Clinical value of obtaining sputum and cough swab samples following inhaled hypertonic saline in children with cystic fibrosis

[CF Lung Disease - a German S3 Guideline: Pseudomonas aeruginosa]

Cystic Fibrosis (CF) is the most common autosomal recessive genetic multisystemic disease. In Germany, it affects at least 8000 people. The disease is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene leading to dysfunction of CFTR, a transmembrane chloride channel. This defect causes insufficient hydration of the airway epithelial lining fluid which leads to reduction of the mucociliary clearance.Even if highly effective, CFTR modulator therapy has been available for some years and people with CF are getting much older than before, recurrent and chronic infections of the airways as well as pulmonary exacerbations still occur. In adult CF life, Pseudomonas aeruginosa (PA) is the most relevant pathogen in colonisation and chronic infection of the lung, leading to further loss of lung function. There are many possibilities to treat PA-infection.This is a S3-clinical guideline which implements a definition for chronic PA-infection and demonstrates evidence-based diagnostic methods and medical treatment in order to give guidance for individual treatment options.

Diagnosis and Management of Cystic Fibrosis Exacerbations

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is acute pulmonary exacerbation (PEx). Clinical and microbial epidemiology studies of CF PEx continue to provide important insight into the disease course, prognosis, and complications. This work has now led to several large-scale clinical trials designed to clarify the treatment paradigm for CF PEx. The primary goal of this review is to provide a summary and update of the pathophysiology, clinical and microbial epidemiology, outcome and treatment of CF PEx, biomarkers for exacerbation, and the impact of highly effective modulator therapy on these events moving forward.

Chest physiotherapy enhances detection of Pseudomonas aeruginosa in nonexpectorating children with cystic fibrosis

Lung damage in cystic fibrosis (CF) is strongly associated with lower airway infections. Early treatment of Pseudomonas aeruginosa is recommended. Pathogen detection requires sampling of lower airway secretions, which remains a challenge in nonexpectorating patients. Our hypothesis was that chest physiotherapy would improve the quality of airway secretion samples and increase the rates of pathogens detected in nonexpectorating patients.

This prospective multicentre study compared three successive methods for sampling airway secretions applied through the same session: 1) an oropharyngeal swab (OP), 2) a chest physiotherapy session followed by a provoked cough to obtain sputum (CP-SP) and 3) a second oropharyngeal swab collected after chest physiotherapy (CP-OP). Haemophilus influenzae, Staphylococcus aureus and P. aeruginosa growth cultures were assessed. Accuracy tests and an equivalence test were performed to compare the three successive methods of collection.

300 nonexpectorating children with CF were included. P. aeruginosa was detected cumulatively in 56 (18.9%) children, and according to the different collection methods in 28 (9.8%), 37 (12.4%) and 44 (14.7%) children by using OP, CP-OP and CP-SP, respectively. Compared with OP, the increased detection rate was +22% for CP-OP (p=0.029) and +57% for CP-SP (p=0.003). CP-SP had the best positive predictive value (86.3%) and negative predictive value (96.0%) for P. aeruginosa compared with the overall detection.

The results of this adequately powered study show differences in the rates of pathogens detected according to the sampling method used. Chest physiotherapy enhanced detection of P. aeruginosa in nonexpectorating children with CF.

Sputum collection after a chest physiotherapy session strongly enhances the detection of P. aeruginosa in nonexpectorating CF children compared with the commonly used oropharyngeal swab method. Oropharyngeal swab after physiotherapy may be an acceptable alternative.https://bit.ly/3757ewq

Diagnostic value of sputum cultures in children under 2 years of age with chronic suppurative lung diseases

BACKGROUND

Acquiring sputum cultures from infants is considered challenging. We describe their yield in infants with cystic fibrosis (CF) and other chronic suppurative lung diseases (CSLDs).

METHODS

Retrospective medical record review over a 4-year period, for infants aged 0-2 years with ≥2 airway bacterial cultures acquired by deep suction or induced sputum ≥4 weeks apart. Data included demographics, culture results, and clinical status.

RESULTS

A total of 98 infants (16 CF) were evaluated and 534 sputum cultures acquired, 201 in CF and 333 in CSLD. There were 12 (2-23), median (range) cultures/CF infant, and 3 (2-21)/CSLD infant. Age at first culture was 3.8 (1-19.5) months for CF and 10.4 (0.5-22) months for CSLD; p = .016. In total, 360 cultures (67%) were positive for any bacteria, with 170/234 (73%) positive during exacerbations, compared with 190/300 (63%) during routine visits; p = .05. More infants with CF than CSLD had cultures positive for Staphylococcus aureus (SA; 75% vs. 34%; p = .004) throughout the period. Pseudomonas aeruginosa (PA) was common in both CF and CSLD (56% and 44%, respectively; p = .42) and increased over time for CF but was high throughout for CSLD. The number of hospital days before PA acquisition was 6 (10.2) for CF and 28.8 (38.7) for CSLD (p = .003). No CF but 6/82 (7%) CSLD infants had chronic PA (p = .56).

