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Serotype and molecular diversity of nasopharyngeal Streptococcus pneumoniae isolates from children before and after vaccination with the ten-valent pneumococcal conjugate vaccine (PCV10) in Ethiopia.
BMC Infect Dis 2019; 19(1):409BI

Abstract

BACKGROUND

Streptococcus pneumoniae is a major human pathogen, and nasopharyngeal colonization is the first step for transmission and pathogenesis of pneumococcal diseases. Ethiopia introduced the 10-valent pneumococcal conjugate vaccine (PCV10) in October 2011. Here we studied nasopharyngeal carriage rates of pneumococci in children and analyzed the serotype and genetic diversity of pneumococcal isolates before first dose and after completion of the vaccine.

METHOD

A longitudinal study was conducted from February 2013 to November 2016. Totally 789 infants were enrolled at the age of 6 weeks before first dose of PCV10 vaccination, 206 were re-sampled at the age of 9 months, and 201 at 2 years of age after the final dose of PCV10 at the age of 14 weeks. One hundred sixteen children were followed during all the three sampling periods. A total of 422 nasopharyngeal isolates were serotyped using gel diffusion and the Quellung reaction, 325 were typed with pulsed field gel electrophoresis (PFGE), and 12 were selected for multi locus sequence typing (MLST).

RESULTS

Pneumococcal carriage rates at the age of 6 weeks, 9 months and 2 years of age were 26.6% (210/789), 56.8% (117/206) and 48.3% (97/201), respectively. Out of 116 children none of them carried the same strain during the three period and the carriage rate at the age of 6 weeks, 9 months and 2 years were 32.7% (38/116), 59.% (69/116) and 49.1% (57/116) respectively. Totally 59 pneumococcal serotypes were identified among 422 isolates. Serotype 6A (5.0%) dominated followed by 34 (4.5%), 10A (4.0%), 11A (4.0%), 19F (3.8%), 15B (3.8%), 23F (3.6%), and 15A (3.6%). The proportion of non-PCV10 serotypes among the isolates recovered at 6 weeks, 9 months and 2 years was 79.4, 88.9 and 89.7% respectively. Molecular typing of 325 isolates collected at 6 weeks and 9 months of age showed a high genetic diversity.

CONCLUSION

This study highlights the presence of very diverse serotypes in Ethiopia where non-vaccine serotypes were predominant. Completion of the PCV10 schedule was associated with an approximately 50% reduction of vaccine-type carriage and increase of non-vaccine types. PCV13 would potentially reduce vaccine-type carriage by further 10%.

Authors+Show Affiliations

Armauer Hansen Research Institute, Jimma Road, 1005, Addis Ababa, Ethiopia. wondewosentsg@gmail.com. Department of Microbiology, Parasitology and Immunology, Saint Paul's Hospital Millennium Medical College, 1271, Addis Ababa, Ethiopia. wondewosentsg@gmail.com.Armauer Hansen Research Institute, Jimma Road, 1005, Addis Ababa, Ethiopia.Department of Microbiology, Immunology and Parasitology, Addis Ababa University, College of Medicine and Health Science, 9086, Addis Ababa, Ethiopia.The Public Health Agency of Sweden, Stockholm, Sweden.The Public Health Agency of Sweden, Stockholm, Sweden.The Public Health Agency of Sweden, Stockholm, Sweden. Department of Microbiology, Tumor and Cell Biology, MTC, Karolinska Institutet, 171 77, Stockholm, Sweden. Clinical Microbiology, Karolinska University Hospital, 171 76, Stockholm, Sweden.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31077141

