G Héry-Arnaud1, E Nowak2, J Caillon3, V David4, A Dirou5, K Revert5, M-R Munck6, I Frachon7, A Haloun8, D Horeau-Langlard8, J Le Bihan5, I Danner-Boucher8, S Ramel5, M-P Pelletier5, S Rosec2, S Gouriou9, E Poulhazan2, C Payan10, C Férec11, G Rault5, G Le Gal2, R Le Berre12. 1. EA 3882-Laboratoire de Biodiversité et d'Ecologie Microbienne, Faculté de Médecine, Université de Brest, Brest, France; Département de Bactériologie-Virologie, Hygiène Hospitalière et Parasitologie-Mycologie, CHRU Brest, Brest, France. Electronic address: genevieve.hery-arnaud@chu-brest.fr. 2. INSERM CIC 1412, CHRU Brest, Brest, France. 3. Laboratoire de Bactériologie-Virologie et Hygiène Hospitalière, CHU Nantes, Nantes, France. 4. Centre de Ressources et de Compétences Mucoviscidose Enfants, CHU Nantes, Nantes, France. 5. Centre de Ressources et de Compétences Mucoviscidose, Centre de Perharidy, Roscoff, France. 6. Département de Pédiatrie et de Génétique Médicale, CHRU Brest, Brest, France. 7. Département de Médecine Interne et de Pneumologie, CHRU Brest, Brest, France. 8. Centre de Ressources et de Compétences Mucoviscidose Adultes, CHU Nantes, Nantes, France. 9. EA 3882-Laboratoire de Biodiversité et d'Ecologie Microbienne, Faculté de Médecine, Université de Brest, Brest, France. 10. EA 3882-Laboratoire de Biodiversité et d'Ecologie Microbienne, Faculté de Médecine, Université de Brest, Brest, France; Département de Bactériologie-Virologie, Hygiène Hospitalière et Parasitologie-Mycologie, CHRU Brest, Brest, France. 11. UMR1078, Institut National de la Santé et de la Recherche Médicale, Brest, France; Laboratoire de Génétique Moléculaire, CHRU Brest, France; Faculté de Médecine et des Sciences de la Santé, Université de Brest, France; Etablissement Français du Sang-Bretagne, Brest, France. 12. EA 3882-Laboratoire de Biodiversité et d'Ecologie Microbienne, Faculté de Médecine, Université de Brest, Brest, France; Département de Médecine Interne et de Pneumologie, CHRU Brest, Brest, France. Electronic address: rozenn.leberre@chu-brest.fr.
Abstract
OBJECTIVES: Early detection of Pseudomonas aeruginosa lung positivity is a key element in cystic fibrosis (CF) management. PCR has increased the accuracy of detection of many microorganisms. Clinical relevance of P. aeruginosa quantitative PCR (qPCR) in this context is unclear. Our aim was to determine P. aeruginosa qPCR sensitivity and specificity, and to assess the possible time saved by qPCR in comparison with standard practice (culture). METHODS: A multicentre cohort study was conducted over a 3-year period in 96 patients with CF without chronic P. aeruginosa colonization. Sputum samples were collected at each visit. Conventional culture and two-step qPCR (oprL qPCR and gyrB/ecfX qPCR) were performed for 707 samples. The positivity criteria were based on the qPCR results, defined in a previous study as follow: oprL qPCR positivity alone if bacterial density was <730 CFU/mL or oprL qPCR combined with gyrB/ecfX qPCR if bacterial density was ≥730 CFU/mL. RESULTS: During follow up, 36 of the 96 patients with CF were diagnosed on culture as colonized with P. aeruginosa. This two-step qPCR displayed a sensitivity of 94.3% (95% CI 79.7%-98.6%), and a specificity of 86.3% (95% CI 83.4%-88.7%). It enabled P. aeruginosa acquisition to be diagnosed earlier in 20 patients, providing a median detection time gain of 8 months (interquartile range 3.7-17.6) for them. CONCLUSIONS: Implementing oprL and gyrB/ecfX qPCR in the management of patients with CF allowed earlier detection of first P. aeruginosa lung positivity than culture alone.
OBJECTIVES: Early detection of Pseudomonas aeruginosa lung positivity is a key element in cystic fibrosis (CF) management. PCR has increased the accuracy of detection of many microorganisms. Clinical relevance of P. aeruginosa quantitative PCR (qPCR) in this context is unclear. Our aim was to determine P. aeruginosa qPCR sensitivity and specificity, and to assess the possible time saved by qPCR in comparison with standard practice (culture). METHODS: A multicentre cohort study was conducted over a 3-year period in 96 patients with CF without chronic P. aeruginosa colonization. Sputum samples were collected at each visit. Conventional culture and two-step qPCR (oprL qPCR and gyrB/ecfX qPCR) were performed for 707 samples. The positivity criteria were based on the qPCR results, defined in a previous study as follow: oprL qPCR positivity alone if bacterial density was <730 CFU/mL or oprL qPCR combined with gyrB/ecfX qPCR if bacterial density was ≥730 CFU/mL. RESULTS: During follow up, 36 of the 96 patients with CF were diagnosed on culture as colonized with P. aeruginosa. This two-step qPCR displayed a sensitivity of 94.3% (95% CI 79.7%-98.6%), and a specificity of 86.3% (95% CI 83.4%-88.7%). It enabled P. aeruginosa acquisition to be diagnosed earlier in 20 patients, providing a median detection time gain of 8 months (interquartile range 3.7-17.6) for them. CONCLUSIONS: Implementing oprL and gyrB/ecfX qPCR in the management of patients with CF allowed earlier detection of first P. aeruginosa lung positivity than culture alone.
Authors: Peter H Gilligan; Damian G Downey; J Stuart Elborn; Patrick A Flume; Sebastian Funk; Deirdre Gilpin; Timothy J Kidd; John McCaughan; B Cherie Millar; Philip G Murphy; Jacqueline C Rendall; Michael M Tunney; John E Moore Journal: J Clin Microbiol Date: 2018-08-27 Impact factor: 5.948
Authors: Trenton J Davis; Ava V Karanjia; Charity N Bhebhe; Sarah B West; Matthew Richardson; Heather D Bean Journal: mSphere Date: 2020-10-07 Impact factor: 4.389