title: Dynamics of the pneumococcal population causing acute exacerbations in COPD patients in a Barcelona hospital (2009-12): comparison with 2001-04 and 2005-08 periods.
abstract: BACKGROUND
  Pneumococci are an important cause of acute exacerbations in patients with chronic obstructive pulmonary disease (COPD). In the last decade, the pneumococcal population has changed, mainly due to the introduction of the 7-valent conjugate vaccine (PCV7).
  
  
  METHODS
  We analysed the antimicrobial susceptibility (microdilution), serotype (PCR) and genotype (PFGE/multilocus sequence typing) of pneumococci causing acute exacerbations during the period 2009-12. Results were compared with two previously published historic periods (2001-04 and 2005-08).
  
  
  RESULTS
  A total of 206 pneumococci were collected from 162 COPD patients with acute exacerbations. Compared with previous periods, no significant changes in the rate of multidrug resistance were observed (36.2% in the 2001-04 period to 33.5% in the 2009-12 period, P = 0.644). The most frequent serotypes in the 2009-12 period were 15A (9.6%), 3 (8.1%), 19F (6.6%), 11A (6.1%) and 6C (5.6%), which accounted for 36.0%. A drastic decrease in PCV7 serotypes was observed throughout the study period (from 39.7% in 2001-04 to 10.9% in 2009-12, P < 0.001); non-PCV13 serotypes increased from 44.9% to 71.2%, especially 15A (from 2.2% to 9.6%) and 6C (from 0.0% to 5.6%) (P < 0.05). The most frequent genotypes (clonal complexes, CCs) in the 2009-12 period were CC63(15A,19F,15F) (9.1%), CC180(3) (4.5%), CC62(11A) (4.0%), CC97(10A) (4.0%), CC386(6C) (3.5%), CC260(3) (3.5%) and CC30(16F) (3.5%). Serotypes 19F, 19A, 6A and 6C were genetically diverse.
  
  
  CONCLUSIONS
  PCV7 serotypes have decreased dramatically. In parallel, two non-PCV7 serotypes (15A and 6C) and their related genotypes (CC63 and CC386) showed a significant increase. Although resistance rates to β-lactams decreased over time, multidrug resistance remained stable.
authors: Microbiology Department, Hospital Universitari de Bellvitge-IDIBELL-Barcelona University, Barcelona, Spain.
authors: Arnau
authors: A
authors: Domenech
authors: Carmen
authors: C
authors: Ardanuy
authors: Anais
authors: A
authors: Tercero
authors: Dolors
authors: D
authors: García-Somoza
authors: Salud
authors: S
authors: Santos
authors: Josefina
authors: J
authors: Liñares
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006761:Hospitals; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology* / Q000382:microbiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D012703:Serotyping; D013030:Spain / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines
keywords: Streptococcus pneumoniae; chronic obstructive pulmonary disease; conjugate vaccines; genotype; serotype