title: Serotypes and antimicrobial susceptibilities of invasive Streptococcus pneumoniae before and after introduction of 7-valent pneumococcal conjugate vaccine, Hong Kong, 1995-2009.
abstract: This study analyzed 828 isolates causing invasive pneumococcal disease (IPD) before (1995-2001, n=265) and after (2007-2009, n=563) the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in Hong Kong. In children <5 years, serotype 14 had declined (36-15.7%, P<0.01) while 19A had increased (0-12.9%, P<0.01) in the before and after periods, respectively. In children aged <5 years, the proportion of PCV7 serotypes declined from 89.5% to 65.7% (72.8% if included cross protection against 6A) with time but that of PCV13 serotypes remained stable (91.4-93.2%). In elderly ≥65 years, 9V and 23F decreased from 3.8% to 0.3% (P=0.01) and from 18.9% to 7.4% (P <0.01), respectively while 7F increased significantly from 0% to 4.1% (P=0.04) over the same periods. Among isolates from aged <5 years, dual penicillin/erythromycin resistance increased from 44.1% to 64.2% (P=0.01). The types that often had dual penicillin/erythromycin resistance were 6B, 14, 19F, 23F, 6A and 19A. The emergence of serotype 19A was associated with expansion of sequence type 320.
authors.affiliation: Department of Microbiology, University of Hong Kong, Hong Kong SAR, China. plho@hkucc.hku.hk
authors.forename: Pak-Leung
authors.initials: PL
authors.lastname: Ho
authors.forename: Susan S
authors.initials: SS
authors.lastname: Chiu
authors.forename: Irene
authors.initials: I
authors.lastname: Ang
authors.forename: Yu-Lung
authors.initials: YL
authors.lastname: Lau
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D015995:Prevalence; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects* / Q000276:immunology / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines