Microbiological monitoring of nasal lavage fluid as a method for early detection and prevention of bacterial lung complications in a patient with cystic fibrosis

The severity of complications in cystic fibrosis are determined by microorganisms colonizing the lower airways. Paranasal sinuses can be a reservoir of aggressive pathogens. We have developed a method for collecting and primary inoculation of nasal lavage fluid from cystic fibrosis patients for microbiological investigation. As a clinical example illustrating the feasibility of this technique, we describe the dynamics of the microflora of a patient with cystic fibrosis. The patient had a clinical and microbiological picture of the eradication of P.aeruginosa from the lung tissue, the antibacterial therapy was stopped. After 6 months, parallel research of the microflora of the nasal lavage fluid and sputum was conducted. The study resulted in growth of P.aeruginosa 102 CFU/mL with no growth of P.aeruginosa in sputum. To resolve the origin of this strain, the degree of genetic relationship between 5 strains obtained from the patient from 2008 to 2016 was assessed based on their protein profiling. A typical strain of P.aeruginosa ATTS 27853 was used as the control. Strains isolated from the patient in 2009 and 2016 were identical. It means that the antibacterial therapy led to the eradication of P.aeruginosa in the lungs, but did not affect in the upper airways. After 4 months, the growth of P.aeruginosa was obtained in sputum. The patient was prescribed the introduction of inhaled antibacterial drugs into paranasal sinuses. Repeated test after 3 months resulted in growth of P.aeruginosa 101 CFU/mL culture from nasal lavage fluid and no growth in sputum. The patient is classified as a risk group for the colonization of the airways of strains from the upper airways. The clinical example illustrates the relevance of conducting a regular microbiological study of nasal lavage fluid in order to identify early clinically significant pathogens to prevent their spread in the lower airways.