R.J. Bright-Thomas

Incidence and clinical impact of respiratory viruses in adults with cystic fibrosis

Background Viral respiratory infection (VRI) is a common cause of pulmonary exacerbations in children with cystic fibrosis (CF). The importance of VRI in adult CF populations is unclear. Objective To determine the incidence and clinical impact of VRI among adults with CF. Methods One hundred adults with CF were followed up prospectively for 12 months. Sputum, nose swabs and throat swabs were collected every 2 months and at onset of pulmonary exacerbation. PCR assays for adenovirus, influenza A&B, human metapneumovirus, parainfluenza 1–3, respiratory syncytial virus and human rhinovirus were performed on each sample. Symptom scores, spirometry and inflammatory markers were measured at each visit. Results One or more respiratory viruses were detected in 191/626 (30.5%) visits. Human rhinovirus accounted for 72.5% of viruses. Overall incidence of VRI was 1.66 (95% CI 1.39 to 1.92) cases/patient-year. VRI was associated with increased risk of pulmonary exacerbation (OR=2.19; 95% CI 1.56 to 3.08; p<0.001) and prescription of antibiotics (OR=2.26; 95% CI 1.63 to 3.13; p<0.001). Virus-positive visits were associated with higher respiratory symptom scores and greater C-reactive protein levels. Virus-positive exacerbations had a lower acute fall in FEV1 than virus-negative exacerbations (12.7% vs 15.6%; p=0.040). The incidence of exacerbations, but not VRI, was associated with greater lung function decline over 12 months (−1.79% per pulmonary exacerbation/year; 95% CI −3.4 to −0.23; p=0.025). Conclusion VRI is common in adults with CF and is associated with substantial morbidity. Respiratory viruses are a potential therapeutic target in CF lung disease.

Hydrogen cyanide concentrations in the breath of adult cystic fibrosis patients with and without Pseudomonas aeruginosa infection

Elevated concentrations of hydrogen cyanide (HCN) have been detected in the headspace of Pseudomonas aeruginosa (PA) cultures and in the breath of children with cystic fibrosis (CF) and PA infection. The use of mouth-exhaled breath HCN as a marker of PA infection in adults is more difficult to assess as some without PA infection generate HCN in their mouths. The analysis of breath exhaled via the nose, thereby avoiding volatile compounds produced in the mouth, will demonstrate elevated concentrations of HCN in adult CF patients chronically infected with PA. Using selected ion flow mass spectrometry (SIFT-MS), the mouth and the nose-exhaled breaths of 20 adult CF patients; 10 with chronic PA infection and 10 free from PA infection, were analysed for HCN. Acetone and ethanol were also measured as controls. SIFT-MS allows direct sampling and analysis of single breath exhalations, obviating the need to collect samples into bags or onto traps, which can compromise samples. HCN was detected in the mouth-exhaled breath of patients in both groups and in the nose-exhaled breath of patients with chronic PA infection. The difference in median (IQR) nose-exhaled HCN between the groups is statistically significant (11 (0.8-18) ppbv versus 0 (0-3.2) ppbv, p = 0.03). The concentrations of acetone and ethanol in nose-exhaled and mouth-exhaled breath are in keeping with previous studies. HCN in nose-exhaled breath is a biomarker of chronic airway infection with PA in adults with CF. Its application as a non-invasive diagnostic test for early PA infection warrants further investigation.

Rapid Detection of Emerging Pathogens and Loss of Microbial Diversity Associated with Severe Lung Disease in Cystic Fibrosis