CONCLUSIONS

Sputum cultures showed that infection, in particular PA, is common in CF and CSLD whereas SA is more common in CF. Prospective studies are warranted to elucidate the role of active surveillance in guiding antibiotic therapy.

Acute Pulmonary Exacerbations in Cystic Fibrosis

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the disease course, prognosis, and complications. This work has now led to a number of large scale clinical trials with the goal of improving the treatment paradigm for CF pulmonary exacerbation. The primary goal of this review is to provide a summary of the pathophysiology, the clinical epidemiology, microbial epidemiology, outcome and the treatment of CF pulmonary exacerbation.

Acute Pain Perception During Different Sampling Methods for Respiratory Culture in Cystic Fibrosis Patients

CONTEXT

Reliable identification of lower respiratory tract pathogens is crucial in the management of cystic fibrosis (CF). The multitude of treatments and clinical procedures are a considerable burden and are potentially provoking pain.

OBJECTIVES

As part of another study (NCT02363764), investigating the bacterial yield of three sampling methods, nasal swabs (NSs), cough swabs (CSs), and (induced) sputum samples ([I]SSs), in both expectorating patients (EPs) and non-expectorating patients (NEPs) with CF, the present study aimed to explore the prevalence of respiratory culture sampling-related pain as assessed by self-report within a cohort of children and adults.

METHODS

Literate patients with CF (aged six years or older) completed a questionnaire on pain perception related to the three aforementioned sampling methods (No/Yes; visual analogue scale for pain [VAS-Pain] [0-10 cm]). In addition, patients were asked to rank these methods by their own preference without taking into account the presumed bacterial yield.

RESULTS

In total, 119 questionnaires were returned. In the EPs-group, CS was most frequently (n%; mean VAS-Pain if pain [range]) reported as painful method: overall (n = 101; 12.9%; 1.8 [0.2-4.8]), children (n = 41; 22.0%; 1.4 [0.2-2.7]), and adults (n = 60; 6.7%; 2.5 [0.5-4.8]). Highest pain intensity scores were observed with NS overall (3.0%; 2.4 [0.3-6.2]) and in children (4.9%; 3.3 [0.3-6.2]), but not in adults (1.7%; 0.6 [-]).NEPs-children (n = 17) reported ISS most frequently and as most painful sampling method (17.6%; 2.0 [1.0-4.0]). The only NEP-adult did not perceive pain. NEPs preferred NS > CS > ISS (61.1%, 33.3%, 5.6%, respectively [P = 0.001]) as primary sampling method, whereas EPs preferred SS > NS > CS (65.7%, 26.3%, 8.1%, respectively [P < 0.0001]). Patients' preference for a specific method inversely correlated to pain perception and intensity in EPs (φ = -0.155 [P = 0.007] and ρ = -0.926 [P = 0.008], respectively), but not in NEPs (φ = -0.226 [P = 0.097] and ρ = -0.135 [P = 0.798], respectively).

CONCLUSION

A relatively large range of pain experiences was observed in patients with CF during respiratory culture sampling, which underlines the importance of individual pain assessment. Nevertheless, clinicians can confidently choose the sampling method based on validity over patients' preference.

Respiratory Bacterial Culture Sampling in Expectorating and Non-expectorating Patients With Cystic Fibrosis

