Early detection using qPCR of Pseudomonas aeruginosa infection in children with cystic fibrosis undergoing eradication treatment

Background

Infection with Pseudomonas aeruginosa (Pa) with a chronic phenotype is associated with antibiotic eradication therapy (AET) failure. Our objective was to determine whether higher levels of Pa (detected using qPCR) prior to culture positivity were associated with AET failure in pediatric CF patients.

Mechanisms of humoral immune response against Pseudomonas aeruginosa biofilm infection in cystic fibrosis

P. aeruginosa chronic lung infection is the major cause of morbidity and mortality in patients with cystic fibrosis (CF), and is characterized by a biofilm mode of growth, increased levels of specific IgG antibodies and immune complex formation. However, despite being designed to combat this infection, such elevated humoral response is not associated with clinical improvement, pointing to a lack of anti-pseudomonas effectiveness. The mode of action of specific antibodies, as well as their structural features, and even the background involving B-cell production, stimulation and differentiation into antibody-producing cells in the CF airways are poorly understood. Thus, the aim of this review is to discuss studies that have addressed the intrinsic features of the humoral immune response and provide new insights regarding its insufficiency in the CF context.     

Outcomes of fundoplication in children with cystic fibrosis

Purpose

Children with cystic fibrosis (CF) have a high prevalence of gastroesophageal reflux disease (GERD). As GERD is associated with chronic respiratory symptoms and feeding problems, fundoplication is often performed in children with CF. Although the outcomes of fundoplication have been described across diverse pediatric groups, there is no published experience with CF.

Methods

The records of 25 children with CF who underwent fundoplication in our center were reviewed. Data on symptoms and diagnostic testing results as well as on complications related to fundoplication were collected. Nutritional parameters and pulmonary function were compared before and after fundoplication.

Results

There was no mortality associated with fundoplication, but 12% had complications that required a subsequent surgical procedure. Whereas 28% were able to discontinue their antireflux medications, 48% developed symptoms of recurrent GERD. Overall, there was no change in body mass index, body mass index percentile, or the slope of forced expiratory volume in 1 second (FEV₁) after fundoplication. Children who had an FEV₁ of less than 60% predicted at the time of fundoplication exhibited an improvement in FEV₁ slope compared to those with FEV₁ of 60% or more (+5.3% vs −8.6% per year, P = .004).

Conclusion

The complication rate of fundoplication is similar to what has been reported in large series in children without CF. There is a high rate of recurrent GERD and little apparent benefit for either nutritional or pulmonary outcomes. The observed difference on FEV₁ slope, in those with moderate-severe vs mild lung disease, highlights the need to thoroughly evaluate the role of fundoplication in children with CF.     

Effectiveness of inhaled tobramycin in eradicating Pseudomonas aeruginosa in children with cystic fibrosis

BackgroundInhaled tobramycin therapy has been shown to be efficacious in clinical trials for the eradication of initial Pseudomonas aeruginosa infection in children with cystic fibrosis (CF). However, the effectiveness of different regimens in eradicating P. aeruginosa and preventing the development of chronic infection in actual clinical settings has yet to be determined.MethodsThis was an observational study of children (< 18 years of age) with CF with incident P. aeruginosa infection from 2005–2012 based on data collected from the Toronto CF Database and medical charts. Patients who received inhaled tobramycin (80 mg/2 ml twice daily for 365 days) were compared to those who received tobramycin inhalation solution (TIS) (300 mg/5 ml twice daily for 28 days) with respect to eradication and development of chronic infection. We also examined the risk factors for recurrence of infection.ResultsDuring the study period, 65 patients were identified with incident P. aeruginosa, of which 7 (11%) failed eradication therapy. Eradication failure was similar between the two treatment groups. A total of 4 patients (6%) developed chronic P. aeruginosa infection in the 12 months following the end of therapy with no differences between treatment groups. Female gender, older age, pancreatic insufficiency, lower lung function and worse nutritional status were identified as risk factors for recurrence of P. aeruginosa infection.ConclusionsBoth regimens of inhaled tobramycin have similar effectiveness in eradicating P. aeruginosa and preventing chronic P. aeruginosa infection in CF patients in clinical practice. Further work is needed, however, to identify patient characteristics and bacterial factors that play a role in eradication failure, in order to develop more effective antimicrobial rescue treatment strategies.     

