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Expression and Purification of Virus-like Particles for Vaccination
Published on: June 2, 2016
Pneumococcal bacteraemia in Belgium (1994 2004): the pre-conjugate vaccine era
Johan Flamaing1, Jan Verhaegen, Jos Vandeven
1Department of Geriatric Medicine, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium. johan.flamaing@uz.kuleuven.be
Insights
Antibiotic resistance in Streptococcus pneumoniae decreased, with a shift from pediatric to non-pediatric serotypes before the 7-valent pneumococcal conjugate vaccine (7PCV) introduction. Further surveillance is crucial for vaccine strategies and at-risk populations.
Area of Science:
- Microbiology
- Epidemiology
- Vaccinology
Background:
- Pneumococcal bacteraemia poses a significant public health threat.
- Understanding antibiotic resistance and serotype distribution is crucial for effective prevention and treatment strategies.
- The introduction of pneumococcal conjugate vaccines (PCVs) has impacted disease epidemiology.
Purpose of the Study:
- To analyze the trends in antibiotic resistance and serotype distribution of Streptococcus pneumoniae causing bacteraemia.
- To evaluate these trends in the period preceding the widespread use of the 7-valent pneumococcal conjugate vaccine (7PCV).
Main Methods:
- Analysis of 11,163 blood isolates of Streptococcus pneumoniae collected between 1994 and 2004.
- Serotyping and antimicrobial susceptibility testing for penicillin and erythromycin were performed.
Main Results:
- Penicillin resistance in pneumococcal bacteraemia initially increased and then decreased, while erythromycin resistance showed a sustained rise.
- Paediatric serogroups/serotypes (SGTs) decreased in prevalence, whereas non-paediatric SGTs increased, particularly in the 5-59 years age group.
- The 7-valent PCV (7PCV) offered substantial coverage for prevalent SGTs in young children, with additional benefits from the 13-valent PCV (13PCV) and 23-valent polysaccharide vaccine (23PPV) in older adults.
Conclusions:
- Despite the absence of 7PCV use during the study, a significant decrease in paediatric SGTs and overall penicillin resistance was observed.
- These changes may be attributed to secular trends, international herd effects, or reduced antibiotic use.
- Continued surveillance of antibiotic resistance and serotype distribution is essential for informing future vaccine development and public health interventions.
Objectives:
To analyse the evolution of antibiotic resistance and serotype distribution in pneumococcal bacteraemia before the introduction of the 7-valent pneumococcal conjugate vaccine (7PCV).
Methods:
Serotyping and susceptibility testing for penicillin and erythromycin were performed on 11 163 blood isolates of Streptococcus pneumoniae collected between 1994 and 2004.
Results:
Penicillin resistance rose from 4.7% in 1994 to 15.2% (P = 0.001) in 2000 and decreased thereafter to 9.7% (P = 0.001) in 2004. Erythromycin resistance rose from 20.4% in 1994 to 34.4% (P = 0.001 in 2001) and stabilized thereafter. Paediatric serogroups/serotypes (SGTs) (SGTs 6, 9, 14, 19 and 23; 47.4% of bacteraemic isolates), characterized by decreasing penicillin and stable erythromycin resistance, decreased by the end of the study period. Non-paediatric SGTs (SGTs 1, 5 and 7; 20.5% of bacteraemic isolates), characterized by temporal fluctuations, the absence of penicillin resistance and rising erythromycin resistance, increased significantly by the end of the study period. The age group 5-59 years was most affected by these changes. Compared with the age group <5 years, the age group >or=60 years has a relative risk of 7.6 (CI: 4-11.6; P = 0.001) of having a pneumococcal bacteraemia with SGT 3. The overall coverage rate of bacteraemic SGTs offered by the 7PCV is 81.9% in the <5 years age group with an additional coverage of 11.6% offered by the 13-valent pneumococcal conjugate vaccine (13PCV) in this age group (P = 0.001). The coverage of bacteraemic isolates offered by the 13PCV and 23-valent pneumococcal polysaccharide vaccine (23PPV) in the >or=60 years age group is 78.7% and 95%, respectively.
Conclusions:
Although the 7PCV was not used in Belgium during the study period, the overall prevalence in paediatric SGTs decreased significantly. This may be linked to secular trends in SGTs not included in the 7PCV and/or herd effects at the international level. Overall penicillin resistance decreased as well and this may be due to a shift towards susceptible serotypes and/or a decrease in antibiotic use in our country. Antibiotic resistance and trends in SGT distribution will need further surveillance in order to assess 7PCV effects on pneumococcal epidemiology, to adapt future vaccine formulations and to target the population at risk.
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