Increased prevalence and resistance of important pathogens recovered from respiratory specimens of cystic fibrosis patients during a decade
Abstract
Background: The study objective was to identify changes of prevalence and resistance of important pathogens in specimens of cystic fibrosis (CF) patients within a decade. Methods: Samples of 94 patients, who attended 2 CF centers from 2001 to 2011 were retrospectively analyzed.
Results: Staphylococcus aureus was the most prevalent organism (74.5% in 2011) with an increase of methicillin-resistant S. aureus in patients (0% vs. 9.6%, n = 9). Resistance of S. aureus to gentamicin decreased (41.8% vs. 21%; P < 0.001), whereas resistance to rifampicin and trimethoprim/sulfamethoxazole (P < 0.05) increased significantly with a trend to increased resistance to clindamycin and erythromycin (P = 0.063).
Methicillin-resistant S. aureus isolates belonged to 6 spa types (t003, t008, t011, t034, t045, t548). There was a significant increase of Pseudomonas aeruginosa prevalence (63.8% in 2011 vs. 46.8% in 2001, P = 0.019).
Resistance of P. aeruginosa increased significantly to imipenem, gentamicin, amikacin, tobramycin, ciprofloxacin and fosfomycin, whereas resistance to piperacillin-tazobactam, meropenem and aztreonam decreased. Significantly fewer Stenotrophomonas maltophilia isolates were susceptible to all the analyzed antibiotics (trimethoprim/sulfamethoxazole, ciprofloxacin and colistin) in 2011 compared with 2001 (13.5% vs. 42.1%; P = 0.023), whereas the resistance to colistin increased significantly (11.1% vs. 62.2%; P < 0.001).
Burkholderia cepacia complex and nontuberculous mycobacteria were not detected in 2001 but in 2011 in 7.4% (n = 9) and 7.4% (n = 9) of patients, respectively. B. cepacia complex isolates belonged to 8 multilocus sequence types.
Conclusions: Our retrospective analysis revealed an increase of important CF-related pathogens, the emergence of new pathogens and a substantial increase of multidrug-resistant CF-specific isolates.