Tracheostomy decannulation in children: a proposal for a structured approach on behalf of the working group chronic respiratory insufficiency within the German-speaking society of pediatric pulmonology.

The number of children with tracheostomies with and without home mechanical ventilation has grown continuously in recent years. For some of these children, the need for tracheostomy resolves and the child can be weaned from the tracheal cannula. Choosing the optimal time point for decannulation after elaborated prior diagnostic work-up needs careful consideration. The decannulation process requires an interdisciplinary team; however, these specialized structures for the experienced care of these children with tracheostomy are not available in all areas. The Working Group on Chronic Respiratory Insufficiency in the German Speaking Pediatric Pneumology Society (GPP) developed these recommendations to guide through a decannulation process. Initial evaluation of decannulation feasibility starts in the outpatient clinic with a detailed history, examination, and a speaking valve trial and is followed by an inpatient workup including sleep study, airway endoscopy and possibly modifications of the tracheal cannula. Downsizing the tracheal cannula allows a stepwise controlled weaning prior to removal of the tracheal cannula. After shrinking of the tracheostomy, the final surgical closure is performed.  Conclusion: An algorithm with diagnostic and therapeutic procedures for a safe and successful decannulation process is proposed. What is Known: • In children tracheostomy decannulation is a complex process that requires careful preparation and surveillance. What is New: • This statement of the German speaking society of pediatric pulmonology provides an expert practice guidance on the decannulation procedure and the value of one-way speaking valves.

Biofilm infection of a central venous port-catheter caused by Mycobacterium avium complex in an immunocompetent child with cystic fibrosis.

BACKGROUND: Mycobacterium (M.) chimaera is a non-tuberculous mycobacterium (NTM) that belongs to M. avium complex (MAC). In patients with cystic fibrosis (CF), MAC can cause bronchopulmonary infections that can be prolonged and difficult to treat. MAC infections of sites other than the lungs or central catheters are rare and almost exclusively associated with immunodeficiency. CASE PRESENTATION: We present a case of an 8-year-old CF patient (delF508 homozygous) with recurrent pulmonary exacerbations, gradual clinical deterioration, B-symptoms (fever, fatigue, weight loss, night sweat), elevated transaminases and intermittent detection of M. chimaera in the sputum without radiological signs of NTM-associated lung disease with a central venous port-catheter. Next-generation sequencing (NGS) revealed M. chimaera port infection that was also confirmed by mycobacterial culture. The patient recovered within 4 weeks after removal of the catheter and initiation of MAC targeted antimicrobial therapy. Electron microscopy of the catheter illustrated the presence of mycobacteria in a biofilm. CONCLUSIONS: MAC central venous catheter infection needs to be considered in immunocompetent people. NGS is a valuable tool for rapid identification of rare infections. MAC capability of biofilm formation renders catheter removal the central therapeutic intervention for the clearance of the infection.

Cough suppression and HRQoL in adult people with cystic fibrosis: an unexplored correlation.

BACKGROUND: Cough suppression assessed by embarrassment about coughing has been shown in adolescents with cystic fibrosis (CF) and negatively affects health-related quality of life (HRQoL) and clinical indicators of disease severity in adolescent females. However, whether cough suppression exists in adults has been studied as little as its effects on clinical and psychological outcomes beyond adolescence. METHODS: Seventy-one subjects completed the self-reported 'Cystic Fibrosis Questionnaire-Revised (CFQ-R + 14)' and a self-report questionnaire about cough suppression, health-related perspectives, and therapy adherence. The status of CF disease was quantified in terms of the percentage of predicted forced expiratory volume in one second (ppFEV1), body mass index (BMI), Pseudomonas aeruginosa, pancreatic status, and CF-related diabetes (CFRD). Additional demographic data for sex, age, graduation, employment, and marital status were assessed. RESULTS: CS exists in adult CF and is associated with impaired HRQoL but not the overall CF disease status regarding BMI, ppFEV1, or health-related perspectives. Despite a higher prevalence of cough suppression in women, no effect of sex regarding either outcome measure was observed. CONCLUSION: The results of this study suggest that mental health indicators have an impact on cough suppression.

Multiple breath washout lung function reveals ventilation inhomogeneity unresponsive to mechanical assisted cough in patients with neuromuscular disease.

