Pulmonary function in infants with cystic fibrosis: the effect of antibiotic treatment

Prophylactic anti-staphylococcal antibiotics for cystic fibrosis

BACKGROUND

Staphylococcus aureus causes pulmonary infection in young children with cystic fibrosis. Prophylactic antibiotics are prescribed hoping to prevent such infection and lung damage. Antibiotics have adverse effects and long-term use might lead to infection with Pseudomonas aeruginosa. This is an update of a previously published review.

OBJECTIVES

To assess continuous oral antibiotic prophylaxis to prevent the acquisition of Staphylococcus aureus versus no prophylaxis in people with cystic fibrosis, we tested the following hypotheses to investigate whether prophylaxis: 1. improves clinical status, lung function and survival; 2. leads to fewer isolates of Staphylococcus aureus; 3. causes adverse effects (e.g. diarrhoea, skin rash, candidiasis); 4. leads to fewer isolates of other common pathogens from respiratory secretions; 5. leads to the emergence of antibiotic resistance and colonisation of the respiratory tract with Pseudomonas aeruginosa.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Companies manufacturing anti-staphylococcal antibiotics were contacted. Most recent search of the Group's Register: 27 February 2020. Online trials registries were also searched. Most recent search of online trials registries: 15 September 2020.

SELECTION CRITERIA

Randomised trials of continuous oral prophylactic antibiotics (given for at least one year) compared to intermittent antibiotics given 'as required', in people with cystic fibrosis of any disease severity.

DATA COLLECTION AND ANALYSIS

The authors assessed studies for eligibility and methodological quality and extracted data. The quality of the evidence was assessed using the GRADE criteria. The review's primary outcomes of interest were lung function by spirometry (forced expiratory volume in one second (FEV₁)) and the number of people with one or more isolates of Staphylococcus aureus (sensitive strains).

MAIN RESULTS

We included four studies, with a total of 401 randomised participants aged zero to seven years on enrolment; one study is ongoing. The two older included studies generally had a higher risk of bias across all domains, but in particular due to a lack of blinding and incomplete outcome data, than the two more recent studies. We only regarded the most recent study as being generally free of bias, although even here we were not certain of the effect of the per protocol analysis on the study results. Evidence quality was judged to be low for all outcomes assessed after being downgraded based on GRADE assessments. Downgrading decisions were due to limitations in study design (all outcomes), for imprecision and for inconsistency . Prophylactic anti-staphylococcal antibiotics probably make little or no difference to lung function measured as FEV₁ % predicted after six years (mean difference (MD) -2.30, 95% confidence interval (CI) -13.59 to 8.99, one study, n = 119, low-quality evidence); but may reduce the number of children having one or more isolates of Staphylococcus aureus at two years (odds ratio (OR) 0.21, 95% CI 0.13 to 0.35, three studies, n = 315, low-quality evidence). At the same time point, there may be little or no effect on nutrition as reported using weight z score (MD 0.06, 95% CI -0.33 to 0.45, two studies, n = 140, low-quality evidence), additional courses of antibiotics (OR 0.18, 95% CI 0.01 to 3.60, one study, n = 119, low-quality evidence) or adverse effects (low-quality evidence). There was no difference in the number of isolates of Pseudomonas aeruginosa between groups at two years (OR 0.74, 95% CI 0.45 to 1.23, three studies, n = 312, low-quality evidence), though there was a trend towards a lower cumulative isolation rate of Pseudomonas aeruginosa in the prophylaxis group at two and three years and towards a higher rate from four to six years. As the studies reviewed lasted six years or less, conclusions cannot be drawn about the long-term effects of prophylaxis.

AUTHORS' CONCLUSIONS

Anti-staphylococcal antibiotic prophylaxis may lead to fewer children having isolates of Staphylococcus aureus, when commenced early in infancy and continued up to six years of age. The clinical importance of this finding is uncertain. Further research may establish whether the trend towards more children with CF with Pseudomonas aeruginosa, after four to six years of prophylaxis, is a chance finding and whether choice of antibiotic or duration of treatment might influence this.

The association between Staphylococcus aureus and subsequent bronchiectasis in children with cystic fibrosis

BACKGROUND

Staphylococcus aureus (S. aureus) may be related to more rapid progression of cystic fibrosis (CF) lung disease.

METHODS

In the AREST CF cohort study, children diagnosed with CF undergo annual bronchoscopies with bronchoalveolar lavage and ultra-low-dose, chest computed tomography (CT) up to 6-years-old. Spirometry was assessed 3-monthly from the age of 4years. Associations between de novo S. aureus acquisition before school age and CT and lung function at ages 5-7years were investigated. Models were adjusted for multiple markers of disease severity at baseline.

RESULTS

De novo S. aureus acquisition at 3-years-old (n/N=12/122) was associated with increased bronchiectasis score at age 5-6years. This association decreased but remained significant after adjustment for confounders. S. aureus at 3 was associated with significantly reduced FEF_25-75 at age 5-7years, but not with FEV₁-%-predicted.

CONCLUSION

De novo S. aureus acquisition at age 3 is associated with later bronchiectasis and FEF_25-75 in children with CF.

Prophylactic anti-staphylococcal antibiotics for cystic fibrosis

BACKGROUND

Staphylococcus aureus causes pulmonary infection in young children with cystic fibrosis. Prophylactic antibiotics are prescribed hoping to prevent such infection and lung damage. Antibiotics have adverse effects and long-term use might lead to infection with Pseudomonas aeruginosa. This is an update of a previously published review.

OBJECTIVES

To assess continuous oral antibiotic prophylaxis to prevent the acquisition of Staphylococcus aureus versus no prophylaxis in people with cystic fibrosis, we tested these hypotheses. Prophylaxis:1. improves clinical status, lung function and survival;2. causes adverse effects (e.g. diarrhoea, skin rash, candidiasis);3. leads to fewer isolates of common pathogens from respiratory secretions;4. leads to the emergence of antibiotic resistance and colonisation of the respiratory tract with Pseudomonas aeruginosa.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Companies manufacturing anti-staphylococcal antibiotics were contacted.Most recent search of the Group's Register: 29 September 2016.

SELECTION CRITERIA

Randomised trials of continuous oral prophylactic antibiotics (given for at least one year) compared to intermittent antibiotics given 'as required', in people with cystic fibrosis of any disease severity.

