• Clinical and Experimental Pediatrics
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• 제57권2호
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• pp.55-66
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• 2014

The 7-valent pneumococcal protein conjugate vaccine (PCV7) has been shown to be highly efficacious against invasive pneumococcal diseases and effective against pneumonia and in reducing otitis media. The introduction of PCV7 has resulted in major changes in the epidemiology of pneumococcal diseases. However, pneumococcal vaccines induce serotype-specific immunity, and a relative increase in non-vaccine serotypes has been reported following the widespread use of PCV7, leading to a need for extended serotype coverage for protection. PCV10 and PCV13 have been licensed on the basis of noninferiority of immunogenicity compared to a licensed conjugate vaccine. In this article, we aimed to review important data regarding the efficacy and effectiveness of the extended-coverage PCVs published or reported thus far and to discuss future implications for pneumococcal vaccines in Korea. After the introduction of PCV10 and PCV13, within a short period of time, evidence of protection conferred by these vaccines against invasive and mucosal infections caused by most of the serotypes included in the vaccines is accumulating. The choice of vaccine should be based on the changes in the dynamics of pneumococcal serotype distribution and diseases in the region where the vaccines are to be used. Continuous surveillance is essential for the appropriate use of pneumococcal vaccines and evaluation of the impact of PCVs on pneumococcal diseases.

• Journal of Microbiology
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• 제41권1호
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• pp.1-6
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• 2003

The genetic relatedness of multidrug-resistant pneumococcal isolates of serotypes 19F and 23F was investigated. The DNA fragments digested with Sma I were resolved by pulsed-field gel electrophoresis (PFGE). PFGE analysis of 365. pneumoniae isolates showed 13 different patterns. Among 22 isolates of serotype 19F, 9 different PFGE patterns were present and 14 isolates of serotype 23F isolates represented 5 distinct PFGE patterns. Two isolates of serotype 19F and six isolates of serotype 23F shared the same PFGE pattern (Pattern I). Based on the genetic relatedness within the strains (one genetic cluster was defined as having more than 85% homology), we divided the pneumococcal strains into genefic clusters (Ⅰ, II, III, IV, V, and VI). The 22 strains of serotype 19F belonged to five distinct genetic clusters (I, II, III, IV, V and VI) and 14 strains of serotype 23F represented two genetic clusters (I and II ). These results showed that strains of serotype 19F are genetically more diverse than those of serotype 23F, Serotype 19F isolates with PFGE patterns H and I appeared to be less related to those of the remaining PFCE patterns (A to G) (less than 60% genetic relatedness), but those strains were genetically closely related with serotype 23f. These results suggest that the latter isolates originated from horizontal transfer of the capsular type 19F gene locus to 23F pneumococcal genotypes. In conclusion, the multidrug-resistant pneumococcal isolates of serotype 19f and 23F isolated in Korea are the result of the spread of a limited number of resistant clones.

• Infection and chemotherapy
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• 제50권4호
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• pp.328-339
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• 2018

Background: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009-2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). Materials and Methods: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ${\geq}2$ non-${\beta}$-lactam antimicrobials. Results: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. Conclusion: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

• Clinical and Experimental Pediatrics
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• 제48권5호
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• pp.506-511
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• 2005

목 적 : 폐구균 혈청형 6B와 6A는 폐구균 감염의 중요한 원인균이다. 6B 백신은 다당질 구조의 유사성으로 6A와 교차 면역반응을 일으키며 6B에 의해 생성된 6A에 대한 항체는 감염에서 방어 작용을 할 수 있다고 생각되고 있다. 이를 규명하기 위해 성인에게 폐구균 백신 접종 후 형성된 6B와 6A에 대한 항체의 옵소닌 작용 능력을 측정하여 교차 면역반응을 연구하였다. 방 법 : 건강한 성인 24명에게 혈청형 6B만 포함된 폐구균 다당질 백신을 접종하고 접종 전과 접종 한달 후 혈청에서 혈청형 6B와 6A에 대한 특이 항체의 옵소닌 작용 역가를 OPKA로 측정하였다. 결 과 : 6B에 대한 옵소닌 작용 역가는 백신 접종 전과 접종 후 모두 6A에 대한 역가보다 의미있게 높았다. 백신 혈청형인 6B에 대해서 뿐 아니라 교차 반응하는 혈청형인 6A에 대해 다당질 백신 접종 후 성인에서 옵소닌 작용 역가가 의미 있게 증가하였으므로 백신에 포함된 6B 다당질은 6A에 대해서 교차 방어 항체를 유도하였으나 모든 경우에 해당되지는 않았다. 1명의 성인에서 접종 후에도 계속적으로 6A에 대한 옵소닌 작용 역가가 측정되지 않았다. 결 론 : 백신에 포함된 폐구균 혈청형 6B에 대한 다당질은 혈청형 6A에 대해 대부분 교차 면역 반응을 일으켜 기능적 항체 형성을 유발하지만 드문 경우 이런 교차 면역 반응이 형성되지 않는 경우도 있다. 앞으로 이에 대한 연구가 소아와 노인 등의 다른 연령 군에서도 시행되어야 할 것이다. 또한 교차 방어 형성의 유무는 폐구균 백신의 임상 연구와 백신 사용 후 분리되는 폐구균의 혈청형 검사를 통한 임상 연구에서 직접적으로 연구되어야 할 것이다.