BACKGROUND: Respiratory involvement defines the clinical outcome of neuromuscular diseases (NMD). The lung clearance index (LCI) is a marker of lung ventilation inhomogeneity and indicates small airway disease. It is determined by mulitple breath washout lung function (MBW). The merit of LCI is undisputed for primary lung diseases like cystic fibrosis, but its role in NMD is unclear. METHODS: We investigated the role of MBW in patients with NMD and the effect of two different tracer gases and cough assist devices on the LCI. Patients and controls performed MBW with nitrogen (N2) and sulfur hexafluoride (SF6), whereas the latter analysis was repeated after the use of a cough assist device in the NMD group. LCI was compared to forced vital capacity (FVC) and peak cough flow (PCF). RESULTS: 24 NMD patients (12 Duchenne Muscular Dystrophy, 8 Spinal Muscular Atrophy, 4 other NMDs) and 15 healthy controls were enrolled. In the NMD group, overall LCI N2 was higher than LCI SF6 (9.67 ± 1.56 vs. 8.71 ± 1.47; mean ± SD; p < 0.033). In controls, LCI N2 did not differ significantly from LCI SF6 (7.03 ± 0.37 vs. 7.05 ± 0.67; p = 0.882). Both LCI N2 and LCI SF6 were significantly higher in NMD patients as in controls (9.67 ± 1.56 vs. 7.03 ± 0.37, p < 0.001, and 8.71 ± 1.478.65 vs. 7.05 ± 0.67, p < 0.001). In the NMD group, both LCI N2 and LCI SF6 showed a negative correlation to FVC (r = - 0.525; p = 0.008 and r = - 0.526; p = 0.008, respectively) and PCF (r = - 0.590; p = 0.002 and r = - 0.641; p = 0.001, respectively). LCI N2 and LCI SF6 correlated well in the NMD group. LCI SF6 did not change significantly after the use of the cough assist in NMD patients (n = 22; 8.65 ± 1.52 pre vs. 8.79 ± 2.03 post, p = 0.667). CONCLUSION: Lung involvement of patients with neuromuscular diseases goes beyond weakness of respiratory muscles. MBW with both N2 and SF6 is suitable to detect ventilation inhomogeneity in NMD patients with respiratory impairment. Cough assist devices with low to moderate pressure levels do not immediately improve the LCI.

Targeted PCR of Mucorales in pediatric bronchoalveolar lavage samples indicates low prevalence of airway colonization and sample contamination.

Mucorales are a large order of ubiquitous saprophytic zygomycete fungi and act as opportunistic pathogens in humans. In pediatric patients, little is known about the role of Mucorales in airway colonization and infection or their role as contaminants of respiratory samples. Currently, polymerase chain reaction (PCR) is the most sensitive mode of detection Mucorales in clinical specimen. In this study, we aimed to determine the prevalence of Mucorales in bronchoalveolar lavage samples (BAL) from a large, diverse group of pediatric patients. We performed commercial Mucorales PCR (MucorGenius®, Pathonostics, Maastricht, NL, USA) on 102 thawed BAL samples of 100 patients. Mucorales PCR was negative in all samples. Our data suggest that Mucorales spp. have a low prevalence in paediatric airways and do not frequently contaminate pediatric BAL samples.

Epidemiological trends in nontuberculous mycobacterial infection among people with cystic fibrosis in Germany.

OBJECTIVES: People with cystic fibrosis (pwCF) are at risk for infection with nontuberculous mycobacteria (NTM). The epidemiology and screening practice of NTM among pwCF in Germany are largely unknown and require investigation. METHODS: We analyzed the data of the German Cystic Fibrosis Registry from 2016 to 2020 for NTM. The annual prevalence and incidence of any NTM, Mycobacterium abscessus complex (MABC), Mycobacterium avium complex (MAC), Mycobacterium gordonae, and other mycobacteria were determined and correlated to patient characteristics. Patients with incident MABC and MAC infection were compared. RESULTS: The annual NTM prevalence and incidence remained stable between 7.53% and 8.76%, as well as 3.31% and 4.95%, respectively, among the approximately 6000 registry participants. MABC was the most common NTM, whereas only the prevalence of MAC increased slightly. In each year, only about one-third of all patients were screened for NTM. An association between NTM infections and Aspergillus fumigatus infection and/or allergic bronchopulmonary aspergillosis was observed. On average, patients with incident MAC infection were older than patients with MABC infection. CONCLUSION: The NTM burden in pwCF in Germany remained unchanged between 2016 and 2020. MABC was the dominant species detected, whereas only MAC infections increased with time and patient age. The previously observed association of Aspergillus fumigatus and NTM was reaffirmed. Awareness of NTM needs to be improved.

