BackgroundPeople with Cystic Fibrosis (pwCF) are prone to bacterial lung infections with P. aeruginosa, which have been linked to chronic inflammation in the lung. Although the highly effective CFTR modulator therapy (Elexacaftor-Tezacaftor-Ivacaftor, ETI) has dramatically improved respiratory outcomes in pwCF, airway inflammation and bacterial colonization persist in the upper and lower respiratory tracts.MethodsWe investigated the effect of ETI in both plasma and fresh primary nasal epithelial (HNE) cells obtained from pwCF pre- and post-three months of ETI treatment. Given that inflammation has been shown to upregulate NFKBIZ and the ATP12A proton pump, we measured their levels in fresh HNE cells and in cultured HNE cells exposed to clinical exoproducts (EXO) of P. aeruginosa or other inflammatory stimuli.ResultsELISA analysis revealed a significant reduction of IL-6, IL-8, and IL-17C in both plasma and HNE cells after ETI treatment. NFKBIZ and ATP12A expression was increased after infection and inflammatory stimuli in CF bronchial epithelial (CFBE) and HNE cells, and this increase was reduced by Dimethyl-Fumarate, an anti-inflammatory drug.ConclusionsThese preclinical studies, using patient-derived tissues, suggest that NFKBIZ and ATP12A may play a relevant role in the pathophysiology and inflammatory response of the CF airway epithelium.

Pseudomonas aeruginosa remains a major cause of morbidity in people with cystic fibrosis (pwCF). The advent of elexacaftor/tezacaftor/ivacaftor (ETI) has transformed clinical outcomes, but its impact on airway microbiology and diagnostic surveillance remains uncertain. We conducted a systematic review of PubMed and Embase (2019-2025) according to PRISMA guidelines, including studies comparing culture with molecular methods for P. aeruginosa detection in pwCF treated with ETI. Fourteen observational studies (n=2525 subjects) were identified. Chronic P. aeruginosa detection declined from 51.4% at baseline to 24.8% after ETI, with nearly half of colonized subjects achieving apparent clearance. Several studies applying molecular techniques reported persistent P. aeruginosa detection despite negative cultures. These findings indicate that ETI markedly reduces bacterial burden and sputum availability, which may limit the sensitivity of culture-based surveillance. However, the clinical and inflammatory significance of PCR+/culture- results remains uncertain. Combining molecular and culture-based surveillance may help guide infection monitoring in the modulator era.

Purpose. Pediatric data integrating methicillin resistance, Panton-Valentine leukocidin (PVL), infection origin, and antimicrobial resistance in Staphylococcus aureus remain limited in Italy. We characterized these features and their temporal and epidemiological correlates. Methods. We conducted a single-center retrospective study of patients aged <18 years with microbiologically confirmed S. aureus infection during 2013–2016 and 2019–2024. Antimicrobial susceptibility and PVL results were analyzed by methicillin susceptibility, infection origin, and study period. Logistic regression identified factors associated with methicillin-resistant S. aureus (MRSA), PVL positivity, and recurrence. Results. Among 524 patients, 112 isolates (21.4%) were MRSA. PVL was detected in 148 of 347 tested isolates (42.7%) and was more frequent in MRSA than methicillin-susceptible isolates (74.4% vs 33.5%; odds ratio, 5.77; 95% CI, 3.27–10.18). MRSA showed higher resistance to clindamycin (27.7% vs 16.5%), erythromycin, gentamicin, fluoroquinolones, tetracycline, and fusidic acid, whereas trimethoprim-sulfamethoxazole resistance was similar (9.8% vs 9.2%). PVL positivity was more frequent in community-acquired than hospital-acquired infections (47.1% vs 9.8%) and was independently associated with foreign nationality and suspected intrafamilial transmission. MRSA prevalence remained stable between periods, while treatment duration and use of amoxicillin/clavulanate and gentamicin decreased. Conclusion. MRSA displayed broader non–β-lactam resistance, including clinically relevant clindamycin resistance, while PVL identified a predominantly community-associated subgroup with household transmission. Local surveillance integrating susceptibility, PVL, and epidemiological context can inform empirical therapy and recurrence prevention.

