Real-life experience with a generic formulation of lumacaftor-ivacaftor in patients with cystic fibrosis homozygous for the Phe508del CFTR mutation.

INTRODUCTION: Cystic fibrosis (CF) is the most frequent recessive autosomal disorder in the Caucasian population. It is caused by mutations that result in a deficient or dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) protein activity. Among CFTR modulators, potentiator compounds increase channel opening, whereas corrector compounds increase CFTR quantity in the cell surface. OBJECTIVE: To report real-life effects of a generic formulation of lumacaftor-ivacaftor use in patients with CF homozygous for the Phe508del CFTR mutation. PATIENTS AND METHODS: Clinical variables (body mass index [BMI], pulmonary exacerbations, sweat test, and pulmonary function) were analyzed in 30 CF patients homozygous for the Phe508del CFTR mutation, treated with lumacaftor-ivacaftor for 12 months, at the Respiratory Center of Hospital de Niños Ricardo Gutiérrez. These clinical variables were compared with those before the use of modulators. RESULTS: A total of 30 patients with CF homozygous for the Phe508del CFTR mutation receiving lumacaftor-ivacaftor therapy were included in this study. The median (interquartile range [IQR]) age at the start of treatment was 10.79 (7.08-14.05) years. Nineteen patients were male. Before treatment, median (IQR) sweat chloride concentration was 80 (72-92) mEq/L, and it had decreased to 74 (68-78) mEq/L (p = .05) 12 months after treatment. Median (IQR) BMI z-score improved from -0.33 (-0.86 to 0.21) to -0.13 (-0.66 to 0.54) (p = .003). A spirometry was performed in 28 of 30 patients. Median (IQR) ppFEV1 was 83.5 (71-91) before treatment and 86.5 (67-103) after treatment (p = .38), 73.3% of patients referred decreased sputum production and 40% reported improvement in their dyspnea at 12 months. Severe pulmonary exacerbations significantly decreased from 60% in the year before treatment, to 30% at 12 months after treatment (p = .037); 13 patients showed an improvement in their exacerbation rates, 2 showed an increased rate, and 15 showed no change. CONCLUSIONS: The use of a generic formulation of lumacaftor-ivacaftor in patients homozygous for the Phe508del CFTR mutation was associated with improvement in nutritional status and respiratory symptoms, and a significant reduction in severe pulmonary exacerbations.

Scedosporium spp. from Clinical Setting in Argentina, with the Proposal of the New Pathogenic Species Scedosporium americanum.

Species of the genus Scedosporium (family Microascaceae, phylum Ascomycota) are responsible for a wide range of opportunistic human infections, and have a low susceptibility to most antifungal drugs. It is well known that the pattern of Scedosporium species distribution varies according to geographic region. To assess the diversity of Scedosporium species in Argentina involved in human infections, we carried out a retrospective study reviewing 49 strains from clinical samples sent for diagnosis to the National Clinical Mycology Reference Laboratory between 1985 and 2019. Then, a phenotypic characterization, a phylogenetic study and and in vitro susceptibility test to antifungals were carried out. An analysis of combined nucleotide sequences dataset of the internal transcribed spacer of the ribosomal DNA (ITS) and of a fragment of the ß-tubulin gene (BT2) demonstrated that 92 % of the strains belonged to the species S. boydii, S. apiospermum and S. angustum, all them pertaining to S. apiospermum species complex. However, two strains (4%) were identified as S. aurantiacum, a species never reported in clinical settings in the Americas'. Surprisingly, one of them displayed a polycytella-like conidiogenesis, up to date only reported for S. apiospermum. In addition, the strain DMic 165285 was phylogenetically located far away from the rest of the species, so is proposed as the novel species Scedosporium americanum. On the other hand, from all seven antifungals tested, voriconazole and posaconazole were the most active drugs against Scedosporium spp.

Comparative genomics of ST5 and ST30 methicillin-resistant Staphylococcus aureus sequential isolates recovered from paediatric patients with cystic fibrosis.

