Transmissible strains ofPseudomonas aeruginosain cystic fibrosis lung infections

Abstract

Pseudomonas aeruginosa chronic lung infections are the major cause of morbidity and mortality associated with cystic fibrosis. For many years, the consensus was that cystic fibrosis patients acquire P. aeruginosa from the environment, and hence harbour their own individual clones. However, in the past 15 yrs the emergence of transmissible strains, in some cases associated with greater morbidity and increased antimicrobial resistance, has changed the way that many clinics treat their patients. Here we provide a summary of reported transmissible strains in the UK, other parts of Europe, Australia and North America. In particular, we discuss the prevalence, epidemiology, unusual genotypic and phenotypic features, and virulence of the most intensively studied transmissible strain, the Liverpool epidemic strain. We also discuss the clinical impact of transmissible strains, in particular the diagnostic and infection control approaches adopted to counter their spread. Genomic analysis carried out so far has provided little evidence that transmissibility is due to shared genetic characteristics between different strains. Previous experiences with transmissible strains should help us to learn lessons for the future. In particular, there is a clear need for strain surveillance if emerging problem strains are to be detected before they are widely transmitted.

Twenty-Five-Year Outbreak of Pseudomonas aeruginosa Infecting Individuals with Cystic Fibrosis: Identification of the Prairie Epidemic Strain

“…The mechanisms by which these strains are capable of being transmitted from one patient to another are poorly understood, but cough aerosol is the most commonly presumed mechanism (16,33). Furthermore, phenotypic characteristics of these transmissible strains enabling patient-to-patient spread are unclear (15).…”

“…Several of these strains are associated with an accelerated clinical deterioration notable for increased treatment burden (13,14), increased exacerbation frequency (14), and progression to respiratory failure (9). For further information on transmissible strains of P. aeruginosa in CF, the reader is referred to a recent review by Fothergill et al (15).…”

Infection Prevention and Control Guideline for Cystic Fibrosis: 2013 Update

“…The epidemiologic and microbiologic basis for epidemic P. aeruginosa strains remains poorly understood, 27 and it is unclear whether all epidemic P. aeruginosa strains have comparable capacity for patient-to-patient transmission. Strain differences in the production of infectious droplets or droplet nuclei that remain suspended in the air under experimental conditions may explain the differences in efficiency of transmission of epidemic P. aeruginosa strains.…”

“…The relative frequency of shared strains of different CF pathogens is shown in Table 6. 27,28,30,66,102,[129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145] III.A.1. Burkholderia spp.…”

“…Newer CF pathogens are increasing in prevalence and are associated with increased rates of morbidity and mortality among individuals with CF. Such pathogens include MRSA, 22,23 Mycobacteria abscessus, 24 Burkholderia dolosa, 25 new species in the Burkholderia cepacia complex, 26 epidemic clones of Pseudomonas aeruginosa (eg, the Liverpool epidemic strain [LES]), [27][28][29] and others. 30 Thanks to the increasing use of molecular typing, strains that are shared among people with CF continue to be identified, suggesting that new strategies beyond those recommended in the 2003 Infection Control Guideline for CF are needed to improve the implementation of IP&C practices and to reduce the transmission of CF pathogens.…”