ABSTRACT Respiratory infection in cystic fibrosis (CF) is polymicrobial, but standard sputum microbiology does not account for the lung microbiome or detect changes in microbial diversity associated with disease. As a clinically applicable CF microbiome surveillance scheme, total sputum nucleic acids isolated by a standard high-throughput robotic method for accredited viral diagnosis were profiled for bacterial diversity using ribosomal intergenic spacer analysis (RISA) PCR. Conventional culture and RISA were performed on 200 paired sputum samples from 93 CF adults; pyrosequencing of the 16S rRNA gene was applied to 59 patients to systematically determine bacterial diversity. Compared to the microbiology data, RISA profiles clustered into two groups: the emerging nonfermenting Gram-negative organisms (eNFGN) and Pseudomonas groups. Patients who were culture positive for Burkholderia, Achromobacter, Stenotrophomonas, and Ralstonia clustered within the eNFGN group. Pseudomonas group RISA profiles were associated with Pseudomonas aeruginosa culture-positive patients. Sequence analysis confirmed the abundance of eNFGN genera and Pseudomonas within these respective groups. Low bacterial diversity was associated with severe lung disease (P < 0.001) and the presence of Burkholderia (P < 0.001). An absence of Streptococcus (P < 0.05) occurred in individuals with lung function in the lowest quartile. In summary, nucleic acids isolated from CF sputum can serve as a single template for both molecular virology and bacteriology, with a RISA PCR rapidly detecting the presence of dominant eNFGN pathogens or P. aeruginosa missed by culture (11% of cases). We provide guidance for how this straightforward CF microbiota profiling scheme may be adopted by clinical laboratories.

Can early Burkholderia cepacia complex infection in cystic fibrosis be eradicated with antibiotic therapy

Introduction: Organisms of the Burkholderia cepacia complex (BCC) are important pathogens in cystic fibrosis (CF). The majority of those who acquire BCC develop chronic infection but it can also result in rapid decline in a significant minority. In addition, chronic infection with Burkholderia cenocepacia in particular is regarded as a contraindication to lung transplantation in many units. Whilst aggressive antibiotic therapy is employed in CF to eradicate Pseudomonas aeruginosa before infection becomes irreversibly established, no formal assessment of such strategies has been previously reported for BCC, despite the apparent widespread adoption of this practice. Methods: UK adult CF centers were surveyed about their current approach to new BCC infection. Outcomes of eradication therapy were assessed in patients attending the Manchester Adult CF Center with new BCC isolates between 1st January 2002 and 1st May 2011. Patients with previous infection with the same strain of BCC were excluded. BCC were identified at the national reference laboratories and confirmed by species-specific PCR and RecA sequencing. Results: Routine use of therapies to attempt eradication of new BCC is commonly used in the UK (12/17 centers who responded). This typically involves a combination of intravenous and nebulised antibiotics. Of 19 eligible cases of new BCC infection, the organism has been eradicated in 7 (37%). Three of these did not receive specific eradication therapy. Of 14 patients who have received eradication therapy and completed follow up, BCC were cleared in only 4 (29%). Conclusions: Attempted eradication of new BCC is a common practice in UK adult CF centers. A minority of patients clear the infection spontaneously and the effects of eradication therapies are at best modest. Early treatment may be associated with better outcomes, though there are insufficient data to support the use of any specific treatment regimen. A prospective, systematic evaluation of treatments and outcomes is required.

Long-term non-invasive ventilation in cystic fibrosis — Experience over two decades ☆

BACKGROUND Non-invasive ventilation (NIV) is accepted as a bridge to lung transplantation in cystic fibrosis (CF) but there is little evidence to support its use outside this setting. METHODS We reviewed the records of all patients with CF who received domiciliary NIV at our centre between 1991 and 2010. RESULTS Of 47 patients studied, 36% underwent lung transplantation, 28% died without transplantation and 30% remain alive on NIV. Median duration of NIV was 16 months (range 2-90). Mean FEV(1) fell by 212 ml over the year before NIV but increased by 18 ml in the following year (p<0.01). Individual response to NIV was associated with lower baseline and more rapid decline in FEV(1). From 1991 to 2000, 70% underwent lung transplantation; from 2001 to 2010 only 27% were transplanted. CONCLUSIONS NIV may slow or reverse the decline in lung function in advanced CF. NIV is increasingly used beyond a bridge to transplantation at our centre.

Itraconazole and inhaled fluticasone causing hypothalamic-pituitary-adrenal axis suppression in adults with cystic fibrosis.