Staphylococcus aureus chronic airway infection in patients with cystic fibrosis (CF) allows this pathogen to adapt over time in response to different selection pressures. We have previously shown that the main sequence types related to community-acquired methicillin-resistant S. aureus (MRSA) infections in Argentina - ST5 and ST30 - are also frequently isolated from the sputum of patients with CF, but in these patients they usually display multi-drug antimicrobial resistance. In this study, we sequenced the genomes of MRSA from four paediatric CF patients with the goal of identifying mutations among sequential isolates, especially those possibly related to antimicrobial resistance and virulence, which might contribute to the adaptation of the pathogen in the airways of patients with CF. Our results revealed genetic differences in sequential MRSA strains isolated from patients with CF in both their core and accessory genomes. Although the genetic adaptation of S. aureus was distinct in different hosts, we detected independent mutations in thyA, htrA, rpsJ and gyrA - which are known to have crucial roles in S. aureus virulence and antimicrobial resistance - in isolates recovered from multiple patients. Moreover, we identified allelic variants that were detected in all of the isolates recovered after a certain time point; these non-synonymous mutations were in genes associated with antimicrobial resistance, virulence, iron scavenging and oxidative stress resistance. In conclusion, our results provide evidence of genetic variability among sequential MRSA isolates that could be implicated in the adaptation of these strains during chronic CF airway infection.

Comparison between two newborn screening strategies for cystic fibrosis in Argentina: IRT/IRT versus IRT/PAP.

BACKGROUND: The benefits of early cystic fibrosis (CF) detection using newborn screening (NBS) has led to widespread use in NBS programs. Since 2002, a two-stage immunoreactive trypsinogen (IRT/IRT) screening strategy has been used as a CFNBS method in all public maternity units in the City of Buenos Aires, Argentina. However, novel screening strategies may be more efficient. The aim of this study is to prospectively compare two CFNBS strategies: IRT/IRT and IRT/PAP (pancreatitis-associated protein). METHODS: A two-year prospective study was performed. IRT was measured in dried blood samples collected 48-72 h after birth. When an IRT value was abnormal, PAP was determined, and a second visit was scheduled to obtain another sample for IRT before 25 days of life. Newborns with a positive CFNBS were referred for a confirmatory sweat test. RESULTS: There were 69,827 births in the City of Buenos Aires during the period studied; 918 (1.31%) had an abnormal IRT. A total of 207 children (22.5%) failed to return for the second IRT, but only two PAP (0.2%) were not performed. IRT/IRT was more likely to lead to a referral for sweat testing than IRT/PAP (odds ratio 2.3 [95% confidence interval 1.8-2.9], p < .001). Sensitivity and specificity were: 80% and 100% and 86.5% and 82.6% for IRT/IRT and IRT/PAP strategies, respectively. CONCLUSION: The IRT/PAP strategy is more sensitive than IRT/IRT and has similar specificity; it avoids a second visit and unnecessary sweat testing, and it reduces loss to follow-up in our population.

Evolución de la función pulmonar en niños con fibrosis quística durante los primeros 3 años de vida / Course of lung function in children with cystic fibrosis in their first 3 years of life

Introducción. La prevención temprana de las complicaciones respiratorias en niños con fibrosis quística determina una mayor sobrevida. La aplicación de pruebas de función pulmonar desde los primeros meses de vida permite detectar el compromiso respiratorio, inclusive en niños asintomáticos. Objetivo. Evaluar la evolución de la función pulmonar en niños con fibrosis quística durante los primeros 3 años de vida e identificar aquellos factores que la comprometen. Población y métodos. Estudio analítico, observacional, retrospectivo. Se incluyeron menores de 36 meses con, al menos, dos estudios funcionales respiratorios. Resultados. Entre 2008 y 2016, se incluyeron 48 pacientes, de los cuales el 85 % fue diagnosticado por pesquisa neonatal. La primera evaluación funcional respiratoria fue a los 5 meses. La mediana de puntaje Z de flujo máximo a nivel de la capacidad residual funcional fue de -0,05 (intervalo intercuartil: de -1,09 a 1,08). La mediana de cambio del puntaje Z del flujo máximo entre las evaluaciones fue de -0,32 (intervalo intercuartil: de -1,11 a 0,25), p = 0,045. Los pacientes con infecciones respiratorias por Staphylococcus aureus, especialmente los resistentes a meticilina, evidenciaron una mayor declinación de la función pulmonar comparados con los no infectados. Ni el sexo ni el tipo de mutación genética se asociaron a la evolución respiratoria. Se evidenció una muy buena recuperación nutricional a lo largo del estudio. Conclusión. Los niños con fibrosis quística presentan una función pulmonar que, progresivamente, desmejora durante los primeros 3 años de vida. Estos hallazgos se asocian a las infecciones respiratorias por Staphylococcus aureus.

