status at enrollment in the cystic fibrosis EPIC observational cohort

SUMMARY BACKGROUND

The EPIC Observational Study is an ongoing prospective cohort study investigating risk factors for and clinical outcomes associated with early Pseudomonas aeruginosa (Pa) acquisition in young children with cystic fibrosis (CF).

OBJECTIVES AND HYPOTHESIS

To describe the baseline characteristics of the cohort and evaluate associations between potential risk factors and nutritional and respiratory characteristics at enrollment. We hypothesized that distinct demographic and environmental risk factors could be identified for poorer nutritional status and lung function at enrollment.

METHODS

During 2004-2006, 1,700 children with CF were enrolled at 59 US CF centers. Children <or=12 years were eligible if they had no prior Pa infection (Pa-Never) or, if prior isolation of Pa from respiratory cultures, at least a 2-year history of Pa negative cultures (Pa-Past).

RESULTS

One thousand one hundred seventeen participants (65.7%) were Pa-Never and 583 (34.3%) Pa-Past. Pa-never patients had a lower proportion of CFTR genotypes with both mutations in functional classes I, II, or III), higher lung function and less respiratory symptoms. Diagnosis after newborn or prenatal screening was associated with significantly higher mean weight, height, and FEV(1) at enrollment, while maternal smoking during pregnancy appeared to worsen these parameters.

CONCLUSIONS

Children in this cohort with a remote history of Pa infection had a higher proportion of CFTR genotypes associated with severely reduced CFTR function as well as lower lung function and more respiratory symptoms than those without prior Pa infection. These observed differences in respiratory indices may reflect the impact of prior Pa airway infection and/or of CFTR genotype or other genetic factors predisposing both to earlier Pa acquisition and more severe lung disease. Key characteristics associated with nutritional and pulmonary status at enrollment included diagnosis after prenatal or neonatal screening (protective) and in utero cigarette exposure (harmful).

Pseudomonas aeruginosa in children with cystic fibrosis diagnosed through newborn screening: assessment of clinic exposures and microbial genotypes

BACKGROUND

Chronic pulmonary infection with Pseudomonas aeruginosa (PA) is responsible for significant morbidity and mortality in cystic fibrosis (CF). Because of the limited studies evaluating early exposure and the progression of genetic variability of PA, our goal was to assess PA in young children with CF followed in two clinic types.

METHODS

A total of 39 infants with CF diagnosed through newborn screening were randomly assigned to either a segregated (PA-free) or mixed (PA-positive) clinic at two different CF centers, one of which replaced an older, mixed clinic where nosocomial acquisition was suspected. Oropharyngeal (OP) swab cultures were examined with subsequent genotyping to characterize the strains of PA isolated.

RESULTS

We found that 13/21 segregated clinic patients and 14/18 mixed clinic patients showed positive PA, with median acquisition ages of 3.3 and 2.2 years, respectively (P = 0.57). The median time to PA acquisition, however, was significantly longer in the new clinic with proper hygiene precautions compared to an old site (5.0 years vs. 1.7 years, P < 0.001). The majority of subjects isolated a single genotype of PA or AP-PCR types during the study period with eight subjects clearing the isolate after only one positive culture. The development of chronic colonization yielded the predominance of a single major genotype or AP-PCR type.

CONCLUSIONS

Segregation of infants and young children with CF in PA-negative or PA-positive clinics did not alter the time to first PA isolation in this randomized assessment of facilities with hygienic precautions. During the early infection period where PA is first isolated in young children with CF, patients cleared different PA strains until a predominant strain established permanent colonization.

Cystic Fibrosis Foundation evidence-based guidelines for management of infants with cystic fibrosis

Newborn screening for cystic fibrosis (CF) offers the opportunity for early medical and nutritional intervention that can lead to improved outcomes. Management of the asymptomatic infant diagnosed with CF through newborn screening, prenatal diagnosis, or sibling screening is different from treatment of the symptomatically diagnosed individual. The focus of management is on maintaining health by preventing nutritional and respiratory complications. The CF Foundation convened a committee to develop recommendations based on a systematic review of the evidence and expert opinion. These guidelines encompass monitoring and treatment recommendations for infants diagnosed with CF and are intended to help guide families, primary care providers, and specialty care centers in the care of infants with CF.

Management of infants with cystic fibrosis: a summary of the evidence for the cystic fibrosis foundation working group on care of infants with cystic fibrosis

OBJECTIVE

To inform the development of Cystic Fibrosis (CF) Foundation guidelines on the care of infants with CF, we systematically reviewed the evidence for diagnosis and assessment of pancreatic and pulmonary disorders; management of pancreatic and pulmonary function; management of nutrition and nutritional disorders; and prevention and control of infections.

STUDY DESIGN

In May-June 2008, we searched The Cochrane Library for existing reviews; and MEDLINE, the National Guideline Clearinghouse, the CF Foundation Clinical Practice Guidelines and Consensus Statements, and the UK CF Trust for existing guidelines. MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the Excerpta Medica Database (EMBASE) were searched for primary studies in January 2008. Bibliographies of eligible articles were searched and expert input was sought. We selected English-language articles of any study design that provided original data on any of our questions on infants up to 2 years of age.

RESULTS

We identified 14 relevant guidelines and 3 Cochrane reviews. Fifty-nine articles (55 primary studies) were included. Only four of these were randomized controlled trials. Sample sizes of infants ranged from 2 to 768 study participants; the median sample size was 24. Of our 21 review topics, 5 topics had only one study while for 5 we identified no relevant studies. We identified one or no primary studies for 20 of 32 review questions.

CONCLUSIONS

There is a paucity of evidence on the care of infants diagnosed with CF. For several of the review questions no guidelines or primary studies were identified, but for other questions, studies limited by weak design and small sample sizes were the only studies identified. With increasing numbers of infants with CF being diagnosed by newborn screening there is an opportunity to study the management of infants diagnosed with CF.

Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Lower respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis (CF). Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.

OBJECTIVES

To determine whether antibiotic treatment of early Pseudomonas aeruginosa infection in children and adults with CF eradicates the organism, improves clinical and microbiological outcome and is superior to or more cost-effective than other strategies.

SEARCH STRATEGY

We searched the Cochrane CF and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 11 December 2008.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of people with CF, in whom Pseudomonas aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo, usual treatment or other combinations of inhaled, oral or intravenous antibiotics. We excluded non-randomised trials, cross-over trials, and those utilising historical controls.

DATA COLLECTION AND ANALYSIS

Both authors independently selected trials, assessed methodological quality and extracted data.

MAIN RESULTS

The search identified 25 trials. Four trials (95 participants) were eligible for inclusion; two trials are ongoing. Evidence from two trials showed treatment of early Pseudomonas aeruginosa infection with inhaled tobramycin results in microbiological eradication of the organism from respiratory secretions more often than placebo, OR 0.15 (95% CI 0.03 to 0.65) and that this effect may persist for up to 12 months. These trials were of low methodological quality.The only identified RCT of oral ciprofloxacin and nebulised colistin versus usual treatment was of poor methodological quality. Results suggested treatment of early infection results in microbiological eradication of Pseudomonas aeruginosa more often than usual treatment, after two years, OR 0.24 (95% CI 0.06 to 0.96). There is insufficient evidence to determine whether antibiotic strategies for the eradication of early Pseudomonas aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment.

AUTHORS' CONCLUSIONS

We found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained in the short term. Overall, there is insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in CF.

Microbial interactions in the respiratory tract

Upper respiratory tract infections are caused by the synergistic and antagonistic interactions between upper respiratory tract viruses and 3 predominant bacterial pathogens: Streptococcus pneumoniae, nontypeable Haemophilus influenzae (NTHi), and Moraxella catarrhalis, which are members of the commensal flora of the nasopharynx. For many bacterial pathogens, colonization of host mucosal surfaces is a first and necessary step in the infectious process. S. pneumoniae and H. influenzae have intricate interactions in the nasopharynx. The host innate immune response may influence these interactions and therefore influence the composition of the colonizing flora and the invading bacteria. S. pneumoniae, nontypeable H. influenzae, and M. catarrhalis can behave as opportunistic pathogens of the middle ear when conditions are optimal. Chronic otitis media (OM) and recurrent OM include a biofilm component. Each of the 3 predominant pathogens of OM can form a biofilm and have been shown to comprise biofilms present on middle ear mucosa specimens recovered from children with recurrent or chronic OM. Some of these characterized biofilms are of mixed bacterial etiology, suggesting that progress made on single-microbe directed strategies for treatment and/or prevention of OM, although highly encouraging, are likely to be inadequate. A significantly greater understanding about microbial physiology is required as it relates to the involvement of biofilms in OM, to identify points in the natural course of the disease that are perhaps more amenable to treatment strategies, as well as to identify biofilm-relevant antigenic targets that would be helpful in the rational design of vaccines to prevent OM.

Immunization of young African green monkeys with OprF epitope 8-OprI-type A- and B-flagellin fusion proteins promotes the production of protective antibodies against nonmucoid Pseudomonas aeruginosa

There is currently no approved vaccine against Pseudomonas aeruginosa, the major cause of morbidity and mortality in cystic fibrosis (CF) patients and a major pathogen in ventilated and burn patients. In a previous study, we demonstrated the immunization of mice with OprF(311-341)-OprI-type A- and B-flagellin fusion proteins dramatically enhanced clearance of nonmucoid P. aeruginosa. The goal of the current study was to evaluate the ability of OprF(311-341)-OprI-flagellins to elicit the production of protective IgG in young (4-6 months old) African green monkeys. Intramuscular immunization of African green monkeys with 1, 3, 10, or 30mug of OprF(311-341)-OprI-flagellins generated robust antigen-specific IgG responses. In addition, immunization with OprF(311-341)-OprI-flagellins elicited high-affinity anti-flagellins, OprI, and OprF IgG that individually promoted extensive deposition of complement component C3 on P. aeruginosa and synergized to facilitate maximal C3 deposition. Passive immunization of mice with plasma from OprF(311-341)-OprI-flagellins immunized monkeys significantly reduced lung bacterial burden three days post-challenge compared to mice that received pre-immunization plasma. Based on our results, OprF(311-341)-OprI-A- and B-flagellin fusion proteins are highly effective in mice and nonhuman primates and thus merit additional development as a potential vaccine for use in humans.

Impact of Pseudomonas and Staphylococcus infection on inflammation and clinical status in young children with cystic fibrosis

OBJECTIVE

To assess the effects of Pseudomonas aeruginosa and Staphylococcus aureus infection on lower airway inflammation and clinical status in young children with cystic fibrosis (CF).

STUDY DESIGN

We studied 111 children age < 6 years who had 2 P aeruginosa-positive oropharyngeal cultures within 12 months. We examined bronchoalveolar lavage fluid (BALF) inflammatory markers (ie, cell count, differential, interleukin [IL]-8, IL-6, neutrophil elastase), CF-related bacterial pathogens, exotoxin A serology, and clinical indicators of disease severity.

RESULTS

Young children with CF with both upper and lower airway P aeruginosa infection had higher neutrophil counts, higher IL-8 and free neutrophil elastase levels, increased likelihood of positive exotoxin A titers, and lower Shwachman scores compared with those with positive upper airway cultures only. S aureus was associated with increased lower airway inflammation, and the presence of both P aeruginosa and S aureus had an additive effect on concentrations of lower airway inflammatory markers. BALF markers of inflammation were increased with the number of different bacterial pathogens detected.

CONCLUSIONS

Young children with CF who have upper and lower airway P aeruginosa infection have increased endobronchial inflammation and poorer clinical status compared with those with only upper airway P aeruginosa infection. The independent and additive effects of S aureus on inflammation support the significance of polymicrobial infection in early CF lung disease.

Nontypeable Haemophilus influenzae as a pathogen in children

Nontypeable Haemophilus influenzae is a significant pathogen in children, causing otitis media, sinusitis, conjunctivitis, pneumonia, and occasionally invasive infections. H. influenzae type b conjugate vaccines have no effect on infections caused by nontypeable strains because nontypeable strains are nonencapsulated. Approximately, one-third of episodes of otitis media are caused by nontypeable H. influenzae and the bacterium is the most common cause of recurrent otitis media. Recent progress in elucidating molecular mechanisms of pathogenesis, understanding the role of biofilms in otitis media and an increasing understanding of immune responses have potential for development of novel strategies to improve prevention and treatment of otitis media caused by nontypeable H. influenzae. Feasibility of vaccination for prevention of otitis media due to nontypeable H. influenzae was recently demonstrated in a clinical trial with a vaccine that included the surface virulence factor, protein D.

Clinical trials in infants with cystic fibrosis detected following newborn screening

Despite the wide implementation of newborn screening for cystic fibrosis there have been few clinical trials aimed at reducing the burden of lung disease in screened infants. Emerging tools such as infant lung function and low-dose computed tomography (CT) provide early indicators of lung disease and could be effective outcome measures in randomized controlled trials (RCTs) of interventions that aim to delay or prevent the onset of bronchiectasis. The most recent data suggest that strategies to reduce neutrophilic inflammation and prevent infection are good candidates for RCTs. However, cooperation between centres is needed if they are to be large enough to detect differences due to the intervention that otherwise may be masked by subtle differences in management practices between centres, and to detect rare but significant adverse effects.