• Clinical and Experimental Pediatrics
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• 제52권4호
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• pp.508-511
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• 2009

폐구균(Streptococcus pneumoniae)은 소아, 특히 어린 영아에서 심한 침습성 질병을 일으키는 중요한 원인균이다. 2003년부터 우리나라에서 접종하기 시작한 7가 폐구균백신(PCV7)은 소아에서 침습성 폐구균성 폐렴과 수막염을 예방하는 것으로 알려져 왔다. 그러나 최근 7가 폐구균백신을 접종한 이후부터 비7가 폐구균 혈청형(non-PCV7 serotype) 감염 발생률이 증가하고 있다. 14개월 된 여아가 내원 3일 전부터 열과 구토가 있었으나 증상 치료만 하고 있던 중 갑작스런 의식불명과 기면(lethargy)으로 응급실로 내원하였다. 입원 후 즉각적인 진단과 치료를 시행했음에도 불구하고 환자는 빠르게 혼수와 뇌사 상태로 진행하였다. 환자는 이전에 3회의 7가 폐구균백신을 접종하였으나 최종 진단은 비7가 폐구균 혈청형인 폐구균 19A 수막염이었고, 입원 20일째 사망하였다. 이는 한국에서 문헌상 보고된 적이 없는, 폐구균 19A 혈청형 수막염으로 사망한 첫번째 증례이므로 이에 보고하는 바이다.

• Clinical and Experimental Pediatrics
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• 제54권4호
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• pp.146-151
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• 2011

Streptococcus pneumoniae remains a leading cause of invasive infections including bacteremia and meningitis, as well as mucosal infections such as otitis media and pneumonia among children and adults. The 7-valent pneumococcal conjugate vaccine (PCV7) was licensed for use among infants and young children in many countries including Korea. The routine use of PCV7 has resulted in a decreased incidence of invasive pneumococcal disease (IPD) by the vaccine serotypes among the vaccinees and substantial declines in IPD among unvaccinated populations such as older children and adults as well. In addition, there are increasing evidences to suggest that routine immunization with PCV7 is changing the epidemiology of pneumococcal diseases such as serotype distribution of IPD, nasopharyngeal colonization, and antibiotic resistance patterns. In contrast, there is an increase in the number of IPDs caused by nonvaccine serotypes, though it is much smaller than overall declines of vaccine serotype diseases. Several vaccines containing additional serotypes have been developed and tested clinically in order to expand the range of serotypes of Streptococcus pneumoniae. Recently two new pneumococcal protein conjugate vaccines, 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13), have been approved for use in several countries including Korea. This report summarizes the recommendations approved by the Committee on Infectious Diseases, the Korean Pediatric Society.

• Clinical and Experimental Pediatrics
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• 제63권7호
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• pp.265-271
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• 2020

Background: Pneumococcal diseases among children aged <5 years worldwide are associated with high annual mortality rates. Purpose: This study aimed to evaluate the immunogenicity and safety of GBP411, a 12-valent pneumococcal conjugant vaccine, with a dosing schedule of 2 primary doses plus 1 booster dose (2p+1) in healthy infants. Methods: This randomized active-controlled (Prevnar 13) double-blind phase 2 trial enrolled healthy subjects aged 6-10 weeks. Three serum concentrations of pneumococcal serotype-specific immunoglobulin G (IgG) were evaluated using the pneumococcal serotype-specific pneumonia polysaccharide enzyme-linked immunosorbent assay at 1 month after the primary doses and before and 1 month after the booster dose. The pneumococcal serotype-specific IgG titer was evaluated using a multiplex opsonophagocytic assay in a subset of 15 subjects per group. Results: After administration of the primary doses, the proportion of subjects who achieved pneumococcal serotype-specific IgG concentrations of >0.35 ㎍/mL was lower for some serotypes in the GBP411 group than in the comparator group (6B: 20.83% vs. 39.22%, P=0.047 and 19A: 58.33% vs. 90.20%, P<0.001). However, after administration of the booster dose, >97% of the subjects in each group achieved IgG concentrations of ≥0.35 ㎍/mL for all 12 serotypes. Increased immunogenicity was observed for some serotypes that showed significant intergroup differences after administration of the primary doses but not after the booster dose. We also found no significant intergroup difference in the overall incidence of solicited local adverse events. Furthermore, the overall incidence of solicited systemic adverse events was significantly lower in the GBP411 group than in the comparator vaccine group (79.59% vs. 98.04%; P=0.003). Conclusion: The GBP411 vaccine with a dosing schedule of 2p+1 may be immunogenic and safe for healthy infants.