Introduction. The early prevention of respiratory complications in children with cystic fibrosis is determining for a longer survival. The implementation of lung function tests in the first months of life allows to detect respiratory involvement, even in asymptomatic children. Objective. To assess the course of lung function in children with cystic fibrosis in their first 3 years of life and identify the factors affecting it. Population and methods. Observational, retrospective, analytical study. Children younger than 36 months with at least 2 lung function tests were included. Results. Between 2008 and 2016, 48 patients were included; 85 % of them had been diagnosed by newborn screening. The first lung function test was done at 5 months old. The median Z-score of maximal flow at functional residual capacity was -0.05 (interquartile range: -1.09 to 1.08). The median change in the maximal flow Z-score between tests was -0.32 (interquartile range: -1.11 to 0.25), p = 0.045. Patients with Staphylococcus aureus respiratory infections, especially methicillin-resistant SA, evidenced a greater deterioration of lung function compared to those without infection. Neither sex nor the type of genetic mutation were associated with the course of lung function. Nutritional recovery throughout the study was really good. Conclusion. Lung function in children with cystic fibrosis worsens progressively during their first 3 years of life. These findings are associated with Staphylococcus aureus respiratory infections.

Factores de riesgo asociados a exacerbaciones respiratorias en pacientes pediátricos con fibrosis quística / Risk factors associated with pulmonary exacerbations in pediatric patients with cystic fibrosis

Introducción. Los pacientes con fibrosis quística presentan exacerbaciones respiratorias (ER) que requieren tratamiento endovenoso. El objetivo fue determinar los factores de riesgo asociados a ER y obtener porcentaje de pacientes que no recuperaban su función pulmonar previa. Población y métodos. Observacional, de cohorte, retrospectivo. Se revisaron las historias clínicas de los pacientes con fibrosis quística atendidos en el Hospital de Niños Ricardo Gutiérrez durante 2013. Se dividieron en: grupo 1, con ER (criterios de Fuchs), y grupo 2, sin ER. Se registró edad, género, mutación p.F508del, porcentaje del volumen espiratorio forzado en el primer segundo basal, puntaje Z de índice de masa corporal basal, colonización crónica (criterios de Leeds) por Pseudomonas aeruginosa, Staphylococcus aureus meticilino resistente y complejo Burkholderia cepacia, porcentaje de diabetes relacionada con fibrosis quística y recuperación del volumen espiratorio forzado en el primer segundo basal. Resultados. Se incluyeron 117 pacientes. Grupo 1: 50; y grupo 2: 67 pacientes. Se asociaron a las ER: el menor puntaje Z de IMC (RR: 1,45; p=0,002), p.F508del (RR: 3,23; p=0,05) y colonización crónica por el complejo Burkholderia cepacia (RR: 3,69; p = 0,002), Pseudomonas aeruginosa (RR: 1,89; p = 0,01) y Staphylococcus aureus meticilino resistente (RR: 2,32; p = 0,002). El 24 % no recuperó su función pulmonar. Conclusiones. p.F508del, el bajo estado nutricional y la colonización crónica fueron factores de riesgo para exacerbación. Una cuarta parte de los pacientes no recuperó su función pulmonar previa.

Introduction. Cystic fibrosis patients develop pulmonary exacerbations (PEs) that require intravenous treatment. The objective of this study was to determine the risk factors associated with PEs and establish the percentage of patients who failed to recover their lung function. Population and methods. Observational, retrospective, cohort study. The medical records of cystic fibrosis patients seen at Hospital de Niños Ricardo Gutiérrez in 2013 were reviewed. Patients were divided into group 1, with PE (Fuchs criteria), and group 2, without PE. Age, sex, p.F508del mutation, percentage of baseline forced expiratory volume in the first second, baseline body mass index Z-score, chronic Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex colonization (Leeds criteria), percentage of cystic fibrosis-related diabetes, and recovery of baseline forced expiratory volume in the first second were recorded. Results. A total of 117 patients were included. Group 1: 50, group 2: 67 patients. PEs were associated with a lower body mass index Z-score (RR: 1.45; p = 0.002), p.F508del mutation (RR: 3.23; p = 0.05), and chronic Burkholderia cepacia complex (RR: 3.69; p = 0.002), Pseudomonas aeruginosa (RR: 1.89; p = 0.01) and methicillin-resistant Staphylococcus aureus colonization (RR: 2.32; p = 0.002). Twenty-four percent of patients failed to recover their lung function. Conclusions. The presence of the p.F508del mutation, a poor nutritional status, and chronic colonization were the risk factors for exacerbation. A fourth of patients failed to recover their lung function.

Course of lung function in children with cystic fibrosis in their first 3 years of life. / Evolución de la función pulmonar en niños con fibrosis quística durante los primeros 3 años de vida.