Purpose: Different respiratory sampling methods exist to identify lower airway pathogens in patients with cystic fibrosis (CF), of which bronchoalveolar lavage (BAL), and expectorated sputum are considered the "gold standard." Because BAL cannot be repeated limitless, the diagnosis of lower respiratory tract infections in non-expectorating patients is challenging. Other sampling techniques are nasal swab, cough swab, and induced sputum. The purpose of this study (NCT02363764) was to compare concordance between the microbiological yield of nasal swab, cough swab, and expectorated sputum in expectorating patients; nasal swab, cough swab, and induced sputum in non-expectorating patients; nasal swab, cough swab, induced sputum, and BAL in patients requiring bronchoscopy ("BAL-group"); and to determine the clinical value of cough swab in non-expectorating patients with CF. Methods: Microbiological yield detected by these different sampling techniques was compared between and within 105 expectorating patients, 30 non-expectorating patients and BAL-group (n = 39) in a single CF clinic. Specificity, sensitivity, positive (PPV), and negative (NPV) predictive values were calculated. Results: Overall low sensitivity (6.3-58.0%) and wide-ranging predictive values (0.0-100.0%) indicated that nasal swab was not appropriate to detect lower airway pathogens [Pseudomonas aeruginosa (Pa), Staphylococcus aureus (Sa), and Haemophilus influenzae (Hi)] in all three patient groups. Microbiological yield, specificity, sensitivity, PPV, and NPV of cough swab and induced sputum were largely similar in non-expectorating patients and in BAL-group (except sensitivity (0.0%) of induced sputum for Hi in BAL-group). Calculations for Pa and Hi could not be performed for non-expectorating patients because of low prevalence (n = 2 and n = 3, respectively). In expectorating patients, concordance was found between cough swab and expectorated sputum, except for Hi (sensitivity of 40.0%). Conclusion: Our findings suggest that cough swab might be helpful in detecting the presence of some typical CF pathogens in the lower airways of clinically stable patients with CF. However, in symptomatic patients, who are unable to expectorate and who have a negative cough swab and induced sample, BAL should be performed as it currently remains the "gold standard."

Mapping targetable inflammation and outcomes with cystic fibrosis biomarkers

Cystic fibrosis is characterized by an overly exuberant neutrophilic inflammatory response to pathogens and other stimuli that starts very early in disease. The overwhelming nature of this response is a primary cause of remodeling and destruction of the airways, suggesting that anti-inflammatory therapies could be beneficial in CF. However, finding therapies that can effectively reduce the inflammatory response without compromising host defenses remains elusive. New approaches towards mapping inflammatory targets promise to aid in developing novel therapeutic strategies and improve outcomes in individuals with CF.

Utility of blood cultures in children admitted to hospital with community-acquired pneumonia

AIM

The aim of the study was to assess the utility of blood cultures in children admitted to hospital with community-acquired pneumonia. The primary outcome was the number of positive blood culture results, and secondary outcomes included the effect of positive blood culture results on management, and the identification of other clinical/biochemical variables that could predict blood culture results or the course of illness.

METHODS

A retrospective data analysis was carried out on all children admitted to Gosford Hospital during the 2-year period from July 2013 to June 2015. Included were patients under 16 years old who had a diagnosis-related group code of pneumonia. A review of blood culture results, chest X-ray, serology, C-reactive protein and white cell count and clinical outcomes were analysed.

RESULTS

There were 215 paediatric admissions with a diagnosis of pneumonia during the 2-year study period. A blood culture was collected in 82.3% (177/215). Although seven had a positive blood culture, only two of these were finally reported as true positives and both were Streptococcus pneumoniae. Both patients were treated with a cephalosporin and demonstrated clinical improvement. No changes were made to their treatment based on the blood culture results.

CONCLUSION

Blood cultures have a low yield and do not appear to be helpful when collected in all patients admitted to hospital with community-acquired pneumonia.

Phase I Studies of Acebilustat: Pharmacokinetics, Pharmacodynamics, Food Effect, and CYP3A Induction

Acebilustat is a new once-daily oral antiinflammatory drug in development for treatment of cystic fibrosis (CF) and other diseases. It is an inhibitor of leukotriene A4 hydrolase; therefore, production of leukotriene B4 (LTB4) in biological fluids provides a direct measure of the pharmacodynamic (PD) response to acebilustat treatment. Here we compare the pharmacokinetics (PK) and PD between CF patients and healthy volunteers, and investigate the food effect and CYP3A4 induction in healthy volunteers. No significant differences between study populations were observed for peak plasma level (C_max ) or exposure (AUC). In healthy volunteers, a shift in time to C_max (T_max ) was observed after a high-fat meal, but there was no change in AUC. LTB4 production was reduced in the blood of both populations and in sputum from CF patients. Acebilustat did not induce CYP3A4. These results support continued clinical study of once-daily oral acebilustat in CF at doses of 50 and 100 mg.

Infection and inflammation in induced sputum from preschool children with chronic airways diseases

BACKGROUND

We hypothesized airway inflammation can be detected non-invasively by induced sputum (IS) or peripheral blood eosinophilia, and IS can detect bacterial and viral infection in preschool children with airway disease, with results comparable to broncho-alveolar lavage (BAL).

METHODS

Preschool children with cystic fibrosis, recurrent wheeze, or wet cough underwent IS with nebulized hypertonic saline, chest physiotherapy, and oropharyngeal suction. Samples were analyzed for inflammation by cytology and bacterial culture, viral detection by PCR. Results were compared to BAL and blood in a sub-group undergoing clinically indicated bronchoscopy.

