Department of Microbiology, Hospital Universitari de Bellvitge-IDIBELL-Barcelona University, Barcelona, Spain.
PLoS One. 2013;8(3):e59027. doi: 10.1371/journal.pone.0059027. Epub 2013 Mar 11.
To analyze the role of the capsular type in pneumococci causing relapse and reinfection episodes of acute exacerbation in COPD patients.
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.
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).
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.
分析肺炎链球菌荚膜型在 COPD 患者急性加重复发和再感染中的作用。
本研究共纳入 79 例由肺炎链球菌引起的 116 例复发性急性加重发作患者（1995-2010 年）。如果两次连续发作由同一菌株（相同血清型和基因型）引起，则认为是复发；否则，认为是再感染。进行抗菌药物敏感性试验（微量稀释法）、血清分型（PCR、Quellung）和分子分型（PFGE/MLST）。
在 116 例复发性发作中，81 例（69.8%）为再感染，由新的肺炎链球菌引起，35 例（30.2%）为复发，由先前存在的菌株引起。4 种血清型（9V、19F、15A 和 11A）引起的复发占大多数（60.0%）。比较引起复发和再感染的血清型时，只有两种血清型与复发相关：9V（OR 8.0；95%CI，1.34-85.59）和 19F（OR 16.1；95%CI，1.84-767.20）。从复发中分离的肺炎链球菌对抗菌药物的耐药性高于从再感染中分离的肺炎链球菌：青霉素（74.3% vs. 34.6%，p<0.001）、环丙沙星（25.7% vs. 9.9%，p<0.027）、左氧氟沙星（22.9% vs. 7.4%，p = 0.029）和复方磺胺甲噁唑（54.3% vs. 25.9%，p<0.001）。
尽管新的肺炎链球菌菌株的获得是复发的最常见原因，但三分之一的复发发作是由先前存在的菌株引起的。这些复发发作主要由血清型 9V 和 19F 引起，提示荚膜型起着重要作用。