INTRODUCTION: The early prevention of respiratory complications in children with cystic fibrosis is determining for a longer survival. The implementation of lung function tests in the first months of life allows to detect respiratory involvement, even in asymptomatic children. OBJECTIVE: To assess the course of lung function in children with cystic fibrosis in their first 3 years of life and identify the factors affecting it. POPULATION AND METHODS: Observational, retrospective, analytical study. Children younger than 36 months with at least 2 lung function tests were included. RESULTS: Between 2008 and 2016, 48 patients were included; 85 % of them had been diagnosed by newborn screening. The first lung function test was done at 5 months old. The median Z-score of maximal flow at functional residual capacity was -0.05 (interquartile range: -1.09 to 1.08). The median change in the maximal flow Z-score between tests was -0.32 (interquartile range: -1.11 to 0.25), p = 0.045. Patients with Staphylococcus aureus respiratory infections, especially methicillin-resistant SA, evidenced a greater deterioration of lung function compared to those without infection. Neither sex nor the type of genetic mutation were associated with the course of lung function. Nutritional recovery throughout the study was really good. CONCLUSION: Lung function in children with cystic fibrosis worsens progressively during their first 3 years of life. These findings are associated with Staphylococcus aureus respiratory infections.

Introducción. La prevención temprana de las complicaciones respiratorias en niños con fibrosis quística determina una mayor sobrevida. La aplicación de pruebas de función pulmonar desde los primeros meses de vida permite detectar el compromiso respiratorio, inclusive en niños asintomáticos. Objetivo. Evaluar la evolución de la función pulmonar en niños con fibrosis quística durante los primeros 3 años de vida e identificar aquellos factores que la comprometen. Población y métodos. Estudio analítico, observacional, retrospectivo. Se incluyeron menores de 36 meses con, al menos, dos estudios funcionales respiratorios. Resultados. Entre 2008 y 2016, se incluyeron 48 pacientes, de los cuales el 85 % fue diagnosticado por pesquisa neonatal. La primera evaluación funcional respiratoria fue a los 5 meses. La mediana de puntaje Z de flujo máximo a nivel de la capacidad residual funcional fue de ­0,05 (intervalo intercuartil: de -1,09 a 1,08). La mediana de cambio del puntaje Z del flujo máximo entre las evaluaciones fue de -0,32 (intervalo intercuartil: de -1,11 a 0,25), p = 0,045. Los pacientes con infecciones respiratorias por Staphylococcus aureus, especialmente los resistentes a meticilina, evidenciaron una mayor declinación de la función pulmonar comparados con los no infectados. Ni el sexo ni el tipo de mutación genética se asociaron a la evolución respiratoria. Se evidenció una muy buena recuperación nutricional a lo largo del estudio. Conclusión. Los niños con fibrosis quística presentan una función pulmonar que, progresivamente, desmejora durante los primeros 3 años de vida. Estos hallazgos se asocian a las infecciones respiratorias por Staphylococcus aureus.

Risk factors associated with pulmonary exacerbations in pediatric patients with cystic fibrosis. / Factores de riesgo asociados a exacerbaciones respiratorias en pacientes pediátricos con fibrosis quística.

INTRODUCTION: Cystic fibrosis patients develop pulmonary exacerbations (PEs) that require intravenous treatment. The objective of this study was to determine the risk factors associated with PEs and establish the percentage of patients who failed to recover their lung function. POPULATION AND METHODS: Observational, retrospective, cohort study. The medical records of cystic fibrosis patients seen at Hospital de Niños Ricardo Gutiérrez in 2013 were reviewed. Patients were divided into group 1, with PE (Fuchs criteria), and group 2, without PE. Age, sex, p.F508del mutation, percentage of baseline forced expiratory volume in the first second, baseline body mass index Z-score, chronic Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex colonization (Leeds criteria), percentage of cystic fibrosis-related diabetes, and recovery of baseline forced expiratory volume in the first second were recorded. RESULTS: A total of 117 patients were included. Group 1: 50, group 2: 67 patients. PEs were associated with a lower body mass index Z-score (RR: 1.45; p = 0.002), p.F508del mutation (RR: 3.23; p = 0.05), and chronic Burkholderia cepacia complex (RR: 3.69; p = 0.002), Pseudomonas aeruginosa (RR: 1.89; p = 0.01) and methicillinresistant Staphylococcus aureus colonization (RR: 2.32; p = 0.002). Twenty-four percent of patients failed to recover their lung function. CONCLUSIONS: The presence of the p.F508del mutation, a poor nutritional status, and chronic colonization were the risk factors for exacerbation. A fourth of patients failed to recover their lung function.

