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New Concepts in Microbiology of Exacerbations of COPD Sanjay Sethi MD Professor Pulmonary, Critical Care and Sleep Medicine University at Buffalo, SUNY ssethi@buffalo.edu
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AECOPD: Perception vs Reality Perception A nuisance problem with no serious consequences A nuisance problem with no serious consequencesReality Contributes to: Contributes to: Cost of health care (35-45%) Poor quality of life Mortality Progression of lung disease Mannino et al. MMWR 2002;51(SS-6):1-16 Andersson et al. Resp Med 2002;96:700-8
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Etiology of AECOPD Obaji & Sethi. Drugs and Aging; 2001;18:1-11
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Etiology of AECOPD Papi et al AJRCCM 2006;173:1114-21
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AECOPD: Bacterial etiology Sputum culture studies Gump et al. ARRD 1976;113:465-473 25 patients Outpatient clinic every 2 weeks for 4 years Sputum culture 1886 clinic visits 116 exacerbations 1870 stable Stable Exacerbation 0 10 20 30 40 50 60 SPNTHI % 33.1 59.9 57.0 37.2
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Bacterial load model of pathogenesis of AECB SESESES 1,E+08 1,E+07 1,E+06 1,E+05 1,E+04 1,E+03 1,E+02 NTHI titer
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Bacterial Load Model 0 1 2 3 4 5 6 7 8 9 10 HIHHMCSPHP Pathogen stable exacerbation Log Titer * * Sethi et al AJRCCM 2007
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Bacterial Infection in COPD Acquisition of new bacterial strain Level of symptoms Exacerbation Strain-specific immune response +/- antibiotics Elimination of infecting strain Colonization Persistent infection Tissue invasion Antigenic alteration Pathogen virulence Host lung defense Change in airway inflammation
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Acquisition of new bacterial strain Level of symptoms Exacerbation Strain-specific immune response +/- antibiotics Elimination of infecting strain Colonization Persistent infection Tissue invasion Antigenic alteration Pathogen virulence Host lung defense Change in airway inflammation Bacterial Infection in COPD
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COPD Study Clinic Aims Aims Dynamics of bacterial infection in COPD Dynamics of bacterial infection in COPD Hypothesis Hypothesis Acquisition of new strains of bacterial pathogens is associated with an increased risk of exacerbation Acquisition of new strains of bacterial pathogens is associated with an increased risk of exacerbation Clinic visits: Clinic visits: Monthly Suspected exacerbation At each visit: At each visit: Clinical evaluation Serum sample Sputum sample for quantitative bacteriology Sethi et al. NEJM 2002, 347:465-471
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ex Patient 6: Time line HI 10 8 10 6 10 8 10 7 1 month 12345678910111213
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Typing the Nontypeable Nontypeable H. influenzae sputum isolates Nontypeable H. influenzae sputum isolates Whole bacterial lysates Analyzed on a SDS- PAGE gel Sethi et al. NEJM 2002, 347:465-471
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Patient 6: Time line 12345678910111213 ex 1 month HI 10 8 10 6 10 8 10 7 AABCC
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33 15.4 26.2 17.1 48.8 16.6 32 18 13.6 18.2 0 10 20 30 40 50 AnyNTHIMCSPPA COPD Study Clinic: New strain isolation and exacerbation * * * * Relative risk (95% CI) of exacerbation: Any 2.15 (1.83–2.63) NTHI 1.69 (1.37–2.09) MC 2.96 (2.39–3.67) SP 1.77 (1.14–2.75) PA 0.61 (0.21–1.82) Sethi et al. NEJM 2002;347:465-71 New strain + New strain – *p<0.05 Exacerbation frequency Pathogen
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AECB: Bacterial etiology Sputum culture studies Gump et al. ARRD 1976;113:465-473 25 patients Outpatient clinic every 2 weeks for 4 years Sputum culture 1886 clinic visits 116 exacerbations 1870 stable Stable Exacerbation 0 10 20 30 40 50 60 SPNTHI % 33.1 59.9 57.0 37.2
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Bacterial Infection in COPD Acquisition of new bacterial strain Level of symptoms Exacerbation Strain-specific immune response +/- antibiotics Elimination of infecting strain Colonization Persistent infection Tissue invasion Antigenic alteration Pathogen virulence Host lung defense Change in airway inflammation
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NTHI Colonization vs Exacerbation strains 10 exacerbation strains 7 colonization strains In vivo mouse model In vitro respiratory epithelial cell line Chin et al AJRCCM 2005
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Bacterial Infection in COPD Acquisition of new bacterial strain Level of symptoms Exacerbation Strain-specific immune response +/- antibiotics Elimination of infecting strain Colonization Persistent infection Tissue invasion Antigenic alteration Pathogen virulence Host lung defense Change in airway inflammation
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Moraxella catarrhalis Frequency of Immune Response p = 0.009 p = 0.11 Murphy et al, AJRCCM 2005
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Lymphocyte Proliferative Response to OMP P6 of NTHI PBMC stimulated with purified OMP P6 PBMC stimulated with purified OMP P6 Groups Groups H: healthy controls H: healthy controls C: COPD without NTHI exacerbation in previous 12 months C: COPD without NTHI exacerbation in previous 12 months N: COPD with NTHI exacerbation in previous 12 months N: COPD with NTHI exacerbation in previous 12 months Abe et al AJRCCM, 165:967-71, 2002
