The Impact of Pseudomonas aeruginosa Infection in Adult Cystic Fibrosis Patients-A Single Polish Centre Study

Abstract

Background: Pseudomonas aeruginosa (PA) is one of the most predominant pathogens of lung infections, often causing exacerbations in adult patients with cystic fibrosis (CF).

Materials and methods: Microbiological characterization of 74 PA isolates and to evaluate the correlations between the bacterial features and 44 adult Polish CF cohort clinical parameters.

Results: The most common variant in the CF transmembrane conductance regulator (CFTR) gene was F508del (76.3%), followed by 3849+10kbC>T (26.3%). A total of 39.4% of the PA isolates showed multiple resistances. In patients with parameters pointing to a decline in lung function, there was a statistically significant moderate correlation with β-lactam resistance and a weak correlation between hospital frequency and colistin resistance. The mucoidity did not correlate with the biofilm formation ability, which showed 41.9% of the isolates. Proteolytic activity, observed in 60.8% of the clinical isolates, was weakly associated with motility detected in 78.4% of the strains. The genetic profiles of the PA were highly heterogeneous, and a weak positive correlation was established between cluster group and biofilm formation.

Conclusion: The findings suggest that there is a high variety in P. aeruginosa populations in adult CF patients. There is a need to monitor PA strains in groups of patients with cystic fibrosis, in particular, in terms of the occurrence of antibiotic resistance related to a decline in lung function.

Keywords: Pseudomonas aeruginosa; antimicrobial drug resistance; cystic fibrosis.

Figure 1

Identified variants (variant legacy names) in CF-relevant target genes and their distribution in the patients. Note: Dark grey circles indicate a variant only in one chromosome, while red circles indicate an F508del homozygote variant (on both chromosomes). Patients without genetic characterization were not included in this figure.

Figure 2

The dendrogram of the P. aeruginosa isolates was calculated based on the RAPD. Note: The evaluation of the band pattern by applying the Dice algorithm and UPGMA grouping method. The isolates’ numbers and the corresponding randomized patient numbers are indicated on the right site. Two bigger clusters were colored orange and blue. (Exemplary: red asterisk indicates two isolates obtained at one visit, the blue asterisks the corresponding two isolates from other visits of patient 38).

Figure 3

Cluster analysis of the genetic relationship of 49 Pseudomonas aeruginosa isolated from 20 CF patients (A) and 71 P. aeruginosa isolates identified in 41 patients with RAPD-pattern (B). The dots ending the RAPD lineages represent the randomized numbers of the patients. Patients with only one isolate were indicated in light grey, and patients with only one isolate analyzed due to missing RAPD-pattern of the other(s) isolate(s) are shown in dark grey. Colored dots indicate patients (color-matched) with more than one analyzed isolate.