Prevalence of Invasive Streptococcus pneumoniae Infections among Iranian Children: A Systematic Review and Meta-Analysis

Emerging pneumococcal serotypes in Iraq: scope for improved vaccine development

Pneumococcal disease is a global public health concern as it affects the young, aged and the immunocompromised. The development of pneumococcal vaccines and their incorporation in the immunization programs has helped to reduce the global burden of disease. However, serotype replacement and the emergence of non-vaccine serotypes as well as the persistence of a few vaccine serotypes underscores the need for development of new and effective vaccines against such pneumococcal serotypes. In the Middle East, places of religious mass gatherings are a hotspot for disease transmission in addition to the global risk factors. Therefore, the periodic surveillance of pneumococcal serotypes circulating in the region to determine the effectiveness of existing prevention strategies and develop improved vaccines is warranted. Currently, there is a lack of serotype prevalence data for Iraq due to inadequate surveillance in the region. Thus, this review aims to determine the pneumococcal serotypes circulating in Iraq which may help in the development and introduction of improved pneumococcal vaccines in the country.

Co-infection with dual Streptococcus pneumoniae serotypes as a cause of pediatric bacterial meningitis in Iran: a multi-center cross-sectional study

Background

Meningitis is considered a life-threatening infection with high mortality all over the world. Hemophilus influenzae (H. influenzae) and Streptococcus pneumoniae (S. pneumoniae) are regarded as the two most common infectious agents causing bacterial meningitis. This study aimed to identify H. influenzae and S. pneumoniae serotypes in blood and cerebrospinal fluid (CSF) of pediatric patients with meningitis, using polymerase chain reaction (PCR).

Methods

This multi-center cross-sectional study included 284 children with suspected meningitis referred to 4 target hospitals. Overall, 412 samples (128 blood and 284 CSF samples) were obtained from the patients from November 14, 2016 to November 15, 2017. The extracted DNA was examined using multiplex real time PCR to screen for S. pneumoniae and H. influenzae. S. pneumoniae serotyping was also done by multiplex PCR.

Results

Out of 284 CSF specimens, 22 were positive for ply S. pneumoniae. Of 20 DNA samples meeting the Quality Control (QC) standards for serotyping, 7 (35%), 6 (30%), 2 (10%), 2 (10%), 2 (10%), 1 (5%), 1 (5%), 1 (5%), 1 (5%) and 1 (5%) were positive for serotypes 3, 11A, 6A, 14, 7C, 23F, 23B, 19A, and 19F and 5, respectively. Overall, nine samples were positive for two serotypes, of whom 3 and 11A were the most common from Tehran province. Of note, one of these CSF samples showed a new co-infection with serotypes 7C and 14. Also, 6 samples (30%) were positive for H. influenzae detected by bexA primer. None of the blood samples were positive for S. pneumoniae or H. influenzae.

Conclusion

Co-infection with S. pneumoniae serotypes can occur in bacterial meningitis and it might be missed if all serotypes are not evaluated in CSF specimens.