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new Pseudomonas aeruginosa infection in cystic fibrosis patients
5. Microbiology 109 Diagnostic value of serological tests against Pseudomonas aeruginosa in cystic fibrosis patients L. Galanternik1 , A. Colom2 , F. Rapoport1 , A. Procopio1 , A. Teper2 . 1 Hospital de Ni˜nos R.Guti´errez, Microbiology, Buenos Aires, Argentina; 2 Hospital de Ni˜nos R.Guti´errez, Respiratory Center, Buenos Aires, Argentina Early diagnosis of P. aeruginosa (PA) colonization in patients with cystic fibrosis (CF) using microbiological culture methods may be difficult. Serology may be a useful technique for early detection of PA in children with CF. The purpose of this study was to assess the value of the measurement of antibodies to PA in diagnosing lung infection by PA in CF patients (pts). Longitudinal prospective study in which respiratory secretion samples for culture − expectorated sputum/oropharyngeal swabs − and also sera were collected over 3.6±2.5 years (range 1−8) in 78 CF pts, median age 2.6 y (range 0.5−18). PA antibody titers were assessed against whole cell protein by enzyme linked immunoassay. Weighed receiver operating characteristic (ROC) curves were used to determine best antibody titer cut off values to predict subsequent PA chronic colonization and PA positive cultures (intermittent or chronic colonization). Serological test performance was evaluated to diagnose PA colonization. The area under the curve was 0.865 (95% CI, 0.82–0.91; p < 0.01) and with a cut off level 4 the sensitivity was 75%, the specificity 89%, and the positive (PPV) and negative predictive value (NPV) were 76% and 88% to identify CF pts with chronic PA colonization respectively. To diagnose intermittent or chronic PA colonization the area under the curve was 0.76 (95% CI, 0.7−0.8; p < 0.01) and a cut off level 3 showed a sensitivity of 54% and specificity 84% with a PPV and NPV of 49% and 20% respectively. Conclusion: In CF patients, serological tests using specific antigens are sensitive for diagnosing chronic PA colonization. However, this method is less useful to detect intermittent infection.
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111 Review of adult CF unit screening programme for P. aeruginosa Liverpool Epidemic Strain by PCR, to study the prevalence of single gene marker anomalous strains C. Laughton1 , J. Foulkes1 , C. Winstanley2 , J. Fothergill2 , M. Curran1 , C. Haworth3 , J. Foweraker1 . 1 Papworth and Addenbrookes Hospitals, Microbiology, Cambridge, United Kingdom; 2 University of Liverpool, Division of Medical Microbiology, Liverpool, United Kingdom; 3 Papworth Hospital, Adult Cystic Fibrosis Centre, Cambridge, United Kingdom The Liverpool Epidemic Strain of P. aeruginosa (LES) has spread widely among CF patients in the UK and is associated with increased morbidity. CF centres are advised to screen and isolate patients with LES to reduce transmission and therefore a rapid and accurate test for LES is needed. Previous work showed that PCR assays for PS21 and LES F9 were able to identify most LES. There were however strains that were positive for only one marker, of which only some were LES by SNP genomotyping (Clondiag tube array) [1]. To measure the prevalence of these anomalous strains, we reviewed 2 years of data from the Papworth Adult CF clinic after PCR screening for LES at each clinic visit was introduced in 2007. 122 patients were tested on average 4−5 times. 33 (27%) were PCR positive for both LES markers, 16 (13%) had a single gene marker, 9 for F9 and 7 for PS21. 9% of the patients had different PCR results on different occasions. Of the 16 single gene positive isolates some were LES by genomotyping, while others were unique strains. P. aeruginosa positive for one of the published markers for LES are common in our patient group. More frequent screening has shown a more complex picture than previously thought. Single gene positive isolates need confirmatory testing as they may or may not be LES. Methods to reliably identify LES that can be used routinely still need to be developed. Reference(s) [1] Fothergill JL et al JCF 2008; 7(Suppl 2): S34.