DATA COLLECTION AND ANALYSIS

The authors assessed studies for eligibility and methodological quality and extracted data.

MAIN RESULTS

We included four studies, with a total of 401 randomised participants aged zero to seven years on enrolment; one study is ongoing. The two older included studies generally had a higher risk of bias across all domains, but in particular due to a lack of blinding and incomplete outcome data, than the two more recent studies. We only regarded the most recent study as being generally free of bias, although even here we were not certain of the effect of the per protocol analysis on the study results. Evidence was downgraded based on GRADE assessments and outcome results ranged from moderate to low quality. Downgrading decisions were due to limitations in study design (all outcomes); for imprecision (number of people needing additional antibiotics); and for inconsistency (weight z score).Fewer children receiving anti-staphylococcal antibiotic prophylaxis had one or more isolates of Staphylococcus aureus (low quality evidence). There was no significant difference between groups in infant or conventional lung function (moderate quality evidence). We found no significant effect on nutrition (low quality evidence), hospital admissions, additional courses of antibiotics (low quality evidence) or adverse effects (moderate quality evidence). There was no significant difference in the number of isolates of Pseudomonas aeruginosa between groups (low quality evidence), though there was a trend towards a lower cumulative isolation rate of Pseudomonas aeruginosa in the prophylaxis group at two and three years and towards a higher rate from four to six years. As the studies reviewed lasted six years or less, conclusions cannot be drawn about the long-term effects of prophylaxis.

AUTHORS' CONCLUSIONS

Anti-staphylococcal antibiotic prophylaxis leads to fewer children having isolates of Staphylococcus aureus, when commenced early in infancy and continued up to six years of age. The clinical importance of this finding is uncertain. Further research may establish whether the trend towards more children with CF with Pseudomonas aeruginosa, after four to six years of prophylaxis, is a chance finding and whether choice of antibiotic or duration of treatment might influence this.

Management of Pulmonary Disease in Patients with Cystic Fibrosis

Cystic fibrosis is the most common, life-shortening autosomal recessive disease, affecting approximately 1 in 3400 live births in the United States. Gastrointestinal and pulmonary manifestations are most common. With the introduction of pancreatic enzyme and vitamin supplementation, lung disease accounts for the vast majority of morbidity and mortality in patients with cystic fibrosis. The lungs of cystic fibrosis patients are essentially normal at birth but demonstrate evidence of airway inflammation and infection in early infancy. A vicious cycle of inflammation, infection and obstruction ultimately leads to destruction of airways, impairment of gas exchange and death.

Current pharmacological management of pulmonary disease targets reducing airway obstruction, controlling infection and more recently, controlling inflammation. An increased recovery of unusual and highly resistant bacteria from patients with more advanced disease has been observed. Aggressive treatment of acute pulmonary exacerbations with combination antibiotic therapy for two to three weeks has shown pronounced beneficial effects. The routine use of prophylactic antistaphylococcal antibiotics is still controversial.

Although current pharmacologic treatment is symptomatic, new agents are being developed and studied that target the underlying defect in the CFTR protein. This review focuses on current pharmacologic management of pulmonary disease in patients with cystic fibrosis and the role of new agents emerging for the treatment of this disease.

Oral anti-pseudomonal antibiotics for cystic fibrosis

BACKGROUND

Pseudomonas aeruginosa is the most common bacterial pathogen causing lung infections in people with cystic fibrosis and appropriate antibiotic therapy is vital. Antibiotics for pulmonary exacerbations are usually given intravenously, and for long-term treatment, via a nebuliser. Oral anti-pseudomonal antibiotics with the same efficacy and safety as intravenous or nebulised antibiotics would benefit people with cystic fibrosis due to ease of treatment and avoidance of hospitalisation. This is an update of a previous review.

OBJECTIVES

To determine the benefit or harm of oral anti-pseudomonal antibiotic therapy for people with cystic fibrosis, colonised with Pseudomonas aeruginosa, in the:1. treatment of a pulmonary exacerbation; and2. long-term treatment of chronic infection.

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.We contacted pharmaceutical companies and checked reference lists of identified trials.Date of last search: 08 July 2016.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing any dose of oral anti-pseudomonal antibiotics, to other combinations of inhaled, oral or intravenous antibiotics, or to placebo or usual treatment for pulmonary exacerbations and long-term treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials, extracted data and assessed quality. We contacted trial authors to obtain missing information.

MAIN RESULTS

We included three trials examining pulmonary exacerbations (171 participants) and two trials examining long-term therapy (85 participants). We regarded the most important outcomes as quality of life and lung function. The analysis did not identify any statistically significant difference between oral anti-pseudomonal antibiotics and other treatments for these outcome measures for either pulmonary exacerbations or long-term treatment. One of the included trials reported significantly better lung function when treating a pulmonary exacerbation with ciprofloxacin when compared with intravenous treatment; however, our analysis did not confirm this finding. We found no evidence of difference between oral anti-pseudomonal antibiotics and other treatments regarding adverse events or development of antibiotic resistance, but trials were not adequately powered to detect this. None of the studies had a low risk of bias from blinding which may have an impact particularly on subjective outcomes such as quality of life. The risk of bias for other criteria could not be clearly stated across the studies.

AUTHORS' CONCLUSIONS

We found no conclusive evidence that an oral anti-pseudomonal antibiotic regimen is more or less effective than an alternative treatment for either pulmonary exacerbations or long-term treatment of chronic infection with P. aeruginosa. Until results of adequately-powered future trials are available, treatment needs to be selected on a pragmatic basis, based upon any available non-randomised evidence, the clinical circumstances of the individual, the known effectiveness of drugs against local strains and upon individual preference.

Clinical outcomes associated with Staphylococcus aureus and Pseudomonas aeruginosa airway infections in adult cystic fibrosis patients

BACKGROUND

Staphylococcus aureus (SA) is the most prevalent organism infecting the respiratory tract of CF children, and remains the second most prevalent organism in CF adults. During early childhood, SA infections are associated with pulmonary inflammation and decline in FEV1, but their clinical significance in adult CF patients is poorly characterized.

METHODS

We conducted a retrospective cross-sectional study to determine the association between airway microbiology and clinical outcomes (FEV1, rate of pulmonary exacerbations, CRP levels and clinical scores).