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Bacterial Infection in COPD Acquisition of new bacterial strain Level of symptoms Exacerbation Strain-specific immune response +/- antibiotics Elimination of infecting strain Colonization Persistent infection Tissue invasion Antigenic alteration Pathogen virulence Host lung defense Change in airway inflammation
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Patient 6:Time line 12345678910111213 ex 1 month HI 10 8 10 6 10 8 10 7 AABCC SP000000
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Changes in Airway Inflammation with Onset of Exacerbations -2 0 1 2 3 4 5 No new strainNew strain IL-8 change ng/ml p = 0.40 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 No new strain New strain TNFα change ng/ml p < 0.001 -100 0 100 200 300 400 500 600 No new strain New strain NE change nM p = 0.01 Airway inflammation increases with exacerbations Bacterial exacerbations are associated with greater neutrophilic inflammation Sethi et al ATS, 2005
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Changes in Airway Inflammation with Resolution of Exacerbations -3 -2 0 1 2 3 Non-resolutionResolution IL-8 change ng/ml p = 0.35p = 0.05 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 Non-resolutionResolution TNFα change ng/ml p = 0.79 p = 0.007 -200 -100 0 100 200 300 400 500 Non-resolutionResolution NE change nM p = 0.18p = 0.02 Sethi et al ATS, 2005 Airway inflammation decreases with resolution of exacerbation Correlation between clinical resolution and resolution of inflammation
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Bacterial Persistence and Airway Inflammation following AECOPD White et al. Thorax 2003;58:680-685 LTB4 (nM) 100 10 1 0.1 0.01 1101 Bacteria eradicated by day 10 Bacteria persisting at day 10 p<0.001 Day MPO (units/ml) 10 1 0.1 0.01 1101 Bacteria eradicated by day 10 Bacteria persisting at day 10 p<0.05 p<0.001 Day
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Bacterial Infection in COPD Acquisition of new bacterial strain Level of symptoms Exacerbation Strain-specific immune response +/- antibiotics Elimination of infecting strain Colonization Persistent infection Tissue invasion Antigenic alteration Pathogen virulence Host lung defense Change in airway inflammation
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H. influenzae: Bactericidal assays % Kill New bactericidal antibody developed to 18 of 26 (69.2%) new strains following exacerbation Sethi et al AJRCCM 169;448-453, 2004
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Strain-specificity of bactericidal antibodies to NTHI Bactericidal antibodies from 10 patients were tested against 9 heterologous strains each. Bactericidal antibodies from 10 patients were tested against 9 heterologous strains each. 79 of 90 (88%) of heterologous strains were not killed. 79 of 90 (88%) of heterologous strains were not killed. 8 of the 10 sera killed only the homologous strain or 1 heterologous strain. 8 of the 10 sera killed only the homologous strain or 1 heterologous strain. Sethi et al AJRCCM 169;448-453, 2004
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Viral AECB:Culture and Serology Studies Carilli 1964, Eadie 1966, McNamara 1969, Lamy 1974, Gump 1976, Buscho 1978, Smith 1980, McHardy 1980
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Viral RTI: Cohort Study 172239 RTVI/RI % 0.520.380.54RTVI/yr 3.01.81.4RI/yr 323055n FEV 1 <50% FEV 1 >50% Controls Greenberg et al AJRCCM, 2000;162:167-173
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Viral RTI: Clinical Manifestations and Lung Function Greenberg et al AJRCCM, 2000;162:167-173
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Greenberg SB, et al. Am J Respir Crit Care Med. 2000;162:167-173. Viral RTI: Pathogens 0 5 10 15 20 25 30 35 Picorna- viruses Para- influenza viruses Corona- viruses Influenza viruses RSVAdeno- viruses Control FEV 1 50% FEV 1 <50% % of Total Identified
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RSV Infection in Elderly High- Risk Adults Falsey AR, et al. New Engl J Med. 2005;1749-1759. Variable RSV infection Influenza A Duration of illness 15 ± 13 days 17 ± 10 days Hospitalization16%20% Housebound41%55% Confined to bed 25%25% Unable to perform ADL 45%60% Deaths4%0%
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Airway Inflammation and Etiology Papi et al AJRCCM 2006;173:1114-21
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New Directions Bacterial-viral-environmental interaction Bacterial-viral-environmental interaction Molecular detection and quantification of infectious pathogens Molecular detection and quantification of infectious pathogens Host susceptibility to infection Host susceptibility to infection
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Effect of Pathogen Combinations on % Decrease in FEV 1 at Exacerbation Wilkinson, T. M. A. et al. Chest 2006;129:317-324
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PCR detection of bacterial pathogens in COPD S. pneumoniae + - lytA psaA p<0.05 El-Dika et al ATS 2007
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Conclusions Exacerbations are important Exacerbations are important Bacteria cause a significant proportion of exacerbations Bacteria cause a significant proportion of exacerbations Understanding Host-Pathogen interaction is key Understanding Host-Pathogen interaction is key Therapeutic intervention Therapeutic intervention
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