title: Analysis of Streptococcus pneumoniae and Haemophilus influenzae isolated from middle ear fluid before and after the introduction of government subsidies for pneumococcal and H. influenzae type b vaccines in Japan.
abstract: This study aimed to identify trends in frequency, serotype, and antimicrobial susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolated from middle ear fluid specimens of children aged≤15 years (mean, 2 years), before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) and the H. influenzae type b vaccine, at a pediatric facility in Japan. Sixty-six S. pneumoniae and 88 H. influenzae strains were isolated from 820 middle ear fluid samples. Serotyping and antimicrobial susceptibility testing were performed. The study time-frame was divided into period 1 (2007-2010) and period 2 (2011-2014), according to the availability of vaccine public funding. The S. pneumoniae detection rate decreased from 9.6% in period 1-6.1% in period 2 (p = 0.042). PCV7 serotypes decreased from 56.8% to 9.1% (p = 0.0002). No significant change was observed for the 13-valent pneumococcal conjugate vaccine (PCV13) serotypes: 72.7% in period 1 and 59.1% in period 2. Penicillin-resistant strains (penicillin G-MIC ≥2 μg/mL) decreased from 25% to 4.5% (p = 0.038). Detection rates for H. influenzae did not change significantly: 10.3% in period 1 and 11.3% in period 2. Serotypes were mostly non-typeable: 97.9% in period 1 and 90.2% in period 2, and only one serotype b strain was isolated in each period. The frequency of ampicillin-resistant strains (MIC ≥4 μg/mL) did not change. These results show a preventative effect of PCV7 on otitis media due to S. pneumoniae. PCV7 was replaced with PCV13 in 2013 in Japan; therefore, a further decrease in pneumococcal otitis media is anticipated in the future.
authors.affiliation: Division of Infectious Diseases, Chiba Children's Hospital, Chiba, Japan. Electronic address: t.hshn12@pref.chiba.lg.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hoshino
authors.affiliation: Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Takeuchi
authors.affiliation: Division of Infectious Diseases, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Fukasawa
authors.affiliation: Division of Infectious Diseases, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Hirose
authors.affiliation: Division of Infectious Diseases, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okui
authors.affiliation: Division of Clinical Laboratory, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Sato
authors.affiliation: Division of Clinical Laboratory, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Sato
authors.affiliation: Division of Otorhinolaryngology, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Arimoto
authors.affiliation: Division of Otorhinolaryngology, Chiba Children's Hospital, Chiba, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nakano
authors.affiliation: Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan.
authors.forename: Naruhiko
authors.initials: N
authors.lastname: Ishiwada
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004432:Ear, Middle / Q000382:microbiology; D005260:Female; D005380:Financing, Government; D006192:Haemophilus Infections / Q000517:prevention & control; D006193:Haemophilus influenzae / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000191:economics / Q000627:therapeutic use*; D007564:Japan; D008297:Male; D010034:Otitis Media with Effusion / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000191:economics / Q000627:therapeutic use*; D012189:Retrospective Studies; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D007252:Influenza Vaccines; D022242:Pneumococcal Vaccines
keywords: Haemophilus influenzae; Japan; Middle ear fluid; Serotypes; Streptococcus pneumoniae