Real-life impact of highly effective CFTR modulator therapy in children with cystic fibrosis.

Introduction: Recently, cystic fibrosis transmembrane regulator modulator therapy with elexacaftor/tezacaftor/ivacaftor has become available for children with cystic fibrosis (CF) carrying at least one F508del mutation. Objective: To assess the intermediate term effects of elexacaftor/tezacaftor/ivacaftor in children with cystic fibrosis in a real-world setting. Methods: We performed a retrospective analysis of records of children with cystic fibrosis, who started elexacaftor/tezacaftor/ivacaftor between 8/2020 and 10/2022. Pulmonary function tests, nutritional status, sweat chloride and laboratory data were assessed before, 3 and 6 months after the start of elexacaftor/tezacaftor/ivacaftor respectively. Results: Elexacaftor/tezacaftor/ivacaftor was started in 22 children 6-11 years and in 24 children 12-17 years. Twenty-seven (59%) patients were homozygous for F508del (F/F) and 23 (50%) patients were transitioned from ivacaftor/lumacaftor (IVA/LUM) or tezacaftor/ivacaftor (TEZ/IVA) to elexacaftor/tezacaftor/ivacaftor. Overall, mean sweat chloride concentration decreased by 59.3 mmol/L (95% confidence interval: -65.0 to -53.7 mmol/L, p < 0.0001) under elexacaftor/tezacaftor/ivacaftor. Sweat chloride concentration also decreased significantly after transition from IVA/LUM or TEZ/IVA to elexacaftor/tezacaftor/ivacaftor (-47.8 mmol/l; 95% confidence interval: -57.6 to -37.8 mmol/l, n = 14, p < 0.0001). Sweat chloride reduction was more marked in children with the F/F than in those with the F/MF genotype (69.4 vs 45.9 mmol/L, p < 0.0001). At 3 months follow-up, body-mass-index-z-score increased by 0.31 (95% CI, 0.2-0.42, p < 0.0001) with no further increase at 6 months. BMI-for-age-z-score was more markedly improved in the older group. Overall pulmonary function (percent predicted FEV1) at 3 months follow-up increased by 11.4% (95% CI: 8.0-14.9, p < 0.0001) with no further significant change after 6 months. No significant differences were noted between the age groups. Children with the F/MF genotype had a greater benefit regarding nutritional status and pulmonary function tests than those with the F/F genotype. Adverse events led to elexacaftor/tezacaftor/ivacaftor dose reduction in three cases and a temporary interruption of therapy in four cases. Conclusion: In a real-world setting, elexacaftor/tezacaftor/ivacaftor therapy had beneficial clinical effects and a good safety profile in eligible children with cystic fibrosis comparable to previously published data from controlled clinical trials. The positive impact on pulmonary function tests and nutritional status seen after 3 months of elexacaftor/tezacaftor/ivacaftor therapy was sustained at 6 months follow-up.

High Prevalence of Alternative Diagnoses in Children and Adolescents with Suspected Long COVID-A Single Center Cohort Study.

BACKGROUND: Long COVID (LC) is a diagnosis that requires exclusion of alternative somatic and mental diseases. The aim of this study was to examine the prevalence of differential diagnoses in suspected pediatric LC patients and assess whether adult LC symptom clusters are applicable to pediatric patients. MATERIALS AND METHODS: Pediatric presentations at the Pediatric Infectious Diseases Department of the University Hospital Essen (Germany) were assessed retrospectively. The correlation of initial symptoms and final diagnoses (LC versus other diseases or unclarified) was assessed. The sensitivity, specificity, negative and positive predictive values of adult LC symptom clusters were calculated. RESULTS: Of 110 patients, 32 (29%) suffered from LC, 52 (47%) were diagnosed with alternative somatic/mental diseases, and 26 (23%) remained unclarified. Combined neurological and respiratory clusters displayed a sensitivity of 0.97 (95% CI 0.91-1.00) and a negative predictive value of 0.97 (0.92-1.00) for LC. DISCUSSION/CONCLUSIONS: The prevalence of alternative somatic and mental diseases in pediatric patients with suspected LC is high. The range of underlying diseases is wide, including chronic and potentially life-threatening conditions. Neurological and respiratory symptom clusters may help to identify patients that are unlikely to be suffering from LC.

