The CF-CIRC study: a French collaborative study to assess the accuracy of Cystic Fibrosis diagnosis in neonatal screening

BACKGROUND: Cystic fibrosis (CF) is caused by mutations in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein, which acts as a chloride channel after activation by cyclic AMP (cAMP). Newborn screening programs for CF usually consist of an immunoreactive trypsinogen (IRT) assay, followed when IRT is elevated by testing for a panel of CF-causing mutations. Some children, however, may have persistent hypertrypsinogenemia, only one or no identified CFTR gene mutation, and sweat chloride concentrations close to normal values. In vivo demonstration of abnormal CFTR protein function would be an important diagnostic aid in this situation. Measurements of transepithelial nasal potential differences (NPD) in adults accurately characterize CFTR-related ion transport. The aim of the present study is to establish reference values for NPD measurements for healthy children and those with CF aged 3 months to 3 years, the age range of most difficult-to-diagnose patients with suspected CF. The ultimate goal of our study is to validate NPD testing as a diagnostic tool for children with borderline results in neonatal screening. METHODS/DESIGN: We adapted the standard NPD protocol for young children, designed a special catheter for them, used a slower perfusion rate, and shortened the protocol to include only measurement of basal PD, transepithelial sodium (Na(+)) transport in response to the Na(+ )channel inhibitor amiloride, and CFTR-mediated chloride (Cl(-)) secretion in response to isoproterenol, a β-agonist in a Cl(- )free solution. The study will include 20 children with CF and 20 healthy control children. CF children will be included only if they carry 2 CF-causing mutations in the CFTR gene or have sweat chloride concentrations > 60 mEq/L or both. The healthy children will be recruited among the siblings of the CF patients, after verification that they do not carry the familial mutation. DISCUSSION: A preliminary study of 3 adult control subjects and 4 children older than 12 years with CF verified that the new protocol was well tolerated and produced NPD measurements that did not differ significantly from those obtained with the standard protocol. This preliminary study will provide a basis for interpreting NPD measurements in patients with suspected CF after neonatal screening. Earlier definitive diagnosis should alleviate parental distress and allow earlier therapeutic intervention and genetic counseling

Contenu médical pédiatrique de la presse médicale (aide ou obstacle au travail du médecin généraliste)

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Les fibroscopes bronchiques souples chez l'enfant au CHU de Rennes (35) entre 2000 et 2003

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Infection à Nocardia farcinica chez un patient porteur d’une mucoviscidose [Nocardia farcinica infection in a patient with cystic fibrosis].

International audienceInfections by Nocardia species are uncommon and generally affect immunocompromised patients. This bacteria has rarely been isolated from cystic fibrosis patients (CF), especially those who are not taking oral corticosteroids. We report a case of a patient with CF harbouring Nocardia farcinica. An 18-year-old male diagnosed with CF at the age of eight (F508 del/G85E) had been treated for allergic bronchopulmonary aspergillosis in 1998 with itraconazole, and a first colonization with Pseudomonas aeruginosa was eradicated in 2003. From May 2006, he presented with recurrent left- and right-sided pneumothorax. In June 2006, he presented with dyspnoea, fever, and nodular eruption on his ankles. Chest X-ray and CT scan revealed a right pneumothorax, severe bronchiectasis and bilateral alveolar consolidation. N. farcinica was idolated from his sputum without any other pathogens. Treatment with intravenous cotrimoxazole associated with imipenem and amikacin was initiated for three weeks followed by oral cotrimoxazole for a further nine months. The patient's symptoms and alveolar consolidation on CT scan improved. During 2007, his respiratory condition worsened and his FEV(1) declined from 50 to 26 % predicted. His pneumothorax recurred. He had chronic colonization with P. aeruginosa and was on the list for lung transplantation. Nocardia, a Gram positive bacillus, causes mainly pulmonary infection, usually in the context of immune suppression. The most frequent species is N. asteroides. In CF, very few cases have been reported; almost always N. asteroides, but exceptionally N. farcinica. In CF patients with worsening pulmonary condition, Nocardia should be considered, as well as other unusual pathogens

Performance of Molecular Approaches for Aspergillus Detection and Azole Resistance Surveillance in Cystic Fibrosis

