Clinical course and risk factors for severe COVID-19 among Italian patients with cystic fibrosis: a study within the Italian Cystic Fibrosis Society.

PURPOSE: To describe the clinical course of COVID-19 in patients with cystic fibrosis (CF) and to identify risk factors for severe COVID-19. METHODS: We conducted a prospective study within the Italian CF Society. CF centers collected baseline and follow-up data of patients with virologically confirmed SARS-CoV-2 infection between March 2020 and June 2021. Odds ratios (ORs) for severe SARS-CoV-2 (as defined by hospital admission) were estimated by logistic regression models. RESULTS: The study included 236 patients with positive molecular test for SARS-CoV-2. Six patients died, 43 patients were admitted to hospital, 4 admitted to intensive care unit. Pancreatic insufficiency was associated with increased risk of severe COVID-19 (OR 4.04, 95% CI 1.52; 10.8). After adjusting for age and pancreatic insufficiency, forced expiratory volume in one second (FEVp) < 40% (OR 4.54, 95% CI 1.56; 13.2), oxygen therapy (OR 12.3, 95% CI 2.91-51.7), underweight (OR 2.92, 95% CI 1.12; 7.57), organ transplantation (OR 7.31, 95% CI 2.59; 20.7), diabetes (OR 2.67, 95% CI 1.23; 5.80) and liver disease (OR 3.67, 95% CI 1.77; 7.59) were associated with increased risk of severe COVID-19, while use of dornase alfa was associated with a reduced risk (OR 0.34, 95% CI 0.13-0.88). No significant changes were observed in FEVp from baseline to a median follow-up of 2 months (median difference: 0, interquartile range: - 4; 5, P = 0.62). CONCLUSION: Clinical features indicative of severe form of CF are associated with increased risk of COVID-19 hospitalization. SARS-CoV-2 infected patients do not experience a deterioration of respiratory function.

Impact of CFTR Modulators on the Impaired Function of Phagocytes in Cystic Fibrosis Lung Disease.

Cystic fibrosis (CF), the most common genetically inherited disease in Caucasian populations, is a multi-systemic life-threatening autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. In 2012, the arrival of CFTR modulators (potentiators, correctors, amplifiers, stabilizers, and read-through agents) revolutionized the therapeutic approach to CF. In this review, we examined the physiopathological mechanism of chronic dysregulated innate immune response in the lungs of CF patients with pulmonary involvement with particular reference to phagocytes, critically analyzing the role of CFTR modulators in influencing and eventually restoring their function. Our literature review highlighted that the role of CFTR in the lungs is crucial not only for the epithelial function but also for host defense, with particular reference to phagocytes. In macrophages and neutrophils, the CFTR dysfunction compromises both the intricate process of phagocytosis and the mechanisms of initiation and control of inflammation which then reverberates on the epithelial environment already burdened by the chronic colonization of pathogens leading to irreversible tissue damage. In this context, investigating the impact of CFTR modulators on phagocytic functions is therefore crucial not only for explaining the underlying mechanisms of pleiotropic effects of these molecules but also to better understand the physiopathological basis of this disease, still partly unexplored, and to develop new complementary or alternative therapeutic approaches.

Ventilation Heterogeneity in Asthma and COPD: The Value of the Poorly Communicating Fraction as the Ratio of Total Lung Capacity to Alveolar Volume.

BACKGROUND: The ventilation heterogeneity (VH) is reliably assessed by the multiple-breath nitrogen washout (MBNW), which provides indices of conductive (Scond) and acinar (Sacin) VH as well as the lung clearance index (LCI), an index of global VH. VH can be alternatively measured by the poorly communicating fraction (PCF), that is, the ratio of total lung capacity by body plethysmography to alveolar volume from the single-breath lung diffusing capacity measurement. OBJECTIVES: Our objective was to assess VH by PCF and MBNW in patients with asthma and with COPD and to compare PCF and MBNW parameters in both patient groups. METHOD: We studied 35 asthmatic patients and 45 patients with COPD. Each patient performed spirometry, body plethysmography, diffusing capacity, and MBNW test. RESULTS: Compared to COPD patients, asthmatics showed a significantly lesser degree of airflow obstruction and lung hyperinflation. In asthmatic patients, both PCF and LCI and Sacin values were significantly lower than the corresponding ones of COPD patients. In addition, in both patient groups, PCF showed a positive correlation with LCI (p < 0.05) and Sacin (p < 0.05), but not with Scond. Lastly, COPD patients with PCF >30% were highly likely to have a value ≥2 of the mMRC dyspnea scale. CONCLUSIONS: These results showed that PCF, a readily measure derived from routine pulmonary function testing, can provide a comprehensive measure of both global and acinar VH in asthma and in COPD patients and can be considered as a comparable tool to the well-established MBNW technique.

