Date Published: September 28, 2018
Publisher: Public Library of Science
Author(s): Kristina Roloff, Gohar Stepanyan, Guillermo Valenzuela, Jose Melo-Cristino.
To determine the prevalence and serotype of oropharyngeal Group B Streptococcal (GBS) colonization of mothers, their family & friends, and health care providers of recently delivered patients as a potential reservoir of neonatal exposure to GBS.
This is a prospective, single-center observational study of: (1) patients, (2) their family and friends, and (3) health care providers all of whom may come in close contact with neonates. Oropharyngeal GBS colonization and serotype was determined.
Three hundred and seventy three samples were collected. The prevalence of oropharyngeal GBS colonization among all study participants was 23.1% (N = 86). The most commonly found serotypes were 1b (12.8%, N = 11), III (27.9%, N = 24), and V (17.4%, N = 15). The prevalence of oropharyngeal GBS colonization among mothers was 26% (N = 31/121), 22% (N = 39/178) in family and friends, and 21.6% (N = 16/74) in health care providers.
Group B Streptococcus colonizes the oropharynx in 1 in 5 mothers, family and friends, and health care providers who come in direct contact with neonates. Further research is needed to determine if this potential reservoir for neonatal exposure could lead to early or late onset neonatal GBS colonization or infection.
Implementation of intrapartum antibiotic prophylaxis has significantly decreased the incidence of early onset neonatal Group B Streptococcal (GBS) sepsis in the United States [1–6]. However, the rates of late onset neonatal sepsis have remained largely unchanged and are now comparable to those of early onset disease . The equivalent rate of early and late onset disease seen after intrapartum prophylaxis to rectovaginal GBS carriers suggests an alternative reservoir of GBS that could account for the plateaued rate of early onset, and persistent rate of late onset infections. Case reports and small case series suggest breast milk is a source of exposure in late onset neonatal GBS infection [8–11]. However, only 6% of neonates with GBS infection have mothers with infected breastmilk . Horizontal transmission within neonatal intensive care units has also been described [13–15]. This suggests an alternative reservoir of GBS may contribute to neonatal GBS infection.
This is a prospective single-center, cross-sectional, observational study of the prevalence of GBS oropharyngeal colonization of three groups known to come into contact with neonates: (1) mothers, (2) their family and friends, and (3) health care providers.
Three hundred and seventy three samples were collected. Thirty-two percent (N = 121) of samples were obtained from mothers, 48% (N = 178) from family and friends, and 20% (N = 74) from health care providers. Overall, 23.1% (N = 86) cultures demonstrated GBS growth. The most commonly found serotypes were 1b (12.8%, N = 11), III (27.9%, N = 24), and V (17.4%, N = 15). Table 1 shows the serotype distribution of oropharyngeal GBS positive cultures in the three study groups. There were no known cases of early or late onset GBS sepsis among infants of mothers included in this study.
Oropharyngeal GBS colonization may be an important reservoir contributing to late onset neonatal GBS colonization or infection. Contact with the neonate (e.g. kissing the baby, leaning close to provide resuscitative measures, etc.…) may directly expose the neonate to GBS. Here, we have shown that more than 1 in 5 mothers, family members and friends who visit the neonate, and health care providers are oropharyngeal GBS carriers.
The incidence of early onset neonatal GBS infection has declined since the introduction of screening and treatment guidelines [1–6]. Despite these efforts, early onset neonatal infection has plateaued and late onset neonatal GBS infection rate has remained largely unchanged [6,7]. In this study, we believe we may have identified an important reservoir of neonatal GBS exposure: asymptomatic oropharyngeal colonization of mothers, their family and friends, and health care providers.