RESULTS

In a cohort of 84 adult CF patients, 24 % were infected with SA only, 60 % were infected with PA, and 16 % had neither PA nor SA. CF patients with SA experienced fewer pulmonary exacerbations and lower CRP levels than those with PA.

CONCLUSION

In adult CF patients, SA infections alone, in the absence of PA, are a marker of milder disease.

Prophylactic anti-staphylococcal antibiotics for cystic fibrosis

BACKGROUND

Staphylococcus aureus causes pulmonary infection in young children with cystic fibrosis. Prophylactic antibiotics are prescribed hoping to prevent such infection and lung damage. Antibiotics have adverse effects and long-term use might lead to infection with Pseudomonas aeruginosa.

OBJECTIVES

To assess continuous oral antibiotic prophylaxis to prevent the acquisition of Staphylococcus aureus versus no prophylaxis in people with cystic fibrosis, we tested these hypotheses. Prophylaxis:1. improves clinical status, lung function and survival;2. causes adverse effects (e.g. diarrhoea, skin rash, candidiasis);3. leads to fewer isolates of common pathogens from respiratory secretions;4. leads to the emergence of antibiotic resistance and colonisation of the respiratory tract with Pseudomonas aeruginosa.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Companies manufacturing anti-staphylococcal antibiotics were contacted.Most recent search of Register: 04 September 2014.

SELECTION CRITERIA

Randomised trials of continuous oral prophylactic antibiotics (given for at least one year) compared to intermittent antibiotics given 'as required', in people with cystic fibrosis of any disease severity.

DATA COLLECTION AND ANALYSIS

The authors assessed studies for eligibility and methodological quality and extracted data.

MAIN RESULTS

We included four studies, totaling 401 randomised participants aged zero to seven years on enrolment. The two older studies generally had a higher risk of bias across all domains, but in particular due to a lack of blinding and incomplete outcome data, than the two more recent studies. We only regarded the most recent study as being generally free of bias, although even here we were not certain of the effect of the per protocol analysis on the study results.Fewer children receiving anti-staphylococcal antibiotic prophylaxis had one or more isolates of Staphylococcus aureus. There was no significant difference between groups in infant or conventional lung function. We found no significant effect on nutrition, hospital admissions, additional courses of antibiotics or adverse effects. There was no significant difference in the number of isolates of Pseudomonas aeruginosa between groups, though there was a trend towards a lower cumulative isolation rate of Pseudomonas aeruginosa in the prophylaxis group at two and three years and towards a higher rate from four to six years. As the studies reviewed lasted six years or less, conclusions cannot be drawn about the long-term effects of prophylaxis.

AUTHORS' CONCLUSIONS

Anti-staphylococcal antibiotic prophylaxis leads to fewer children having isolates of Staphylococcus aureus, when commenced early in infancy and continued up to six years of age. The clinical importance of this finding is uncertain. Further research may establish whether the trend towards more children with CF with Pseudomonas aeruginosa, after four to six years of prophylaxis, is a chance finding and whether choice of antibiotic or duration of treatment might influence this.

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.

An official American Thoracic Society workshop report: optimal lung function tests for monitoring cystic fibrosis, bronchopulmonary dysplasia, and recurrent wheezing in children less than 6 years of age

Although pulmonary function testing plays a key role in the diagnosis and management of chronic pulmonary conditions in children under 6 years of age, objective physiologic assessment is limited in the clinical care of infants and children less than 6 years old, due to the challenges of measuring lung function in this age range. Ongoing research in lung function testing in infants, toddlers, and preschoolers has resulted in techniques that show promise as safe, feasible, and potentially clinically useful tests. Official American Thoracic Society workshops were convened in 2009 and 2010 to review six lung function tests based on a comprehensive review of the literature (infant raised-volume rapid thoracic compression and plethysmography, preschool spirometry, specific airway resistance, forced oscillation, the interrupter technique, and multiple-breath washout). In these proceedings, the current state of the art for each of these tests is reviewed as it applies to the clinical management of infants and children under 6 years of age with cystic fibrosis, bronchopulmonary dysplasia, and recurrent wheeze, using a standardized format that allows easy comparison between the measures. Although insufficient evidence exists to recommend incorporation of these tests into the routine diagnostic evaluation and clinical monitoring of infants and young children with cystic fibrosis, bronchopulmonary dysplasia, or recurrent wheeze, they may be valuable tools with which to address specific concerns, such as ongoing symptoms or monitoring response to treatment, and as outcome measures in clinical research studies.

Oral anti-pseudomonal antibiotics for cystic fibrosis

BACKGROUND

Pseudomonas aeruginosa is the most common bacterial pathogen causing lung infections in people with CF and appropriate antibiotic therapy is vital. Antibiotics for pulmonary exacerbations are usually given intravenously, and for long-term treatment, via a nebuliser. Oral anti-pseudomonal antibiotics with the same efficacy and safety as intravenous or nebulised antibiotics would benefit people with CF due to ease of treatment and avoidance of hospitalisation.

OBJECTIVES

To determine the benefit or harm of oral anti-pseudomonal antibiotic therapy for people with CF, colonised with Pseudomonas aeruginosa, in the:1. treatment of a pulmonary exacerbation; and 2. long-term treatment of chronic infection.

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.We contacted pharmaceutical companies and checked reference lists of identified trials.Date of last search: 28 June 2013.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing any dose of oral anti-pseudomonal antibiotics, to other combinations of inhaled, oral or intravenous antibiotics, or to placebo or usual treatment for pulmonary exacerbations and long-term treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials, extracted data and assessed quality. We contacted trial authors to obtain missing information.

MAIN RESULTS

We included three trials examining pulmonary exacerbations (171 participants) and two trials examining long-term therapy (85 participants). We regarded the most important outcomes as quality of life and lung function. The analysis did not identify any statistically significant difference between oral anti-pseudomonal antibiotics and other treatments for these outcome measures for either pulmonary exacerbations or long-term treatment. One of the included trials reported significantly better lung function when treating a pulmonary exacerbation with ciprofloxacin when compared with intravenous treatment; however, our analysis did not confirm this finding. We found no evidence of difference between oral anti-pseudomonal antibiotics and other treatments regarding adverse events or development of antibiotic resistance, but trials were not adequately powered to detect this. None of the studies had a low risk of bias from blinding which may have an impact particularly on subjective outcomes such as quality of life. The risk of bias for other criteria could not be clearly stated across the studies.

