Serotypes and genotypes of Streptococcus pneumoniae causing pneumonia and acute exacerbations in patients with chronic obstructive pulmonary disease

Abstract

This study aimed to compare the antibiotic susceptibilities, serotypes and genotypes of pneumococci causing pneumonia or acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with COPD. A total of 611 pneumococci collected from 487 COPD patients with pneumonia (n = 255, 94 bacteraemic pneumonia) or AECOPD episodes (n = 356), from 2001 to 2008, were analysed. Antibiotic susceptibility was studied by microdilution. Serotypes (PCR or Quellung) and genotypes (PFGE and multilocus sequence typing) were determined. Pneumococci isolated from AECOPD episodes were significantly more resistant to co-trimoxazole and chloramphenicol than those isolated from pneumonia episodes (39.0% versus 29.7% and 13.8% versus 8.2%, respectively, P < 0.05). Comparing serotypes of isolates causing bacteraemic pneumonia, non-bacteraemic pneumonia and AECOPD, serotypes 4, 5 and 8 were associated with bacteraemic pneumonia (P < 0.05), serotypes 1 and 3 were associated with bacteraemic and non-bacteraemic pneumonia (P < 0.05) and serotypes 16F and 11A and non-typeable pneumococci were associated with AECOPD episodes (P < 0.05). The genotypes related to serotypes 3 (Netherlands³-ST180 and ST260³), 1 (Sweden¹-ST306), 5 (Colombia⁵-ST289) and 8 (Netherlands⁸-ST53) were isolated more frequently in pneumonia episodes (P < 0.05), whereas genotype ST30^16F (serotype 16F) was more frequently recovered from AECOPD episodes. In our experience, serotype 3 pneumococci (Netherlands³-ST180 and ST260³ genotypes) commonly cause pneumonia and acute exacerbations in COPD patients. Pneumococci of serotypes 1 (Sweden¹-ST306), 4 (ST247⁴), 5 (Colombia⁵-ST289) and 8 (Netherlands⁸-ST53) were more often associated with pneumonia. Non-typeable pneumococci may play an important role in acute exacerbations.