Use of a commercial PCR-based line blot method for identification of bacterial pathogens and the mecA and van genes from BacTAlert blood culture bottles.

In this study, the PCR-based DNA strip assay GenoType BC for the identification of bacteria and the resistance genes mecA, vanA, vanB, vanC1, and vanC2/3 directly from positive BacTAlert blood culture bottles was evaluated in a multicenter study. Of a total of 511 positive blood cultures, correct identification percentages for Gram-negative bacteria, Gram-positive bacteria, and the mecA gene were 96.1%, 89.9%, and 92.9%, respectively. Results were available 4 h after growth detection.

GenoType CM Direct® and VisionArray Myco® for the Rapid Identification of Mycobacteria from Clinical Specimens.

M. tuberculosis is the single infectious agent responsible for most deaths worldwide outside of pandemics. Diseases due to non-tuberculous mycobacteria (NTM) are increasing in many regions of the world. The two molecular assays GenoType CM direct® (GTCMd) (Bruker, Billerica, MA, USA) and VisionArray Myco® (VAM) (ZytoVision, Bremerhaven, Germany) are based on the DNA/DNA hybridization technique, and allow for the identification of tuberculous and the most clinically relevant non-tuberculous mycobacterial species from clinical specimens. We evaluated the performance of both assays for the identification of mycobacteria from 65 clinical specimens of 65 patients and compared it with the results of conventional culture. Based on conventional culture that recovered 37 mycobacterial isolates including 11 tuberculous and 26 NTM isolates, sensitivity, specificity, positive predictive value and negative predictive value were 89.2%, 81.5%, 86.8% and 84.6% for GTCMd and 73.0%, 96.3%, 96.4% and 72.2% for VAM. Additionally, GTCMd identified mycobacteria from five and VAM from one culture-negative sample. Both assays identified a mycobacterium in one sample overgrown by other microorganisms. Two M. abscessus subsp. abscessus isolates grown from culture were identified as M. chelonae by GTCMd assay. In conclusion, both assays improve the rapid identification of mycobacteria directly from clinical specimens.

Indications and outcome of home high-flow nasal therapy in children, a single-center experience.

High-flow nasal therapy (HFNT) is a safe and simple way to deliver humidified air and oxygen for respiratory support in infants and children. HFNT is well established in an inpatient setting, but home HFNT lacks evidence. In the current study, we studied characteristics and outcomes of pediatric patients with home HFNT. In a monocentric retrospective analysis of data for 10 years (April 2010-April 2020), patient characteristics from the time point of the first discharge from hospital with home HFNT-treatment and the subsequent course were analyzed. Patients were divided into three HFNT indication groups: (1) bronchopulmonary dysplasia (BPD), (2) upper airway obstruction (UAO), and (3) other indications. Forty patients received home HFNT in the study period. Seventeen patients were treated for BPD, 15 for UAO, and 8 had other indications. Twenty-two patients (55%) were successfully weaned from HFNT (12 [70.6%] BPD, 7 [46.7%] UAO, 3 [37.5%] other), while seven patients (17.5%) died during follow-up (4 BPD, 2 UAO, 1 other). Twenty-three patients (57.5%) required (intermittent) additional oxygen application (14 [82.4%] BPD, 6 [40%] UAO, 4 [50%] other). Weaning success and need for additional oxygen were significantly more probable in BPD patients compared to the UOA group. In conclusion, HFNT plays an increasing role in home treatment of respiratory insufficiency of various etiologies in childhood. It often represents a temporary intervention, especially for children with BPD but might also serve as long-term treatment for children in whom other forms of ventilatory support are not feasible or desired.

Development of restrictive eating disorders in children and adolescents with long-COVID-associated smell and taste dysfunction.