AUTHORS' CONCLUSIONS

We found no conclusive evidence that an oral anti-pseudomonal antibiotic regimen is more or less effective than an alternative treatment for either pulmonary exacerbations or long-term treatment of chronic infection with P. aeruginosa. Until results of adequately-powered future trials are available, treatment needs to be selected on a pragmatic basis, based upon any available non-RCT evidence, the clinical circumstances of the individual, the known effectiveness of drugs against local strains and upon individual preference.

Novel end points for clinical trials in young children with cystic fibrosis

Cystic fibrosis (CF) lung disease commences early in the disease progression and is the most common cause of mortality. While new CF disease-modifying agents are currently undergoing clinical trial evaluation, the implementation of such trials in young children is limited by the lack of age-appropriate clinical trial end points. Advances in infant and preschool lung function testing, imaging of the chest and the development of biochemical biomarkers have led to increased possibility of quantifying mild lung disease in young children with CF and objectively monitoring disease progression over the course of an intervention. Despite this, further standardization and development of these techniques is required to provide robust objective measures for clinical trials in this age group.

Prophylactic anti-staphylococcal antibiotics for cystic fibrosis

BACKGROUND

Staphylococcus aureus causes pulmonary infection in young children with cystic fibrosis (CF). Prophylactic antibiotics are prescribed hoping to prevent such infection and lung damage. Antibiotics have adverse effects and long-term use might lead to infection with Pseudomonas aeruginosa.

OBJECTIVES

To assess continuous oral antibiotic prophylaxis to prevent the acquisition of Staphylococcus aureus versus no prophylaxis in people with CF, we tested these hypotheses. Prophylaxis: 1. improves clinical status, lung function and survival; 2. causes adverse effects (eg diarrhoea, skin rash, candidiasis); 3. leads to fewer isolates of common pathogens from respiratory secretions; 4. leads to the emergence of antibiotic resistance and colonisation of the respiratory tract with Pseudomonas aeruginosa.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Companies manufacturing anti-staphylococcal antibiotics were contacted.Most recent search of Register: 02 August 2012.

SELECTION CRITERIA

Randomised trials of continuous oral prophylactic antibiotics (given for at least one year) compared to intermittent antibiotics given 'as required', in people with CF of any disease severity.

DATA COLLECTION AND ANALYSIS

The authors assessed studies for eligibility and methodological quality and extracted data.

MAIN RESULTS

We included four studies, totaling 401 randomised participants aged zero to seven years on enrolment. Fewer children receiving anti-staphylococcal antibiotic prophylaxis had one or more isolates of Staphylococcus aureus. There was no significant difference between groups in infant or conventional lung function. We found no significant effect on nutrition, hospital admissions, additional courses of antibiotics or adverse effects. There was no significant difference in the number of isolates of Pseudomonas aeruginosa between groups, though there was a trend towards a lower cumulative isolation rate of Pseudomonas aeruginosa in the prophylaxis group at two and three years and towards a higher rate from four to six years. As the studies reviewed lasted six years or less, conclusions cannot be drawn about the long-term effects of prophylaxis.

AUTHORS' CONCLUSIONS

Anti-staphylococcal antibiotic prophylaxis leads to fewer children having isolates of Staphylococcus aureus, when commenced early in infancy and continued up to six years of age. The clinical importance of this finding is uncertain. Further research may establish whether the trend towards more children with CF with Pseudomonas aeruginosa, after four to six years of prophylaxis, is a chance finding and whether choice of antibiotic or duration of treatment might influence this.

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.

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.

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.

Cystic fibrosis pulmonary guidelines: chronic medications for maintenance of lung health

RATIONALE

Cystic fibrosis is a recessive genetic disease characterized by dehydration of the airway surface liquid and impaired mucociliary clearance. As a result, individuals with the disease have difficulty clearing pathogens from the lung and experience chronic pulmonary infections and inflammation. Death is usually a result of respiratory failure. Newly introduced therapies and aggressive management of the lung disease have resulted in great improvements in length and quality of life, with the result that the median expected survival age has reached 36 years. However, as the number of treatments expands, the medical regimen becomes increasingly burdensome in time, money, and health resources. Hence, it is important that treatments should be recommended on the basis of available evidence of efficacy and safety.

OBJECTIVES

The Cystic Fibrosis Foundation therefore established a committee to examine the clinical evidence for each therapy and to provide guidance for the prescription of these therapies.

METHODS

The committee members developed and refined a series of questions related to drug therapies used in the maintenance of pulmonary function. We addressed the questions in one of three ways, based on available evidence: (1) commissioned systematic review, (2) modified systematic review, or (3) summary of existing Cochrane reviews.

CONCLUSIONS

It is hoped that the guidelines provided in this article will facilitate the appropriate application of these treatments to improve and extend the lives of all individuals with cystic fibrosis.

Oral anti-pseudomonal antibiotics for cystic fibrosis

BACKGROUND

Pseudomonas aeruginosa is the most common bacterial pathogen causing infection in the lungs of people with CF and appropriate antibiotic therapy is vital. Antibiotics for exacerbations are usually given intravenously, and for long-term treatment, via a nebuliser. Oral anti-pseudomonal antibiotics with the same efficacy and safety as intravenous or nebulised antibiotics would benefit the quality of life of people with CF due to ease of treatment and avoidance of hospitalisation.

OBJECTIVES

To determine the benefit or harm of oral anti-pseudomonal antibiotic therapy for people with CF, colonised with Pseudomonas aeruginosa, in the: (1) treatment of an exacerbation of respiratory tract infection; and (2) long-term treatment in chronic infection.

SEARCH STRATEGY

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. We contacted pharmaceutical companies for information on relevant trials and checked reference lists of identified trials. Most recent search: March 2007.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing any dose of oral anti-pseudomonal antibiotics, with other combinations of inhaled, oral or intravenous antibiotics, or with placebo or usual treatment for exacerbations and long-term treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials, extracted data and assessed quality. We contacted trialists to obtain missing information.

