Phenotypic and genotypic characterization of Pseudomonas aeruginosa from cystic fibrosis patients

Abstract

Pseudomonas aeruginosa accounts for about one half of all pulmonary infections of cystic fibrosis (CF) patients. In this study, we analyzed 135 P. aeruginosa strains isolated from the expectorations of 55 CF adult patients attending a CF referral center over a period of five years. We assessed the genotype of the strains by pulsed-field gel electrophoresis (PFGE) and analyzed some phenotypic characteristics, such as O serotype, enzyme and mucous production, antibiotics susceptibility, and motility. PFGE allowed the typification of 97.1% of strains, revealing the presence of nine different genomic patterns. The pattern indicated as B was the most frequent, whereas patterns H and I were the most uncommon. Serotyping failed to identify 37.8% of strains and 29 out of 55 patients harbored almost one non-typable (NT) strain. During the five years of the study, we observed a progressive reduction of O6 and O10 types, but an increase of the O1 type and of NT strains. Most strains produced protease, hemolysin, and gelatinase, and were mobile. Several patients harbored the same serotype or genotype in sequential isolates, though characterized by a different susceptibility to antimicrobials. We did not observe a relationship between bacterial genotype and phenotype. This could be due to the fact that PFGE is not sensitive enough to detect subtle genotypic differences. The epidemiological importance of the genotypic characterization of bacteria-colonizing CF subjects and the surveillance measures to be adopted in CF centers are briefly discussed.

Phenotypic characterization and PCR-Ribotypic profile of Pseudomonas aeruginosa isolated from cystic fibrosis patients in Iran

“…About the influence of these antibiotics on adult CF patients, different results have been reported by L. Leone and M. R. O Carroll et al .,[2728] and contradicted with our result. Therefore, It seems that adult CF patients and those (urinary Patients, Hospital personnel exposed to antibiotics and the Hospital Environment (sets, wards, showers, sinks, drug shelfs, blankets,…) were colonized with P. aeruginusa for a long time are in antibiotic resistance risk.…”

Phenotypic Heterogeneity of Pseudomonas aeruginosa Populations in a Cystic Fibrosis Patient

“…Evidence presented in the current study suggests that non-mucoid isolates are just as prevalent as mucoid isolates. Similarly, we found both motile and non-motile isolates in relatively equal abundance, which has been observed previously [32], [35], [36]. The implication of this is that rather than a single phenotype dominating the lung environment, a number of phenotypes can evolve, including but not restricted to, mucoid phenotypes.…”

“…P. aeruginosa isolates, even clonal isolates from the same sample, have been shown to have large variations in motility [34], [35], quorum sensing [29], [34], virulence factor production [34]–[36], antibiotic susceptibility [30], [31], [36] and biofilm formation [34]. A recent study examined phenotypic and genetic variability in the P. aeruginosa Liverpool Epidemic Strain (LES) from 10 adult CF patients and found large diversity in virulence factors, auxotrophy, hypermutability, antibiotic resistance, presence of prophage, and colony morphotype [32].…”

Catheter-related infections caused byPseudomonas aeruginosa: virulence factors involved and their relationships

“…No significant correlation was detected between the motility types. The number of motile strains isolated from catheter‐related infections was twice as high as that of isolates from CF patients (Leone et al ., ; Deligianni et al ., ). It seems likely that the bacterial benefit from the motility is higher during the process of infection development than in an already established infection (i.e.…”