BACKGROUND Although there have been case reports of hypothalamic-pituitary-adrenal (HPA) axis suppression in patients with cystic fibrosis (CF) caused by the combination of oral itraconazole and inhaled fluticasone, to date no study has assessed the incidence of this potentially serious side effect. METHODS Synacthen tests were conducted on all patients with CF receiving itraconazole and inhaled fluticasone and an equal number of patients with CF receiving inhaled fluticasone but not itraconazole. Itraconazole levels were measured in patients receiving the therapy. RESULTS Twelve patients receiving itraconazole and fluticasone underwent synacthen tests. All 12 had abnormal synacthen test results and 10/12 (83%) had HPA axis suppression. Two patients had severe HPA axis suppression with a peak cortisol <75 nmol/L and further 3 patients had moderately severe suppression with a peak cortisol <250 nmol/L. In contrast, only 2/12 on fluticasone alone had HPA axis suppression (both mild). The median (range) basal cortisol levels were significantly lower in those patients receiving itraconazole and inhaled fluticasone compared to those on fluticasone alone (219(22-508)nmol/L v 348(41-738)nnmol/L, p=0.02), similar results were seen for peak cortisol levels (404(59-706)nmol/L v 672(432-1178)nmol/L, p<0.001) and cortisol rise (179(37-240)nmol/L v 368(210-539)nmol/L, p<0.001). The median (range) itraconazole level was 5.5(1.7-14.7)mg/L. Neither itraconazole levels nor fluticasone dose correlated with the degree of adrenal suppression. CONCLUSIONS In this study, all patients receiving itraconazole and inhaled fluticasone had abnormal synacthen test results. The incidence of HPA axis suppression with this treatment combination appears to be higher than that previously reported with itraconazole and inhaled budesonide.

Is Hydrogen Cyanide a Marker of Burkholderia cepacia Complex

ABSTRACT Biofilm cultures of Burkholderia cepacia complex (BCC) infection have been found to generate the nonvolatile cyanide ion. We investigated if gaseous hydrogen cyanide (HCN) was a marker of BCC infection. Selected ion flow tube mass spectrometry analysis showed HCN was not elevated in the headspace of planktonic or biofilm cultures or in the exhaled breath of adult cystic fibrosis patients with chronic BCC infection. HCN is therefore not an in vitro or in vivo marker of BCC.

Pulmonary artery pressure in cystic fibrosis adults: Characteristics, clinical correlates and long-term follow-up

BACKGROUND We examined pulmonary artery pressure (PAP) characteristics of CF adults, studied clinical correlates and long-term survival. METHODS Comprehensive clinical data were collected and Doppler echocardiography was used to estimate PAP in 109 stable CF adults and 50 healthy controls. RESULTS CF patients had lower day and night-time oxygen status, elevated CRP and BNP, and elevated PAP (27.7(13.2, 62.8) mmHg patients v 17.9(11.3, 30.9) mmHg controls, p<0.001). Even patients with mild pulmonary disease had raised PAP. PAP measurements strongly correlated with arterial partial pressure of oxygen (PaO(2), r=-0.673, p<0.001), and FEV(1) percentage predicted (FEV(1)%, r=-0.642, p<0.001) which were both independent predictors of PAP. At 10 year follow up PAP measurements were related to survival but FEV(1)% and PaO(2) were both stronger predictors of death. CONCLUSIONS PAP is raised in CF adults and correlates with pulmonary disease severity. Unlike PaO(2) and FEV(1)%, it does not appear to be an independent prognostic marker.

Chronic Rhinovirus Infection in an Adult with Cystic Fibrosis

ABSTRACT Rhinovirus is a common cause of exacerbations of cystic fibrosis (CF) and is usually considered a self-limiting infection. We report a case of chronic infection with rhinovirus A type 33 in a 43-year-old male with CF which has persisted for over 2 years.

Successful treatment of cepacia syndrome with a combination of intravenous cyclosporin, antibiotics and oral corticosteroids

Burkholderia cepacia complex (BCC) is a group of 17 closely related bacterial species that can cause pulmonary infection in patients with cystic fibrosis (CF). The clinical manifestations of BCC infection are varied but can include cepacia syndrome, which is a rapidly progressing necrotising pneumonia with an almost universally fatal outcome. We report the case of a 38 year old man, known to have chronic infection with the ET12 strain of Burkholderia cenocepacia who developed cepacia syndrome 26 years after initial infection. Aggressive treatment with a combination of 4 intravenous antibiotics, oral corticosteroids and cyclosporin brought about clinical, radiological and biochemical resolution of his cepacia syndrome. This case highlights the possible role of cyclosporin in the treatment of cepacia syndrome.