The value of high-resolution computed tomography (HRCT) to determine exercise ventilatory inefficiency and dynamic hyperinflation in adult patients with cystic fibrosis.

INTRODUCTION: In Cystic Fibrosis (CF), exercise ventilatory inefficiency and dynamic hyperinflation (DH) cause exercise limitation and induce poor exercise tolerance. High-resolution computed tomography (HRCT) of the lung can detect pulmonary abnormalities in CF patients. We aimed to identify the determinants of exercise ventilatory inefficiency and DH using HRCT-derived metrics. METHODS: Fifty-two adult CF patients were prospectively enrolled; all participants underwent cardio-pulmonary exercise test (CPET) and HRCT. Radiological impairment was evaluated by the Brody II scoring system. Slope and intercept of the minute ventilation/CO2 production (V'E/V'CO2) regression line and the ratio of inspiratory capacity/total lung capacity (IC/TLC) at rest and at peak of exercise were measured. RESULTS: Four groups of patients were identified based on the combination of ventilatory efficiency (Vef) or inefficiency (Vin) and the presence/absence of DH. Compared to other groups, CF adults with Vin and DH had worse functional status and higher total (T), bronchiectasis (B) and air trapping (AT) scores at HRCT. Significant correlations were found between V'E/V'CO2 intercept and V'E/V'CO2 slope (ρ - 0.455, p = 0.001) and between V'E/V'CO2 intercept and Δ inspiratory capacity (IC) (ρ - 0.334, p = 0.015). Regression analysis identified AT score (cut-off 7.9, odds ratio-OR 3.50) as the only independent predictor of Vin and T (cut-off 53.6, OR 4.98), B (cut-off 16.1, OR 4.88), airways wall thickening (AWT) (cut-off 13, OR 3.41), and mucous plugging (MP) scores (cut-off 11.7, OR 4.18) as significant predictors of DH. CONCLUSION: In adult CF cohort, values of HRCT metrics are determinants of Vin (AT) and DH (T, B, AWT, MP).

Development of inhalation powders containing lactic acid bacteria with antimicrobial activity against Pseudomonas aeruginosa.

OBJECTIVES: The aim of the project was to develop and characterise powders containing a probiotic (Lactiplantibacillus plantarum [Lpb. plantarum], Lacticaseibacillus rhamnosus, or Lactobacillus acidophilus) to be administered to the lung for the containment of pathogen growth in patients with lung infections. METHODS: The optimised spray drying process for the powder manufacturing was able to preserve viability of the bacteria, which decreased of only one log unit and was maintained up to 30 days. RESULTS: Probiotic powders showed a high respirability (42%-50% of particles had a size < 5 µm) suitable for lung deposition and were proven safe on A549 and Calu-3 cells up to a concentration of 107 colony-forming units/mL. The Lpb. plantarum adhesion to both cell lines tested was at least 10%. Surprisingly, Lpb. plantarum powder was bactericidal at a concentration of 106 colony-forming units/mL on P. aeruginosa, whereas the other two strains were bacteriostatic. CONCLUSION: This work represents a promising starting point to consider a probiotic inhalation powder a value in keeping the growth of pathogenic microflora in check during the antibiotic inhalation therapy suspension in cystic fibrosis treatment regimen. This approach could also be advantageous for interfering competitively with pathogenic bacteria and promoting the restoration of the healthy microbiota.

Prevalence of Scoliosis in Children and Adolescents with Cystic Fibrosis.

The prevalence of scoliosis in people with cystic fibrosis (CF) seems to be greater than in the normal population. Over the last two years, a screening for spinal deformities was carried out in patients with CF aged 5 to 18 years, followed up at the CF regional Centre in Parma (Italy). Forty-three patients (twenty-seven males, mean age: 11.8 ± 4.5 years) were enrolled in the study. Nine patients (20.9%) were diagnosed with scoliosis, with a mean Cobb angle of 20.8 ± 9.4 (12-38°). Five patients (11.6%) were diagnosed with a postural kyphosis attitude and one with pathological fixed kyphosis. All patients with scoliosis and postural kyphosis started daily physiotherapeutic scoliosis-specific exercises (PSSE). Compared to people without CF, the prevalence of scoliosis in our paediatric CF population seems to be higher and more present in males; the curves were thoracic and mostly right-sided. CF disease, hyposthenic postural attitude and sedentary lifestyle can contribute to the pathogenesis of this musculoskeletal alteration. Spinal deformities may negatively affect pulmonary function, resulting in disability, pain and a decreased quality of life. Since the prevention of musculoskeletal deformities is easier than restoration, in CF population targeted screening during growth and interventions, including regular physical exercise, are mandatory.

