title: Changes in nasopharyngeal carriage and serotype distribution of antibiotic-resistant Streptococcus pneumoniae before and after the introduction of 7-valent pneumococcal conjugate vaccine in Hong Kong.
abstract: This study assessed the changes in serotype distribution and antibiotic resistance of Streptococcus pneumoniae isolates in children before and after introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in Hong Kong. Nasopharyngeal specimens were collected from 1978 and 2211 children (ages, 2 to 6 years) attending day care centers or kindergartens in period 1 (1999-2000) and period 2 (2009-2010), respectively. Carriage of PCV7 serotypes decreased from 12.8% to 8.6% (P < 0.01). The relative contribution of PCV7 serotypes 14 and 18C had decreased, whereas that for non-PCV7 serotypes 19A, 6A, 6C, 23A, and 15B had increased. In period 2, PCV7 penetration rate (at least 1 dose) for children aged 2, 3, 4, and 5 years was 43%, 35.7%, 26.7%, and 20.4%, respectively. In multivariate analysis, PCV7 use was the only independent variable associated with fewer PCV7 serotype carriages (odds ratio 0.5; P = 0.001). In period 2, high rates of dual penicillin/erythromycin nonsusceptibility were found in serotypes 6B (77.3%), 14 (100%), 19F (100%), 23F (78%), 19A (75%), 6A (87.8%), 6C (59.3%), and 23A (78.9%).
authors: Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, China. plho@hkucc.hku.hk
authors: Pak-Leung
authors: PL
authors: Ho
authors: Susan S
authors: SS
authors: Chiu
authors: Maggie Y
authors: MY
authors: Chan
authors: Irene
authors: I
authors: Ang
authors: Kin-Hung
authors: KH
authors: Chow
authors: Yu-Lung
authors: YL
authors: Lau
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008826:Microbial Sensitivity Tests; D009305:Nasopharynx / Q000382:microbiology*; D010406:Penicillins / Q000494:pharmacology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D010406:Penicillins; D022242:Pneumococcal Vaccines; D004917:Erythromycin