Predictors of mucoid Pseudomonas colonization in cystic fibrosis patients

RATIONALE

Chronic mucoid Pseudomonas aeruginosa within the airway in cystic fibrosis (CF) patients can determine prognosis. Understanding the risk factors of mucoid P. aeruginosa acquisition may change how we deliver care. This study aims to evaluate whether presence of risk factors reported to predict disease severity including gender, CFTR genotype, bacterial organisms in airway cultures, and serum levels of vitamins A and E, albumin, C-reactive protein, alpha 1-antitrypsin, and immunoglobulins increased the risk of mucoid P. aeruginosa acquisition.

METHODS

Primary endpoint was age at first transition from negative to positive culture for mucoid P. aeruginosa. Cox proportional hazards regression with time-dependent covariates examined development of mucoid P. aeruginosa infection and its association with longitudinally measured serum biomarkers, pulmonary function, and culture results for other organisms.

RESULTS

Median ages at CF diagnosis and at first culture were 0.55 and 5.7 years, respectively. Median number of cultures/patient was 17. Of the 323 subjects, 150 developed mucoid P. aeruginosa during a median 8.1 years' follow-up. In multivariate analysis, gender (relative hazard [RH] 0.55 for male vs. female, P = 0.001), number of DF508 alleles (RH 1.66 for 1 or 2 vs. 0, P = 0.04), FEV(1) % (RH 1.16 for 10% decrease, P = 0.008), and most recent Staphylococcus aureus status (RH 0.24 for positive vs. negative, P < 0.0001) remained statistically significant.

CONCLUSION

Female gender, number of DF508 alleles, decreased lung function, and lack of S. aureus on recent sputum culture are important risk factors for early detection of mucoid P. aeruginosa.

Cutaneous manifestations of cystic fibrosis

Cystic fibrosis is an autosomal recessive disease reported in 1 in 2500 live births in Northern American and Northern European Caucasian populations. Classic disease findings include chronic bacterial infection of airways and sinuses, malabsorption of fat, infertility in men, and elevated concentrations of chloride in sweat. Less well-recognized findings associated with cystic fibrosis include cutaneous findings, which can be primary or secondary manifestations of the disease process. Patients demonstrate more atopic and drug hypersensitivity reactions than the general population, but have similar rates of urticaria compared with the general population. In atypical presentations of cystic fibrosis, the nutrient deficiency dermatitis of the disease may aid with diagnosis, and notably can be the presenting sign. Other dermatologic manifestations of cystic fibrosis include early aquagenic skin wrinkling and cutaneous vasculitis, which can be associated with arthralgias. Familiarity with the nutrient deficiency dermatitis of this entity may play a role in the timely diagnosis of the disease, and the other cutaneous findings add to our understanding of the protean nature of its manifestations.

Is newborn screening for cystic fibrosis a basic human right?

Because it is clearly in the best interests of children with cystic fibrosis to be diagnosed early at <2 months, which can only be achieved routinely by newborn screening, it can be argued that this should be a human right. However, if more harm than good is likely, or if regional "readiness" does not exist, newborn screening should be deferred.

The role of respiratory viruses in cystic fibrosis

Background

Previous studies have suggested a role played by respiratory viruses in the exacerbation of cystic fibrosis (CF). However, the impact of respiratory viruses could have been underestimated because of the low detection rate by conventional laboratory methods.

Methods

Children with CF had nasal swabs and sputum samples obtained on a routine basis and when they developed respiratory exacerbations. Nucleic Acid Sequence Based Amplification (NASBA) was used to detect respiratory viruses from nasal swabs. The definition of a respiratory exacerbation was when the symptom score totalled to 4 or more, or if the peak expiratory flow fell by more than 50 l/min from the child's usual best value, or if the parent subjectively felt that the child was developing a cold.

Results

71 patients had 165 reported episodes of respiratory exacerbations. 138 exacerbation samples were obtained of which 63 (46%) were positive for respiratory viruses. In contrast, 23 of 136 asymptomatic nasal swabs (16.9%) were positive for respiratory viruses. There was significantly more viruses being detected during respiratory exacerbations, in particular influenza A, influenza B and rhinovirus (p < 0.05).

Upper respiratory symptoms significantly correlated with positive respiratory viral detection (p < 0.05). This study also showed that viral respiratory exacerbations in CF could be independent from bacterial infections.

Conclusions

Respiratory viruses are associated with exacerbations in CF and upper respiratory symptoms are strong predictors for their presence. ‘Real-time’ NASBA has a rapid turn-around time and has the potential to aid clinical decision making, such as the use of anti-virals and administration of antibiotics.

