Detection of Bacteriophage Particles Containing Antibiotic Resistance Genes in the Sputum of Cystic Fibrosis Patients.

Cystic fibrosis (CF) is a chronic disease in which the bacterial colonization of the lung is linked to an excessive inflammatory response that leads to respiratory failure. The microbiology of CF is complex. Staphylococcus aureus is the first bacterium to colonize the lungs in 30% of pediatric CF patients, and 80% of adult patients develop a chronic Pseudomonas aeruginosa infection, but other microorganisms can also be found. The use of antibiotics is essential to treat the disease, but antibiotic performance is compromised by resistance mechanisms. Among various mechanisms of transfer of antibiotic resistance genes (ARGs), the recently been reported bacteriophages are the least explored in clinical settings. To determine the role of phages in CF as mobile genetic elements (MGEs) carrying ARGs, we evaluated their presence in 71 CF patients. 71 sputum samples taken from these patients were screened for eight ARGs (blaTEM, blaCTX-M-1-group, blaCTX-M-9-group, blaOXA-48, blaVIM, mecA, qnrA, and qnrS) in the bacteriophage DNA fraction. The phages found were also purified and observed by electron microscopy. 32.4% of CF patients harbored ARGs in phage DNA. ß-lactamase genes, particularly blaVIM and blaTEM, were the most prevalent and abundant, whereas mecA, qnrA, and qnrS were very rare. Siphoviridae phage particles capable of infecting P. aeruginosa and Klebsiella pneumoniae were detected in CF sputum. Phage particles harboring ARGs were found to be abundant in the lungs of both CF patients and healthy individuals and could contribute to the colonization of multiresistant strains.

Eradication failure of newly acquired Pseudomonas aeruginosa isolates in cystic fibrosis.

Eradication of Pseudomonas aeruginosa (PA) is critical in cystic fibrosis (CF) patients. OBJECTIVES: To determine eradication success rate of newly acquired PA and to identify characteristics associated with eradication failure. METHODS: In an observational study, data from patients with newly acquired PA infection from 2007 to 2013 were collected. Clinical variables were compared in patients with and without successful eradication for ≥1year. RESULTS: Of 183 patients out of 740 (25%) from 7 CF Centers that had newly acquired PA, eradication succeeded in 72%. Patients with the highest risk of failure had multi-resistant PA, fewer sputum cultures taken, were older, and were diagnosed at a later age. The risk of eradication failure increased by 1.3% with each year of delayed CF diagnosis; successful eradication increased by 17% with each additional sputum culture taken. CONCLUSIONS: Delayed detection of PA infection leading to delayed treatment and growth of multi-resistant organisms is associated with eradication failure.