MAIN RESULTS

We included four trials examining exacerbations (197 participants) and two trials examining long-term therapy (85 participants). We regarded the most important outcomes as quality of life and lung function. In our analysis, we were unable to identify any statistically significant difference between oral anti-pseudomonal antibiotics and other treatments for these outcome measures for either exacerbations or long-term treatment. One of the included trials reported significantly better lung function when treating an exacerbation with ciprofloxacin when compared with intravenous treatment; however, our analysis did not confirm this finding. We found no evidence of difference between oral anti-pseudomonal antibiotics and other treatments regarding adverse events or development of antibiotic resistance, but trials were not adequately powered to detect this.

AUTHORS' CONCLUSIONS

We found no conclusive evidence that an oral anti-pseudomonal antibiotic regimen is more or less effective than an alternative treatment for either exacerbations or long-term treatment of chronic infection with P. aeruginosa. Until results of adequately-powered future trials are available, treatment needs to be selected on a pragmatic basis, based upon known effectiveness against local strains and upon individual preference.

Early detection of cystic fibrosis lung disease: multiple-breath washout versus raised volume tests

BACKGROUND

Lung clearance index (LCI), a measure of ventilation inhomogeneity derived from the multiple-breath inert gas washout (MBW) technique, has been shown to detect abnormal lung function more readily than spirometry in preschool children with cystic fibrosis, but whether this holds true during infancy is unknown.

OBJECTIVES

To compare the extent to which parameters derived from the MBW and the raised lung volume rapid thoraco-abdominal compression (RVRTC) techniques identify diminished airway function in infants with cystic fibrosis when compared with healthy controls.

METHODS

Measurements were performed during quiet sleep, with the tidal breathing MBW technique being performed before the forced expiratory manoeuvres.

RESULTS

Measurements were obtained in 39 infants with cystic fibrosis (mean (SD) age 41.4 (22.0) weeks) and 21 controls (37.0 (15.1) weeks). Infants with cystic fibrosis had a significantly higher respiratory rate (38 (10) vs 32 (5) bpm) and LCI (8.4 (1.5) vs 7.2 (0.3)), and significantly lower values for all forced expiratory flow-volume parameters compared with controls. Girls with cystic fibrosis had significantly lower forced expiratory volume (FEV(0.5) and FEF(25-75 )) than boys (mean (95% CI girls-boys): -1.2 (-2.1 to -0.3) for FEV(0.5) Z score; FEF(25-75): -1.2 (-2.2 to -0.15)). When using both the MBW and RVRTC techniques, abnormalities were detected in 72% of the infants with cystic fibrosis, with abnormalities detected in 41% using both techniques and a further 15% by each of the two tests performed.

CONCLUSIONS

These findings support the view that inflammatory and/or structural changes in the airways of children with cystic fibrosis start early in life, and have important implications regarding early detection and interventions. Monitoring of early lung disease and functional status in infants and young children with cystic fibrosis may be enhanced by using both MBW and the RVRTC.

Rational treatment of pulmonary infections in patients with cystic fibrosis

The life expectancy of patients with cystic fibrosis has increased markedly during the past two decades due in large part to improved clinical care, including the use of more effective antimicrobial agents for Pseudomonas. However, the chronic lung disease of CF remains the principal cause of mortality. A growing understanding of the complex interactions between infection and inflammation has led to new approaches for treatment, including chronic use of aerosolized antibiotics, particularly tobramycin, in patients known to be colonized/infected with P. aeruginosa and anti-inflammatory treatments to slow the progression of lung disease.

Lung function tests in neonates and infants with chronic lung disease of infancy: functional residual capacity

This is the second paper in a review series that will summarize available data and discuss the potential role of lung function testing in infants and young children with acute neonatal respiratory disorders and chronic lung disease of infancy. The current paper addresses the expansive subject of measurements of lung volume using plethysmography and gas dilution/washout techniques. Following orientation of the reader to the subject area, we focus our comments on areas of inquiry proposed in the introductory paper to this series. The quality of the published literature is reviewed critically, and recommendations are provided to guide future investigation in this field. Measurements of lung volume are important both for assessing growth and development of lungs in health and disease, and for interpreting volume-dependent lung function parameters such as respiratory compliance, resistance, forced expiratory flows, and indices of gas-mixing efficiency. Acute neonatal lung disease is characterized by severely reduced functional residual capacity (FRC), with treatments aimed at securing optimal lung recruitment. While FRC may remain reduced in established chronic lung disease of infancy, more commonly it becomes normalized or even elevated due to hyperinflation, with or without gas-trapping, secondary to airway obstruction. Ideally, accurate and reliable bedside measurements of FRC would be feasible from birth, throughout all phases of postnatal care (including assisted ventilation), and during subsequent long-term follow-up. Although lung volume measurements in extremely preterm infants were described in a research environment, resolution of several issues is required before such investigations can be translated into routine clinical monitoring.

Prophylactic antibiotics in cystic fibrosis: a conviction without evidence?

Pulmonary infection with Staphylococcus aureus occurs in young children with cystic fibrosis, and may contribute to the cycle of infection, inflammation, and destruction of lung tissue which leads to bronchiectasis. Practice guidelines in North America and the UK differ greatly with regard to the advice given on prescribing prophylactic antistaphylococcal antibiotics to young children with cystic fibrosis. This article reviews the evidence behind these guidelines, and suggests a pragmatic approach to clinical practice. The implications for research are also discussed, and suggestions are made for clinical trials to inform future guidelines.

Limitations of electronic compensation for measuring plethysmographic airway resistance in infants

Electronic compensation to overcome thermal artifacts during plethysmographic estimations of airway resistance is now used routinely in adults and school-age children, and was shown to be a valuable means of discriminating airway function between preschool children with and without lung disease. A similar system is now commercially available for infants, which could increase the applicability of this technique. However, we noted marked discrepancies in electronically calculated values of airway resistance in this age group, both with respect to absolute values displayed and marked within-subject variability on a single test occasion. The aim of this technical report is to summarize our recent findings in order to alert other users to potential problems. Airway resistance (R(aw)) was measured in 62 infants (28 with cystic fibrosis (CF); 34 healthy). Three to five epochs of quiet regular tidal breathing were collected in each infant. Marked within-subject, within-test variability was observed, with the median coefficient of variation (CV) being 9.1% (range, 1.2-52.6%) within and 8.5% (0.1-112%) between epochs. Among healthy infants, R(aw) varied from 0.1-6.4 (kPa x liter(-1) x sec), with no relationship to either body or lung size and complete overlap of results with those from infants with CF, despite abnormal lung function in the latter when assessed by other means. The marked within- and between-subject variability in healthy infants, and lack of discriminative power of R(aw) when derived from electronically compensated values, currently preclude application in either clinical or research studies.