KB001-A,a novel anti-inflammatory,found to be safe and well-tolerated in cystic fibrosis patients infected with Pseudomonas aeruginosa

Background

Chronic Pseudomonas aeruginosa (Pa) airways infection, exuberant local inflammation, and progressive lung function loss are hallmarks of cystic fibrosis (CF). KB001-A is an anti-PcrV PEGylated monoclonal antibody fragment to the Type III secretion system of Pa.This 16-week study evaluated KB001-A associated effect on time-to-need for antibiotics for worsening respiratory signs and symptoms, as well as safety, and treatment-associated changes in symptom scores, inflammatory markers, and spirometry.

Voriconazole therapy in children with cystic fibrosis

BACKGROUND: There is increasing evidence for the efficacy of the antifungal voriconazole, particularly in immunosuppression. We describe our experience of using voriconazole in children with CF. METHODS: We performed a retrospective case note review of children with CF treated with voriconazole in a single centre over an 18 month period. RESULTS: A total of 21 children aged 5 to 16 years (median 11.3) received voriconazole for between 1 and 50 (22) weeks. Voriconazole was used as monotherapy in 2 children with recurrent allergic bronchopulmonary aspergillosis (ABPA); significant and sustained improvements in clinical and serological parameters for up to 13 months were observed, without recourse to oral steroids. Voriconazole was used in combination with an immunomodulatory agent in a further 11 children with ABPA, with significant improvement in pulmonary function and serology. 8 children without ABPA but who had recurrent Aspergillus fumigatus isolates and increased symptoms also received voriconazole; this group did not improve with treatment. Adverse effects occurred in 7 children (33%: photosensitivity reaction 3, nausea 2, rise in hepatic enzymes 1, hair loss 1). CONCLUSIONS: Voriconazole may be a useful adjunctive therapy for ABPA in CF. Voriconazole monotherapy appears to be an alternative treatment strategy when oral corticosteroids may not be suitable.     

Club cell secretory protein and lung function in children with cystic fibrosis

BackgroundClub cell secretory protein (CC16) exerts anti-inflammatory functions in lung disease. We sought to determine the relation of serum CC16 deficits and genetic variants that control serum CC16 to lung function among children with cystic fibrosis (CF).MethodsWe used longitudinal data from CF children (EPIC Study) with no positive cultures for Pseudomonas aeruginosa prior to enrollment. Circulating levels of CC16 and an inflammatory score (generated from CRP, SAA, calprotectin, G-CSF) were compared between participants with the lowest and highest FEV₁ levels in adolescence (LLF and HLF groups, respectively; N = 130-per-group). Single nucleotide variants (SNVs) in the SCGB1A1, EHF-APIP loci were tested for association with circulating CC16 and with decline of FEV₁ and FEV₁/FVC% predicted levels between ages 7–16 using mixed models.ResultsCompared with the HLF group, the LLF group had lower levels of CC16 (geometric means: 8.2 vs 6.5 ng/ml, respectively; p = 0.0002) and higher levels of the normalized inflammatory score (-0.21 vs 0.21, p = 0.0007). Participants in the lowest CC16 and highest inflammation tertile had the highest odds for having LLF (p<0.0001 for comparison with participants in the highest CC16 and lowest inflammation tertile). Among seven SNVs associated with circulating CC16, the top SNV rs3741240 was associated with decline of FEV₁/FVC and, marginally, FEV₁ (p = 0.003 and 0.025, respectively; N = 611 participants, 20,801 lung function observations).ConclusionsSerum CC16 deficits are strongly associated with severity of CF lung disease and their effects are additive with systemic inflammation. The rs3741240 A allele is associated with low circulating CC16 and, possibly, accelerated lung function decline in CF.     

IgG avidity to Pseudomonas aeruginosa over the course of chronic lung biofilm infection in cystic fibrosis

Background and objectives

The mechanisms leading to low effectiveness of the humoral immune response against P. aeruginosa in cystic fibrosis (CF) are poorly understood. The aim of the present study was to assess the avidity maturation of specific antipseudomonal IgG before and during the development of chronic lung infection in a cohort of Danish CF patients.

Combined lung-liver-pancreas transplantation in a recipient with cystic fibrosis

Cystic fibrosis (CF) affects multiple organs including the lung, liver, and pancreas. Lung transplant, liver transplant, and combined lung-liver transplant have become well-established therapies for CF patients with end-stage organ failure. Thus far, however, there has been limited experience with pancreas transplantation in CF. In this report, we detail the clinical history, transplant procedure, and post-operative recovery of a patient who underwent combined lung-liver-pancreas transplant for advanced CF.     