Telemedicine and Its Application in Cystic Fibrosis.

The care of cystic fibrosis (CF) traditionally consists of regular visits to the clinic where a multidisciplinary team can visit the patient, adjust treatments and monitor the disease. During the COVID-19 pandemic when access to hospitals and medical environments was very limited, the role of telemedicine was crucial to keep in touch with patients with chronic diseases such as CF. Increasing evidence demonstrates that electronic health can successfully support healthcare professionals in the management of people with CF. The use of devices connected to digital platforms or smartphones results in a continuous flow of data that can be shared with the clinician and the team in order to improve the knowledge of patients' diseases and the level of care needed. This narrative review aims to describe the application of telemedicine in CF disease with pros and cons. A literature analysis showed that telemedicine has several advantages in the management of patients with CF. With the evolving support of digital technology, telemedicine can promote clinical visits, adherence to daily treatment, including respiratory physiotherapy and physical exercise, early identification of pulmonary exacerbations and management of psychological issues. The main disadvantages are missed physical exam findings, lack of physical contact that can prevent conversation on sensitive topics, lack of access to technology and lack of technological skills. Furthermore, healthcare operators need appropriate training for telemedicine systems and need time to organise and analyse data generated remotely, which may increase the burden of daily work. Hybrid personalised care models that marge telemedicine and traditional care can be an ideal solution.

Nutritional Care in Children with Cystic Fibrosis.

Patients with cystic fibrosis (CF) are prone to malnutrition and growth failure, mostly due to malabsorption caused by the derangement in the chloride transport across epithelial surfaces. Thus, optimal nutritional care and support should be an integral part of the management of the disease, with the aim of ameliorating clinical outcomes and life expectancy. In this report, we analyzed the nutrition support across the different ages, in patients with CF, with a focus on the relationships with growth, nutritional status, disease outcomes and the use of the CF transmembrane conductance regulator (CFTR) modulators. The nutrition support goal in CF care should begin as early as possible after diagnosis and include the achievement of an optimal nutritional status to support the growth stages and puberty development in children, that will further support the maintenance of an optimal nutritional status in adult life. The cornerstone of nutrition in patients with CF is a high calorie, high-fat diet, in conjunction with a better control of malabsorption due to pancreatic enzyme replacement therapy, and attention to the adequate supplementation of fat-soluble vitamins. When the oral caloric intake is not enough for reaching the anthropometric nutritional goals, supplemental enteral feeding should be initiated to improve growth and the nutritional status. In the last decade, the therapeutic possibilities towards CF have grown in a consistent way. The positive effects of CFTR modulators on nutritional status mainly consist in the improvement in weight gain and BMI, both in children and adults, and in an amelioration in terms of the pulmonary function and reduction of exacerbations. Several challenges need to be overcome with the development of new drugs, to transform CF from a fatal disease to a treatable chronic disease with specialized multidisciplinary care.

Early Origins of Chronic Obstructive Pulmonary Disease: Prenatal and Early Life Risk Factors.

The main risk factor for chronic obstructive pulmonary disease (COPD) is active smoking. However, a considerable amount of people with COPD never smoked, and increasing evidence suggests that adult lung disease can have its origins in prenatal and early life. This article reviews some of the factors that can potentially affect lung development and lung function trajectories throughout the lifespan from genetics and prematurity to respiratory tract infections and childhood asthma. Maternal smoking and air pollution exposure were also analyzed among the environmental factors. The adoption of preventive strategies to avoid these risk factors since the prenatal period may be crucial to prevent, delay the onset or modify the progression of COPD lung disease throughout life.

Impact of SARS-CoV-2 Infection in Children with Asthma and Impact of COVID-19 Vaccination: Current Evidence and Review of the Literature.

