Concordant genotype of upper and lower airways P aeruginosa and S aureus isolates in cystic fibrosis
- J G Mainz1,
- L Naehrlich2,
- M Schien1,
- M Käding3,
- I Schiller1,
- S Mayr4,
- G Schneider5,
- B Wiedemann6,
- L Wiehlmann7,
- N Cramer7,
- W Pfister8,
- B C Kahl9,
- J F Beck1,
- B Tümmler7
- 1Department of Pediatrics, CF Center, University Hospital of Jena, Germany
- 2Department of Pediatrics, CF Center, University of Erlangen-Nuernberg, Germany
- 3CF Center, Chemnitz Hospital, Germany
- 4Otorhinolaryngology, University of Erlangen-Nuernberg, Germany
- 5Otorhinolaryngology, University Hospital of Jena, Germany
- 6Department of Medical Informatics and Biometrics, University of Dresden, Germany
- 7Klinische Forschergruppe, Pediatric Pneumology, Medizinische Hochschule Hannover, Germany
- 8Institute of Medical Microbiology, University Hospital of Jena, Germany
- 9Institute of Medical Microbiology, University Hospital Münster, Germany
- Dr J G Mainz, Cystic Fibrosis Center, Department of Pediatrics, University of Jena, Kochstrasse 2, D-07740 Jena, Germany; Jochen.Mainz{at}med.uni-jena.de
- Received 11 July 2008
- Accepted 25 February 2009
- Published Online First 11 March 2009
Abstract
Rationale: Lower airway (LAW) infection with Pseudomonas aeruginosa and Staphylococcus aureus is the leading cause of morbidity in cystic fibrosis (CF). The upper airways (UAW) were shown to be a gateway for acquisition of opportunistic bacteria and to act as a reservoir for them. Therefore, tools for UAW assessment within CF routine care require evaluation.
Objectives: The aims of the study were non-invasive assessment of UAW and LAW microbial colonisation, and genotyping of P aeruginosa and S aureus strains from both segments.
Methods: 182 patients with CF were evaluated (age 0.4–68 years, median 17 years). LAW specimens were preferably sampled as expectorated sputum and UAW specimens by nasal lavage. P aeruginosa and S aureus isolates were typed by informative single nucleotide polymorphisms (SNPs) or by spa typing, respectively.
Results: Of the typable S aureus and P aeruginosa isolates from concomitant UAW- and LAW-positive specimens, 31 of 36 patients were carrying identical S aureus spa types and 23 of 24 patients identical P aeruginosa SNP genotypes in both compartments. Detection of S aureus or P aeruginosa in LAW specimens was associated with a 15- or 88-fold higher likelihood also to identify S aureus or P aeruginosa in a UAW specimen from the same patient.
Conclusions: The presence of identical genotypes in UAW and LAW suggests that the UAW play a role as a reservoir of S aureus and P aeruginosa in CF. Nasal lavage appears to be suitable for non-invasive UAW sampling, but further longitudinal analyses and comparison with invasive methods are required. While UAW bacterial colonisation is typically not assessed in regular CF care, the data challenge the need to discuss diagnostic and therapeutic standards for this airway compartment.
Trial registration number: NCT00266474.
Footnotes
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Competing interests: None.
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Funding: The study was supported by funds from Hoffmann-La Roche, Novartis, InfectoPharm, Pari and Gruenenthal. We confirm that the financial support did not influence any aspect of the study and that no other financial resources were provided.
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Contributors: JM was principal investigator. LN and MK conducted and supervised the study in participating CF centres. SM and GS were coinvestigators in participating ENT units. JM contributed to the concept and design of the study together with BT, JFB, IS and MS. BT, BCK, LW, NC and WP performed the microbiological analyses including genotyping of P aeruginosa and S aureus strains. BT, BCK, IS, MS and BW contributed to the analysis and interpretation of data.
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Patient consent: Obtained.
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Ethics approval: The trial was approved by the Jena University Ethics Committee.
