M. Ni Chroinin

Molecular epidemiology of Mycobacterium abscessus complex isolates in Ireland

BACKGROUND The Mycobacterium abscessus complex are the rapidly growing mycobacteria (RGM) most commonly causing lung disease, especially in cystic fibrosis (CF) patients. Ireland has the worlds highest CF incidence. The molecular epidemiology of M. abscessus complex in Ireland is unreported. METHODS We performed rpoB gene sequencing and multi-locus sequence typing (MLST) on M. abscessus complex strains isolated from thirty-six patients in 2006-2012 (eighteen known CF patients). RESULTS Twenty-eight strains (78%) were M. abscessus subsp. abscessus, eight M. abscessus subsp. massiliense, none were M. abscessus subsp. bolletii. Sequence type 1 (ST1) and ST26 (M. abscessus subsp. abscessus) were commonest. Seven M. abscessus subsp. abscessus STs (25%) were novel (two with novel alleles). Seven M. abscessus subsp. massiliense STs were previously reported (88%), including two ST23, the globally successful clone. In 2012, of 552 CF patients screened, eleven were infected with M. abscessus complex strains (2%). CONCLUSIONS The most prevalent M. abscessus subsp. abscessus and M. abscessus subsp. massiliense strains in Ireland belong to widely-distributed STs, but there is evidence of high M. abscessus subsp. abscessus diversity.

BCG protects toddlers during a tuberculosis outbreak

In 2007, an outbreak of tuberculosis occurred in a toddler population attending two child care centres in Cork, Ireland. Of 268 children exposed, 18 were eventually diagnosed with active tuberculosis. We present the initial clinical and radiographic characteristics of the active disease group. Mantoux testing was positive in only 66% of cases. All cases were either pulmonary or involved hilar adenopathy on chest radiograph; there were no cases of disseminated disease or meningitis. 24% of the exposed children had been previously vaccinated with BCG, and no case of active disease was found in this group (p = 0.016), suggesting a profound protective effect of BCG in this population. Our experience provides evidence supporting a protective effect of BCG against pulmonary disease in young children.

59 Ralstonia mannitolilytica – an emerging threat in cystic fibrosis and lung transplantation

Background Ralstonia mannitolilytica is a rarely reported pathogen in cystic fibrosis. It is frequently resistant to antimicrobials and can be misidentified as Burkholderia cepacia complex using biochemical techniques. Methods We identified 7 CF patients from 4 centres in Ireland, all with advanced lung disease that were colonized or infected with this organism. Each isolate was confirmed by gyrB sequence analysis and genetic relatedness was determined using PFGE. MIC testing was performed as well as combination testing using the multiple combination bactericidal test (MCBT). Whole genome sequencing was also performed. Results Four patients from the same institution had strains that were indistinguishable by PFGE. One patient died aged 14 years awaiting lung transplantation 18 months after acquisition; another patient underwent successful lung transplantation and remains culture negative. The remaining two patients are siblings who are at present requiring frequent courses of IV antibiotics and have significant decline in FEV1 since acquisition. Three other patient strains were unique by PFGE; one patient died age 38 y. Tigecycline and minocyline were the most active single agents showing inhibition by MIC to six and five strains, respectively. Minocycline/piperacillin–tazobactam was the most active combination but was not bactericidal against any strain. Tobramycin/piperacillin–tazobactam demonstrated bactericidal activity against three strains. Conclusion Ralstonia mannitolilytica is emerging as a significant pathogen in advanced CF. Early recognition and targeted treatment may reduce cross infection and improve clinical outcome in patients undergoing transplantation.

