Epidemiological Features of Chronic Lung Infection in Patients with Cystic Fibrosis

Abstract

Relevance. Life expectancy of cystic fibrosis patients mostly depends on the degree of respiratory system damage caused by opportunistic microorganisms, which is due to the fact that 90-95% of deaths of cystic fibrosis patients are caused by lung infections. Goal. To define epidemiologic characteristics of chronic lung infection caused by the most common agents (S. aureus, P. aeruginosa, B. cepacia-like bacteria (Bcc) and Achromobacter spp.) using a novel chronic lung infection in cystic fibrosis patients microbiological diagnosis algorithm. Materials and methods. Over a period of 7 years (2008-2016) 300 children with cystic fibrosis living in Moscow, Moscow region and several other regions of Russian Federation have been checked-up. 260 sputum samples from 100 adult patients, who were under care at the Pulmonology Research Institute, were studied. Sputum samples from children were taken before and after antibiotic therapy with intervals of 15-45 days and over 6 months. 30 of the children were also subjected to a microbiologic monitoring of the state of chronic infection in the period between 4 and 15 months. Sputum sample from adult patients were also taken before and after antibiotic therapy with intervals of 0, 15-45 days and over 6 months. Results. P. aeruginosa, S. aureus, H. influenzae and Burkholderia cepacia-like bacteria were confirmed to be the most common agents of lung infection in cystic fibrosis patients. Children with cystic fibrosis over the years develop foci of chronic lung infection, mainly caused by P. aeruginosa and S. aureus. Conclusions. Chronic lung infection can be caused by community-acquired or nosocomial S. aureus и P. aeruginosa. Chronic lung infection is a complex, dynamically changing disease which requires constant monitoring and is mainly caused by S. aureus, P. aeruginosa, Bcc bacteria and Achromobacter spp. As populations of the agents can be diverse, it is necessary to study all colonies with differing phenotypes (mucoid and non-mucoid variants, small colony variants, variants with different pigments) and to take samples of several colonies when testing antibiotic resistance. Bcc and Achromobacter spp. cannot be eradicated with antibiotics, thus the only effective measure against these bacteria can only be vaccination which requires developing a vaccine.