International audienceAspergillus fumigatus triazole resistance is an emerging concern for treating chronically infected/colonized patients. This study sought to evaluate the performance of PCR assays to detect Aspergillus fungi together with azole resistance in sputum samples from cystic fibrosis (CF) patients. In total, 119 sputum samples from 87 CF patients were prospectively processed for Aspergillus detection by means of mycological culture and four qPCR assays, 2 in-house methods and two commercial multiplex real-time PCR assays simultaneously detecting Aspergillus and the most relevant cyp51A gene mutations (MycoGENIE (R) and AsperGenius (R)). Azole susceptibility of A. fumigatus isolates was assessed using Etest (R) method and cyp51A gene mutation were characterized by sequencing. The overall rate of Aspergillus detection with the four qPCR assays ranged from 47.9 to 57.1%, contrasting with 42/119 (35.3%) positive cultures with A. fumigatus. The high sensitivity of PCR on sputum could then contribute to more effective grading of Aspergillus disease in CF patients. Five out of 41 isolated strains (12.2%) exhibited azoleresistant MIC patterns, three of which harbored cyp51A mutations and only 1/3 with the sequence TR34/L98H. Combined with culture, PCR assay achieved high sensitivity Aspergillus screening in CF samples. However, cyp51A targeting was only moderately effective for azole resistance monitoring, while Aspergillus resistance remains of great concern

Determination of amoxicillin and cotrimoxazole concentrations in sputum of patients with cystic fibrosis

International audienceIn the management of cystic fibrosis, treatments against Staphylococcus aureus and Haemophilus influenzae such as amoxicillin or cotrimoxazole have to be prescribed and the antibiotherapy efficacy may be linked to the concentration that reaches the infected site. As cystic fibrosis patients present disturbed pharmacokinetics parameters, a drug monitoring would be relevant to assess lungs distribution of antibiotics and to optimize dosing regimens. In this context, the aim of the study was to develop and validate HPLC-based methods for the determination of both antibiotics in bronchial sputum from cystic fibrosis patients, in order to assess drugs distribution into lungs. Plasma proteins were precipitated by acetonitrile, amoxicillin concentrations in sputum were determined by HPLC coupled with tandem-mass spectrometry. Following a liquid extraction with ethyl acetate, cotrimoxazole was quantified by HPLC using ultraviolet detection. Both methods were found rapid, specific, accurate and reproducible. The method was applied to patient’s samples. In three treated patients, concentration of amoxicillin in sputum were closed and below the lower limit of quantification (0.1 μg/g) and in six patients, sputum concentrations up to 11.1 μg/g and 6.4 μg/g were measured for sulfamethoxazole and trimethoprim respectively

Prévalence de Pneumocystis jirovecii chez les patients atteints de mucoviscidose en Bretagne

National audiencePneumocystis jirovecii (P. jirovecii) est un champignon atypique et transmissible à fort tropisme pulmonaire. La prévalence de P. jirovecii chez les patients atteints de mucoviscidose a été évaluée en Allemagne à 7,4 %, en Espagne à 21,6 % et au Brésil à 38,2 %. En revanche, les données concernant la prévalence de P. jirovecii chez les patients atteints de mucoviscidose en France restent parcellaires en particulier en Bretagne, région où la prévalence de la mucoviscidose est élevée. L’objectif de ce travail a été de déterminer la prévalence de la colonisation de P. jirovecii en Bretagne chez les patients mucoviscidosiques suivis dans les CRCM de Rennes et de Brest-Roscoff. Les expectorations de 86 patients (178 prélèvements) suivis à Rennes et 76 patients (146 prélèvements) suivis à Brest-Roscoff ont été analysées rétrospectivement. La détection de P. jirovecii a été réalisée à l’aide d’une PCR en temps réel ciblant le gène codant pour l’ARN de la grande sous-unité du ribosome de la mitochondrie. P. jirovecii a été détecté chez 3/86 patients (3,5 %) suivis à Rennes et 1/76 patients (1,3 %) suivis à Brest-Roscoff, soit une prévalence globale de 2,5 %. Ces résultats portant sur 2 centres bretons montrent que la prévalence de P. jirovecii chez les patients atteints de mucoviscidose en Bretagne est faible en comparaison de celle observée en Allemagne, en Espagne et au Brésil. Cette étude constitue l’étape préalable indispensable pour déterminer les facteurs de risque d’acquisition du champignon chez les patients mucoviscidosiques et expliquer ces différences de prévalenc