Cystic fibrosis (CF) represents the most prevalent life-threatening autosomal recessive disorder in Europe, primarily affecting the respiratory tract, exocrine pancreatic function, and lipid metabolism. Immunoreactive trypsinogen (IRT) quantification constitutes the first-tier test in neonatal CF screening programs; however, elevated IRT levels may also be detected in infants who do not develop CF, generating false-positive (FP) results. The biological basis underlying increased IRT in these cases remains poorly understood and may involve genetic determinants independent of CFTR. Dried blood spot (DBS) samples were collected from full-term neonates with normal growth parameters, classified as true negatives (TN) or FP through CF newborn screening programs across multiple European centers. IRT levels were measured via standardized immunoassay, and genomic DNA extracted from DBS underwent whole-exome sequencing (WES). Bioinformatic analyses integrated functional prediction, evolutionary conservation, and allele frequency data, with variant prioritization restricted to a curated panel of genes implicated in pancreatic disease. Following quality control, 212 samples (94 FP, 118 TN) were included. Comparative analyses identified significant enrichment of variants in five genes among FP subjects. Notably, top loci localized to regulatory regions and genes involved in oxidative stress, suggesting a mechanistic link with pancreatic inflammation and elevated IRT. Several variants clustered within high linkage disequilibrium regions, supporting the presence of susceptibility haplotypes. Burden testing of rare variants confirmed significant associations for CFTR, PRSS1, and PRSS2 after multiple testing corrections. These results suggest that genetic variation beyond CFTR is associated with elevated neonatal IRT in infants without CF and support further investigation of pancreatic-related pathways in false-positive CF newborn screening.

Background: Nocardia species are an emergent pathogen in people with CF (pwCF) or bronchiectasis. Their clinical role and management remain unclear, and their isolation is a challenge. In this paper, we describe four cases of Nocardia detection, in two pwCF and two patients with non-CF bronchiectasis or primary ciliary dyskinesia (PCD). Methods: We conducted a multicenter retrospective study, involving pwCF and non-CF people with bronchiectasis who presented with a Nocardia detection and were followed at three CF Italian centers (Florence, Verona, and Cerignola). Results: Nocardia detection was associated with clinical and radiological respiratory exacerbation and decline in lung function. In one CF patient, Nocardia was not detected in sputum cultures after starting Elexacaftor-Tezacaftor-Ivacaftor therapy. Conclusions: Managing Nocardia detection in patients with underlying lung diseases such as CF, PCD, or bronchiectasis presents significant challenges for clinicians.

This study aimed to determine the prevalence of Staphylococcus aureus small colony variants (SCV) in people with cystic fibrosis (pwCF), evaluate the clinical differences of single versus multiple detections of SCVs in respiratory cultures, and assess antibiotic resistance. This monocentric retrospective study included pwCF colonised by S. aureus SCVs between January 1, 2017, and December 31, 2023, at the CF centre of Florence, Italy. Clinical data were collected, and patients with single versus recurrent SCV detections were compared to identify risk factors for recurrent SCVs. Among 154 pwCF (62 children, 92 adults), SCV was detected in 38.31

BACKGROUND:Pseudomonas aeruginosa chronic infection can cause lung function decline in people with cystic fibrosis, and early antibiotic treatment (EAT) is crucial to prevent it. While culture methods are standard for monitoring treatment efficacy, serology may be a complementary tool. The primary objective of this study was to evaluate the accuracy of two commercially available tests in measuring the immune response to P. aeruginosa antigens in people with cystic fibrosis who had undergone EAT. METHODS:Two commercially available ELISA panels, CF-St-Ag or AP, ELA and ExoA antigens, were used to assess immune responses at initial P. aeruginosa detection and 12 months after EAT. Receiver operating characteristic curves were used to determine the optimal antibody titre cut-off for detecting P. aeruginosa infection. RESULTS:Over 14 years, 170 episodes of initial P. aeruginosa infection in 134 modulator-naïve people with cystic fibrosis (median age 11.2 years) were treated with early eradication treatment, achieving a 77.1 % sustained eradication rate. Of 333 sera samples, titres ExoA showed a sensitivity of 76.9 %, specificity of 95.8 %, and a negative predictive value of 85 %. At 12 months, successful EAT resulted in significantly lower antibody titres compared to treatment failure (p < 0.05). A statistically significant association between any anti-P. aeruginosa antibody titre and microbiological outcome was observed for all antigens tested. CONCLUSIONS:No significant differences were observed when comparing the performance of the two kits. Serology is a useful adjunct test for monitoring the effectiveness of EAT against initial P. aeruginosa infection and appropriate antibody titre cut-offs should be used in the early stages of P. aeruginosa infection.

