Estimation of Group B Streptococcus Colonization in High-Risk Neonates by PCR and Standard Culture

طبقه‌بندی مطلب


Background: Group B Streptococcus (GBS) (Streptococcus agalactiae) is the leading cause of morbidity and mortality of newborn infants
considered as a leading factor causing septicemia after birth. The standard method for the diagnosis of GBS colonization is culture in a
selective broth medium. Today, it is accepted that PCR has a high sensitivity and specifically in diagnosis. Objectives: The goal of this study was to estimate the colonization of GBS in rectum of neonates of high-risk mother by culture and PCR
method. Patients and Methods: Samples were taken from rectal mucus of 154neonatesof high-risk mothers for GBS by swab. Samples were tested
by standard culture using Todd Hewitt broth and blood agar and also by PCR using primers specific for cfb gene. Results: Of 154neonates, Culture identified 17 (11%) neonates as colonized by GBS; and the PCR assay could identify 27 (17%) neonates with
positive results for GBS. Mothers age range was 17-40 years (mean = 26.1 ± 5.1). Maternal age was significantly lower in PCR positive group (P
= 0.038) and in culture positive group (P = 0.015). Using culture as the gold standard, sensitivity, NPV, specificity, and PPV of PCR were 100%,
100%, 92%, and 62%, respectively. The time required for PCR assay and culture were 2hours and 36hours, respectively. Conclusions: This study showed that incidence of GBS in Iranian high-risk neonates is high, so we strongly recommend screening of highrisk
neonates for detection of GBS.


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