RESUMEN
To determine the prevalent serotypes of Streptococcus pneumoniae and the rate of penicillin-nonsusceptibility among pneumococci in Oman. Pneumococcal isolates encountered during the period of September 2002 to December 2007 in the Royal Hospital were serotyped. Clinical information as well as the penicillin susceptibility reports were retrieved from the hospital information system and medical records, 120 strains of Streptococcus pneumoniae were isolated of which 85 strains were seroptyped. 20 different serotypes were identified; the most common seroptypes were 9A, 6B, 19F, 14 and 23F. 56% of the strains were not susceptible to pencillin, while 99% of these were susceptible to ceftriaxone. 74.3% and 46.1% of the serotypes are covered by the pneumococcal polysaccharide vaccine and the 7-valent pneumococcal conjugate vaccine respectively, Certain few pneumococcal serotypes such as 9A, 6B and 19F are more prevalent in the Omani community than others. More than half of S. pneumoniae are not susceptible to penicillin while the great majority of the strains are susceptible to ceftriaxone