Multidrug-Resistant Bacteria in Children and Adolescents with Cystic Fibrosis

: In patients with cystic fibrosis (CF), multidrug-resistant (MDR) bacteria can predispose to exacerbations, limit the effectiveness of antibiotic treatments and promote the progression of lung disease. The aim of this retrospective study was to compare pulmonary exacerbations (Pex), hospitalizations, lung function and nutritional status in a group of children and adolescents with CF colonized by MDR bacteria and in a noncolonized control group. Overall, 7/54 pediatric patients (12.9%) were colonized by MDR bacteria and enrolled (3 with Achromobacter xyloxidans, 3 with Stenotrophomonas maltophilia and 1 with Burkholderia cepacia). The control group included 14 sex- and age-matched CF patients (8/14 colonized by Staphylococcus aureus, 2/14 by Pseudomonas aeruginosa, 2/14 by both microorganisms and 2/14 germ free). At the time of enrollment and 12 months before the first detection of the MDR microorganism, children colonized by MDR bacteria showed lower body mass index (BMI) and lower FEV1/FVC compared to the control group. Over the previous year before the first detection, children colonized with MDR had more Pex compared to control group; those colonized by S. maltophilia experienced the highest number of Pex. In the 12 months following the first detection of MDR bacteria, all seven patients colonized by MDR had at least one Pex and patients colonized by S. maltophilia had the highest number (mean ± SD: 6 ± 2.6 vs. 1.7 ± 2.3). Our study suggests that CF pediatric patients infected by MDR bacteria have lower BMI, more obstructive disease and experience more exacerbations than patients without MDR bacteria. These differences are present even before being infected, suggesting that children and adolescents with more severe disease are predisposed to be colonized by MDR bacteria. S. maltophilia appeared to be the most aggressive pathogen. Further studies and the implementation of antimicrobial stewardship programs are necessary to clarify when and how to treat patients with CF and MDR bacteria in order to avoid the improper use of antibiotics and the development of antibiotic resistance.