Ahead of Print -Changes in Capsule and Drug Resistance of Pneumococci after Introduction of PCV7, Japan, 2010–2013 - Volume 20, Number 7—July 2014 - Emerging Infectious Disease journal - CDC
Volume 20, Number 7—July 2014
Changes in Capsule and Drug Resistance of Pneumococci after Introduction of PCV7, Japan, 2010–2013
Naoko Chiba, Miyuki Morozumi, Michi Shouji, Takeaki Wajima, Satoshi Iwata, Kimiko Ubukata , and the Invasive Pneumococcal Diseases Surveillance Study Group
Author affiliations: Keio University School of Medicine, Tokyo, Japan (N. Chiba, M. Morozumi, S. Iwata, K. Ubukata); Kitasato University, Tokyo (N. Chiba, M. Morozumi, K. Ubukata); National Cancer Center Hospital, Tokyo (M. Shouji); Tokyo University of Pharmacy and Life Sciences, Tokyo (T. Wajima)
Invasive pneumococcal disease (IPD), such as meningitis, sepsis, and empyema, substantially contributes to illness and death in children (1,2). After increasing numbers of cases caused by penicillin (PEN)–resistant Streptococcus pneumoniae (PRSP) emerged and rapidly spread worldwide during the 1990s (3,4), the need for a vaccine effective in infants became clear. In the United States, a 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2000 and made available for routine use in all children 2–23 months of age and in children 24–59 months of age at risk for pneumococcal infection (5). Subsequent surveillance studies demonstrated a marked decrease in prevalence of pneumococcal infection caused by vaccine serotypes, including PRSP (6–8). In particular, PCV7 appears to have decreased incidence of meningitis caused by vaccine serotypes (9), and cases caused by non-PCV7 serotype strains, such as PRSP with serotype 19A, have increased in the United States (8,10,11). Such changes suggest that nonvaccine serotypes are replacing vaccine serotypes in some countries (12–14).
A next-generation 13-valent pneumococcal conjugate vaccine (PCV13) was licensed for use in the United States in 2010 (15). PCV13 has been approved in 128 countries, and children in 83 countries have undergone routine PCV13 vaccination. Recently, Richter et al. reported that an increase of type 19A was halted by introduction of PCV13, whereas serotype 35B increased; coverage provided by PCV13 was effective in only 41.4% of children <5 years of age in 2010 and 2011 (16). Furthermore, Kaplan et al. reported a slight increase in serotype 33F (17).
In Japan, PRSP has increased rapidly as a cause of respiratory tract infections, acute otitis media, and IPD in children since the late 1990s (18,19). PCV7 received final approval in October 2009 and has been used clinically in infants on a voluntary basis since February 2010. Since November 2010, PCV7 use has been encouraged for children <5 years of age throughout Japan by an official program, the Provisional Special Fund for the Urgent Promotion of Vaccination. As a result, estimated rates of PCV7 vaccination for such children were <10% in 2010, 50%–60% in 2011, and 80%–90% in 2012.
PCV7 was incorporated into the routine vaccination schedule for children in Japan beginning in April 2013; before then, however, its coverage rate against IPD had decreased rapidly from 71.8% in 2006 to 51.6% in 2011 (20). Most recently, PCV13 was approved by the government in June 2013, later replacing PCV7 as a routine vaccination in December 2013. The purpose of our study was to clarify changes during April 2010–March 2013 of serotypes and genotypes mediating β-lactam and macrolide resistance in S. pneumoniae isolates from children <18 years of age who had IPD before and after PCV7 introduction.
Dr Chiba is a microbiologist at Keio University School of Medicine. Her research interests include molecular epidemiology, particularly pathogens causing respiratory infection.
Our study was funded in part by a grant under the category, “Research on Emerging and Re-emerging Infectious Diseases” (H22-013), from the Japanese Ministry of Health, Labour and Welfare to K.U.
- Figure 1. Distribution of general hospitals participating in surveillance for invasive pneumococcal disease, Japan, April 2010–March 2013Numbers in light gray circles show the number of the hospitals in each prefectureNumbers in...
- Figure 2. Changes in serotype number and penicillin resistance according to genotype, Japan, April 2010–March 2013gPSSP, genotypic penicillin-susceptible Streptococcus pneumoniae; gPISP, genotypic penicillin-intermediate resistant Spneumoniae; gPRSP, penicillin-resistantSpneumoniaeThe parentheses express abnormal...
- Figure 3. Proportional yearly changes in macrolide resistance according to resistance geneserm(B) and mef(A) identified by real-time PCR, Japan, April 2010–March 2013The percentage of each resistance gene was calculated from...
- Figure 4. Changes in serotype number and macrolide resistance of Streptococcus pneumoniaestrains according to genotype, Japan, April 2010–March 2013MLS, macrolide-susceptible strains not possessing any resistance gene; MLR-mef(A), macrolide-resistant strain possessing...
- Table 1. Vaccine and nonvaccine serotypes of Streptococcus pneumoniae in children after introduction of PCV7, Japan, April 2010–March 2013
- Table 2. Year-to-year changes in prevalence of vaccine and nonvaccine serotypes ofStreptococcus pneumoniae in children after introduction of PCV7, Japan, April 2010–March 2013
- Table 3. Pneumococcal vaccination history and age for 156 children with invasive pneumococcal disease, Japan, 2012
Suggested citation for this article: Chiba N, Morozumi M, Shouji M, Wajima T, Iwata S, Ubukata K et al. Changes in capsule and drug resistance of pneumococci after introduction of PCV7, Japan, 2010–2013. Emerg Infect Dis [Internet]. 2014 Jul [date cited].http://dx.doi.org/10.3201/eid2007.131485