Comparison of two treatment regimens for eradication of Pseudomonas aeruginosa infection in children with cystic fibrosis

In patients with cystic fibrosis (CF), treatment of new Pseudomonas aeruginosa (Pa) infection postpones the occurrence of chronic infection, but the best eradication regimen is unknown .Aim of the studyCompare 2 Pa eradication regimens in children with new Pa infection.MethodsChildren with CF (0–18 years) and a new isolation of Pa from sputum, cough swab or BAL were randomized to treatment with tobramycin inhalation solution for 28 days (TIS) or inhaled sodiumcolistimethate (2 × 2 mill U/day) plus oral ciprofloxacin (30 mg/kg/day) for 3 months (CC). Airway cultures were taken for 6 consecutive months, then every 3 months. The primary outcome was Pa eradication at the end of treatment. Secondary outcome parameters were: time to Pa relapse from end of treatment, total and Pa specific IgG, FEV₁, BMI and Pa status at 2 year follow-up.Results58 patients with new Pa isolation were randomized. Their median age was 9 years (IQR 4.7–13.1) and their median FEV₁ 98% predicted (IQR 87–107). Eighteen treatments concerned the first Pa isolation ‘ever’ (TIS: 8; CC: 10). For the remaining, median time since previous Pa was 19 months (IQR 9–41). Eradication at end of treatment was similar for both treatments: 26/29 CC and 23/29 in TOBI treated patients (p = 0.47). Median time to recurrence of Pa was 9 months (95% CI 0.0–19.0) for CC and 5 months (95% CI 1.7–8.3) for TIS (p = 0.608). After 1 year, the 2 groups did not differ in change in total and Pa specific IgG, FEV₁ and BMI. After 2 years, 10% of patients had chronic Pa infection.ConclusionIn children with CF and new Pa infection, inhalation of TIS (28 days) or CC (3 months) resulted in similar eradication success at the end of treatment (80 and 90% respectively) and similar clinical evolution during the first 2 years of follow-up.     

Zinc therapy for night blindness in cystic fibrosis

This is the first report of a supplemented CF patient presenting with clinical vitamin A deficiency to be successfully treated with zinc therapy alone. Therefore in addition to retinol supplementation, normalizing serum zinc levels may be important in maintaining the vitamin A status of CF patients. The interactions and synergistic effects between the two micronutrients are discussed.     

Caregiver burden of parents of young children with cystic fibrosis

Background

There is a paucity of research examining the impact of informal caregiving on parents of young children with cystic fibrosis (CF). The aim of this study was to examine caregiver burden and identify risk factors associated with high caregiver burden in mothers and fathers of young children with CF.

Mucoid Pseudomonas aeruginosa and regional inflammation in the cystic fibrosis lung

BackgroundPseudomonas aeruginosa is the prominent bacterial pathogen in the cystic fibrosis (CF) lung and contributes to significant morbidity and mortality. Though P. aeruginosa strains initially colonizing the CF lung have a nonmucoid colony morphology, they often mutate into mucoid variants that are associated with clinical deterioration. Both nonmucoid and mucoid P. aeruginosa variants are often co-isolated on microbiological cultures of sputum collected from CF patients. With regional variation in bronchiectasis, tissue damage, inflammation, and microbial colonization, lobar distribution of nonmucoid and mucoid P. aeruginosa variants may impact local microenvironments in the CF lung, but this has not been well-studied.MethodsWe prospectively collected lobe-specific bronchoalveolar lavage (BAL) fluid from a CF patient cohort (n = 14) using a standardized bronchoscopic protocol where collection was performed in 6 lobar regions. The lobar BAL specimens were plated on P. aeruginosa-selective media and proinflammatory cytokines (IL-1, TNF, IL-6 and IL-8) were measured via cytokine array. Correlations between infecting P. aeruginosa variants (nonmucoid, mucoid, or mixed-variant populations), the lobar regions in which these variants were found, and regional proinflammatory cytokine concentrations were measured.ResultsP. aeruginosa mucoid and nonmucoid variants were homogenously distributed throughout the CF lung. However, infection with mucoid variants (found within single- or mixed-variant populations) was associated with significantly greater regional inflammation. The upper and lower lobes of the CF lung did not exhibit differences in inflammatory cytokine concentrations.ConclusionsMucoid P. aeruginosa infection is a microbial determinant of regional inflammation within the CF lung.     