Approaches to the Treatment of Initial Pseudomonas aeruginosa Infection in Children Who Have Cystic Fibrosis

Pseudomonas aeruginosa remains an important cause of pulmonary disease in patients who have cystic fibrosis. The development of antimicrobial therapy directed against this organism has resulted in the preservation of lung function and improved longevity. Efficacy has been demonstrated with agents administered via parenteral, inhaled, and oral routes. The optimal antibiotic regimen remains unclear. There is an active effort to use randomized, controlled clinical trials to rigorously test effective antibiotic for the eradication of P aeruginosa in young children or at least to delay the establishment of chronic infection.

Ten years of viral and non-bacterial serology in adults with cystic fibrosis

Viral infections are associated with pulmonary exacerbations in children with cystic fibrosis (CF), but few studies have addressed the frequency in adults. This paper investigates the frequency and impact of viral infections in adults with CF receiving intravenous antibiotics. Pre- and post-treatment spirometry, inflammatory markers and antibody titres against influenza A, influenza B, adenovirus, respiratory syncytial virus, Mycoplasma pneumoniae, Chlamydia psittaci, and Coxiella burnetti were analysed over a 10-year period. Non-bacterial infections were identified in 5.1% of 3156 courses of treatment. The annual incidence of admissions per patient associated with viral infection was 4.9%. The presence of viral infection in association with a pulmonary exacerbation did not adversely affect lung function or inflammatory markers in the short term. Adults with CF have a lower incidence of respiratory viral infections associated with pulmonary exacerbations requiring intravenous antibiotics compared to children and infants with CF.

Human metapneumovirus and respiratory syncytial virus infections in older children with cystic fibrosis

BACKGROUND

Human metapneumovirus (hMPV) has been isolated from children with acute respiratory infection worldwide. Its epidemiology remains to be defined in children with cystic fibrosis (CF). We describe the epidemiology and clinical impact of hMPV in CF children and compared it to respiratory syncytial virus (RSV).

METHODS

CF children ages 7-18 years were studied prospectively during the 1998 -1999 RSV season. Nasopharyngeal specimens were collected during acute respiratory illnesses and tested for respiratory viruses. Blood specimens were drawn early, mid, and end of the RSV season, and tested for serological evidence of hMPV and RSV infections. Rates of lower respiratory tract illnesses (LRTI) and hospitalizations for pulmonary exacerbations were compared during the time intervals they developed serological evidence of infection to their non-infection intervals.

RESULTS

Six of 44 CF children had a virus positive respiratory illness in 56 LTRI events and 18 hospitalizations. Serological evidence of hMPV and RSV infections occurred in 16 and 20 CF children, respectively; 8 had infections with both viruses. A greater proportion of CF children had >or=1 LRTI during their infection intervals compared to their non-infection intervals (13/25 vs. 5/25; P=0.03). A trend for higher rates of LRTI was observed in the infection intervals compared to non-infection intervals (9.5 +/- 11.0 vs. 4.2 +/- 9.9 per 1,000 child-days; P=0.06), and it was significantly greater with a more conservative estimate (one event per child per interval; 7.4 +/- 7.7 vs. 2.6 +/- 5.4 per 1,000 child-days; P <or=0.01). No differences in hospitalizations rates were detected.

CONCLUSION

The infection rates and clinical impact observed for hMPV were comparable to that for RSV in CF children 7-18 years of age.

Haemophilus influenzae forms biofilms on airway epithelia: implications in cystic fibrosis

RATIONALE

Nontypeable Haemophilus influenzae (NTHi) commonly infects patients with cystic fibrosis (CF), especially early in childhood. Bacteria biofilms are increasingly recognized as contributing to bacterial persistence and disease pathogenesis in CF.

OBJECTIVES

This study investigated ability of NTHi to form biofilms and its impact on airway epithelia using in vivo and in vitro analyses.

METHODS

We evaluated bronchoalveolar lavage fluid from young patients with CF for evidence of NTHi biofilms. To further investigate the pathogenesis of NTHi in respiratory infections, we developed a novel in vitro coculture model of NTHi biofilm formation on polarized human airway epithelial cells grown at the air-liquid interface.

MEASUREMENTS AND MAIN RESULTS

In bronchoalveolar lavage fluid samples from young, asymptomatic patients with CF, we found morphologic evidence suggestive of NTHi biofilm formation. In addition, 10 clinical NTHi isolates from patients with CF formed biofilms on plastic surfaces. NTHi formed biofilms on the apical surface of cultured airway epithelia. These biofilms exhibited decreased susceptibility to antibiotics and were adherent to epithelial surfaces. Airway epithelial cells remained viable throughout 4 d of coculture, and responded to NTHi with nuclear factor-kappaB signaling, and increased chemokine and cytokine secretion.