Cystic fibrosis (CF) is a genetic disorder caused by variants in the CFTR gene. CFTR modulators, especially elexacaftor/tezacaftor/ivacaftor (ETI), have significantly improved CF care, but their effectiveness in children and adolescents with normal spirometry remains unexplored. This prospective study included 103 individuals with CF under 18 years old, all with baseline percent predicted forced expiratory volume in one second (ppFEV1) ≥ 90

Background: Cystic fibrosis (CF) is characterized by chronic neutrophilic inflammation in the airways. Elexacaftor/tezacaftor/ivacaftor (ETI) therapy has demonstrably improved clinical outcomes and quality of life in people with CF (pwCF), but its effects on systemic inflammatory parameters remain unclear. Objective: To evaluate the impact of ETI on systemic inflammation in children and adolescents with CF. Design: Retrospective, dual-center observational, propensity score-matching study of pediatric pwCF on ETI. Methods: PwCF aged ⩽ 18 years treated with ETI at two Italian reference centers were included in this study. Data on immunoglobulins (Ig) (A, G, and M), γ-globulin, leukocyte levels, percent predicted forced expiratory volume in the first second (ppFEV1), sweat chloride (SC) concentration, and sputum cultures were collected at baseline, 12, and 24 months of treatment. Laboratory data of a control group (pwCF, not in ETI therapy, same demographic characteristics as the study group) were also collected. Results: Sixty-six patients (30 males, median age: 12 years, F508del homozygous: 23) were included. Mean IgG levels (SD) significantly decreased ( p = 0.001) from 1168.20 mg/dl (344.41) at baseline to 1093.05 mg/dl (258.73; 12 months) and 1092.87 mg/dl (232.42; 24 months). Similar reductions were observed for IgA and γ-globulin; IgM reduction was not statistically significant. Leukocyte levels also decreased significantly from 8.04 × 10 3 /µl (3.23 × 10 3 ) at baseline to 6.61 × 10 3 /µl (1.74 × 10 3 ) (12 months) and 6.45 × 10 3 /µl (1.70 × 10 3 ; 24 months). As for the control group, no significant changes in the levels of Ig, leukocytes, and γ-globulin were detected throughout the study period ( p > 0.05). The mean (SD) ppFEV1 and the overall mean (SD) SC concentration significantly decreased during the follow-up. Regarding cultures, 18 (27%) of the 27 patients positive (41%) for Staphylococcus aureus at baseline became negative during treatment. Three patients (4%) with persistently positive cultures for Pseudomonas aeruginosa during the first 12 months, became negative after 24 months. One patient (1.5%), with a baseline positive culture for Pseudomonas Aeruginosa , showed negative cultures after 12 months. Conclusion: ETI treatment improved respiratory outcomes and significantly reduced values of IgG, IgA, γ-globulin, and leukocytes, suggesting an effect on the systemic inflammatory response. Further research is warranted to elucidate the role of inflammatory parameters in monitoring response to therapy.