• Clinical and Experimental Pediatrics
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• 제49권3호
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• pp.235-241
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• 2006

Streptococus pneumoniae is an important cause of invasive infections as well as non-invasive infections such as acute otitis media and sinusitis both in children and adults. Resistance of S. pneumoniae to multiple antimicrobials is increasing and poses therapeutic challenges, and prevention became more important. 23-valent polysaccharide vaccine has been used for the last several decades, but is not effective in children <2 years of age, the highest risk group of invasive diseases. Recently, a 7-valent pneumococcal protein conjugate vaccine(PCV) which is effective in infants and young children has been developed. The efficacy of PCVs against invasive pneumococcal disease and pneumonia is well established and is documented in several well-conducted studies. However, the effect of PCVs on otitis media is less obvious and more complex. PCVs clearly reduce diseases caused by vaccine-type(VT) pneumococci, but replacement of VT serotypes by non-VT serotypes in nasopharyngeal carriage of S. pneumoniae is responsible for the increase in acute otitis media caused by non-VT serotypes. Three years after introduction of PCV in the US, some increase of invasive infections with serotype 19A possibly due to serotype switching within certain vaccine type strains has been noted. Since most antibiotic-resistance in S. pneumoniae is confined to VT serotypes, vaccine use also reduces antibiotic resistance. With development of PCV, there was a great advance in the prevention of pneumococcal diseases, but replacement with potential virulent organisms and development of antibiotic resistance in non-VT pneumococci is a possibility that needs careful monitoring.

• Pediatric Infection and Vaccine
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• 제15권1호
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• pp.45-51
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• 2008

목 적 : 국내의 소아에서의 폐구균 혈청형의 분포양상 및 변화를 알아보는 것은 중이염의 예방과 치료 계획을 수립하는 데 있어 매우 중요하다. 단일기관에서의 경험을 토대로 중이염에서의 폐구균의 혈청형 분포양상을 알아보고자 하였다. 방 법 : 2001년 1월부터 2006년 12월까지 세브란스병원에서 중이염으로 진단받은 15세 미만의 소아 중 동반된 이루의 배양검사에서 폐구균이 분리된 경우를 대상으로 혈청형과 항생제 감수성을 알아보았다. 결 과 : 모두 54명의 환아로부터 54개의 검체를 얻었으며 이 들의 연령의 중앙값은 13개월이었고 5세 미만의 환아가 차지하는 비율은 81%였다. 혈청형 빈도는 19A(44%), 19F(28%), 6B(7%), 6A(4%), 9V(4%), 1(4%) 등의 순이었다. 전체 혈청형 중 19A와 19F가 차지하는 비율이 72%이었으며, 특히 5세 미만의 소아에서는 84%나 차지하여 5세 이상 소아에서의 20%에 비해 높은 비율을 보였다.(P<0.001) 연도별 19A나 19F이 차지하는 비율은 차이가 없었으며, 7가 단백결합 폐구균백신 도입 이전과 이후 시기 사이에도 차이가 없었다. 전체 폐구균 중 백신혈청형이 차지하는 비율은 43%이었다. 진단 이전 7가 단백결합 폐구균백신을 접종한 3명의 환아에서 동정된 혈청형은 모두 19A였다. 혈청형 별 항생제 비감수성 폐구균의 비율에서 19A는 다른 비백신혈청형에 비해 페니실린, erythromycin, trimethoprim-sulfamethoxazole 등에 비감수성 비율이 더 높았다. 다제 내성률도 다른 비백신혈청형에서 29%인데 반해 19A에서는 96%였다.(P=0.001) 결 론 : 5세 미만의 중이염 환아의 이루에서 분리된 폐구균 중 19A가 가장 흔한 혈청형이었고 매우 높은 다제 내성률을 보였다.

• Journal of Korean Medical Science
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• 제33권51호
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• pp.340.1-340.14
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• 2018

Background: Various pneumococcal vaccines have been evaluated for immunogenicity by opsonophagocytic assay (OPA). A multiplexed OPA (MOPA) for 13 pneumococcal serotypes was developed by Nahm and Burton, and expanded to 26 serotypes in 2012. The development of new conjugate vaccines with increased valence has necessitated expanded MOPAs to include these additional serotypes. In this study, we validated this expanded MOPA platform and applied to measure antibodies against 11 additional serotypes (2, 8, 9N, 10A, 11A, 12F, 15B, 17F, 20B, 22F, and 33F) in human sera. Methods: All materials, including serum, complement, bacterial master stocks, and HL-60 cells, were evaluated for assay optimization. Following optimization, the assay was validated for accuracy, specificity, and intra- and inter-assay precision with sera from adult donors following standard protocols. The assay was applied to evaluate functional antibodies of 42 sera immunized with 23-valent pneumococcal polysaccharide vaccine (PPV23). Results: The expanded MOPA platform was specific for all serotypes, with the exception of serotype 20. The assay results were highly correlated with those obtained from single-serotype OPA, indicating acceptable accuracy. The coefficients of variation were 7%-24% and 13%-39% in tests of intra- and inter-assay precision, respectively, using three quality-control samples. A MOPA that included 11 additional serotypes in the PPV23 was established and validated with respect to accuracy, specificity, and precision. The opsonic indices of immune sera were obtained using this validated assay. Conclusion: The expanded MOPA will be useful for evaluation of the immunogenicity of PPV23 and future conjugate vaccine formulations.