Citation

Sime, Wondewosen Tsegaye, et al. "Serotype and Molecular Diversity of Nasopharyngeal Streptococcus Pneumoniae Isolates From Children Before and After Vaccination With the Ten-valent Pneumococcal Conjugate Vaccine (PCV10) in Ethiopia." BMC Infectious Diseases, vol. 19, no. 1, 2019, p. 409.
Sime WT, Aseffa A, Woldeamanuel Y, et al. Serotype and molecular diversity of nasopharyngeal Streptococcus pneumoniae isolates from children before and after vaccination with the ten-valent pneumococcal conjugate vaccine (PCV10) in Ethiopia. BMC Infect Dis. 2019;19(1):409.
Sime, W. T., Aseffa, A., Woldeamanuel, Y., Brovall, S., Morfeldt, E., & Henriques-Normark, B. (2019). Serotype and molecular diversity of nasopharyngeal Streptococcus pneumoniae isolates from children before and after vaccination with the ten-valent pneumococcal conjugate vaccine (PCV10) in Ethiopia. BMC Infectious Diseases, 19(1), p. 409. doi:10.1186/s12879-019-4024-1.
Sime WT, et al. Serotype and Molecular Diversity of Nasopharyngeal Streptococcus Pneumoniae Isolates From Children Before and After Vaccination With the Ten-valent Pneumococcal Conjugate Vaccine (PCV10) in Ethiopia. BMC Infect Dis. 2019 May 10;19(1):409. PubMed PMID: 31077141.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Serotype and molecular diversity of nasopharyngeal Streptococcus pneumoniae isolates from children before and after vaccination with the ten-valent pneumococcal conjugate vaccine (PCV10) in Ethiopia. AU - Sime,Wondewosen Tsegaye, AU - Aseffa,Abraham, AU - Woldeamanuel,Yimtubezenash, AU - Brovall,Sarah, AU - Morfeldt,Eva, AU - Henriques-Normark,Birgitta, Y1 - 2019/05/10/ PY - 2019/01/08/received PY - 2019/04/25/accepted PY - 2019/5/12/entrez PY - 2019/5/12/pubmed PY - 2019/5/12/medline KW - Carriage KW - Ethiopia KW - Infants KW - PCV KW - Serotype KW - Streptococcus pneumoniae KW - Vaccination SP - 409 EP - 409 JF - BMC infectious diseases JO - BMC Infect. Dis. VL - 19 IS - 1 N2 - BACKGROUND: Streptococcus pneumoniae is a major human pathogen, and nasopharyngeal colonization is the first step for transmission and pathogenesis of pneumococcal diseases. Ethiopia introduced the 10-valent pneumococcal conjugate vaccine (PCV10) in October 2011. Here we studied nasopharyngeal carriage rates of pneumococci in children and analyzed the serotype and genetic diversity of pneumococcal isolates before first dose and after completion of the vaccine. METHOD: A longitudinal study was conducted from February 2013 to November 2016. Totally 789 infants were enrolled at the age of 6 weeks before first dose of PCV10 vaccination, 206 were re-sampled at the age of 9 months, and 201 at 2 years of age after the final dose of PCV10 at the age of 14 weeks. One hundred sixteen children were followed during all the three sampling periods. A total of 422 nasopharyngeal isolates were serotyped using gel diffusion and the Quellung reaction, 325 were typed with pulsed field gel electrophoresis (PFGE), and 12 were selected for multi locus sequence typing (MLST). RESULTS: Pneumococcal carriage rates at the age of 6 weeks, 9 months and 2 years of age were 26.6% (210/789), 56.8% (117/206) and 48.3% (97/201), respectively. Out of 116 children none of them carried the same strain during the three period and the carriage rate at the age of 6 weeks, 9 months and 2 years were 32.7% (38/116), 59.% (69/116) and 49.1% (57/116) respectively. Totally 59 pneumococcal serotypes were identified among 422 isolates. Serotype 6A (5.0%) dominated followed by 34 (4.5%), 10A (4.0%), 11A (4.0%), 19F (3.8%), 15B (3.8%), 23F (3.6%), and 15A (3.6%). The proportion of non-PCV10 serotypes among the isolates recovered at 6 weeks, 9 months and 2 years was 79.4, 88.9 and 89.7% respectively. Molecular typing of 325 isolates collected at 6 weeks and 9 months of age showed a high genetic diversity. CONCLUSION: This study highlights the presence of very diverse serotypes in Ethiopia where non-vaccine serotypes were predominant. Completion of the PCV10 schedule was associated with an approximately 50% reduction of vaccine-type carriage and increase of non-vaccine types. PCV13 would potentially reduce vaccine-type carriage by further 10%. SN - 1471-2334 UR - https://www.unboundmedicine.com/medline/citation/31077141/Serotype_and_molecular_diversity_of_nasopharyngeal_Streptococcus_pneumoniae_isolates_from_children_before_and_after_vaccination_with_the_ten-valent_pneumococcal_conjugate_vaccine_(PCV10)_in_Ethiopia L2 - https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-019-4024-1 DB - PRIME DP - Unbound Medicine ER -