RESULTS

64 children (median age 33 [7-76] months) underwent IS without adverse events. IS was obtained from 61/64. Twenty out of sixty-four underwent BAL and IS, no IS was obtained in 2/23. Thirteen out of twenty-one (62%) had matching bacteria and viruses, 4/21 had positive BAL bacterial growth with negative IS, and 3/21 had negative BAL growth with positive IS. 67% of sputum samples were processed for cytology, 46% had <80% squamous cells; the proportion of squamous cells reduced with increasing age (r = -0.55, P < 0.01). IS was significantly more neutrophilic and less eosinophilic than BAL; 2/21 IS samples contained eosinophils compared to 17/23 BAL. There was a positive correlation between blood and BAL eosinophilia (r = 0.75, P < 0.01).

CONCLUSION

IS from preschool children can be used to assess infection. BAL and IS culture concurred in approximately two-thirds. However, inflammation was measureable in only one-third of IS samples and the cell differential was predominantly neutrophilic compared to BAL. Blood eosinophils may provide a better reflection of lower airway eosinophilia in this age group. Pediatr Pulmonol. 2016;51:778-786. © 2015 WileyPeriodicals, Inc.

Microbiological yield from induced sputum compared to oropharyngeal swab in young children with cystic fibrosis

BACKGROUND

Standard respiratory sampling in young children with cystic fibrosis (CF) is by oropharyngeal swab (OPS) as they cannot spontaneously expectorate. Sputum induction (IS) has been poorly investigated in this population. We aimed to compare the bacteriological yield of OPS vs. IS in young children with CF.

METHODS

Sequentially paired OPS followed by IS samples was collected in children <5years of age attending a CF clinic in Cape Town, South Africa.

RESULTS

IS was successfully paired with OPS in 98/113 (85%) attempts in 32 children (mean±SD 19±16months), with no serious adverse events. IS culture yield for any CF-associated bacteria from IS was 46% vs. 28% from OPS (p=0.01). The sensitivity, specificity, PPV and NPV of OPS compared to IS in isolating CF-associated bacteria were 56%, 96%, 93%, and 72% respectively.

CONCLUSION

Sputum induction is feasible, safe and superior to OPS for detecting CF-associated bacteria in young children with CF.

Induced sputum in young healthy children with cystic fibrosis

Young children with CF are often asymptomatic and non-productive, yet CF lung disease occurs early in life. Cough swabs are used routinely to sample bacteria from the CF respiratory tract in non-productive healthy children; bronchoscopy is used to definitively sample the lower airway, but is an invasive procedure. Induced sputum is a non-invasive approach to sampling the lower airway. The article concentrates on how well it is tolerated in children, how successful it is in identifying respiratory pathogens, and how it may be important in routine surveillance if 16S technology is to be used in the clinical forum.

Sputum induction improves detection of pathogens in children with cystic fibrosis

BACKGROUND

Sputum induction is a safe, well tolerated means of obtaining lower airway secretions from children with cystic fibrosis (CF), particularly for assessment of airway inflammation but the clinical value in diagnosing outpatient infections has not been extensively studied.

OBJECTIVES

Investigate the success rate and microbiologic yield of induced sputum (IS) compared to oropharyngeal swabs (OP) and expectorated sputum (ES) samples in children with CF, and determine if IS culture results impact treatment.

METHODS

Two cohorts were included in this prospective, longitudinal comparative study. In one cohort, simultaneously collected OP, ES, and IS specimens were obtained from 17 CF children at three visits over 1 year. In the second group, sputum induction was performed in 35 CF subjects at four annual visits, and culture results were compared to their nearest respiratory culture within 4 months. Antimicrobial treatment regimens were captured retrospectively.

RESULTS

Sputum induction was successful in 149 of 158 (94%) visit encounters. Polymicrobial infection (combined P = 0.005) and gram negative organisms (combined P = 0.003) were detected more frequently in IS samples compared to OP, as were the individual pathogens Pseudomonas aeruginosa (combined P = 0.04) and Stenotrophomonas maltophilia (combined P = 0.05). The microbiologic yield of serial IS samples collected over 1 year was stable. IS culture results led to antibiotic changes in 6% of visit encounters. However, based on current practice 13% of visits could have resulted in treatment changes.

CONCLUSIONS

Sputum induction is feasible in the outpatient setting and appears to improve pathogen detection in children with CF.

