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Background: During its persistence in cystic fibrosis (CF) airways, P. aeruginosa develops a series of phenotypic changes by the accumulation of pathoadaptive mutations. A better understanding of the role of these mutations in the adaptive process, with particular reference to the development of multidrug resistance (MDR), is essential for future development of novel therapeutic approaches, including the identification of new drug targets and the implementation of more efficient antibiotic therapy. Although several whole-genome sequencing studies on P. aeruginosa CF lineages have been published, the evolutionary trajectories in relation to the development of antimicrobial resistance remain mostly unexplored to date. In this study, we monitored the adaptive changes of P. aeruginosa during its microevolution in the CF airways to provide an innovative, genome-wide picture of mutations and persistent phenotypes and to point out potential novel mechanisms allowing survival in CF patients under antibiotic therapy.Results: We obtained whole genome sequences of 40 P. aeruginosa clinical CF strains isolated at Trentino Regional Support CF Centre (Rovereto, Italy) from a single CF patient over an 8-year period (2007–2014). Genotypic analysis of the P. aeruginosa isolates revealed a clonal population dominated by the Sequence Type 390 and three closely related variants, indicating that all members of the population likely belong to the same clonal lineage and evolved from a common ancestor. While the majority of early isolates were susceptible to most antibiotics tested, over time resistant phenotypes increased in the persistent population. Genomic analyses of the population indicated a correlation between the evolution of antibiotic resistance profiles and phylogenetic relationships, and a number of putative pathoadaptive variations were identified.Conclusion: This study provides valuable insights into the within-host adaptation and microevolution of P. aeruginosa in the CF lung and revealed the emergence of an MDR phenotype over time, which could not be comprehensively explained by the variations found in known resistance genes. Further investigations on uncharacterized variations disclosed in this study should help to increase our understanding of the development of MDR phenotype and the poor outcome of antibiotic therapies in many CF patients.

Pulmonary infections in patients with cystic fibrosis (CF), are a major cause of morbidity and mortality. Prevention, diagnosis and therapy in cystic fibrosis, lead to the necessary collaboration between clinical and laboratory to identify effective strategies and appropriate solutions to address the problems inherent isolation micro-organisms, antibiotic strategies, overcoming of bacterial resistance and other problems management of these patients. The task of the microbiology laboratory and research in quickly and accurately, the agents responsible for these infectious processes, in order to isolate them from material, identify and determine their sensitivity antibiotics. A microbiological surveillance on 34 patients (13 males and 21 females) with CF and related to the “Support Services Provincial Trento for the treatment of cystic fibrosis “in the period July 2005 - August 2008, was carried out. 180 Gram positive and 278 of Gram negative bacteria as well as 235 fungi wre collected. Staphylococcus aureus was the most frequently organism found in patients with CF with an incidence of 23% on 156 strains isolated, Pseudomonas aeruginosa was collected 19% of all microorganisms isolated corresponding to 131 strains, Candida albicans is the yeast often isolated with a frequency 22% equal to 149 isolates, Aspergillus fumigatus was isolated at a rate of 8%. From the data we collected and processed has been noted that the local epidemiology of CF patients reflects as reported in the scientific literature and national international consulting, both as a type microorganisms that frequency also isolated compared to age groups. Considering the score of Bartlett as discriminating respiratory fitness of the material, it has been observed that only 32 samples over 327 total (10%) would materials insignificant. It follows therefore that the time of sample collection, followed by personnel (physiotherapists dedicated to CF patients), represents a crucial step in guarantee the quality of the preanalytical phase.

Moraxella catarrhalis is a Gram-negative aerobic diplococcus, commensal of the oro-pharingeal cavity, actually playing an emerging role in the upper respiratory tract infections together with Streptococcus pneumoniae and Haemophilus influenzae. This study reports the case of a twoyearold child who was admitted into hospital with fever, headache and vomit. The chest radiograph showed signs of basal lung involvementmaking the clinical suspicion of bacterial infectionlikely. From blood culture a Moraxella catarrhalis strain was isolated. In young children M. catarrhalis is known to cause otitis media and sinusitis, but only rarely bacteremia. In this case the child showed a clinical picture of lung infection and consequent sepsis due to M. catarrhalis.