Molecular detection of an atypical, highly resistant, clonal Pseudomonas aeruginosa isolate in cystic fibrosis patients.
BACKGROUND
The identification of Pseudomonas aeruginosa (P. aeruginosa) isolates in sputum from cystic fibrosis (CF) patients can be challenging due to the multitude of phenotypic changes isolates undergo during adaptation to the microenvironment of the CF lung.


METHODS
We report the occurrence of shared P. aeruginosa isolates which failed identification by phenotypic methodologies and required species specific polymerase chain reaction. P. aeruginosa isolates were genotyped by macrorestriction analysis.


RESULTS
Analysis of atypical isolates revealed one clonal P. aeruginosa isolate and three smaller clusters. In contrast molecular typing of phenotypically characteristic P. aeruginosa isolates revealed only small clusters. Despite exhibiting higher levels of antimicrobial resistance, acquisition of atypical strains was not associated with significant changes in clinical decline.


CONCLUSIONS
Our experience highlights the importance of accurate identification of bacterial isolates in CF lung disease to detect clonal spread of atypical isolates.
Department of Medical Microbiology, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
Deirdre
D
Keating
Department of Medical Microbiology, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
Mary J
MJ
Crowe
Department of Respiratory Medicine, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
Barry
B
Kennedy
Department of Medical Microbiology, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
Abigail
A
Salmon
Department of Medical Microbiology, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
David
D
Britton
Department of Respiratory Medicine, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
Charles G
CG
Gallagher
Department of Respiratory Medicine, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
Edward F
EF
McKone
Department of Medical Microbiology, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland. Electronic address: kirsten.e.schaffer@ucd.ie.
Kirsten
K
Schaffer
D015373:Bacterial Typing Techniques; D003550:Cystic Fibrosis / Q000382:microbiology* / Q000503:physiopathology; D004269:DNA, Bacterial / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D013183:Sputum / Q000382:microbiology
D004269:DNA, Bacterial