Bicarbonate in cystic fibrosis

Background

Cystic fibrosis (CF, mucoviscidosis) is caused by mutations in the gene encoding CF transmembrane conductance regulator (CFTR), which is a chloride and bicarbonate channel necessary for fluid secretion and extracellular alkalization. For a long time, research concentrated on abnormal Cl^- and Na⁺ transport, but neglected bicarbonate as a crucial factor in CF.

Multilocus amplicon sequencing of Pseudomonas aeruginosa cystic fibrosis airways isolates collected prior to and after early antipseudomonal chemotherapy

Background

Early antimicrobial chemotherapy can prevent or at least delay chronic cystic fibrosis (CF) airways infections with Pseudomonas aeruginosa.

Establishing the diagnosis of chronic colonization with Pseudomonas aeruginosa of cystic fibrosis patients: Comparison of the European consensus criteria with genotyping of P. aeruginosa isolates

After antibiotic eradication treatment for a first ever Pseudomonas aeruginosa isolation, the European consensus criteria (ECC) are widely used to assess colonization status with P. aeruginosa in CF-patients. We evaluated to what extent genotyping (GT) of subsequent P. aeruginosa isolates could predict/assess chronic colonization (CC), in comparison with the ECC.

Longitudinal development of initial,chronic and mucoid Pseudomonas aeruginosa infection in young children with cystic fibrosis

Background

While the emergence of chronic and mucoid Pseudomonas aeruginosa (Pa) infection are both associated with poorer outcomes among CF patients, their relationship is poorly understood. We examined the longitudinal relationship of incident, chronic and mucoid Pa in a contemporary, young CF cohort in the current era of Pa eradication therapy.

The effects of intravenous tobramycin on renal tubular function in children with cystic fibrosis

BACKGROUND: Tobramycin, used to treat respiratory exacerbations in cystic fibrosis (CF), is also a renal tubular toxin. Tubular dysfunction leads to increased urinary levels of the proximal tubular lysosomal enzyme, N-acetyl-beta-D-glucosaminidase (NAG) and the proximal tubular protein, retinol-binding protein (RBP). Hypermagnesuria and resulting hypomagnesaemia are indicative of more severe tubular damage, occasionally seen following repeated courses of intravenous tobramycin. Using these biochemical markers we studied the effect of a 2-week course of this agent on tubular function. METHODS: Twenty-two children (11 boys) with CF were studied. Median age = 10.9 years, range 3.1-16.4 years. All had a normal predicted glomerular filtration rate (pGFR). They received tobramycin 3 mg/kg/dose tds. Urinary NAG, RBP, creatinine and plasma magnesium and creatinine were assayed: a) immediately before commencing tobramycin, b) immediately following the course, c) 4 weeks after the end of the course. RESULTS: Mean log UrNAG and UrRBP rose significantly between time points a) and b) before falling to almost pre-treatment levels by time c). Using two way ANOVA analysis the results for UrNAG and UrRBP were both highly statistically significant (p<0.0001). Paired t-tests on the logged values revealed highly significant differences between all time points for UrNAG and in the case of UrRBP for all other than a) compared to c). In all patients plasma magnesium and pGFR remained within normal limits. CONCLUSIONS: Intravenous tobramycin produces acute tubular injury, which showed evidence of almost complete recovery after 4 weeks. The insult to the tubules was not sufficient to produce hypomagnesaemia in our study group. To assess cumulative tubular damage in more detail it would be necessary to repeat this study after further courses of tobramycin. We recommend monitoring plasma magnesium during courses of intravenous tobramycin.     

The potential of phage therapy in cystic fibrosis: Essential human-bacterial-phage interactions and delivery considerations for use in Pseudomonas aeruginosa-infected airways

As antimicrobial-resistant microbes become increasingly common and a significant global issue, novel approaches to treating these infections particularly in those at high risk are required. This is evident in people with cystic fibrosis (CF), who suffer from chronic airway infection caused by antibiotic resistant bacteria, typically Pseudomonas aeruginosa. One option is bacteriophage (phage) therapy, which utilises the natural predation of phage viruses upon their host bacteria. This review summarises the essential and unique aspects of the phage-microbe-human lung interactions in CF that must be addressed to successfully develop and deliver phage to CF airways. The current evidence regarding phage biology, phage-bacterial interactions, potential airway immune responses to phages, previous use of phages in humans and method of phage delivery to the lung are also summarised.