How to use: bacterial cultures in diagnosing lower respiratory tract infections in cystic fibrosis

Respiratory infections are the leading cause of morbidity and mortality in cystic fibrosis. Certain bacteria, such as Pseudomonas aeruginosa, are associated with a worse clinical outcome than others, but can be completely eradicated if identified and treated early. The diagnosis of lower respiratory tract infections can be challenging in the non-expectorating patient, in whom upper airway samples, such as cough swabs, are a surrogate for lower airway sampling. However, the results of these often do not fit with the clinical picture, presenting a management dilemma. Frequently, clinicians are faced with a negative culture result in a progressively symptomatic patient and vice versa. When judging the clinical significance of a positive upper airway culture result in an asymptomatic patient, it is important to consider the prognostic significance of the organism cultured. Given that the reported sensitivity of upper airway swabs (which includes throat swabs) is variable, ranging from 35.7% to 71% for Pseudomonas aeruginosa, 50% to 86% for Staphylococcus aureus and 11% to 92% for Haemophilus influenza, upper airway samples may fail to identify lower airway infections. Therefore, in symptomatic children, a repeatedly negative upper airway swab should not be considered as reassuring, and alternative sampling methods, such as induced sputum or bronchoalveolar lavage, should be considered. Here we use some examples of common scenarios to illustrate how best to use bacterial cultures to aid management decisions in cystic fibrosis.

Induced sputum compared to bronchoalveolar lavage in young, non-expectorating cystic fibrosis children

BACKGROUND

Induced sputum (IS) is feasible and safe in young CF children and is a readily accessible, non-invasive technique. However, it has not been compared to bronchoalveolar lavage (BAL), the gold standard for diagnosing lower airway infection.

METHODS

We compared bacterial yield from IS and BAL in 11 non-expectorating CF children, aged 3 to 7.4 years. IS samples were obtained in 10/11 cases.

RESULTS

Eight out of ten had the same predominant bacteria cultured from IS and BAL: Pseudomonas aeruginosa and Stenotrophomonas maltophilia[1], Staphylococcus aureus[3], and upper respiratory tract flora [4]. In one, Serratia marcescens and Haemophilus parainfluenzae were cultured from IS alone, whereas in one, non-group B Haemophilus influenzae was cultured from BAL alone.

CONCLUSIONS

As proof of principle, IS samples showed good bacteriologic correlation with BAL. Larger studies are recommended to confirm IS as a clinically valuable tool and measure for early intervention studies in young CF children.

Exhaled breath condensate adenosine tracks lung function changes in cystic fibrosis

Measurement of exhaled breath condensate (EBC) biomarkers offers a noninvasive means to assess airway disease, but the ability of EBC biomarkers to track longitudinal changes in disease severity remains unproven. EBC was collected from pediatric patients with cystic fibrosis (CF) during regular clinic visits over 1 yr. EBC biomarkers urea, adenosine (Ado), and phenylalanine (Phe) were measured by mass spectrometry, and biomarker ratios were used to control for variable dilution of airway secretions. EBC biomarker ratios were assessed relative to lung function in longitudinal, multivariate models and compared with sputum inflammatory markers and quality of life assessment (CFQ-R). EBC was successfully analyzed from 51 subjects during 184 visits (3.6 ± 0.9 visits per subject). EBC Ado/urea ratio was reproducible in duplicate samples (r = 0.62, P < 0.01, n = 20) and correlated with sputum neutrophil elastase (β = 2.5, P < 0.05). EBC Ado/urea correlated with the percentage predicted of forced expiratory volume in 1 s in longitudinal, multivariate models (β = -2.9, P < 0.01); EBC Ado/Phe performed similarly (β = -2.1, P < 0.05). In contrast, IL-8 and elastase measured in spontaneously expectorated sputum (n = 57 samples from 25 subjects) and the CFQ-R respiratory scale (n = 90 tests from 47 subjects) were not significantly correlated with lung function. EBC was readily collected in a clinic setting from a wide range of subjects. EBC Ado tracked longitudinal changes in lung function in CF, with results similar to or better than established measures.

Exhaled breath condensate purines correlate with lung function in infants and preschoolers

RATIONALE

Although airway inflammation begins early in life in children with chronic respiratory diseases, current methods to assess this inflammation are invasive and entail significant risk. Measurement of exhaled breath condensate (EBC) purines and other biomarkers offers a less invasive method to assess airway inflammation; however, the feasibility and utility of EBC biomarkers in young children has not been established.

METHODS

EBC was collected from children <3 years old with cystic fibrosis or other lung diseases during clinically indicated infant pulmonary function tests (iPFTs). EBC concentrations of the purine biomarkers adenosine (Ado), adenosine monophosphate (AMP), and the dilution marker urea were measured using mass spectrometry.

