Background: Invasive pneumococcal disease is a significant cause of morbidity and mortality worldwide and it is a major cause for childhood deaths in Nepal.

Objectives: The aim of this study was to establish the antimicrobial susceptibility pattern of Streptococcus pneumoniae and perform serotype responsible for pneumococcal disease in Nepal.

Materials and methods: All together 3774 children from 2 to 60 months who fulfilled the enrollment criteria for suspect of bacterial pneumonia, sepsis or meningitis were enrolled for etiologic studies of severe illness. During the study period 60 isolates of Streptococcus pneumoniae were isolated and the antimicrobial susceptibility testing and serotyping were performed.

Results: The study showed that 24 (52.17%) isolates were resistant to Cotrimoxazole, 3 (6.5%) isolates were intermediately resistant to Penicillin but no Penicillin resistant strains were isolated. The 1 (2.17%) isolate was recorded as Erythromycin and Chloramphenicol resistant and only 1 (2.17%) isolate was found intermediately resistant to Cefotaxime. Of the 60 isolates, serotyping result was available only for 46 isolates. The most common serotypes were serotype 1 (27. 65%) followed by serotype 5 (19.14%) and serotype 4 (8. 5%) respectively followed by serotype 39, 23F, 7F, 19B, 12A, 14, 18F, 6B, 32, 16, 19F and 25F.

Conclusions: Alarming level of Cotrimoxazole resistance demands revision of pneumonia treatment policy in Nepal and rising tendency of other drug resistance against Streptococcus pneumoniae showed use of these drugs for the treatment of meningitis, pneumonia and other serious infections needs extended research. The common serotype 1, 5 and 4 need to be incorporated in pneumococcal vaccine to immunise children in Nepal.