The clinical aspects of SARS-CoV-2 infection, as well as the COVID-19 vaccines' safety, efficacy and effectiveness in pediatric patients with asthma, are crucial to adapting clinical management in this fragile population and for prevention strategies. The aim of this narrative review was to evaluate the impact of SARS-CoV-2 infection in children with asthma and the impact of COVID-19 vaccination. Systematic research using the principal medical databases was conducted using specific search query strings from the early spreading of COVID-19 globally until March 2023; further relevant data were drawn from the main national and supranational institutions. No significant differences in SARS-CoV-2 incidence and morbidity were found in asthmatic pediatric patients compared to non-asthmatic ones; however, subjects with uncontrolled asthma were found to be at increased risk of developing a serious disease during SARS-CoV-2 infection. Regarding COVID-19 vaccines, accumulating data support their safety, efficacy and effectiveness on asthmatic children regardless of asthma severity. Further cohort-based studies are needed as the evidence of new epidemic waves caused by new viral variants makes the current knowledge outdated.

Structural changes in lung morphology detected by MRI after modulating therapy with elexacaftor/tezacaftor/ivacaftor in adolescent and adult patients with cystic fibrosis.

INTRODUCTION: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves CFTR function in cystic fibrosis (CF) patients homozygous or heterozygous for F508del mutation. The aim of the study was to evaluate the response to ELX/TEZ/IVA treatment both clinically and morphologically in terms of bronchiectasis, bronchial wall thickening, mucus plugging, abscess and consolidations. METHODS: We retrospectively collected data from CF patients followed at Parma CF Centre (Italy) treated by ELX/TEZ/IVA between March and November 2021. Post-treatment changes in respiratory function, quality of life, sweat chloride concentration, body mass index, pulmonary exacerbations and lung structure by chest magnetic resonance imaging (MRI) were assessed. T2-and T1-weighted sequences were acquired with a 20 min-long scanning protocol on a 1.5T MRI scanner (Philips Ingenia) without administration of intravenous contrast media. RESULTS: 19 patients (32.5 ± 10.2 years) were included in the study. After 6 months of treatment with ELX/TEZ/IVA, MRI showed significant improvements in the morphological score (p < 0.001), with a reduction in bronchial wall thickening (p < 0.001) and mucus plugging (p 0.01). Respiratory function showed significant improvement in predicted FEV1% (58.5 ± 17.5 vs 71.4 ± 20.1, p < 0.001), FVC% (79.0 ± 11.1 vs 88.3 ± 14.4, p < 0.001), FEV1/FVC (0.61 ± 0.16 vs 0.67 ± 0.15, <0.001) and LCI2.5% (17.8 ± 4.3 vs 15.8 ± 4.1 p < 0.005). Significant improvement was found in body mass index (20.6 ± 2.7 vs 21.9 ± 2.4, p < 0.001), pulmonary exacerbations (2.3 ± 1.3 vs 1.4 ± 1.3 p 0.018) and sweat chloride concentration (96.5 ± 36.6 vs 41.1 ± 16.9, p < 0.001). CONCLUSIONS: Our study confirms the efficacy of ELX/TEZ/IVA in CF patients not only from a clinical point of view but also in terms of morphological changes of the lungs.

The impact of elexacaftor/tezacaftor/ivacaftor therapy on the pulmonary management of adults with cystic fibrosis: An expert-based Delphi consensus.

BACKGROUND: The advent of elexacaftor/tezacaftor/ivacaftor (ETI) resulted in unprecedented clinical benefits for eligible adults with CF. As a result, the question of whether chronic treatments can be safely stopped or adapted to this new situation has become a matter of great interest. Our objective was to derive a consensus among Italian experts on the impact of ETI on the current clinical management of CF lung disease. METHODS: From December 2021 to April 2022 a panel of Italian experts endorsed by the national CF scientific society derived and graded a set of statements on the pulmonary management of adults with cystic fibrosis through a modified Delphi methodology. RESULTS: The panel produced 13 statements exploring possible modifications in the fields of inhaled antibiotics and mucoactives; airway clearance and physical activity; chronic macrolides and bronchodilators; and lung transplant referral. The areas that the experts considered most urgent to explore were the impact of ETI on the role of inhaled antibiotics and lung transplant. CONCLUSIONS: The list of priorities that emerged from this study could be useful to guide and inform clinical research on the most urgent area of impact of ETI on CF lung disease and its clinical management.

Overweight is associated with airflow obstruction and poor disease control but not with exhaled nitric oxide change in an asthmatic population.