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.

Efficacy of fluticasone propionate on lung function and symptoms in wheezy infants

The role of inhaled corticosteroids in the treatment of recurrent or persistent wheeze in infancy remains unclear. We evaluated the effect of 3 months of treatment with inhaled fluticasone propionate, 200 microg daily (FP200), on lung function and symptom scores in wheezy infants. Moreover, we evaluated whether infants with atopy and/or eczema respond better to FP200 as compared with non-atopic infants. Forced expiratory flow (Vmax(FRC)) was measured at baseline and after treatment. Sixty-five infants were randomized to receive FP200 or placebo, and 62 infants (mean age, 11.3 months) completed the study. Mean Vmax(FRC), expressed as a Z score, was significantly below normal at baseline and after treatment in both groups. The change from baseline of Vmax(FRC) was not different between the two treatment arms. After 6 weeks of treatment, and not after 13 weeks, the FP200 group had a significantly higher percentage of symptom-free days and a significant reduction in mean daily cough score compared with placebo. Separate analysis of treatment effect in infants with atopy or eczema showed no effect modification. We conclude that in wheezy infants, after 3 months of treatment with fluticasone, there was no improvement in lung function and no reduction in respiratory symptoms compared with placebo.

Pathophysiology and management of pulmonary infections in cystic fibrosis

This comprehensive State of the Art review summarizes the current published knowledge base regarding the pathophysiology and microbiology of pulmonary disease in cystic fibrosis (CF). The molecular basis of CF lung disease including the impact of defective cystic fibrosis transmembrane regulator (CFTR) protein function on airway physiology, mucociliary clearance, and establishment of Pseudomonas aeruginosa infection is described. An extensive review of the microbiology of CF lung disease with particular reference to infection with P. aeruginosa is provided. Other pathogens commonly associated with CF lung disease including Staphylococcal aureus, Burkholderia cepacia, Stenotrophomonas maltophilia, Achromobacter xylosoxidans and atypical mycobacteria are also described. Clinical presentation and assessment of CF lung disease including diagnostic microbiology and other measures of pulmonary health are reviewed. Current recommendations for management of CF lung disease are provided. An extensive review of antipseudomonal therapies in the settings of treatment for early P. aeruginosa infection, maintenance for patients with chronic P. aeruginosa infection, and treatment of exacerbation in pulmonary symptoms, as well as antibiotic therapies for other CF respiratory pathogens, are included. In addition, the article discusses infection control policies, therapies to optimize airway clearance and reduce inflammation, and potential future therapies.

Traitement anti-infectieux en dehors du Pseudomonas aeruginosa

Hemophilus influenzae and Staphylococcus aureus (SA) are the predominant pathogens in infants with cystic fibrosis (CF). SA was the major cause of death in the pre-antibiotic era. The reason of the association of SA in CF is unclear. SA causes early damage of the respiratory tract and paves the way for Pseudomonas aeruginosa (PA). Based of this hypothesis, some centers use prophylactic antibiotics, but their efficacy is not proved and may favor growth of PA. Treatment of exacerbations is mandatory. Oral antibiotics are preferred in most cases, although few controlled clinical studies have been reported. Emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains appeared during the recent years. Treatment of MRSA is difficult, patients segregation is discussed.

Prophylactic antibiotics for cystic fibrosis

BACKGROUND

Staphylococcus aureus causes pulmonary infection in young children with cystic fibrosis (CF). Prophylactic antibiotics are widely prescribed in the hope of preventing infection with Staphylococcus aureus and lung damage. Antibiotics also have adverse effects and long-term use might lead to chronic infection with organisms like Pseudomonas aeruginosa.

OBJECTIVES

To assess the effect of continuous oral antibiotic prophylaxis compared to no prophylaxis in people with CF, we tested these hypotheses. Prophylaxis: (1) improves clinical status, lung function and survival; (2) causes adverse effects (eg diarrhoea, skin rash, candidiasis); (3) leads to fewer isolates of common pathogens from respiratory secretions; (4) leads to the emergence of antibiotic resistance and the colonisation of the respiratory tract with organisms, e.g. Pseudomonas aeruginosa.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register, comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings. Companies manufacturing anti-staphylococcal antibiotics were approached for unpublished data. Most recent search of the Group's register: March 2003.

SELECTION CRITERIA

Randomised trials of continuous oral prophylactic antibiotics (given for at least one year) compared to intermittent antibiotic therapy given "as required," in people with CF of any disease severity.

DATA COLLECTION AND ANALYSIS

The reviewers assessed trials for eligibility and methodological quality and extracted data.

MAIN RESULTS

Four studies, totalling 303 participants (139 boys) aged zero to seven years on enrollment, were included. Fewer children receiving anti-staphylococcal antibiotic prophylaxis had one or more isolates of Staphylococcus aureus. There was no significant difference between groups in infant or conventional lung function tests. We found no significant effect on nutrition, hospital admissions, additional courses of antibiotics or adverse effects. There is no significant difference in the number of isolates of Pseudomonas aeruginosa between groups, though there was a trend towards a lower cumulative isolation rate of Pseudomonas aeruginosa in the prophylaxis group, at two and three years and a trend towards a higher rate from four to six years. However, as the duration of the studies reviewed has been of six years or less, conclusions cannot be drawn about the long-term effects of prophylaxis.

REVIEWER'S CONCLUSIONS

Anti-staphylococcal antibiotic prophylaxis leads to fewer children having isolates of Staphylococcus aureus, when commenced early in infancy and continued up to six years of age. The clinical importance of this finding is uncertain. Further research may establish whether the trend towards more children with CF with Pseudomonas aeruginosa, after four to six years of prophylaxis, is a chance finding. Future work should explore whether choice of prophylactic antibiotic or duration of treatment might influence infection with Pseudomonas aeruginosa.

