AUTHOR=Moore John E. , McCaughan John , Rendall Jacqueline C. , Millar Beverley C. 

TITLE=The Microbiology of Non-aeruginosa Pseudomonas Isolated From Adults With Cystic Fibrosis: Criteria to Help Determine the Clinical Significance of Non-aeruginosa Pseudomonas in CF Lung Pathology

JOURNAL=British Journal of Biomedical Science

VOLUME=Volume 79 - 2022

YEAR=2022

URL=https://www.frontierspartnerships.org/journals/british-journal-of-biomedical-science/articles/10.3389/bjbs.2022.10468

DOI=10.3389/bjbs.2022.10468

ISSN=2474-0896

ABSTRACT=The purpose of the article:  Whilst Pseudomonas aeruginosa is the species most frequently isolated bacterium from the sputum of patients with cystic fibrosis, other species of Pseudomonas have been isolated from CF patients.  Currently, there is a paucity of reports on these non-aeruginosa Pseudomonas (NAPs), hence it was the aim of this study to (i). examine the diversity and frequency of NAPs in an adult CF population and (ii) compare and contrast the microbiology and genomics of NAPs in comparison to P. aeruginosa and (iii) to propose clinical and laboratory criteria that will help determine the clinical significance of non-aeruginosa Pseudomonas in CF lung pathology.

Materials and methods: Microbiological data was examined from 100 adult patients with cystic fibrosis from birth to present (31/12/2021), equating to 2455 patient years. 16S rDNA phylogenetic relatedness of NAPs was determined, as well as bioinformatical comparison of whole genomes of P. aeruginosa against P. fluorescens.

Results: Ten species were isolated from this patient cohort during this time period, with three species, i.e. P. fluorescens, P. putida and P. stutzeri, accounting for the majority (87.5%) of non-aeruginosa reports, with the remaining seven species being isolated sporadically from a single patient.  This is the first report of the isolation of P. fragi, P. nitroreducens, P. oryzihabitans and P. veronii in patients with cystic fibrosis.  The mean time to first detection of any non-aeruginosa species was 183 months (15.25 years) [median = 229 months (19.1 years)], with a range from 11 months to 338 months (28.2 years).  Several of the NAPs were closely related to P. aeruginosa.


Conclusion: NAPs were isolated infrequently and were transient colonisers of the CF airways, in those patients with CF in which they were isolated.  A set of ten clinical and laboratory criteria are proposed to provide some key indicators, as to the clinical importance of the non-aeruginosa species isolated.  Future studies should aim to elucidate why non-aeruginosa species of Pseudomonas are infrequent colonisers and poor bacterial pathogens in CF, which in turn could help our understanding as to why their close phylogenetic neighbour, P. aeruginosa, is such a successful CF pathogen.