RESULTS

EBC was successfully collected (average volume 330 ± 170 µl) from preschool children (age 2.3 ± 0.8 years) in 15 of 17 iPFTs. No significant changes in oxygen saturation (96.9 ± 1.6 start, 96.8 ± 1.7 end, P = 0.389) or respiratory rate (35.2 ± 7.5 start, 34.6 ± 7.9 end, P = 0.443) were observed during collection. Ado and AMP were successfully measured in 13/15 samples [8 cystic fibrosis (CF)]. EBC AMP to Ado ratio (AMP/Ado) negatively correlated with forced expiratory volume at 0.5 sec (FEV(0.5) , r = -0.71, P < 0.01) and positively with the ratio of residual volume to total lung capacity (RV/TLC, r = 0.66, P = 0.015). These correlations remained statistically significant in the subset with CF.

CONCLUSIONS

EBC can be safely collected and analyzed in preschool children using commercially available equipment. The EBC AMP/Ado ratio correlates with measures of infant lung function and may be a less invasive means of monitoring airway inflammation in this population.

Prevention of chronic Pseudomonas aeruginosa infection in people with cystic fibrosis

Cystic fibrosis is the most common genetically inherited disease in the Caucasian population, with approximately 30,000 patients in the USA and more than 50,000 patients worldwide. The primary defect in the cystic fibrosis transmembrane regulator gene affects the production and/or function of the cystic fibrosis transmembrane regulator protein. Depending on the severity of the genetic defect, patients may have minimal disease expression (e.g., male infertility) or multisystem involvement, including recurrent respiratory infection progressing to respiratory failure, hepatobiliary disease, exocrine pancreatic insufficiency, diabetes mellitus and gastrointestinal tract motility problems. Pseudomonas aeruginosa is commonly isolated from the lower respiratory tract in early childhood. Chronic infection is associated with increased morbidity and mortality. P. aeruginosa infection may be acquired from the environment or by person-to-person contact. Clinicians should adopt a proactive protocol to prevent chronic infection. The cornerstones of such a policy are microbiological surveillance, infection control and antibiotic-based eradication regimens.

Specimen collection for the diagnosis of pediatric pneumonia

Diagnosing the etiologic agent of pneumonia has an essential role in ensuring the most appropriate and effective therapy for individual patients and is critical to guiding the development of treatment and prevention strategies. However, establishing the etiology of pneumonia remains challenging because of the relative inaccessibility of the infected tissue and the difficulty in obtaining samples without contamination by upper respiratory tract secretions. Here, we review the published and unpublished literature on various specimens available for the diagnosis of pediatric pneumonia. We discuss the advantages and limitations of each specimen, and discuss the rationale for the specimens to be collected for the Pneumonia Etiology Research for Child Health study.

Hypertonic saline in treatment of pulmonary disease in cystic fibrosis

The pathogenesis of lung disease in cystic fibrosis is characterised by decreased airway surface liquid volume and subsequent failure of normal mucociliary clearance. Mucus within the cystic fibrosis airways is enriched in negatively charged matrices composed of DNA released from colonizing bacteria or inflammatory cells, as well as F-actin and elevated concentrations of anionic glycosaminoglycans. Therapies acting against airway mucus in cystic fibrosis include aerosolized hypertonic saline. It has been shown that hypertonic saline possesses mucolytic properties and aids mucociliary clearance by restoring the liquid layer lining the airways. However, recent clinical and bench-top studies are beginning to broaden our view on the beneficial effects of hypertonic saline, which now extend to include anti-infective as well as anti-inflammatory properties. This review aims to discuss the described therapeutic benefits of hypertonic saline and specifically to identify novel models of hypertonic saline action independent of airway hydration.

Sputum induction in routine clinical care of children with cystic fibrosis

OBJECTIVE

To determine the microbiological yield of induced sputum (IS) samples compared with conventional airway samples, spontaneously expectorated sputum and throat swabs, in children with cystic fibrosis (CF) attending an outpatient clinic.

STUDY DESIGN

Ninety-five children with CF (75 able to spontaneously expectorate sputum) were included in this prospective cross-sectional comparative study. After obtaining expectorated sputum or throat swabs samples, IS was obtained by performing the sputum induction procedure using an eFlow device (PARI, Starnberg, Germany). CF bacterial culture results were compared between the two procedures.