CONCLUSIONS

NTHi formed adherent biofilms on the apical surface airway epithelia with decreased susceptibility to antibiotics, and respiratory cells exhibited inflammatory and host defense responses-evidence of a dynamic host-pathogen interaction. The data presented here have implications both for understanding early CF lung disease pathogenesis and for the treatment of early, asymptomatic colonization of patients with CF with H. influenzae.

Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Lower respiratory tract infection with Pseudomonas aeruginosa (P. aeruginosa) occurs in most people with cystic fibrosis. Once chronic infection is established, P. aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.

OBJECTIVES

To determine whether antibiotic treatment of early P. aeruginosa infection in children and adults with cystic fibrosis eradicates the organism and improves clinical and microbiological outcome.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of most recent search: May 2004

SELECTION CRITERIA

We included randomised controlled trials of people with cystic fibrosis, in whom P. aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo or usual treatment (or both) or other combinations of inhaled, oral or intravenous antibiotics. We excluded non-randomised trials, cross-over trials, and those utilising historical controls.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed selected trials, assessed methodological quality and extracted data.

MAIN RESULTS

The search identified 15 trials. Three trials (69 participants) were eligible for inclusion. There is evidence from two randomised controlled trials, of questionable methodological quality, that treatment of early P. aeruginosa infection with inhaled tobramycin results in microbiological eradication of the organism from respiratory secretions more often than placebo and that this effect may persist for up to 12 months, however incomplete data from one of the trials precludes an accurate analysis. One randomised controlled trial of oral ciprofloxacin and nebulised colisitin versus usual treatment was identified. This trial was of poor methodological quality. The results suggested treatment of early infection results in microbiological eradication of P. aeruginosa more often than usual treatment, after two years, RR 0.24 (95% CI 0.06 to 0.96). There is insufficient evidence to determine whether antibiotic strategies for the eradication of early P. aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment.

AUTHORS' CONCLUSIONS

From the three trials included in this review, there is some evidence that antibiotic treatment of early P. aeruginosa results in short-term eradication but it remains uncertain whether there is clinical benefit to people with cystic fibrosis.

Antimicrobial therapy for pulmonary pathogenic colonisation and infection by Pseudomonas aeruginosa in cystic fibrosis patients

Pseudomonas aeruginosa colonisation has a negative effect on pulmonary function in cystic fibrosis patients. The organism can only be eradicated in the early stage of colonisation, while reduction of bacterial density is desirable during chronic colonisation or exacerbations. Monthly, or at least 3-monthly, microbiological culture is advisable for patients without previous evidence of P. aeruginosa colonisation. Cultures should be performed at least every 2-3 months in patients with well-established colonisation, and always during exacerbations or hospitalisations. Treatment of patients following the first isolation of P. aeruginosa, but with no clinical signs of colonisation, should be with oral ciprofloxacin (15-20 mg/kg twice-daily for 3-4 weeks) plus inhaled tobramycin or colistin (intravenous treatment with or without inhaled treatment can be used as an alternative), while patients with acute infection should be treated for 14-21 days with high doses of two intravenous antimicrobial agents, with or without an inhaled treatment during or at the end of the intravenous treatment. Maintenance treatment after development of chronic P. aeruginosa infection/colonisation (pathogenic colonisation) in stable patients (aged>6 years) should be with inhaled tobramycin (300 mg twice-daily) in 28-day cycles (on-off) or, as an alternative, colistin (1-3 million units twice-daily). Colistin is also a possible choice for patients aged<6 years. Treatment can be completed with oral ciprofloxacin (3-4 weeks every 3-4 months) for patients with mild pulmonary symptoms, or intravenously (every 3-4 months) for those with severe symptoms or isolates with ciprofloxacin resistance. Moderate and serious exacerbations can be treated with intravenous ceftazidime (50-70 mg/kg three-times-daily) or cefepime (50 mg/kg three-times-daily) plus tobramycin (5-10 mg/kg every 24 h) or amikacin (20-30 mg/kg every 24 h) for 2-3 weeks. Oral ciprofloxacin is recommended for patients with mild pulmonary disease. If multiresistant P. aeruginosa is isolated, antimicrobial agents that retain activity are recommended and epidemiological control measures should be established.

Evidence on improved outcomes with early diagnosis of cystic fibrosis through neonatal screening: enough is enough!