Background: Absent or abnormal senses of smell and taste have been frequently reported during both acute and long COVID in adult patients. In contrast, pediatric patients who test positive for SARS-CoV-2 are often asymptomatic and the loss of smell and/or taste has been infrequently reported. After observing several young patients with COVID-associated anosmia and ageusia at our clinic, we decided to investigate the incidence of subsequent eating disorders in these patients and in SARS-CoV-2 positive patients who did not experience anosmia and ageusia during the same period. Material and methods: A single-site retrospective cohort study of 84 pediatric patients with suspected long COVID who were treated in the Pediatric Infectious Diseases Outpatient Clinic at the University Hospital Essen were evaluated for persistent symptoms of COVID-19. Smell and taste dysfunction as well as eating behaviors were among the signs and symptoms analyzed in this study. Results: 24 out of 84 children and adolescents described smell and taste dysfunction after confirmed or suspected SARS-CoV-2 infections. A large number of these patients (6 out of 24) demonstrated increased fixation on their eating behavior post-COVID and over time these patients developed anorexia nervosa. Discussion/Conclusion: In this study we saw a possible association of long-lasting post-COVID smell and taste dysfunction with subsequent development of eating disorders. This observation is worrisome and merits further investigation by healthcare providers at multiple clinical sites.

Phenotypic spectrum in recessive STING-associated vasculopathy with onset in infancy: Four novel cases and analysis of previously reported cases.

Gain-of-function variants in the stimulator of interferon response cGAMP interactor 1 (STING1) gene cause STING-Associated Vasculopathy with onset in Infancy (SAVI). Previously, only heterozygous and mostly de novo STING1 variants have been reported to cause SAVI. Interestingly, one variant that only leads to SAVI when homozygous, namely c.841C>T p.(Arg281Trp), has recently been described. However, there are no entries in public databases regarding an autosomal recessive pattern of inheritance. Here, we report four additional unrelated SAVI patients carrying c.841C>T in homozygous state. All patients had interstitial lung disease and displayed typical interferon activation patterns. Only one child displayed cutaneous vasculitis, while three other patients presented with a relatively mild SAVI phenotype. Steroid and baricitinib treatment had a mitigating effect on the disease phenotype in two cases, but failed to halt disease progression. Heterozygous c.841C>T carriers in our analysis were healthy and showed normal interferon activation. Literature review identified eight additional cases with autosomal recessive SAVI caused by c.841C>T homozygosity. In summary, we present four novel and eight historic cases of autosomal recessive SAVI. We provide comprehensive clinical data and show treatment regimens and clinical responses. To date, SAVI has been listed as an exclusively autosomal dominant inherited trait in relevant databases. With this report, we aim to raise awareness for autosomal recessive inheritance in this rare, severe disease which may aid in early diagnosis and development of optimized treatment strategies.

Nusinersen does not improve lung function in a cohort of children with spinal muscular atrophy - A single-center retrospective study.

OBJECTIVE: To examine the effect of intrathecal application of nusinersen on the respiratory function in terms of vital capacity in pediatric patients with spinal muscular atrophy (SMA). SMA is characterized by on-going muscular atrophy and weakness that lead to respiratory insufficiency. In recent years therapy with nusinersen has been shown to improve motor function in patients with SMA. METHODS: We retrospectively analyzed data from 12 pediatric patients (aged 4-12 years) with SMA II or III (7 walkers, 5 sitters) treated with nusinersen. We examined forced vital capacity (FVC) at baseline (i.e., before treatment) and 180 and 300 days after initiation of treatment. RESULTS: No significant difference in the ranks of FVC of patients with SMA at baseline and day 300 was found and, thus, stable FVCs are implied (n = 6; Z = - 0.105, pexact = 1.000; Medianbaseline = 96.0%, 95%-CI [86.5, 110.5]; Medianday300 = 96.0%, 95%-CI [92.0, 109.5]; s. Table 1). This also applied to the comparison between baseline and day 180 (n = 7; Z = 0.00, pexact = 1.00; Medianbaseline = 93.0%, 95%-CI [85.0, 110.0]; Medianday180 = 91.0%, 95%-CI [72.0, 118.0]) and day 180 and 300 (n = 9; Z = - 0.533, pexact = .652; Medianday180 = 95.0%, 95%-CI [72.0, 118.0]; Medianday300 = 90.0%, 95%-CI [74.0, 105.0]). CONCLUSION: Nusinersen therapy alone may not improve lung function of pediatric patients with SMA type II or III.