Recurrent respiratory infections are a leading cause of morbidity and mortality in persons with Cystic Fibrosis (pwCF). Recently, the emergence of Nocardia species as a potential pathogen in CF has raised questions about its role and management, as its clinical significance and the optimal patient management remain unclear in current clinical practice. This review explores the clinical implications of Nocardia species in patients with Cystic Fibrosis (pwCF) through a comprehensive literature review. Key objectives include assessing its impact on lung function, identifying colonization risk factors, and evaluating an appropriate treatment. The literature review, conducted until June 30, 2023, from databases like MEDLINE, PubMed, Embase, and Cochrane, included 16 articles involving 89 pwCF with Nocardia species isolation according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline recommendations. Articles reporting Nocardia prevalence and symptoms based on original data in adult and paediatric pwCF were included. All the retrieved studies were observational ones, thus, they were categorized by study type as case report and case series. Overall 89 pwCF and Nocardia species isolation were included: 42 children and 47 adults. Where reported, we found these main following bacterial species: Nocardia asteroides (35

Bacterial infections of the lower airways are the main cause of mortality and morbidity in cystic fibrosis. The most frequently isolated pathogens are S. aureus and P. aeruginosa; bacterial co-infections are frequently observed. The aim of this review is to provide, in the current context, the indications regarding the best antibiotic strategy to adopt in subjects affected by CF infected with the most common pathogens. We selected relevant publications (guidelines, systematic reviews and clinical studies published so far on these topics) and we analysed the sampling methods used and antibiotic strategies adopted. Oropharyngeal sampling methods are considered less sensitive for pathogen detection than sputum. In non-expectorating people, induced sputum is considered equivalent to two-lobe bronchoalveolar lavage, which is considered invasive. Antibiotic treatment against the main pathogens can consist in eradication treatment in the early stages of infection, chronic suppressive therapy and treatment of the pulmonary exacerbations. This scheme is valid for P. aeruginosa but remains to be demonstrated for the other pathogens. For S. aureus, no evidence-based therapeutic strategies on how to treat the different stages of bacterial infection have been established with certainty. With regard to the treatment of the other classic pathogens (B. cepacia complex, A. xylosoxidans and S. maltophilia), no evidence-based indications exist and decision is left to the clinician. The recent introduction of highly effective modulators on the CFTR protein, in addition to the favourable effects described in regulatory trials, has led to a reduction in bacterial isolations; the real effect of which in clinical practice has still to be assessed on the basis of scientific data. The reliability of culture examination depends on sampling methods, and expectorated sputum continues to be the best method as it is simple and non-invasive. P. aeruginosa is the pathogen for which antibiotic strategies for the various stages of infection appear best established, and the efficacy of early eradication treatment and chronic suppressive therapy have been underlined in clinical trials and systematic reviews. The recent introduction of modulators into clinical practice, despite their widely described efficacy, has not yet led to suggestions for changes in antibiotic strategies against the pathogens most frequently isolated.

Background: The upper airways of cystic fibrosis (CF) persons are an evolutionary niche where genetically adapted bacterial strains are selected for lung infection. The microbiological studies conducted up to now on the upper airways are not easily comparable. Methods: Using classical culture methods, we simultaneously studied the microbiological status of upper and lower airways in persons not chronically infected with P. aeruginosa. Each person had a single upper airways sampling and a concomitant lower airways sampling. Lower airways sampling was performed by oropharyngeal swab or sputum collection. Using a quasi-experimental design of study, we evaluated the performance of 2 different upper airways’ sampling methods, nasal lavage according to method described by Mainz or nasal lavage with a rhino-set. Pain was measured with appropriate scales. Results: A total of 194 persons were enrolled in this study. Pathogenic flora was found in 128 (6.6%) of 194 upper airways samples and in 164 (84.6%) lower airways samples. A statistically significant difference between the upper airways and the lower airways was found in the isolation of S. aureus and non-fermenter gram negatives. Nasal lavage according to Mainz resulted in the isolation of more non-fermenter gramnegatives than the rhino-set (p < 0.05). No differences were found in the pain caused bythe two methods. Conclusions: In our study population, cultures of the upper airway and lower airway differ in CF persons. In people sampled with nasal lavage according to Mainz more non-fermenter gram negatives were detected than with rhino-set. The two sampling methods were comparable with regard to the caused pain, nasal lavage according to Mainz method being quicker to perform.

