الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Streptococcus pneumoniae (pneumococcus) is a bacterial pathogen that affects children and adults worldwide. Although S pneumoniae is the leading bacterial cause of respiratory tract infections, it is also capable of causing a wide variety of infectious syndromes including meningitis, peritonitis, and sepsis. Virulence factors include capsule,pnemolysin, the Pneumococcal Pilus, Choline-Binding Proteins (CBPs) and pneumococcal surface proteins and other surface proteins.
Nasopharyngeal colonization usually is acquired around 6 months of age but can occur as early as the first weeks of life, and although the average length of carriage is 3 to 4 months, some individuals (especially young infants) may harbor pneumococci for over a year and colonization of S pneumoniae in children mainly depends on age.
Socioeconomic and environmental risk factors include family size, income, smoking and antibiotic use.
The nasopharyngeal flora become established during the first months of life. A broad variety of microorganisms including S pneumoniae, H influenzae, and M catarrhalis.
Colonization not only is obligatory for invasive disease, but also provides the basis for horizontal spread of pneumococci.
The serotype distribution among nasopharyngeal carriage isolates varies slightly by country and age-group. On the basis of the results of these clinical trials, in 2000, ACIP recommended routine use of PCV7 for all children aged 2-59 month.
The 13-valent pneumococcal conjugate vaccine (PCV13) contains serotypes 1, 3,4, 5, 6A,6B, 7F,9V, 14, 18C, 19A, 19F, and 23F.
This cross sectional study conducted over a period of 14 months. Healthy infants below the age of 60 days presented to the outpatient clinic of- Alexandria university children’s hospital were enrolled in this study.
The results revealed that 0.75 % (n=4/531) of infants showed positive carriage of pneumococcus in their nasopharynx. After serotyping, only one case of 4 Strept. pneumonae identified as vaccine included type and the remaining 3 were of non –vaccine type and this result was checked by real-time PCR serogrouping. Seventy five percent of cases were sensitive to penicillin and the remaining 25% were resistant.