Species-Specific Interferon-Gamma Release Assay for the Diagnosis of Mycobacterium abscessus Complex Infection.

Mycobacterium abscessus complex (MABC) infection has a devastating impact on the course of cystic fibrosis (CF) and non-CF lung disease. Diagnosis of MABC pulmonary disease is challenging, and current diagnostic approaches lack accuracy, especially in CF. In this study, we aimed to establish an MABC-specific interferon-γ release assay to detect host immune responses to MABC and improve diagnostics of MABC infection by the detection of antigen-specific T cells. Four species-specific proteins of MABC were overexpressed in an Escherichia coli expression system. Purified proteins were used to stimulate peripheral blood mononuclear cells of study subjects in an ELISpot assay. Interferon-γ response of 12 subjects with established diagnosis of MABC infection (10 CF and two non-CF) was compared with 35 controls (22 CF and 13 non-CF) distributed to three control groups, 17 CF subjects without NTM infection, nine subjects with NTM infection other than MABC, and nine subjects with tuberculosis. Cellular in vitro responses in the MABC group were stronger than in the control groups, especially toward the protein MAB_0405c (39 vs. 4 spots per 300,000 PBMC, p = 0.004; data represent mean values) in all patients and also in the subgroup of CF subjects (39 spots vs. 1 spot, p = 0.003). Receiver operating characteristic curve analysis indicated that spot numbers of at least 20 were highly predictive of MABC infection (all patients: area under curve 0.773, sensitivity 58%, and specificity 94%; CF patients: area under curve 0.818, sensitivity 60%, and specificity 100%). In conclusion, we identified MAB_0405c as a protein that may stimulate MABC-specific interferon-γ secretion and may add to the diagnosis of MABC infection in affected patients.

Home Noninvasive Ventilation in Pediatric Subjects With Neuromuscular Diseases: One Size Fits All.

BACKGROUND: Home noninvasive ventilation (NIV) improves disease courses of patients with respiratory insufficiency due to neuromuscular diseases. Data about appropriate ventilator settings for pediatric patients are missing. METHODS: In this retrospective study, ventilator settings of 128 subjects with neuromuscular disease aged 0-17 y with NIV were compared between 4 age groups (< 1 y, 0-5 y, 6-11 y, and 12-17 y). Additionally, correlations of ventilator settings with age and vital capacity were investigated in an ungrouped approach. RESULTS: Ventilator backup rate decreased significantly with age, leading to significant backup rate differences between all groups except the oldest two. Median (interquartile range) backup rates were 36 (11.5), 24 (4), 20 (4), and 20 (3) breaths/min in groups 1-4, respectively. Median [IQR] expiratory positive airway pressures (4 [0.5], 4 [0], 4 [0], 4 [1] cm H2O, respectively) and median [IQR] inspiratory positive airway pressures (12 [1.5], 12 [5], 12 [2.3], and 14 [4] cm H2O, respectively) showed no significant differences. However, correlation analyses indicated an increase of inspiratory positive airway pressure with age and decreasing FVC, as well as an increase of backup rates with decreasing FVC. CONCLUSIONS: Similar NIV settings fit all age groups of pediatric subjects with neuromuscular disease. Thus, we propose an expiratory positive airway pressure of 4-5 cm H2O, an inspiratory pressure delta of 8-10 cm H2O, and an age-oriented backup rate as a starting point for NIV titration. Patients with advanced disease stages might require slightly higher inspiratory positive airway pressures and backup rates.

Reducing the frequency of respiratory tract infections in severe neurological disorders by inhaled antibiotics: a retrospective data analysis.

