P073 Use of qPCR to analyse changes in total bacterial and Pseudomonas aeruginosa load in cystic fibrosis patients when clinically stable and during exacerbations C. MCGettigan 1 , C. Spence 1 , A.J. Lee 1 , L. Sherrard 1 , E. Johnston 1 , G.G. Einarsson 1 , J.S. Elborn 1,2 , D. Downey 1,3 , M. Muhlebach 4 , R. Boucher 4 , G. MCElvaney 5 , M. Michelle 5 , G. Lavelle 5 , M.M. Tunney 1 , D.F. Gilpin 1 . 1 Queen’s University Belfast, Belfast, United Kingdom; 2 Imperial College and Royal Brompton Foundation Trust, London, United Kingdom; 3 Belast Helath and Social Care Trust, Belfast, United Kingdom; 4 University of North Carolina, Chapel Hill, United States; 5 Royal College of Surgeons in Ireland, Dublin, Ireland Objectives: Bacterial load, an important endpoint in clinical trials assessing the efficacy of antimicrobials, is currently determined via culture and is subject to the limitations of bacterial growth in vitro. This study aimed to compare changes in total bacterial and Pseudomonas aeruginosa (PA) load via qPCR and quantitative culture (QC) (total viable count, TVC) in clinical respiratory samples from CF patients when clinically stable and at exacerbation. Methods: Matched sputum samples were collected from CF patients in Belfast, Dublin (RCSI) and Chapel Hill during stable disease (S) and at the start (E1) and end (E2) of IV antibiotic treatment for an exacerbation (Table 1). Total bacterial and PA load was determined by QC and qPCR (LightCycler ® ) using a probe-based detection system targeting 16S rRNA and oprL genes. Results: Table 1. Total bacterial and total PA load via qPCR Method of quantification S (Mean±SD) E1 (Mean±SD) E2 (Mean±SD) P value Post-Hoc p value (S1 vs E2) TVC Total load (n = 12) 3.77 × 10 8 cfu/ml ± 5.86 × 10 8 1.75 × 10 8 cfu/ml ± 3.92 × 10 8 9.60 × 10 7 cfu/ml ± 2.91 × 10 8 0.0131 <0.05 PA (n = 4) 1.80 × 10 7 cfu/ml ± 1.41 × 10 7 2.14 × 10 6 cfu/ml ± 2.00 × 10 6 1.17 × 10 5 cfu/ml ± 8.93 × 10 4 ns ns qPCR Total load (n = 37) 2.61 × 10 7 copy number/ml ± 3.23 × 10 7 1.69 × 10 7 copy number/ml ± 1.927 × 10 7 2.01 × 10 7 copy number/ml ± 3.02 × 10 7 ns ns PA (n = 17) 1.23 × 10 7 copy number/ml ± 1.58 × 10 7 6.89 × 10 6 copy number/ml ± 1.13 × 10 7 3.78 × 10 6 copy number/ml ± 7.35 × 10 6 0.0194 <0.05 PA load was significantly lower at E2 vs. S via qPCR (p < 0.05) but not by QC. Conversely, there was no change in total bacterial load at E2 vs. S via qPCR. However, there was a decrease in total bacterial load at E2 vs. S via QC ( p < 0.05). Conclusion: The change in total bacterial and PA load observed differed depending on the quantification method used with these differences potentially due to small sample size for QC. Further work is required to establish the correlation between QC and qPCR, and hence the potential of qPCR as an endpoint in clinical trials. P074 Information value of non-invasive specimens for airway bacteriome research O. Voronina 1 , N. Ryzhova 1 , M. Kunda 1 , E. Aksenova 1 , N. Sharapova 1 , V. Sherman 2 , A. Voronkova 2 , E. Kondratyeva 2 , A. Gintsburg 1 . 1 N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Moscow, Russian Federation; 2 Research Centre for Medical Genetics, Moscow, Russian Federation Objectives: Early identification of bacterium causing respiratory tract infection is the milestone of appropriate treatment for pathogen eradication. Since Rosenfeld (1999) fundamental research oropharyngeal cough swab (OCS) has been believed the traditional specimen for infants with cystic fibrosis (CF), which accurately reflect the microbial populations in the low airways. OCS remains the main noninvasive specimen for patients, which are not able to expectorate. The necessity of upper airway investigation is questionable. So we analyzed three possible noninvasive specimens to appreciate the informative value of each of them in the investigation of airways bacteriome. Methods: Samples of sputum, nasopharyngeal and oropharyngeal cough swabs from 62 CF patients (3 month – 17 years of age) were analyzed. High-throughput sequencing of 16S rDNA amplicons was used for analysis of bacterial community. Results: 