OBJECTIVE

To generate and examine evidence in support of diagnosing cystic fibrosis (CF) early through newborn screening (NBS).

STUDY DESIGN

Using a randomized controlled trial with unique unblinding/surveillance, we evaluated patients with CF receiving similar treatment after assignment to an early diagnosis (screened) group or to a control group. Outcomes studied at diagnosis and longitudinally included measures of nutritional status and lung disease.

RESULTS

Assessment of patients with CF without meconium ileus who had pancreatic insufficiency revealed marked differences in age and condition at diagnosis--screened patients had significantly better length/height, weight, and head circumference. Follow-up evaluation for 16 years showed that height and weight differences persisted long term. Although screened patients had better chest x-ray scores at diagnosis, our trial suggests that the effects of confounders such as Pseudomonas aeruginosa infections led to deterioration of their scores after 10 years, but there were no significant differences between the 2 CF/pancreatic insufficiency subgroups.

CONCLUSIONS

Early diagnosis of CF and aggressive nutritional management can prevent malnutrition and growth failure. Although CF NBS provides a potential opportunity for better pulmonary outcomes, it appears that other factors can predominate over time in pulmonary prognosis. Overall, the Wisconsin trial is positive and provides enough evidence for routine CF NBS.

Method for detection of respiratory viruses in the sputa of patients with cystic fibrosis

Since the role of respiratory viruses in lung exacerbations of patients with cystic fibrosis has been hampered by the difficulty of detecting viruses in viscous sputum specimens, a multiplex reverse transcriptase PCR (RT-PCR) assay combined with colorimetric amplicon detection was tested for the identification of seven common respiratory viruses in the sputa of cystic fibrosis patients. Of 52 sputa from 38 patients, 12 (23%) samples from 12 patients were positive for a respiratory virus (4 for influenza B, 3 for parainfluenza 1, 3 for influenza A and 2 for respiratory syncytial virus). These results suggest that the RT-PCR method carried out on sputum may provide a convenient means of investigating the role of virus infection in lung exacerbations of cystic fibrosis patients.

Immunoglobulin and IgG subclass levels in a regional pediatric cystic fibrosis clinic

The aim of this study was to report serum immunoglobulin (Ig) and IgG subclass levels in a large pediatric population with cystic fibrosis, and relate these to measures of disease severity. Total immunoglobulin levels were measured in 154 patients, and IgG subclass levels were measured in 136 patients and compared to age-related normal population data and to levels reported in previously published studies of children with cystic fibrosis. Clinical data were also collected: genotype; height, weight, and BMI standard deviation scores; FEV(1) (as percent predicted); Shwachmann-Kulczycki (S-K) and Northern chest X-ray scores; and Pseudomonas aeruginosa infection status. The clinical well-being of patients with hypo- or hyper-gammaglobulinemia was compared with age- and sex-matched control patients who had normal levels of gammaglobulin. IgG subclass levels were measured, and the results were compared with previous studies. Eleven patients had hypergammaglobulinemia (7.8% compared with 0-69% in the published literature). Patients with hypergammaglobulinemia had lower FEV(1) percent-predicted values, and worse S-K and Northern chest X-ray scores than controls. Three patients had hypogammaglobulinemia (1.9% compared with 0-10.8% in the published literature). There was no difference in any clinical parameter between controls and those with hypogammaglobulinemia. Nineteen patients (14%) had low levels of IgG1, and 40 patients (29%) had low levels of IgG2. The low percentage of patients with abnormally high immunoglobulin levels probably reflects the improved respiratory status of today's children with CF. The low percentage of those with low IgG probably reflects better nutritional status. The finding of worse lung function and clinical scores in patients with hypergammaglobulinemia agrees with the published literature. The high percentage of patients with low IgG2 was unexpected and was not previously reported. The clinical significance of this in patients with CF is unknown.

Type III secretion phenotypes of Pseudomonas aeruginosa strains change during infection of individuals with cystic fibrosis

