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Some pneumococcal serotypes are more frequently associated with relapses of acute exacerbations in COPD patients
Arnau Domenech1, Carmen Ardanuy, Roman Pallares
1Department of Microbiology, Hospital Universitari de Bellvitge-IDIBELL-Barcelona University, Barcelona, Spain. c.ardanuy@bellvitgehospital.cat
Objectives:
To analyze the role of the capsular type in pneumococci causing relapse and reinfection episodes of acute exacerbation in COPD patients.
Methods:
A total of 79 patients with 116 recurrent episodes of acute exacerbations caused by S. pneumoniae were included into this study (1995-2010). A relapse episode was considered when two consecutive episodes were caused by the same strain (identical serotype and genotype); otherwise it was considered reinfection. Antimicrobial susceptibility testing (microdilution), serotyping (PCR, Quellung) and molecular typing (PFGE/MLST) were performed.
Results:
Among 116 recurrent episodes, 81 (69.8%) were reinfections, caused by the acquisition of a new pneumococcus, and 35 (30.2%) were relapses, caused by a pre-existing strain. Four serotypes (9V, 19F, 15A and 11A) caused the majority (60.0%) of relapses. When serotypes causing relapses and reinfection were compared, only two serotypes were associated with relapses: 9V (OR 8.0; 95% CI, 1.34-85.59) and 19F (OR 16.1; 95% CI, 1.84-767.20). Pneumococci isolated from relapses were more resistant to antimicrobials than those isolated from the reinfection episodes: penicillin (74.3% vs. 34.6%, p<0.001), ciprofloxacin (25.7% vs. 9.9%, p<0.027), levofloxacin (22.9% vs. 7.4%, p = 0.029), and co-trimoxazole (54.3% vs. 25.9%, p<0.001).
Conclusions:
Although the acquisition of a new S. pneumoniae strain was the most frequent cause of recurrences, a third of the recurrent episodes were caused by a pre-existing strain. These relapse episodes were mainly caused by serotypes 9V and 19F, suggesting an important role for capsular type.
Insights
Recurrent acute exacerbations in COPD patients are often reinfections, but relapses caused by pre-existing Streptococcus pneumoniae strains, particularly serotypes 9V and 19F, are significant. These relapse strains show increased antimicrobial resistance.
Area of Science:
- Microbiology
- Pulmonology
- Infectious Diseases
Background:
- Recurrent acute exacerbations in Chronic Obstructive Pulmonary Disease (COPD) significantly impact patient morbidity and mortality.
- Streptococcus pneumoniae is a primary pathogen implicated in COPD exacerbations, with recurrence posing a clinical challenge.
Purpose of the Study:
- To investigate the role of Streptococcus pneumoniae capsular types in causing relapse versus reinfection episodes of acute exacerbations in COPD patients.
- To determine if specific pneumococcal serotypes are associated with relapse or reinfection and to assess antimicrobial resistance patterns.
Main Methods:
- Analysis of 116 recurrent acute exacerbation episodes in 79 COPD patients between 1995 and 2010.
- Distinguishing relapse (same strain) from reinfection (new strain) based on serotype and genotype.
- Utilizing antimicrobial susceptibility testing, serotyping (PCR, Quellung), and molecular typing (PFGE/MLST).
Main Results:
- Reinfection accounted for 69.8% of recurrent episodes, while relapse due to pre-existing strains comprised 30.2%.
- Four serotypes (9V, 19F, 15A, 11A) were prominent in relapses, with serotypes 9V and 19F specifically linked to relapse episodes (OR 8.0 and 16.1, respectively).
- Pneumococci from relapse episodes exhibited significantly higher resistance to penicillin, ciprofloxacin, levofloxacin, and co-trimoxazole compared to those from reinfection episodes.
Conclusions:
- While new strain acquisition is the most common cause of recurrent COPD exacerbations, a substantial proportion result from relapse by pre-existing strains.
- Specific pneumococcal capsular types, notably 9V and 19F, play a critical role in facilitating relapse episodes.
- Relapse-associated pneumococcal strains demonstrate increased antimicrobial resistance, highlighting the importance of serotype in treatment and prevention strategies.
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