Relative ability of full and partial forced expiratory maneuvers to identify diminished airway function in infants with cystic fibrosis

The tidal and raised volume rapid thoracoabdominal compression techniques are increasingly used to detect diminished airway function in infancy. The aim of this study was to assess the relative ability of parameters measured by these techniques to identify diminished airway function in infants newly diagnosed with cystic fibrosis (CF) with and without clinical evidence of prior lower respiratory illness. A cross-sectional, prospective study design was used in which maximal flow at functional residual capacity (VmaxFRC) from the tidal technique and FVC, FEV0.5, FEF75, and FEF25-75 from the raised volume technique were measured in 47 infants with CF and 187 healthy infants of similar body size, sex distribution, ethnic group, and exposure to maternal smoking. Multiple linear regression was used to assess group differences and to calculate SD scores for each parameter for the infants with CF. Airway function was also compared with clinical assessments of respiratory status made by pediatric pulmonologists. FEV0.5 was significantly diminished in 13 infants with CF, of whom 4 had been identified by clinicians as having normal respiratory status. Only one infant with CF had a VmaxFRC below the estimated normal range. Airway function is diminished in infants with CF irrespective of prior lower respiratory illness and in those whose respiratory status is considered normal by pediatric pulmonologists. In infants with CF, the raised volume technique identified diminished airway function more frequently than the tidal technique.

Monitoring early inflammation in CF. Infant pulmonary function testing

Infant pulmonary function tests (iPFTs) have primarily been used as research tools to further define physiologic pulmonary abnormalities in infants and young children with cystic fibrosis (CF). Methodologies used to measure pulmonary function in infants are described, with particular relevance to CF. A comprehensive review of studies and findings in CF infants using iPFTs is presented. Further goals in improving methodologies and in defining pulmonary disease in CF are presented.

Sex-specific prediction equations for Vmax(FRC) in infancy: a multicenter collaborative study

Measurements of maximal flow at functional residual capacity (Vmax(FRC)) from partial forced expiratory maneuvers remain the most popular method for assessing small airway function in infants and young children. However, the lack of appropriate reference data that are both applicable outside the centers that developed them and reflect the normal variability between healthy subjects has limited interpretation of Vmax(FRC) results in both clinical practice and research. To address this problem, we collated Vmax(FRC) data from 459 healthy infants (226 boys) tested on 654 occasions during the first 20 months of life from three collaborating centers. Multiple linear regression analysis indicated that sex, age, and length were important predictors of Vmax (FRC), which was, on average, 20% higher in girls than in boys during the first 9 months of life. (Vmax(FRC))0.5 (ml x second(-1)) = 4.22 + 0.00210 x length2 (cm) for boys (RSD = 3.01; R2 = 0.48), and -1.23 + 0.242 x length for girls (RSD = 2.72; R2 = 0.49). Alternative models incorporating both age and length z scores are also described. Failure to use sex-specific prediction equations for Vmax(FRC) may preclude detection of clinically significant changes in girls and lead to false reports of diminished airway function in boys. Appropriate use of z scores, which indicate a "normal" range (z scores of 0 +/- 2) for Vmax(FRC), during infancy should also improve interpretation of both clinical and research studies.

Inflammation, infection, and pulmonary function in infants and young children with cystic fibrosis

Our aim was to study the effect of lower airway infection on clinical parameters, pulmonary function tests, and inflammation in clinically stable infants and young children with cystic fibrosis (CF). To accomplish this goal, a prospective cohort of screened CF patients under 4 years of age were studied, using elective anesthesia and intubation for: passive respiratory mechanics (single breath occlusion passive deflation) and lung volumes (nitrogen washout), under neuromuscular blockade; and bronchoalveolar lavage (BAL) of 3 main bronchi for cytology, cytokine interleukin (IL)-8, and quantitative microbiology. There were 22 children studied, with a mean age of 23.2 months (6.7-44 months). A greater relative risk of lower airway pathogens was associated with prior respiratory admission (3.60, 95% confidence interval [CI] 2.87-4.51), history of asthma (1.75, 95% CI 1.52-2.03), and chronic symptoms (1.50, 95% CI 1.23-1.83), especially wheeze (1.88, 95% CI 1.61-2.19). Lower respiratory pathogens (> or = 10 cfu/ml BAL) were found in 14 out of 22, and greater than 10(5) cfu/ml in 8 out of 22 subjects. The level of pathogens in BAL (log10 cfu/ml) explained 78% of the variability in percent neutrophils and 34% of the variability in IL-8 levels. Pathogen level also correlated with pulmonary function tests of specific respiratory system compliance (r -0.49, p = 0.02) and functional residual capacity over total lung capacity (r 0.49, p = 0.03). We conclude that the presence of pathogens in the lower airways correlated with levels of inflammation, respiratory system compliance, and degree of air trapping.

Changes in strategies for optimal antibacterial therapy in cystic fibrosis

Aggressive antibiotic therapy of bacterial airway infection is one of the main reasons for the dramatic increase in life expectancy over the last few decades. Staphylococcus aureus and Haemophilus influenzae are the predominant pathogens in younger patients, but the choice of antibiotic therapy against these pathogens remains highly controversial. There is general agreement that patients with pulmonary exacerbations should be treated and many cystic fibrosis (CF) centres will also try to eradicate bacteria in the absence of symptoms. Prophylactic antibiotic therapy, with anti-staphylococcal medications started at the time of diagnosis, is advocated by some groups but its positive effect remains unproven. In fact, recent studies have suggested that continuous prophylactic treatment with anti-staphylococcal antibiotics may increase the risk of early colonisation with Pseudomonas aeruginosa. P. aeruginosa is the main pathogen in older children with CF. While chronic airway infection with mucoid P. aeruginosa is considered irreversible, both the combination of oral ciprofloxacin with inhaled colistin and inhaled tobramycin alone has been used successfully in the early phase of colonisation. In patients chronically infected with P. aeruginosa, standard treatment of pulmonary exacerbations consists of intravenous combination therapy for 2-3 weeks. Controversy exists whether this treatment should be performed routinely every 3 months or only in the presence of a pulmonary exacerbation. Inhaled antibiotics such as tobramycin have been shown to improve lung function and reduce sputum density of P. aeruginosa, but both the optimal dose and the duration of therapy are unclear at the present time.

