Epidemiological significance of home environment for cystic fibrosis patients with Pseudomonas aeruginosa lung infections

Background. For patients with cystic fibrosis (CF), respiratory tract infections caused by Pseudomonas aeruginosa, S. aureus, B. cepacia complex, and other non-fermenting bacteria (NGOs) are significant risk factors. Insufficient disinfection of environmental objects and care items used by children suffering from cystic fibrosis, as well as the circulation of pathogens in the home environment, can lead to reinfection and superinfection.

Objective. To determine the epidemiological significance of the home environment in the transmission of P. aeruginosa bacteria to children with CF and to evaluate the effectiveness of preventive measures at home.

Materials and methods. The living conditions of 27 children with CF with a chronic lung infection caused by P. aeruginosa and their families were assessed. A total of 265 samples collected from home environmental objects were analyzed. Surface samples were collected using swabs. The study was conducted using bacteriological and molecular genetic methods.

Results. An analysis of questionnaires revealed that 26% of families of children with CF did not use detergents or disinfectants to care for their inhalers. 41% of families did not adhere to the specified time (schedule) for sink disinfection. 83% of bathroom sinks were contaminated with microorganisms. Among the isolated microorganisms, the rate of P. aeruginosa isolation was 20%. Monitoring of the home environment revealed that sink drains were the main reservoirs of P. aeruginosa. Pseudomonas aeruginosa contamination of nebulizer masks and toothbrushes was also detected. PCR data obtained from studying P. aeruginosa isolates from different objects indicate the possibility of the circulation of a single genotype in the home environment. The effectiveness of preventive measures for disinfecting nebulizers and sinks was established to be insufficient. After disinfection, opportunistic pathogens were isolated from 22% of nebulizer surfaces. A. lwoffii, Aspergillus niger, Candida albicans, and S. aureus were isolated from nebulizer compressor filters and toothbrushes. These bacteria can infect the lungs of patients with CF, including in association with P. aeruginosa.

Conclusion. Control over microbiological risks in the home environment, including regular monitoring and strict protocols for the treatment of key objects, should be mandatory for patients with CF to achieve eradication of lung pathogens.

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