13 patients were able to expectorate. Comparison of sputum and OCS demonstrated that pathogenic Proteobacteria detected in sputum in 50–90% were less abundant in OCS (0.1–10%). Only 1 patient had equal amount of Proteobacteria in both specimens. Subsequent sputum samples contained similar amount of every bacterial taxon. Proteobacteria amount in repeat OCS was 11 times different. Nasopharyngeal swabs contained 3–100% Proteobacteria (avg. 51.2%). Pseudomonas, Stenotrophomonas, Klebsiella, and representatives of Moraxellaceae, Sphingomonadaceae, Burkholderiaceae and so on were identified. Firmicutes were more variable in nasopharyngeal swabs. Actinobacteria were up to 71% in some specimens. Conclusion: Nasopharyngeal swabs together with sputum are informative specimens for airway bacteriome analysis. The results our investigation suggested that nasopharynx may be the additive source of lung infection for CF patients. P075 Anti-fungal therapeutic drug monitoring in adults with cystic fibrosis K. Dave 1 , M. Di Paolo 1,2 , A. Vijayasingam 1 , R. Sheth 1 , E. Luke 1 , A. Scourfield 3 , L. Nwankwo 3 , S. Schelenz 3 , J.S. Elborn 1,4 , D. Armstrong-James 3 , A. Shah 1 . 1 Royal Brompton and Harefield NHS Foundation Trust, Adult Cystic Fibrosis Department, London, United Kingdom; 2 “sapienza” University of Rome, Department of Public Health and Infectious Diseases, Rome, Italy; 3 Royal Brompton and Harefield NHS Foundation Trust, Microbiology Department, London, United Kingdom; 4 National Heart and Lung Institute, Imperial College London, London, United Kingdom Background: Fungal disease is a complication of Cystic Fibrosis (CF) and is associated with poor outcomes. The mainstay of treatment is azoles, which require antimicrobial sensitivity testing for drug choice and therapeutic drug monitoring (TDM) to optimise dose. Due to variable pharmacokin- etics, achieving therapeutic concentrations in CF is problematic, potentially leading to poor clinical outcome and antimicrobial resistance (AMR). Aims: To determine in a single-centre study the use of antifungal therapy, frequency of TDM over a 12-month period and its relation to AMR. Methods: A retrospective analysis between 2016–17 of adults with CF on azole therapy followed at the Royal Brompton & Harefield NHS Foundation Trust (600 patients). Indication of use, duration, TDM frequency and microbiology including AMR was collected. Results: 98 adults were treated with an azole (itraconazole 63.3%, voriconazole 7.1%, posaconazole 26.5%, isavuconazole 3.1%). Main indica- tions of usewere ABPA (51%), persistently positive fungal culture (28.6%) and Aspergillus bronchitis (11.2%).165 samples for TDM were taken, median per patient was 2 (range: 0–4). No TDM was performed in 15 patients (15.3%). Azole levels were sub-therapeutic in 50.3%. Therapeutic dosage was corrected in only 21 of 91 (23.1%) occasions where TDM was out of normal range.196 of 831 sputum samples (23.6%) were positive for fungi (A. fumigatus 44.9%, S. apiospermum 24%, E. dermatitidis 20.4%). Azole resistance was reported in 18.6%: 15.7% to itraconazole, 2.9% to voricona- zole; nil for posaconazole/isavuconazole. AMR prevalence in those with sub-therapeutic azole levels was significantly higher compared to those with therapeutic levels (52.4% vs 13.3%, p = 0.045). Conclusion: There is high variability in azole TDM in CF adults associated with frequent sub-therapeutic levels and poor drug optimisation. There is a high prevalence of fungal AMR in adults with CF with a significant association with sub-therapeutic azole levels. P076 What should you do after stopping flucloxacillin in children? K. Azzopardi, S. Hall, J. Forton, L. Thia, I. Doull. Children’s Hospital of Wales, Cardiff, United Kingdom Objectives: The NICE guideline for the diagnosis and management of Cystic Fibrosis (2017) states that children should be offered flucloxacillin as a prophylactic antibiotic against staphylococcus aureus from diagnosis until the age of 3 at least, with consideration given to continuing to 6 years of Poster Sessions / Journal of Cystic Fibrosis 17S3 (2018) S59–S138 S80