Group B streptococcal carriage, serotype distribution and antibiotic susceptibilities in pregnant women at the time of delivery in a refugee population on the Thai-Myanmar border

Abstract

BackgroundGroup B Streptococcus (GBS) is the leading cause of neonatal sepsis in the developed world. Little is known about its epidemiology in the developing world, where the majority of deaths from neonatal infections occur. Maternal carriage of GBS is a prerequisite for the development of early onset GBS neonatal sepsis but there is a paucity of carriage data published from the developing world, in particular South East Asia.MethodsWe undertook a cross sectional study over a 13 month period in a remote South East Asian setting on the Thai-Myanmar border. During labour, 549 mothers had a combined vaginal rectal swab taken for GBS culture. All swabs underwent both conventional culture as well as PCR for GBS detection. Cultured GBS isolates were serotyped by latex agglutination, those that were negative or had a weak positive reaction and those that were PCR positive but culture negative were additionally tested using multiplex PCR based on the detection of GBS capsular polysaccharide genes.ResultsThe GBS carriage rate was 12.0% (95% CI: 9.4-15.0), with 8.6% positive by both culture and PCR and an additional 3.5% positive by PCR alone. Serotypes, Ia, Ib, II, III, IV, V, VI and VII were identified, with II the predominant serotype. All GBS isolates were susceptible to penicillin, ceftriaxone and vancomycin and 43/47 (91.5%) were susceptible to erythromycin and clindamycin.ConclusionsGBS carriage is not uncommon in pregnant women living on the Thai-Myanmar border with a large range of serotypes represented.

Serotype Distribution, Population Structure, and Antimicrobial Resistance of Group B Streptococcus Strains Recovered from Colonized Pregnant Women

“…GBS strains colonize the gastrointestinal and genital tracts of 10 to 30% of healthy humans (13)(14)(15)(16). In many countries, including Canada and the United States, the screening of pregnant women for GBS colonization at 35 to 37 weeks gestation and intrapartum antibiotic prophylaxis (IAP) for colonized women have substantially reduced the burden of EOD (17,18).…”

Antibody-Mediated Complement C3b/iC3b Binding to Group B Streptococcus in Paired Mother and Baby Serum Samples in a Refugee Population on the Thailand-Myanmar Border

“…The study population was described by Turner et al (18). In brief, mothers enrolled in the study were residents of the Maela refugee camp located on the Thailand-Myanmar border.…”

“…Clinical data were obtained from the mothers enrolled in the study and the neonates (18). These data included GBS carriage status of the mother, ethnic group, past obstetric history, recent antibiotic exposure, and any complications occurring during birth.…”

“…Of the sera collected, a total of 543 serum samples from mothers and 525 serum samples from umbilical cords were available for this study. Data were also collected on the GBS carriage status of the mother at the time of birth, which was assessed by culture of vaginal and rectal swabs (18 GBS isolates used in the complement deposition assay were grown in Todd-Hewitt broth at 37°C with shaking (200 rpm). Once an optical density at 600 nm (OD 600 ) of 1.0 was reached, cultures were centrifuged at 3,060 ϫ g for 5 min to pellet the bacteria.…”

“…We evaluated the antibody-mediated deposition of complement C3b/iC3b onto bacteria representing five GBS serotypes with 534 serum sample pairs from mother and cord blood samples from a population located on the Thailand-Myanmar border (18). This was evaluated using flow cytometry, and as opsonization of bacteria by antibody and complement is required for uptake and killing by phagocytic cells, this may be a surrogate for opsonophagocytosis.…”