Epidemiology Of Chronic Pseudomonas aeruginosa Infections In Cystic Fibrosis

Abstract

The epidemiology of chronic colonization of airways with Pseudomonas aeruginosa was monitored in 44 patients with cystic fibrosis (CF) by DraI/SpeI macrorestriction analyses of 489 isolates. Sequential P. aeruginosa isolates (144) that had been collected from 32 CF patients over < or = 2.5 years were investigated, and 12 patients were followed for 8 years after onset of colonization. Forty-eight different genotypes were uncovered from 481 typeable isolates. Ten genotypes were found in > 1 unrelated CF patient. The 6 most frequent clones were identified in 58% of isolates. Ten of the 12 patients monitored for 8 years were harboring their initially acquired P. aeruginosa clone at all times, with subtle shifts of fragment patterns indicating subclonal variation. During colonization, the bacteria gradually lost pyocin and phage typing responses, supporting the view that genotypically discordant P. aeruginosa strains develop a common phenotype.

Genetic features of Pseudomonas aeruginosa isolates from cystic fibrosis patients compared with those of isolates from other origins

“…Therefore, strains of this group may also have emerged from the environment. This is in accordance with the conclusion of another European study, which found that 28 % of CF isolates were related to 21 % of P. aeruginosa isolates from an aquatic habitat (Romling et al, 1994).…”

“…Thus, the gene was probably acquired by horizontal transfer, as observed previously for some other bacterial sialidase genes (Roggentin et al, 1993). The prevalence of nan1 in plant strains, the stability of the genotype of P. aeruginosa isolates from the pulmonary tract of CF patients (Romling et al, 1994;Renders et al, 1996) and the strong correlation between RAPD and MLEE results suggest that such genetic events probably originated in environmental populations of strains rather than in CF populations.…”

“…Previous studies have suggested that there is no correlation between P. aeruginosa clones and diseases or environmental habitats (Foght et al, 1996;Kiewitz & Tummler, 2000;Pirnay et al, 2002;Romling et al, 1994). The use of one or a few strains to represent one disease or environmental habitat may have limited the conclusions of these studies.…”

“…Most of these studies have included few or no CF isolates (Denamur et al, 1993;Kiewitz & Tummler, 2000;Lomholt et al, 2001;Pirnay et al, 2002;Ruimy et al, 2001) or have specifically explored the genome of P. aeruginosa isolates from CF patients, especially for epidemiological purposes (Boukadida et al, 1993;Hoogkamp-Korstanje et al, 1995). Fewer studies have demonstrated a link between isolates from CF patients and isolates from environmental habitats (Romling et al, 1994). Therefore, the genetic relationships between CF isolates and populations of isolates from patients with other diseases remain unexplored.…”

Molecular typing and biological characteristics of Pseudomonas aeruginosa isolated from cystic fibrosis patients in Brazil

“…32 The most relevant result of our study is the fi nding that four main bacterium clusters, with the predominance of two clusters, are responsible for colonizing CF patients. This suggests that either there is a strong selection towards a specifi c genotype, which could originate by chromosome rearrangements, 33,34 or that primarily specifi c isolates containing pathogenic gene islands may be responsible for the initial and subsequent colonization processes. As this study was carried out using a small number of patientes and strains this statement cannot be generalized for all cystic fi brosis population and further studies must be accomplished to confi rm it.…”