BACKGROUND: In patients with severe neurological impairment, recurrent respiratory tract infections frequently occur as a result of impaired clearance of airway secretions and microbial airway colonisation. We hypothesised that inhaled antibiotic therapy may improve the morbidity of these patients. METHODS: A retrospective data analysis of 20 patients (11 nontracheotomised and nine tracheotomised) with neurological impairment and microbial airway colonisation was carried out at a children's university hospital. Two questionnaires that asked about the number of respiratory tract infections, antibiotic therapies and hospitalisations were distributed to the patients/caregivers: a first questionnaire representing the 12 months prior to the initiation of inhaled antibiotics and a second questionnaire describing the first 12 months under therapy. RESULTS: During the first 12 months of therapy, the frequency of respiratory tract infections among all participants was reduced from a mean of 6.8 episodes (median (interquartile range (IQR)) 6.0 (4.0-10.0) episodes) to a mean of 2.5 episodes (median (IQR) 2.0 (1.0-3.0) episodes; p<0.001). In addition, a significant decrease of systemic antibiotic therapies (mean 7.7, median (IQR) 6.0 (4.0-10.0) versus 2.5, 2.5 (0.0-3.75) episodes; p<0.001) and hospitalisations (mean 3.9, median (IQR) 3.5 (1.0-5.0) versus 0.9, 0.0 (0.0-1.0) episodes; p<0.001) was noted. This significant therapeutic effect could be demonstrated in a subgroup analysis in both tracheotomised and nontracheotomised subjects. The reduction of respiratory tract infections and systemic antibiotic therapies (and thus the therapeutic success) was significantly greater in the nontracheotomised group compared with the tracheotomised group. CONCLUSIONS: The presented data suggest that inhaled antibiotics might play a role in treating recurrent respiratory tract infections in neuromuscular diseases.

A proteomics approach for the identification of species-specific immunogenic proteins in the Mycobacterium abscessus complex.

The Mycobacterium abscessus complex can cause fatal pulmonary disease, especially in cystic fibrosis patients. Diagnosing M. abscessus complex pulmonary disease is challenging. Immunologic assays specific for M. abscessus are not available. In this study seven clinical M. abscessus complex strains and the M. abscessus reference strain ATCC19977 were used to find species-specific proteins for their use in immune assays. Six strains showed rough and smooth colony morphotypes simultaneously, two strains only showed rough mophotypes, resulting in 14 separate isolates. Clinical isolates were submitted to whole genome sequencing. Proteomic analysis was performed on bacterial lysates and culture supernatant of all 14 isolates. Species-specificity for M. abscessus complex was determined by a BLAST search for proteins present in all supernatants. Species-specific proteins underwent in silico B- and T-cell epitope prediction. All clinical strains were found to be M. abscessus ssp. abscessus. Mutations in MAB_4099c as a likely genetic basis of the rough morphotype were found in six out of seven clinical isolates. 79 proteins were present in every supernatant, of which 12 are exclusively encoded by all members of M. abscessus complex plus Mycobacterium immunogenum. In silico analyses predicted B- and T-cell epitopes in all of these 12 species-specific proteins.

Rapid detection and immune characterization of Mycobacterium abscessus infection in cystic fibrosis patients.

Cystic fibrosis patients are highly susceptible to infections with non-tuberculous mycobacteria. Especially Mycobacterium abscessus infections are common but reliable diagnosis is hampered by non-specific clinical symptoms and insensitive mycobacterial culture. In the present study we established novel methods for rapid detection and immune characterization of Mycobacterium abscessus infection in cystic fibrosis patients. We performed Mycobacterium abscessus specific DNA-strip- and quantitative PCR-based analyses of non-cultured sputum samples to detect and characterize Mycobacterium abscessus infections. Concomitantly in vitro T-cell reactivation with purified protein derivatives (PPDs) from different mycobacterial species was used to determine Mycobacterium abscessus specific T-cell cytokine expression of infected cystic fibrosis patients. Four of 35 cystic fibrosis patients (11.4%) were Mycobacterium abscessus culture positive and showed concordant DNA-strip-test results. Quantitative PCR revealed marked differences of mycobacterial burden between cystic fibrosis patients and during disease course. Tandem-repeat analysis classified distinct Mycobacterium abscessus strains of infected cystic fibrosis patients and excluded patient-to-patient transmission. Mycobacterium abscessus specific T-cells were detected in the blood of cystic fibrosis patients with confirmed chronic infection and a subgroup of patients without evidence of Mycobacterium abscessus infection. Comparison of cytokine expression and phenotypic markers revealed increased proportions of CD40L positive T-cells that lack Interleukin-2 expression as a marker for chronic Mycobacterium abscessus infections in cystic fibrosis patients. Direct sputum examination enabled rapid diagnosis and quantification of Mycobacterium abscessus in cystic fibrosis patients. T-cell in vitro reactivation and cytokine expression analyses may contribute to diagnosis of chronic Mycobacterium abscessus infection.