BACKGROUND: The role of an elevated body mass index (BMI) in asthma remains controversial. OBJECTIVES: To investigate the relationship between overweight (BMI >25 and ≤30), lung function, disease control, and airway inflammation in an asthmatic population. METHODS: We consecutively studied 348 patients (age 43 ± 16 years; 211 females). In all patients, BMI, spirometry, the Asthma Control Test (ACT), and fractional exhaled nitric oxide (FeNO; ppb) were measured. RESULTS: One hundred forty-five patients were overweight and, as compared to those with normal BMI, had lower values of FVC, FEV(1), and FEV(1)/FVC and of FEF(25-75) even when normalized for FVC (p < 0.05 for each comparison). The ratio between the number of patients with well-controlled asthma (ACT ≥20) and that of patients with poorly controlled asthma (ACT < 20) was significantly lower in overweight patients (1.07 vs. 1.84; χ(2) = 6.030, p < 0.01). In overweight patients, the odds ratio of uncontrolled asthma expressed by logistic regression analysis was 1.632 (95% CI = 1.043-2.553), independently of gender, atopy, smoking habit, and inhaled steroid therapy. No difference was observed in FeNO values between overweight and normal weight patients (27.7 ± 2.3 vs. 27.9 ± 2.2 ppb). CONCLUSIONS: Our results show that, in an asthmatic population, overweight is associated with airflow obstruction and poor disease control but not with FeNO change. The findings of the present study support the view that other factors besides airway inflammation alone may explain the relationship between asthma and an elevated BMI.

Asthma phenotypes and endotypes in childhood.

Asthma is a very heterogeneous disease and since early childhood many classifications have been proposed according to phenotype and endotype. The phenotype includes the clinical features of asthma such as age of onset, triggers, comorbidities, response to treatment and evolution over time. The endotype is more difficult to define, includes the underlying immunopathological mechanisms of the disease and requires reliable biomarkers. A deep knowledge of phenotype and endotype of the patient may guide a tailored therapeutic approach. In this review the main phenotypes and endotypes of asthma acknowledged in children will be discussed.

An Overview of the Obese-Asthma Phenotype in Children.

Asthma is the most common chronic disease in childhood. Overweight and obesity are included among the comorbidities considered in patients with difficult-to-treat asthma, suggesting a specific phenotype of the disease. Therefore, the constant increase in obesity prevalence in children and adolescents raises concerns about the parallel increase of obesity-associated asthma. The possible correlation between obesity and asthma has been investigated over the last decade by different authors, who suggest a complex multifactorial relationship. Although the particular non-eosinophilic endotype of obesity-related asthma supports the concept that high body weight precedes asthma development, there is ongoing debate about the direct causality of these two entities. A number of mechanisms may be involved in asthma in combination with obesity disease in children, including reduced physical activity, abnormal ventilation, chronic systemic inflammation, hormonal influences, genetics and additional comorbidities, such as gastroesophageal reflux and dysfunctional breathing. The identification of the obesity-related asthma phenotype is crucial to initiate specific therapeutic management. Besides the cornerstones of asthma treatment, lifestyle should be optimized, with interventions aiming to promote physical exercise, healthy diet, and comorbidities. Future studies should clarify the exact association between asthma and obesity and the mechanisms underlying the pathogenesis of these two related conditions with the aim to define personalized therapeutic strategies for asthma management in this population.

The remaining unsolved problems for rational antibiotic therapy use in pediatric community-acquired pneumonia.

INTRODUCTION: Despite availability of several official guidelines, not all the problems related to the most effective and safe use of antibiotics in children with community-acquired pneumonia (CAP) have been solved. Presently, too many children receive unneeded antibiotics or, when antibiotics are mandatory, the choice of the drug is not appropriate. AREAS COVERED: In this paper, the authors discuss the remaining unsolved problems for rational antibiotic therapy use in pediatric community-acquired pneumonia and provide their expert perspectives. EXPERT OPINION: Further improvement in pediatric CAP management could be derived from physician education on antibiotic use and a larger use, particularly in office practice, of point of care testing or new technologies (i.e. artificial intelligence) to define etiology of a lower respiratory infection. However, recommendations regarding the duration of antibiotic therapy vary largely because of the absence of reliable data on the optimal CAP treatment according to the bacterial etiology of the disease, its severity, and child characteristics. Available evidence seems to confirm that a short course of antibiotics, approximately 5 days, can be effective and lead to results not substantially different from those obtained with prolonged-course antibiotic therapy, at least in patients with mild to moderate disease.