RESULTS

Differences in culture results between samples were observed in 25 of 94 (27%) patients. IS had a significantly higher yield for CF pathogens, with 80% of the differences being due to detection of additional organisms in IS samples. Overall, SI was well tolerated, but 12 of 95 cases had a >20% postinduction decline in forced expiratory volume in 1 second. The whole SI procedure took 30 to 85 minutes of clinic time, and its estimated additional cost was $150 (US)/patient.

CONCLUSIONS

Induced sputum has a higher microbiological yield compared with the conventional samples in children with CF, even in patients capable of expectorating sputum spontaneously. Although sputum induction is safe and tolerable, it is time-consuming and expensive in routine clinical settings.

Eradication of early Pseudomonas infection in cystic fibrosis

Chronic infection with the environmental bacterium Pseudomonas aeruginosa is associated with greater morbidity and mortality for people with cystic fibrosis. Strict infection control measures including segregation appear to reduce but not eliminate the risk of initial acquisition of the organism. There is now good evidence from randomized controlled trials that early eradication regimens consisting of anti-pseudomonal antibiotics are effective in clearing P. aeruginosa and delaying the development of chronic infection in the majority of subjects. These regimens are safe and cost-effective. Ensuring that such regimens are widely adopted is therefore of considerable importance to improving outcomes for people with cystic fibrosis. The most effective antibiotic regimen, and the effects of new nebulizer technologies and methods to improve concordance remain to be determined.

Safety and tolerability of inhaled hypertonic saline in young children with cystic fibrosis

BACKGROUND

Inhaled hypertonic saline (HS) improves lung function and decreases pulmonary exacerbations in older patients with cystic fibrosis (CF). Initiating therapies in young patients has potential to preserve lung function. Before conducting a therapeutic trial of HS in this population, its safety must be evaluated and protocols for monitoring response must be tested.

METHODS

We administered single dose 3% and 7% HS post-albuterol to 4-7 year-olds with CF able to perform spirometry ("preschool" group) and 4 month to 3 year-olds ("infant" group) using the raised volume rapid thoracoabdominal compression technique (RVRTC). Vital signs and cough episodes were measured after each inhaled treatment.

RESULTS

Eight preschool subjects (mean age 5.7 +/- 0.8 years) and 6 infants (1.6 +/- 1.0 years) completed the 3% HS protocol, and no clinically important change in vital signs or decrease in FVC, FEV(1), FEV(0.5), or FEF(25-75) occurred post-HS. Preschoolers had more cough episodes post-HS (P = 0.01). Seven preschoolers (6.1 +/- 0.7 years) and 8 infants (1.6 +/- 0.7 years) completed the 7% HS protocol. In the preschool group, FVC, FEV(0.5), and FEF(25-75) did not change significantly. A statistically significant drop in median FEV(1) occurred post-7% HS attributable to a transient >20% drop in one subject. Infant PFT parameters were unchanged post-7% HS. Preschoolers had more cough episodes post-HS (P = 0.03).

CONCLUSION

Acute administration of 3% and 7% HS appears to be safe and well-tolerated in most young children with CF. Given the demonstrated benefits in older patients, a therapeutic trial in this age group is warranted.

Microbiological diagnostic procedures in respiratory infections: suppurative lung disease

Pursuing a microbiological diagnosis in suppurative lung disease can enable focused antibiotic therapy, identify pathogens of potential concern for infection control, and in some cases delineate a specific pathological process. Suppurative lung disease can be categorized as acute or chronic. Acute disease most commonly consists of lung abscess or parapneumonic empyema. The vast majority of chronic suppurative lung disease in childhood is due to cystic fibrosis. Samples from the respiratory tract offer the most useful information for diagnosis and management, but adjunctive information can also be obtained from serological methods, blood cultures and molecular techniques. The quality of respiratory tract samples is vital to aid accurate interpretation of results, and this varies according to the technique of collection. Antibiotic sensitivity testing is of particular importance in an era of evolving antibiotic resistance and can be problematical in cystic fibrosis.

Assessment of pulmonary antibodies with induced sputum and bronchoalveolar lavage induced by nasal vaccination against Pseudomonas aeruginosa: a clinical phase I/II study

Background

Vaccination against Pseudomonas aeruginosa is a desirable albeit challenging strategy for prevention of airway infection in patients with cystic fibrosis. We assessed the immunogenicity of a nasal vaccine based on the outer membrane proteins F and I from Pseudomonas aeruginosa in the lower airways in a phase I/II clinical trial.

Methods

N = 12 healthy volunteers received 2 nasal vaccinations with an OprF-OprI gel as a primary and a systemic (n = 6) or a nasal booster vaccination (n = 6). Antibodies were assessed in induced sputum (IS), bronchoalveolar lavage (BAL), and in serum.

