History and Objectives: Considering the various report on incidence of Streptococcus type-B in rectum and its role in premature infantile infection and lack of information in the region and for determination of its prevalence in pregnant women, this study was carried out in Shabihkhani hospital in Kashan in 2000.

Materials and Methods: The descriptive strategy of this study was conducted on 400 pregnant women at a gestational age greater than 35 weeks. For this purpose, a questionnaire was designed for collection of data including age, occupation, academic history, nationality, inhabitation, multiparous state, number of abortion, labor type and antibiotic consumption. Sampling from rectum was done using a sterile swab. Then, it was cultured in special medium and isolated bacteria were identified using biochemical tests. All of the infants up to 48h after labor and those from mothers with signs of positive colonization up to one week were followed up. From the latter group, sampling was done and the related bacteria were identified. For statistical analysis, X² and Fischer tests were used.

Results: Out of 400 samples from rectum, 30 cases (7.5%) with streptococcus type-B and in 2 cases (6.7%) from mothers with positive culture were identified. In addition there was a relationship between streptococcus type-B rectal colonization and premature infantile premature infection (P=0.0055).

Conclusion and Recommendations: Considering a 7.5% incidence of this bacterium in rectum and its relationship with type-B streptococcal rectal colonization and premature infections and its complications, it is recommended to conduct more studies in pregnant women.