[Prevalence of colonization by group B Streptococcus in pregnant women from a public maternity of Northwest region of Brazil].

PURPOSE: to assess the prevalence of group B streptococcus colonization (GBS) in pregnant women in prodrome or in labor.

METHODS

vaginal and rectal cultures were collected from 201 pregnant women, in the admission sector of a public maternity center in the northeast region of Brazil (São Luís, Maranhão). The samples obtained were inoculated in a Todd-Hewith's selective culture medium and after that they were sub-cultivated in blood-agar plates. The CAMP (Christie, Atkins, Munch-Petersen) test was used to identify GBS, which was then serologically confirmed by the BioMérieux Api 20 Strep kit microtest. GBS positive samples were submitted to an antibiotic sensitivity test. Sociodemographic variables, gynecological-obstetrical antecedents, and perinatal outcomes were studied. The Epi-Info 3.3.2 programs from World Health Organization and Statistical Package for Social Sciences 14.0 version were used for the statistical analysis. The prevalence ratio was used as risk measure, considering p<0.05 as significance level, and accepting 80% power.

RESULTS

the prevalence of SGB colonization in the mothers was 20.4%. There was no association between the sociodemographic variables or gynecological-obstetrical antecedents and a larger presence of SGB colonization. There were two cases of infectious outbreak among neonatal babies from colonized mothers, but hemocultures resulted negative. High resistance rates were found for the following antibiotics: clindamycin, 25.4%; erythromycin, 23.4% and ceftriaxone, 12.7%.

CONCLUSIONS

the prevalence of SGB colonization was high among the mothers, similar to what had been described in other studies. The elevated rates of antimicrobial resistance, especially to ceftriaxone indicate the need for further studies to determine the serology of this agent and of orientation protocols for rational use of antimicrobials.