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

OBJECTIVES: 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.
METHODS: 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.
RESULTS: 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 (Netherlands(3)-ST180 and ST260(3)), 1 (Sweden(1)-ST306), 5 (Colombia(5)-ST289) and 8 (Netherlands(8)-ST53) were isolated more frequently in pneumonia episodes (P < 0.05), whereas genotype ST30(16F) (serotype 16F) was more frequently recovered from AECOPD episodes.
CONCLUSIONS: In our experience, serotype 3 pneumococci (Netherlands(3)-ST180 and ST260(3) genotypes) commonly cause pneumonia and acute exacerbations in COPD patients. Pneumococci of serotypes 1 (Sweden(1)-ST306), 4 (ST247(4)), 5 (Colombia(5)-ST289) and 8 (Netherlands(8)-ST53) were more often associated with pneumonia. Non-typeable pneumococci may play an important role in acute exacerbations.