37 Clinical outcomes of real world Kalydeco (CORK) study

36 The effect of ivacaftor therapy on clinical and PCR-identified microbial diversity of cystic fibrosis lung infection H. Green1,2, C. Paisey3, A. Smith3, P. Barry1, W. Flight1, A. Jones1,2, J. Marchesi3, A. Horsley1,2, E. Mahenthiralingam3. 1University Hospital of South Manchester NHS Foundation Trust, Manchester Adult Cystic Fibrosis Centre, Manchester, United Kingdom; 2University of Manchester, Institute of Inflammation and Repair, Manchester, United Kingdom; 3Cardiff University, Cardiff School of Biosciences, Cardiff, United Kingdom

X-linked agammaglobulinaemia (XLA) presenting with neutropenia and Pseudomonas aeruginosa cellulitis

A 13-month-old fully vaccinated boy presented with a 2-day history of dactylitis, paronychia and fever. He was noted to be neutropaenic with neutrophil count of <0.1×109/L. Incision and drainage of the abscess was performed and culture of drained pus was unexpectedly positive for P seudomonas aeruginosa. He …

WS20.4 Clinical outcomes of Real-World Kalydeco (CORK) study – a prospective 12 month analysis addressing the impact of CFTR modulation on the cystic fibrosis lung

Objectives Ivacaftor produces significant benefit in patients with cystic fibrosis (CF) with the G551D mutation. Prevalence of this mutation at Cork University Hospital (CUH) is 23% making it uniquely placed to provide single centre insight into CFTR modulation. Methods 33 Ivacaftor-naive Patients with CF (age ≥6) consented to routine quarterly clinical follow up (median 1 year follow up) where clinical changes pre and post ivacaftor were recorded. 3 monthly sputum, blood and low dose CT Thoraces were performed at baseline and post-ivacaftor. Sputum bacteria were detected by plating on selective agars, quantified by total viable count and identified by PCR and sequencing of 16S rRNA genes. Circulating cytokines were measured in blood samples using an MSD platform. CT Thoraces were Bhalla scored. Results Significant mean improvements in FEV1 (10.26%), BMI (1.2 kg/m2), Sweat test (–57.65 mmol/l), Respiratory Domain of CFQ-R (17.51 point), exacerbation rate requiring IV antibiotics were observed, with a significant increase in Sputum diversity (P Conclusion In a large single centre cohort CFTR modulation is associated with a sustained improvement in clinical phenotype, decrease in inflammatory markers, change in lung microbiome and reduction in intraluminal bronchiectatic radiological complications.

WS13.2 The role of PGE2 in cystic fibrosis (CF) lung inflammation and the potential association with ivacaftor therapy and treatment response

Objectives CF causes recurrent lung infections and inflammation which causes lung damage and pulmonary decline. The cyclooxgenase signalling pathway and its major metabolite PGE 2 have been shown to increase lung inflammation. PGE 2 signals through four different receptor subtypes, EP1–EP4. Exact mechanisms underpinning mode of action of new therapies such as ivacaftor may be multifactorial with potential downstream signaling consequences. Methods PGE 2 plasma levels were detected in clinically stable CF patients (n = 25) with a G551D mutation pre and post ivacaftor treatment. CF bronchial epithelial cells (DF508 homozygote, CFBE41o-) and human bronchial epithelial cells (16HBEo-) were seeded at2×10 5 cells/ml. EP1 receptor expression was determined by qRT-PCR. Cells were stimulated with PGE 2 or EP1 receptor antagonist and cell supernatant harvested. Cell proliferation was determined and changes in cytokine levels of IL-6, IL-8 and TNFa following PGE 2 stimulation and IL-6 following EP1 receptor antagonism were detected by ELISA. Results Treatment of CF patients with ivacaftor significantly reduced PGE 2 plasma levels (p 2 stimulation significantly increased expression of IL-6, IL-8 and TNFα in CFBE41o-cells compared to 16HBEo- in vitro. EP1 receptor antagonism significantly reduced IL-6 secretion in CFBE41o- cells. No significant change in cell proliferation was detected. Conclusion The findings underscore the value of unravelling the mechanisms regulating PGE 2 signalling, potentially advancing our understanding of the mechanisms of action of existing novel therapies in CF.