الفهرس 
Introduction and aim of the work
Epidemiology and Pathogenesis of Pneumococcal infectionOnly 14 pages are availabe for public view
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Abstract
Pneumococcal infection refers to an infection caused by Streptococcus pneumoniae (the pneumococcus). It is a major cause of pneumonia, meningitis, bacteremia, sinusitis, and otitis media, and it occasionally infects tissues at other sites.
The World Health Organization estimates that 1.6 million people, including up to 1 million children aged <5 years, die of IPD every year with developing countries bearing the greatest burden.
The aim of this study was to determine the rate of nasopharyngeal carriage and serotype distribution of Streptococcus pneumoniae isolates colonizing the nasopharynx of children less than five years in Egypt in order to evaluate the effectiveness of introduction the pneumococcal conjugated vaccines in Egypt.
We used PCR techniques to detect the rate of nasopharyngeal carriage, since carriage precedes invasive disease. We used three multiplex reactions to determine the serotypes distribution of Streptococcus pneumoniae isolates colonizing the nasopharynx of children less than five years. The nasopharyngeal carriage of S. pneumonia was 56.5% by using RT-PCR technique, and the prevalence of pneumococcal carriage was highest in the first few years of life, peaking at approximately 70.3% in hosts 6 months-1 year of age and decreasing in higher age groups. This rate of carriage is similar to that in the neighboring region prevalence studies on the nasopharyngeal carriage of S. pneumonia.
We correctly identified the serotypes of 65.5% of the samples by multiplex PCR reactions. In our study the most common serotype was 6A/6B of total typeable S. pneumonia serotypes followed by 19 F, 23 F, 3, 9V, 14, 19 A, 4, 5, 18 in a decreasing order. These results agree with previous studies conducted in Egypt except for serotype1, which was not detected in any isolate.
Worldwide prevalence studies on the nasopharyngeal carriage of S. pneumoniae have shown that, mostly, the above mentioned serotypes are involved but with slight differences in percentages among them.
The vaccines coverage in our study were 60.2%, 62%, 63.7% and 65.5% for 7, 10, 11 and 13 polyvalent conjugate vaccines respectively. Employing the PCV13 vaccine increases the protective spectrum.
Our findings demonstrated co-colonization with different serotypes of S. pneumoniae among carriers. Rate of co-colonization was 11.5% among all pneumococci carriers (13/113) and 17.6% among the serotyped carrier isolates(13/74).