While Cystic Fibrosis is characterized by a high phenotypic variability, a correlation is reported between the pancreatic status and the CFTR genotype. Here we report an unusual case of a child with Cystic Fibrosis (F508del-duplication of exons 1–3 genotype) diagnosed at 8 years old for pancreatic insufficiency and non-pathological sweat test, in absence of respiratory symptoms and acute episodes of pancreatitis. Nasal potential differences and intestinal current measurements were normal, while the short-circuit current measured on patient-derived colonoids grown on Transwell® indicated the presence of a reduced CFTR-dependent current relative to non-CF colonoids with, a modest improvement of CFTR activity record following treatment with elexacaftor/tezacaftor/ivacaftor. This case opens the discussion on the importance of performing CFTR sequencing and the search for large gene rearrangements in cases of pancreatic insufficiency of unclear etiology, also in the presence of non-pathological sweat test. Children with CF and non-pathological sweat chloride are likely to develop higher concentrations if they truly have CF.

The sweat test (ST) is the current diagnostic gold standard for cystic fibrosis (CF). Many CF centres have switched from the Gibson-Cooke method to the Macroduct system-based method. We used these methods simultaneously to compare CF screening outcomes. STs using both methods were performed simultaneously between March and December 2022 at CF Centre in Florence. We included newborns who underwent newborn bloodspot screening (NBS), newborns undergoing transfusion immediately after birth, and children with CF screen-positive, inconclusive diagnosis (CFSPID). We assessed 72 subjects (median age 4.4 months; range 0-76.7): 30 (41.7%) NBS-positive, 18 (25.0%) newborns who underwent transfusion, and 24 (33.3%) children with CFSPID. No significant differences were found between valid sample numbers, by patient ages and groups (p = 0.10) and between chloride concentrations (p = 0.13), except for sweat chloride (SC) measured by the Gibson-Cooke and Macroduct methods in CFSPID group (29.0, IQR: 20.0-48.0 and 22.5, IQR: 15.5-30.8, respectively; p = 0.01). The Macroduct and Gibson-Cooke methods showed substantial agreement with the SC values, except for CFSPID, whose result may depend on the method of sweat collection. In case of invalid values with Macroduct, the test should be repeated with Gibson-Cooke method.

Respiratory infections represent the leading cause of lung damage in CF patients. A strong correlation has been shown between the flora colonizing the upper (UAW) and lower airways (LAW). We analyzed UAW and LAW to evaluate the role of bacterial infections of paranasal sinuses in the development of subsequent lung infections. Paired samples of UAW and LAW were screened performing microbiological analyses. UAW specimens were collected by nasal lavage. LAW specimens were collected as throat swab or sputum. Between December 2020 and March 2022, 109 adult patients in total were enrolled, including 83 (76.1%) not chronically colonized by Pseudomonas aeruginosa (PA) (Group A: 62.7% male; median age 29y; range 18-58), and 26 (23.9%) transplanted subjects (Group B: 61.5% male; median age 39y; range 19-60). Overall, 187 paired samples of UAW and LAW were screened, 141 for Group A, and 46 for Group B. The most prevalent bacterium in group A was Staphylococcus aureus (SA) in both UAW (41.1%) and LAW (69.5%) cultures (p<.05), followed by Enterobacteriaceae (UAW 17.7%, LAW 14.2%), Achromobacter xylosoxidans (UAW 3.5%, LAW 7.8%), methicillin-resistant SA (UAW 4.3%, LAW 3.5%), and PA (UAW 1.4%, LAW 6.4%; p<.05). Compared to group A, group B exhibited a higher prevalence of PA (UAW 36.1%, LAW 52.8%), a lower presence of SA (UAW 41.7%, LAW 44.4%) with lower bacterial diversity. The two groups of patients showed different airways microbiota. Upper airways could play a role as reservoir in the initial phases of lung disease and progression towards chronicity. In transplant patients the high PA prevalence in UAW could infect the allografts, conditioning the organ rejection. This work was supported by the Tuscany Region