Introducción. Los pacientes con fibrosis quística presentan exacerbaciones respiratorias (ER) que requieren tratamiento endovenoso. El objetivo fue determinar los factores de riesgo asociados a ER y obtener porcentaje de pacientes que no recuperaban su función pulmonar previa. Población y métodos. Observacional, de cohorte, retrospectivo. Se revisaron las historias clínicas de los pacientes con fibrosis quística atendidos en el Hospital de Niños Ricardo Gutiérrez durante 2013. Se dividieron en: grupo 1, con ER (criterios de Fuchs), y grupo 2, sin ER. Se registró edad, género, mutación p.F508del, porcentaje del volumen espiratorio forzado en el primer segundo basal, puntaje Z de índice de masa corporal basal, colonización crónica (criterios de Leeds) por Pseudomonas aeruginosa, Staphylococcus aureus meticilino resistente y complejo Burkholderia cepacia, porcentaje de diabetes relacionada con fibrosis quística y recuperación del volumen espiratorio forzado en el primer segundo basal. Resultados. Se incluyeron 117 pacientes. Grupo 1: 50; y grupo 2: 67 pacientes. Se asociaron a las ER: el menor puntaje Z de IMC (RR: 1,45; p = 0,002), p.F508del (RR: 3,23; p = 0,05) y colonización crónica por el complejo Burkholderia cepacia (RR: 3,69; p = 0,002), Pseudomonas aeruginosa (RR: 1,89; p = 0,01) y Staphylococcus aureus meticilino resistente (RR: 2,32; p = 0,002). El 24 % no recuperó su función pulmonar. Conclusiones. p.F508del, el bajo estado nutricional y la colonización crónica fueron factores de riesgo para exacerbación. Una cuarta parte de los pacientes no recuperó su función pulmonar previa.

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Cystic Fibrosis Patients from Argentina.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in cystic fibrosis (CF) patients is an increasing problem in many countries. In our Respiratory Center at the Hospital de Niños "Dr. Ricardo Gutiérrez", Buenos Aires, Argentina, the prevalence has climbed from 23% in 1995 up to 32% in 2011. Our objective was to analyze the diversity of MRSA isolates recovered from respiratory samples of CF patients attending our center, characterizing their phenotypes and clonal distribution. Therefore, a prospective study was conducted on all CF patients attending the pediatric Respiratory Center between June 2012 and May 2013 to collect MRSA isolates. Antibiotic susceptibility testing, multilocus sequence typing, pulsed-field gel electrophoresis, spa typing, and agr genotyping were performed on collected isolates. The prevalence of MRSA during this period was 34.2%, and 71.9% of the patients were infected with isolates that carried SCCmec IV. High resistance rates were detected for gentamicin, erythromycin, clindamycin, ciprofloxacin, and rifampicin. Strains related to the community-associated MRSA clones, ST5-IV and ST30-IV, were the most frequently recovered. Remarkably, even though most of the isolates were related to these clones, the rate of multi-resistance shown in CF patients was higher than that reported for the same lineages recovered from other infections in our country.

Understanding the Pathogenicity of Burkholderia contaminans, an Emerging Pathogen in Cystic Fibrosis.

Several bacterial species from the Burkholderia cepacia complex (Bcc) are feared opportunistic pathogens that lead to debilitating lung infections with a high risk of developing fatal septicemia in cystic fibrosis (CF) patients. However, the pathogenic potential of other Bcc species is yet unknown. To elucidate clinical relevance of Burkholderia contaminans, a species frequently isolated from CF respiratory samples in Ibero-American countries, we aimed to identify its key virulence factors possibly linked with an unfavorable clinical outcome. We performed a genome-wide comparative analysis of two isolates of B. contaminans ST872 from sputum and blood culture of a female CF patient in Argentina. RNA-seq data showed significant changes in expression for quorum sensing-regulated virulence factors and motility and chemotaxis. Furthermore, we detected expression changes in a recently described low-oxygen-activated (lxa) locus which encodes stress-related proteins, and for two clusters responsible for the biosynthesis of antifungal and hemolytic compounds pyrrolnitrin and occidiofungin. Based on phenotypic assays that confirmed changes in motility and in proteolytic, hemolytic and antifungal activities, we were able to distinguish two phenotypes of B. contaminans that coexisted in the host and entered her bloodstream. Whole genome sequencing revealed that the sputum and bloodstream isolates (each representing a distinct phenotype) differed by over 1,400 mutations as a result of a mismatch repair-deficient hypermutable state of the sputum isolate. The inferred lack of purifying selection against nonsynonymous mutations and the high rate of pseudogenization in the derived isolate indicated limited evolutionary pressure during evolution in the nutrient-rich, stable CF sputum environment. The present study is the first to examine the genomic and transcriptomic differences between longitudinal isolates of B. contaminans. Detected activity of a number of putative virulence factors implies a genuine pathogenic nature of this novel Bcc species.