Complications in community acquired pneumonia: magnitude of problem, risk factors, and management in pediatric age.

INTRODUCTION: In the last decades, the large use of several effective vaccines has dramatically reduced the incidence of community acquired pneumonia (CAP) in infants and children. Moreover, the availability of new antibiotics effective against emerging resistant strains of bacteria has greatly improved the early and long-term prognosis of this disease. AREAS COVERED: The aim of this manuscript is to evaluate the burden of complicated CAP in pediatric age and to discuss its appropriate management. EXPERT OPINION: Complicated CAP remains a problem for children in industrialized and developing countries. A larger use of lung ultrasonography (US) as first diagnostic approach could significantly improve early identification of cases at higher risk of complications. Difficult to solve, is the problem of the use of an antibiotic therapy able to assure adequate control in all the CAP cases, including those at high risk of or with already established complications. All these findings reveal that control of the incidence of complicated CAP remains difficult and will not be significantly changed in the next few years. Any attempt to improve complicated CAP management must be made. Consensus documents on better definition of the use of corticosteroids, fibrinolytic agents, and interventional procedures (including surgery) can allow us to reach this goal.

Probiotics Administration in Cystic Fibrosis: What Is the Evidence?

In the last 20 years, gut microbiota in patients with cystic fibrosis (CF) has become an object of interest. It was shown that these patients had gut dysbiosis and this could explain not only the intestinal manifestations of the disease but also part of those involving the respiratory tract. The acquisition of previously unknown information about the importance of some bacteria, i.e., those partially or totally disappeared in the gut of CF patients, in the regulation of the activity and function of the gut and the lung was the base to suggest the use of probiotics in CF patients. The main aim of this paper is to discuss the biological basis for probiotic administration to CF patients and which results could be expected. Literature analysis showed that CF intestinal dysbiosis depends on the same genetic mutations that condition the clinical picture of the diseases and is aggravated by a series of therapeutic interventions, such as dietary modifications, the use of antibiotics, and the administration of antacids. All this translates into a significant worsening of the structure and function of organs, including the lung and intestine, already deeply penalized by the genetic alterations of CF. Probiotics can intervene on dysbiosis, reducing the negative effects derived from it. However, the available data cannot be considered sufficient to indicate that these bacteria are essential elements of CF therapy. Further studies that take into account the still unsolved aspects on how to use probiotics are absolutely necessary.

Multidrug-Resistant Bacteria in Children and Adolescents with Cystic Fibrosis.

In patients with cystic fibrosis (CF), multidrug-resistant (MDR) bacteria can predispose to exacerbations, limit the effectiveness of antibiotic treatments and promote the progression of lung disease. The aim of this retrospective study was to compare pulmonary exacerbations (Pex), hospitalizations, lung function and nutritional status in a group of children and adolescents with CF colonized by MDR bacteria and in a noncolonized control group. Overall, 7/54 pediatric patients (12.9%) were colonized by MDR bacteria and enrolled (3 with Achromobacter xyloxidans, 3 with Stenotrophomonas maltophilia and 1 with Burkholderia cepacia). The control group included 14 sex- and age-matched CF patients (8/14 colonized by Staphylococcus aureus, 2/14 by Pseudomonas aeruginosa, 2/14 by both microorganisms and 2/14 germ free). At the time of enrollment and 12 months before the first detection of the MDR microorganism, children colonized by MDR bacteria showed lower body mass index (BMI) and lower FEV1/FVC compared to the control group. Over the previous year before the first detection, children colonized with MDR had more Pex compared to control group; those colonized by S. maltophilia experienced the highest number of Pex. In the 12 months following the first detection of MDR bacteria, all seven patients colonized by MDR had at least one Pex and patients colonized by S. maltophilia had the highest number (mean ± SD: 6 ± 2.6 vs. 1.7 ± 2.3). Our study suggests that CF pediatric patients infected by MDR bacteria have lower BMI, more obstructive disease and experience more exacerbations than patients without MDR bacteria. These differences are present even before being infected, suggesting that children and adolescents with more severe disease are predisposed to be colonized by MDR bacteria. S. maltophilia appeared to be the most aggressive pathogen. Further studies and the implementation of antimicrobial stewardship programs are necessary to clarify when and how to treat patients with CF and MDR bacteria in order to avoid the improper use of antibiotics and the development of antibiotic resistance.