110 Epidemiology of first/new Pseudomonas aeruginosa infection in cystic fibrosis patients L. Zavataro1 , G. Taccetti1 , L. Cariani2 , N. Ravenni1 , G. Braccini1 , S. Bresci1 , F. Trevisan1 , C. Braggion1 , S. Campana1 , Italian Group for Early Eradication Treatment. 1 CF Center, Meyer Children’s Hospital, Florence, Italy; 2 CF Center Microbiology Laboratory, Milan, Italy Chronic P. aeruginosa (Pa) infection is considered an unfavorable event for the prognosis of CF patients. Eradication of Pa at first/new isolation could be a simple and efficacious way to improve prognosis. We analyzed the demographic characteristics of a large group of patients with first/new Pa infections and the pattern of Pa antibiotic resistance as part of a multicenter randomised controlled trial analyzing the efficacy of two eradicating treatment protocols (inh colistin/oral cipro versus inh tobramycin/oral cipro). Patients older than 1 year were considered eligible to participate in this trial. Thirteen Italian clinical centers participated and 198 patients (94 females, 102 males, 2 missing) were randomized in 24 months. 47.9% patients were treated with colistin inh/oral cipro; 52.1% patients were treated with tobramycin inh/oral cipro. 11% of patients dropped out. Pa first/new infection happened in patients aged 1−5 years in 36.9%; in patients aged 5−12 years in 37.9% and in patients older than 12 years in 25.2%. 78 patients, free from Pa infection and eligible for the study, were previously infected by Pa, whereas it was the first infection for the remaining 120 patients. Mean age at first Pa infection was 9.3±7 yrs, median 8, range 1−37. The culture was performed on sputum in 35.3% of patients, on throat swab in 25.6%, on laryngeal suction in 31.7% (missing data 7.4%). Pa strains showed complete susceptibility to colistin, tobramycin and ciprofloxacin. Supported by the Italian Cystic fibrosis Research Foundation (grant FFC#17/2007) with the contribution of “Delegazione FFC di Vicenza”.
112* Populations of the Pseudomonas aeruginosa Liverpool Epidemic Strain are highly diverse and fluctuate in chronically-infected cystic fibrosis patients E. Mowat1 , J.L. Fothergill1,2 , M.J. Ledson3 , M.J. Walshaw3 , S. Paterson4 , M.A. Brockhurst4 , C. Winstanley1 . 1 University of Liverpool, Division of Medical Microbiology, Liverpool, United Kingdom; 2 Royal Liverpool and Broadgreen University Hospitals NHS Trust, NIHR Biomedical Research Centre in Microbial Disease, Liverpool, United Kingdom; 3 Liverpool Heart and Chest Hospital, Liverpool, United Kingdom; 4 University of Liverpool, School of Biological Sciences, Liverpool, United Kingdom The most predominant transmissible epidemic strain of Pseudomonas aeruginosa across the UK is the Liverpool Epidemic Strain (LES), which possesses novel genomic islands and prophages and exhibits a hypervirulent phenotype characterised by the over-expression of the quorum sensing (QS) regulon (including pyocyanin). We collected sputum samples from ten adult LES-infected CF patients during periods of stability and during pulmonary exacerbations. Forty LES isolates from each sample were subjected to a range of tests to establish various phenotypic and genotypic characteristics (15 in all). Extensive diversity was found: the first 1360 LES isolates could be sub-divided into >350 sub-types (haplotypes). Our analyses of sequential samples indicated that LES haplotype populations are dynamic within individual patients. Interestingly, over-production of the toxin pyocyanin was significantly associated (P < 0.05) with samples taken during exacerbations. The presence or absence of novel LES-specific genomic islands and prophage regions varied between individual patients and sample type. This study indicates that populations of the P. aeruginosa LES are highly variable and fluctuate in chronically infected CF patients. The diversity and adaptability of this strain may enhance its ability to transmit and contribute to its overall virulence within CF patients. We acknowledge funding from the Dr Hadwen Trust and NIHR.
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111 Review of adult CF unit screening programme for P. aeruginosa Liverpool Epidemic Strain by PCR, to study the prevalence of single gene marker anomalous strains C. Laughton1 , J. Foulkes1 , C. Winstanley2 , J. Fothergill2 , M. Curran1 , C. Haworth3 , J. Foweraker1 . 1 Papworth and Addenbrookes Hospitals, Microbiology, Cambridge, United Kingdom; 2 University of Liverpool, Division of Medical Microbiology, Liverpool, United Kingdom; 3 Papworth Hospital, Adult Cystic Fibrosis Centre, Cambridge, United Kingdom The Liverpool Epidemic Strain of P. aeruginosa (LES) has spread widely among CF patients in the UK and is associated with increased morbidity. CF centres are advised to screen and isolate patients with LES to reduce transmission and therefore a rapid and accurate test for LES is needed. Previous work showed that PCR assays for PS21 and LES F9 were able to identify most LES. There were however strains that were positive for only one marker, of which only some were LES by SNP genomotyping (Clondiag tube array) [1]. To measure the prevalence of these anomalous strains, we reviewed 2 years of data from the Papworth Adult CF clinic after PCR screening for LES at each clinic visit was introduced in 2007. 122 patients were tested on average 4−5 times. 33 (27%) were PCR positive for both LES markers, 16 (13%) had a single gene marker, 9 for F9 and 7 for PS21. 9% of the patients had different PCR results on different occasions. Of the 16 single gene positive isolates some were LES by genomotyping, while others were unique strains. P. aeruginosa positive for one of the published markers for LES are common in our patient group. More frequent screening has shown a more complex picture than previously thought. Single gene positive isolates need confirmatory testing as they may or may not be LES. Methods to reliably identify LES that can be used routinely still need to be developed. Reference(s) [1] Fothergill JL et al JCF 2008; 7(Suppl 2): S34.