Pseudomonas aeruginosa is a frequent cause of respiratory exacerbations in individuals with cystic fibrosis. An important virulence determinant of this pathogen is its type III protein secretion system. In this study, the type III secretion properties of 435 P. aeruginosa respiratory isolates from 56 chronically infected individuals with cystic fibrosis were investigated. Although it had been previously reported that 75 to 90% of P. aeruginosa isolates from patients with hospital-acquired pneumonia secreted type III proteins, only 12% of isolates from cystic fibrosis patients did so, with nearly all of these isolates secreting ExoS and ExoT but not ExoU. Despite the low overall prevalence of type III protein-secreting isolates, at least one secreting isolate was cultured from one-third of cystic fibrosis patients. Interestingly, the fraction of cystic fibrosis patient isolates capable of secreting type III proteins decreased with duration of infection. Although 90% of isolates from the environment, the presumed reservoir for the majority of P. aeruginosa strains that infect patients with cystic fibrosis, secreted type III proteins, only 49% of isolates from newly infected children, 18% of isolates from chronically infected children, and 4% of isolates from chronically infected adults with cystic fibrosis secreted these proteins. Within individual patients, isolates of clonal origin differed in their secretion phenotypes, indicating that as strains persisted in cystic fibrosis patient airways, their type III protein secretion properties changed. Together, these findings indicate that following infection of cystic fibrosis patient airways, P. aeruginosa strains gradually change from a type III protein secretion-positive phenotype to a secretion-negative phenotype.

DNase in stable cystic fibrosis infants: a pilot study

OBJECTIVE

To assess the feasibility of measuring short-term effects of inhaled recombinant human deoxyribonuclease (rhDNase, Pulmozyme on lung function, pulse oximetry and symptom scores in infants and toddlers with stable cystic fibrosis.

DESIGN

open-label randomized placebo controlled cross-over pilot study.

PATIENTS AND METHODS

We treated nine CF patients (0.7-1.9 years) with nebulised rhDNase (2.5 mg) and NaCl 0.9% (10 ml) via jet nebulizer cross-over once daily during 2-week treatment blocks. Measurements were performed at baseline and after treatment blocks and consisted of lung function tests (plethysmography and tidal rapid thoraco-abdominal compression technique), overnight pulse oximetry, and daily symptom scores.

RESULTS

DNase treatment and the different assessments were well tolerated by all children and their parents. Lung function showed increased airway patency after treatment with rhDNase (P < 0.001), but not after NaCl 0.9%. Overnight pulse oximetry and daily symptom scores did not change during the study period.

CONCLUSIONS

This pilot study indicates that objective assessment of the effects of rhDNase is feasible in infants with CF who have little or no respiratory symptoms. Our results warrant a larger randomized placebo-controlled trial.

Pseudomonal infection in cystic fibrosis: the battle continues

Pseudomonas aeruginosa lung infection is the major cause of morbidity and mortality in patients with cystic fibrosis. Infection usually begins in childhood and is responsible for respiratory failure and death in most patients with cystic fibrosis. The organism triggers an exuberant chronic inflammatory reaction which damages the airways and leads to progressive loss of lung function. Over the last decade significant advances have been made in the understanding of the pathophysiology of cystic fibrosis airways disease. These should assist the development of new and better therapies to treat this pathogen. This review provides an overview of pseudomonal infection in cystic fibrosis, including mechanisms by which the bacteria may colonize the cystic fibrosis airway, persistence of pseudomonal infection and the biofilm mode of growth. Available treatments and possible novel approaches to therapy will be discussed.

Microbiology of early CF lung disease

Recent bronchoscopy studies using assays to measure inflammation and molecular typing techniques have facilitated an increased understanding of the early events that occur within the lungs of young children with cystic fibrosis and provided additional insights into the natural history of lung disease in children. In 2000, the US CF National Patient Registry data showed that among 1000 infants <2 years of age, the first bacterial pathogens detected are Haemophilus influenzae, Staphylococcus aureus, and Pseudomonas aeruginosa and the prevalence of these pathogens in these young infants are 19%, 42%, and 29%, respectively. In addition, 7% harbour Stenotrophomonas maltophilia and <1% harbour Burkholderia cepacia complex. Several investigators have performed bronchoscopy studies on young infants to further examine the natural history of lung disease. In one such study of 40 CF infants, 65%, 63% and 70% of children at 1, 2, and 3 years of age harboured at least one CF pathogen. H. influenzae was most common (38%) in infants at 1 year of age, and S. aureus was most common in 2 (37%) and 3 (36%) year olds. P. aeruginosa increased from 18% at 1 year of age to 33% at 3 years of age and was usually present in high numbers, i.e., > or =10(5) CFU/ml of BAL fluid. Investigators have studied the microbiology of young CF infants using specimens derived from the upper airway (deep throat) compared with the lower airway (broncheoalveolar lavage specimens) to determine if the upper airway is predictive of pathogens in the lower airway. In general, these studies have shown that a negative oropharyngeal culture indicated that isolation of P. aeruginosa from the lower airway was unlikely, but a positive culture did not predict lower airway infection. Similar findings were noted for H. influenzae and S. aureus.