[Bacterial isolates from respiratory samples of pediatric patients with cystic fibrosis and their distribution by ages].

The bacterial isolates from respiratory samples of 50 pediatric patients with cystic fibrosis, their distribution by ages and antimicrobial resistance pattern as well as the intermittence of isolations and coinfections, were investigated. Staphylococcus aureus was isolated in 72 % of patients, followed by Pseudomonas aeruginosa (58 %), Haemophilus. influenzae (56 %), and the Burkholderia cepacia complex (12 %). The frequency of resistance of P. aeruginosa isolates to β-lactam antibiotics was low (13.8 %). Fifty percent of S. aureus isolates was methicillin-resistant, and 57.1 % of H. influenza was ampicillin resistant due to β-lactamase production. In children under 4 years-old, S. aureus was predominant, followed by P. aeruginosa and H. influenzae. This order of predominance was observed in all the groups studied, except in that of children between 10 and 14 years-old. Stenotrophomonas maltophilia and Achromobacter xylosoxidans isolates were intermittent and accompanied by other microorganisms. Finally, we observed a great variety of bacterial species, which imposes stringent performance requirements for microbiological studies in all respiratory samples of these patients.