Prevalence, capsular type distribution, anthropometric and obstetric factors of group B Streptococcus (Streptococcus agalactiae) colonization in pregnancy.

OBJECTIVE: To establish the prevalence, serotype distribution, anthropometry and obstetric factors of Group B Streptococcus (GBS) colonization in pregnant women. DESIGN: Cross sectional survey. SETTING: Chinhoyi General Hospital. SUBJECTS: 206 pregnant women attending the antenatal clinic at Chinhoyi General Hospital were systematically randomly sampled. MAIN OUTCOME MEASURES: All the isolates were serotyped on the basis of capsular polysaccharide (CHO) antigen designated, Ia, Ib, II, III, IV and V. RESULTS: 65 (31.6%) were carriers of GBS. The serotypes found were, type III (41.8%), type V (37.4%), type Ia (11.0%), type IV (3.3%), type Ib (3.3%) type II (1.0%) and 2.0% of the isolates were non-typable. All isolates were sensitive to penicillin and resistant to gentamycin. Colonization was more common in women with parity 0 to 2 (4.6%) and age group 20 to 24 years (43.1%). There was some evidence (p = 0.063) to suggest that GBS was more often isolated from the vagina (12.6%) than from the rectum (6.3%). CONCLUSION: There was a high prevalence of GBS colonization among pregnant women in Chinhoyi. Types III and V were the most common serotypes found.