Effect of continuous antistaphylococcal therapy on the rate of P. aeruginosa acquisition in patients with cystic fibrosis

SUMMARY. Continuous therapy with antistaphylococcal antibiotics is advocated by some cystic fibrosis (CF) centers, but it is unclear whether this strategy favors early colonization with P. aeruginosa. We used the data base for the German Centers of the European Registry for Cystic Fibrosis (ERCF) to assess the effect of continuous antistaphyloccocal therapy on the rate of P. aeruginosa acquisition in CF patients. Patients included in this analysis had to be < 18 years of age, P. aeruginosa-negative prior to entry in the ERCF, and to have had at least 2 additional P. aeruginosa-negative respiratory cultures while followed in the ERCF. Of the 639 patients fulfilling these criteria, 48.2% received continuous antistaphyloccocal therapy, 40.4% intermittent antibiotic therapy, and 11.4% no antibiotic therapy. There were no differences between the groups in body mass index, as well as forced vital capacity (FVC) and forced expired volume in 1 sec (FEV(1)) at baseline. The rate at which patients acquired positive respiratory cultures for Staph. aureus was significantly lower in the group receiving continuous antistaphyloccocal antibiotic therapy than in those not receiving such therapy. Patients receiving continuous antistaphyloccocal antibiotic therapy had a significantly higher rate of P. aeruginosa acquisition compared to patients receiving only intermittent or no antibiotic therapy. This difference was especially apparent for children younger than age 6 years. We conclude that continuous therapy with antistapyloccocal antibiotics directed against Staph. aureus increases the risk of colonization with P. aeruginosa. How this affects the clinical outcome of these patients remains to be determined.

Falsely elevated serum tobramycin concentrations in cystic fibrosis patients treated with concurrent intravenous and inhaled tobramycin

A recently developed tobramycin preparation for inhalation (TOBI(R), Pathogenesis Corp., Seattle, WA) is widely used in CF patients. It is often used in conjunction with intravenous tobramycin. Renal and ototoxicity associated with the use of tobramycin require that serum drug concentrations be monitored during therapy. We report on two patients with falsely elevated, toxic serum tobramycin concentrations while receiving concurrent intravenous and inhaled tobramycin. These cases point out the need for guidelines governing the use and monitoring of simultaneous inhaled and intravenous tobramycin therapy. Pediatr Pulmonol. 2000; 29:43- 45.

Systematic review of antistaphylococcal antibiotic therapy in cystic fibrosis

BACKGROUND

The respiratory tract in patients with cystic fibrosis is frequently colonised with Staphylococcus aureus. There is great diversity of clinical practice in this area of cystic fibrosis. A systematic review was conducted to study the evidence relating antistaphylococcal therapy to clinical outcome in patients with cystic fibrosis.

METHODS

A search strategy already evaluated for the study of the epidemiology of cystic fibrosis clinical trials was used. This yielded 3188 references from which 13 clinical trials of antistaphylococcal therapy were identified.

RESULTS

Substantial heterogeneity was observed between trials. In the 13 clinical trials a total of 19 antibiotics were used to assess a wide variety of outcome measures (11 clinical, six laboratory). Both intermittent and continuous treatment strategies were used. Sputum clearance of S aureus was more frequently achieved than any other beneficial outcome. A beneficial effect on pulmonary function was rarely measured or observed. Although five randomised clinical trials were identified, the extent of heterogeneity precluded the use of meta-analysis for further synthesis of information.

CONCLUSIONS

Antistaphylococcal treatment achieves sputum clearance of S aureus in patients with cystic fibrosis. Prophylactic antistaphylococcal treatment in young children with cystic fibrosis is likely to be of clinical benefit. It remains to be determined whether the use of "prophylactic" versus "intermittent" antistaphylococcal therapy in cystic fibrosis is associated with improved lung function and/or chest radiographic scores, an increase in bacterial resistance, or earlier acquisition of Pseudomonas aeruginosa. A large randomised clinical trial lasting approximately two years is urgently required to address this problem.

Pulmonary function in hospitalized infants and toddlers with cystic fibrosis

In older children with cystic fibrosis (CF), well-documented improvements in lung function occur during hospitalization for treatment of pulmonary exacerbations.

OBJECTIVES

(1) To test the hypothesis that improvement in lung function occurs in infants and toddlers hospitalized because of CF pulmonary exacerbations. (2) To compare changes in lung function measured during forced expiratory flow and tidal breathing.

STUDY DESIGN

Seventeen infants and toddlers with CF were evaluated at the beginning and end of hospitalization by the rapid thoracic compression technique to yield maximal flow at forced residual capacity. Tidal mechanics were measured by the esophageal balloon technique to yield lung conductance and compliance.

RESULTS

Lung function improved during the course of hospitalization. The greatest change was observed in measurements of maximal flow at functional residual capacity (.VmaxFRC), increasing from 38.5% +/- 6% predicted (mean +/- SEM) to 59.8% +/- 6% at the end (p < 0.005). Lung conductance (GL) increased from 60% +/- 6% to 78% +/- 8% (p < 0.02); lung compliance (CL) increased from 66% +/- 5% to 75% +/- 5% (p < 0.03). The degree of improvement of .VmaxFRC, GL, and CL was related to baseline measurements; those with poorer pulmonary function at baseline had the greatest degree of improvement during hospitalization.

CONCLUSION

Assessments of airflow obstruction from measurements of .VmaxFRC and GL do not necessarily demonstrate similar findings in a given infant with CF, perhaps because these two techniques measure different physiologic properties. Changes in .VmaxFRC may best reflect the predominant pathophysiology of lung disease in infants and toddlers with CF.

Lung function from infancy to school age in cystic fibrosis

The aim was to investigate pulmonary mechanics in patients with cystic fibrosis during infancy and again in early childhood to see whether infant tests predicted status at school age. Plethysmographic measurements of thoracic gas volume and airways resistance were made in 29 patients at 6 months and again at 5 years 10 months. Maximum flow at functional residual capacity was measured during infancy for comparison with maximum expiratory flow rates during childhood. While many patients had normal measurements during infancy, pulmonary function had deteriorated by school age. Thoracic gas volume at school age was significantly related to the values in infancy, but other measurements made during childhood were independent of infant values. The relations between measurements in infancy and early childhood described here provide a background against which the role of external factors on pulmonary function in young children with cystic fibrosis can be investigated.