Emergence of serogroup 15 Streptococcus pneumoniae of diverse genetic backgrounds following the introduction of pneumococcal conjugate vaccines in Hong Kong

Pneumococcal carriage in young children after introduction of PCV13 in Hong Kong

“…Serotype replacement in pneumococcal carriage in these children was evident with the emergence of serogroup 15 and serotype 6C. Local prevalence of pneumococcal carriage as shown by our study was low when compared with data from other countries which show carriage rates of 28.8-35% in children under 2 years old [12,14,15,[23][24][25]. Previous local surveillance studies have also shown lower pneumococcal carriage rates than Caucasian and other Asian populations [12,14-17,23-26], which may explain the lower IPD burden in Hong Kong than other countries [27].…”

“…With the use of PCV13, it was predicted that the prevalence of both carriage and IPD would be further reduced due to the coverage of the additional serotypes. However, its use also poses an additional selective pressure increasing the prevalence of non-PCV13 serotypes [12,[14][15][16][17]. Lee et al reported serotype 15B/C as the most common carriage serotype, followed by 19A, 6C and 11A, one year after introduction of PCV13 in Massachusetts [14].…”

The impact of a pneumococcal conjugate vaccination program on the nasopharyngeal carriage, serotype distribution and antimicrobial resistance of Streptococcus pneumoniae among healthy children in Turkey

“…The circulation of VTserotypes, particularly serotype 19F, corroborate the findings of previous studies [12], which determined that PCV7 was less effective in reducing serotype 19F carriage and that PCV13 does not appear to reduce serotype 19F carriage more than does PCV7 as the serotype's prevalence remained virtually unchanged in our study [13.5%] (a 3 year PCV7 period followed by a 2 year PCV13 period) and was 15.2% during the 3 year PCV7 period, as stated in the survey by Ozdemir et al [25]. However, Ozdemir et al [25] determined that serotypes 15, 22 and 35 may become the dominant NVT serotypes in the near future, as has happened in other regions of the world [15,16]. The total antibiotic usage in Turkey was reported as 42.3% of the World Health Organization defined daily dose, the highest rate observed among European countries.…”

“…Most of these studies demonstrated that the carriage of PCV13 serotypes decreased; however, this resulted in shift toward non-PCV13 serotypes; overall NP carriage was not influenced by PCV13 vaccination [12][13][14]. Moreover, increased SPNP carriage of serotype 15 was noted following the introduction of PCV13, although this increase was not as significant as that observed for serotype 19A following the introduction of PCV7 [15][16][17]. In our country, PCV7 was introduced into the NIP at a dosing schedule of three doses and one booster dose (3 + 1) in November 2008 and was replaced by PCV13 in April 2011; the following immunization schedule was used: 3 primary doses for children between 6 weeks and 6 months of age, with an interval of two months between doses (first dose at 2 months of age, second dose at 4 months of age and third dose at 6 months of age) and a single dose at 12 months of age.…”

Genetic Analyses of Penicillin Binding Protein Determinants in Multidrug-Resistant Streptococcus pneumoniae Serogroup 19 CC320/271 Clone with High-Level Resistance to Third-Generation Cephalosporins

“…The HKSAR was the first region in Asia Pacific to introduce PCV7 in the childhood immunization schedule in September 2009 and has subsequently switched to the extended-spectrum vaccines. As with other countries with childhood conjugate vaccination, capsular replacement with the new serotypes 6C and 6D (10) and new clones of serogroup 15A, 15B, and 15C have been reported to have a role in carriage and disease in children (26). In Hong Kong, the clonal expansion of ST271 serotype 19F, described here, was identified mainly for isolates from the adult group.…”