Results

OprF-OprI-specific IgG and IgA antibodies were found in both BAL and IS at comparable rates, but differed in the predominant isotype. IgA antibodies in IS did not correlate to the respective serum levels. Pulmonary antibodies were detectable in all vaccinees even 1 year after the vaccination. The systemic booster group had higher IgG levels in serum. However, the nasal booster group had the better long-term response with bronchial antibodies of both isotypes.

Conclusion

The nasal OprF-OprI-vaccine induces a lasting antibody response at both, systemic and airway mucosal site. IS is a feasible method to non-invasively assess bronchial antibodies. A further optimization of the vaccination schedule is warranted.

Exacerbations in cystic fibrosis. 1: Epidemiology and pathogenesis

With the improving survival of patients with cystic fibrosis (CF), the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the course, prognosis and complications of the disease. This review provides a summary of the pathophysiology, clinical epidemiology and microbial epidemiology of a CF pulmonary exacerbation.

Pilot study of safety and tolerability of inhaled hypertonic saline in infants with cystic fibrosis

Inhaled hypertonic saline (HS) positively affects both lung function and pulmonary exacerbations in children and adults with cystic fibrosis (CF). Early initiation of treatment may potentially reduce lung function decline and improve outcome of CF patients. However, the safety and tolerability of HS have not been established in infants and young children. We conducted a prospective trial of inhaled HS in infants with CF. Raised volume rapid thoracoabdominal compression (RVRTC) maneuvers were performed at baseline, 10 min after salbutamol inhalation and 15 min after inhalation of a 7% HS solution. Oxygen saturation, respiratory rate, heart rate, and cough frequency were recorded during each inhalation. A clinically important change in lung function was defined a priori as a change in FEV 0.5 of > or =20%. Thirteen infants (5 female) aged 25-140 weeks were enrolled in the study. Overall, there was no difference between FEV(0.5) or FEF(25-75) at baseline, after bronchodilator or after HS. Respiratory and heart rate as well as oxygen saturation remained stable during inhalation of the HS. Three infants had cough during inhalation; one of the infants woke up due to cough but recovered within 5 min. No other side effects were observed during or immediately after inhalation. There was no difference in microbiologic yield between pre- and post-HS throat swabs. In this pilot study, inhalation of HS was well tolerated in CF infants. These results support a study of the efficacy of HS in this age group.

Comparison of throat swabs and nasopharyngeal suction specimens in non-sputum-producing patients with cystic fibrosis

Both throat swabs and nasopharyngeal suction (NPS) specimens are used for microbiological assessment in non-sputum-producing patients with cystic fibrosis (CF), but studies comparing their diagnostic yield are lacking. We, therefore, conducted a prospective study in young CF patients, in which both techniques were performed in random order. Forty-seven consecutive CF children aged 6 months to 10 years were studied during routine visits to the clinic. CF relevant pathogens were found in the majority of patients with no significant differences in the rate of positive cultures for Staphylococcus aureus, Haemophilus influenzae, or Pseudomonas aeruginosa. A statistically significant difference was observed in the rate of detection of other organisms with only 9/47 (19%) of throat swab specimens and 27/47 (57%) of NPS specimens being positive (P = 0.0004). This included 12 positive cultures for Streptococcus pneumoniae and 11 cultures that were positive for Moraxella catarrhalis, both of which are frequent colonizers of the upper airway. Therefore, the most common bacterial pathogens affecting the CF lung appear to be detected in similar frequency by throat swab as by nasopharyngeal suction. There is evidence that nasopharyngeal suction yields more specimens of Streptococcus pneumoniae and Moraxella catarrhalis, which may reflect upper airway colonization rather than lower airway infection. We conclude that nasopharyngeal suction is not routinely warranted as there is no benefit over throat swab in detection of CF pathogens in infants and young children with CF.

Detection of Pseudomonas aeruginosa in patients with cystic fibrosis

Chronic pulmonary colonisation with Pseudomonas aeruginosa (PA) in patients with CF is associated with a high morbidity and mortality. Adequate treatment of first acquisition of PA might prevent or postpone chronic colonisation. Early detection of PA is therefore of major importance. Currently, cultures of oropharynx or sputum are most commonly practised. However, oropharyngeal culture has limitations both in the positive and negative predictive value for the presence of PA in the lower respiratory tract. Induction of sputum has little benefit in detection of PA. Serology might have additional value in early detection, when bacterial density is too low to be detected by culture. Molecular techniques are not yet widespread used for detection of PA, but have in general a high sensitivity. In this review, we describe the value of different diagnostic techniques for detecting PA.