Background: This study describes the resistance pattern of Streptococcus pneumoniae isolates obtained from pediatric patients in a Saudi Arabian hospital.
Material/Methods: This is a retrospective analysis of the antibiotic resistance of S. pneumoniae isolates (n=141) obtained from children in a Saudi Arabian hospital 1999–2004. Clinical data and antibiotic sensitivity were retrieved from microbiology data and analyzed.
Results: Of the total isolates of S. pneumoniae, 57.6% were susceptible to penicillin, 28.8% intermediately susceptible, and 13.7% were resistant organisms. Over the study period, high-level penicillin resistance of S. pneumoniae was 0% in 1999, 23% in 2001, and 3.4% in 2004. Intermediate penicillin resistance was 21% in 1999, 41% in 2001, and 27.6% in 2004. The resistance rates to other antibiotics were as follows: erythromycin 33.4%, tetracycline 30%, trimethoprim sulfamethoxazole 40%, and clindamycin 21.6%. Children less than 2 years of age showed a higher rate of intermediately penicillin-susceptible isolates (41.9% versus 22.7%, P=0.0.02). They also had higher rates of resistance to tetracycline (42.4% versus 25%, P=0.03), trimethoprim-sulfamethoxazole (54% versus 33.8%, P=0.02), and clindamycin (33% versus 17%, P=0.04). All tested isolates were susceptibility to ceftriaxone and vancomycin.
Conclusions: The overall high-level penicillin resistance of S. pneumonaie from 1999–2004 was 13.7%. The percentage of intermediately penicillin-susceptible organisms was higher in the age group under 2 years of age (41.9%) than in patients 2 years of age or older (22.7%).

Keywords: Streptococcus pneumoniae - metabolism, Streptococcal Infections - drug therapy, Saudi Arabia, Pneumococcal Infections - drug therapy, Penicillins - pharmacology, Penicillin Resistance, Microbial Sensitivity Tests, Adolescent, Drug Resistance, Microbial, Child, Preschool, Child, Anti-Bacterial Agents - pharmacology