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 collection and primary inoculation of nasal lavage fluid from cystic fibrosis patients for microbiological investigation. As a clinical case illustrating the feasibility of this technique, we describe the dynamics of the microflora composition in a patient with cystic fibrosis. The patient had a clinical and microbiological picture of P. aeruginosa eradication from the lung tissue, owing to which the antibacterial therapy was stopped. Six months later, the microflora in the nasal lavage fluid and sputum were assessed in parallel. The growth of P. aeruginosa (10² CFU/mL) but not P. aeruginosa in sputum was detected. To determine origin of this strain, the degree of genetic relationship between 5 strains obtained from the patient from 2008 to 2016 was assessed based on bacterial protein profiling. A typical strain of P. aeruginosa ATTS 27853 was used as a control. Strains isolated from the patient in 2009 and 2016 were identical suggesting that the antibacterial therapy led to eradication of P. aeruginosa in the lungs, but not in the upper airways. Four months later, the growth of P. aeruginosa was found in sputum. The patient was prescribed to use antibacterial drugs inhaled into paranasal sinuses. Repeated test performed 3 months later resulted in growth of P. aeruginosa 10¹ CFU/mL from nasal lavage fluid, but not from sputum. The patient was referred to a risk group on airway colonization by pathogen strains derived from the upper airway tract. The clinical example illustrates relevance of conducting a regular microbiological study of nasal lavage fluid in order to early identify clinically significant pathogens to prevent their spread to the lower airway tract.