PREVALENCE AND RISK FACTORS ASSOCIATED WITH GROUP B STREPTOCOCCUS COLONIZATION AMONG HIV-POSITIVE PREGNANT WOMEN IN ILE-IFE

Abstract

Background: Group B Streptococcus (GBS) is a significant public health issue
and a leading cause of chorioamionitis, puerperal endometritis and infectious
morbidity in the newborn. The study objective was to determine the prevalence
of Group B Streptococcus (GBS) colonization among HIV positive pregnant
women compared with HIV negative pregnant women and to identify risk
factors associated with GBS colonization among the study groups.
Methodology: This descriptive cross sectional comparative study was
conducted between July and December 2011, on 200 pregnant women
attending antenatal clinic at OAUTHC who were divided into two groups: HIV
positive group (n=67) and a control group consisting of HIV negative pregnant
women (n=133), to assess the regional colonization by Group B Streptococcus
(GBS). Vaginal and anal swabs were collected at 35-37 weeks of gestation and
cultured in Todd-Hewitt broth, followed by a confirmatory test. For a control
group with an anticipation proportion based on literature research of 14.1%
and alpha=0.05, a sample size of 133 would have a power of 80% to detect a
difference of 15% or greater with a study group in the proportion of 2:1. Patient
socio-demographic characteristics and CD4 counts were extracted from the
records and statistical analysis was done with SPSS 16.
Results: There were 198 analyzable samples from the participants. The overall
anogenital prevalence of GBS colonization was 36/198 (18.2%): 13(19.4%) of
the HIV infected pregnant women were GBS colonized and 23(17.6%) of the
women in the control group. No significant difference was observed in GBS
colonization between the study and the control groups. Maternal GBS
colonization in HIV infected pregnant women was found not to be associated
with CD4 counts. Increasing body mass index (BMI) was found to be
independently associated with GBS colonization among HIV infected pregnant
women (OR= 1.25, 95% CI 1.04-1.51, P=0.019) and diabetes mellitus was also
significantly associated with the risk of GBS colonization among HIV positive
pregnant women but not among HIV negative pregnant women (p=0.040). Most
of the GBS isolates showed susceptibility to ampicillin (86.6%) and penicillin
(80.6%).
Conclusions: This study showed that the prevalence of GBS colonization
among pregnant women in OAUTHC is high with is attendant risk factors;
although the public health consequences of these carriage findings are unclear
at present. Further larger study of the interaction of HIV and GBS colonization,
risk of neonatal disease and treatment protocols is advocated.

PREVALENCE AND RISK FACTORS ASSOCIATED WITH GROUP B STREPTOCOCCUS COLONIZATION AMONG HIV-POSITIVE PREGNANT WOMEN IN ILE-IFE