110 Epidemiology of first/new Pseudomonas aeruginosa infection in cystic fibrosis patients L. Zavataro1 , G. Taccetti1 , L. Cariani2 , N. Ravenni1 , G. Braccini1 , S. Bresci1 , F. Trevisan1 , C. Braggion1 , S. Campana1 , Italian Group for Early Eradication Treatment. 1 CF Center, Meyer Children’s Hospital, Florence, Italy; 2 CF Center Microbiology Laboratory, Milan, Italy Chronic P. aeruginosa (Pa) infection is considered an unfavorable event for the prognosis of CF patients. Eradication of Pa at first/new isolation could be a simple and efficacious way to improve prognosis. We analyzed the demographic characteristics of a large group of patients with first/new Pa infections and the pattern of Pa antibiotic resistance as part of a multicenter randomised controlled trial analyzing the efficacy of two eradicating treatment protocols (inh colistin/oral cipro versus inh tobramycin/oral cipro). Patients older than 1 year were considered eligible to participate in this trial. Thirteen Italian clinical centers participated and 198 patients (94 females, 102 males, 2 missing) were randomized in 24 months. 47.9% patients were treated with colistin inh/oral cipro; 52.1% patients were treated with tobramycin inh/oral cipro. 11% of patients dropped out. Pa first/new infection happened in patients aged 1−5 years in 36.9%; in patients aged 5−12 years in 37.9% and in patients older than 12 years in 25.2%. 78 patients, free from Pa infection and eligible for the study, were previously infected by Pa, whereas it was the first infection for the remaining 120 patients. Mean age at first Pa infection was 9.3±7 yrs, median 8, range 1−37. The culture was performed on sputum in 35.3% of patients, on throat swab in 25.6%, on laryngeal suction in 31.7% (missing data 7.4%). Pa strains showed complete susceptibility to colistin, tobramycin and ciprofloxacin. Supported by the Italian Cystic fibrosis Research Foundation (grant FFC#17/2007) with the contribution of “Delegazione FFC di Vicenza”.
112* Populations of the Pseudomonas aeruginosa Liverpool Epidemic Strain are highly diverse and fluctuate in chronically-infected cystic fibrosis patients E. Mowat1 , J.L. Fothergill1,2 , M.J. Ledson3 , M.J. Walshaw3 , S. Paterson4 , M.A. Brockhurst4 , C. Winstanley1 . 1 University of Liverpool, Division of Medical Microbiology, Liverpool, United Kingdom; 2 Royal Liverpool and Broadgreen University Hospitals NHS Trust, NIHR Biomedical Research Centre in Microbial Disease, Liverpool, United Kingdom; 3 Liverpool Heart and Chest Hospital, Liverpool, United Kingdom; 4 University of Liverpool, School of Biological Sciences, Liverpool, United Kingdom The most predominant transmissible epidemic strain of Pseudomonas aeruginosa across the UK is the Liverpool Epidemic Strain (LES), which possesses novel genomic islands and prophages and exhibits a hypervirulent phenotype characterised by the over-expression of the quorum sensing (QS) regulon (including pyocyanin). We collected sputum samples from ten adult LES-infected CF patients during periods of stability and during pulmonary exacerbations. Forty LES isolates from each sample were subjected to a range of tests to establish various phenotypic and genotypic characteristics (15 in all). Extensive diversity was found: the first 1360 LES isolates could be sub-divided into >350 sub-types (haplotypes). Our analyses of sequential samples indicated that LES haplotype populations are dynamic within individual patients. Interestingly, over-production of the toxin pyocyanin was significantly associated (P < 0.05) with samples taken during exacerbations. The presence or absence of novel LES-specific genomic islands and prophage regions varied between individual patients and sample type. This study indicates that populations of the P. aeruginosa LES are highly variable and fluctuate in chronically infected CF patients. The diversity and adaptability of this strain may enhance its ability to transmit and contribute to its overall virulence within CF patients. We acknowledge funding from the Dr Hadwen Trust and NIHR.