Early microbial colonization of cystic fibrosis patients identified by neonatal screening, with emphasis on Staphylococcus aureus

Abstract

Objectives: To assess bacterial colonization prospectively in patients with cystic fibrosis identified by neonatal screening. To assess susceptibility to antimicrobials and to perform the molecular typing of Staphylococcus aureus strains isolated from the oropharynx of patients during the study.Methods: Twenty-five cystic fibrosis patients receiving regular treatment at the Cystic Fibrosis Outpatient Clinic of Hospital de Clínicas of Universidade Federal do Paraná, Brazil, were included in the study. All patients were identified by trypsin-like immunoreactivity and their diagnosis was confirmed by two or more sweat tests. Oropharyngeal swabs were collected and cultured according to routine methods; bacterial colonies were phenotypically identified and their susceptibility to antimicrobials was tested. S. aureus isolates were submitted to molecular typing using pulsed-field gel electrophoresis.Results: Out of 234 oropharyngeal swabs, S. aureus was the most frequently isolated strain (76% of patients, 42% of swabs), followed by Pseudomonas aeruginosa (36% of patients, 16% of swabs) and Haemophilus spp. (76% of patients; 19% of swabs). Seventy-three isolates were obtained from 19 patients colonized with S. aureus, of which 18 were oxacillin-resistant (24.6%), isolated from two patients, with the same electrophoretic profiles as that of the Brazilian clone. The remaining oxacillin-sensitive isolates were distributed into 18 electrophoretic profiles. Conclusion:There was higher prevalence of S. aureus, with earlier isolation than other pathogens. Multi-sensitive isolates were distributed into different clones, characterizing non-transmissibility among community-acquired strains. The isolated oxacillin-resistant S. aureus showed identical electrophoretic profiles, probably acquired in hospital. P. aeruginosa was not so frequent in the studied population.

Staphylococcus aureus α toxin potentiates opportunistic bacterial lung infections

“…Epidemiologic studies identified a strong correlation between S. aureus colonization in the upper airway and onset of VAP, and a transition from S. aureus to P. aeruginosa as the primary pathogens in early-to late-onset VAP (37,38). A similar transition is observed in cystic fibrosis patients (39)(40)(41). This sequence of infections suggests that S. aureus colonization and co-infection may promote infection by other bacterial species.…”

Impact of Staphylococcus aureus on the pathogenesis of chronic cystic fibrosis lung disease

“…Cross-sectional data from the international databases indicate that the airways of CF patients are colonized early in their life by S. aureus. Recently, a Brazilian study followed early microbial colonization of cystic fibrosis patients during a 17-month prospective single center study including 25 patients identified by neonatal screening (Souza et al, 2006). S. aureus was the first pathogen in 18 patients (72%), 2 patients were colonized by MRSA strains (Brazilian clone).…”

Idiopathic Interstitial Pneumonias and COVID-19 Pneumonia: Review of the Main Radiological Features and Differential Diagnosis

“…Occasionally, millimetric nodular calcifications may be appreciated [ 33 ]. Mediastinal lymphadenopathies [ 34 ] and coexisting emphysema may occur. Patients presenting with typical UIP features do not undergo lung biopsy and are diagnosed as IPF patients [ 18 ] ( Figure 3 a).…”