Comparative Molecular and Microbiologic Diagnosis of Vaginal Colonization by Group B Streptococcus in Pregnant Women during Labor

Objective(s) Rapid tests for detection of Streptococcus agalactiae or Group B Streptococci (GBS) at the onset of labor are needed to permit early intrapartum antibiotic prophylaxis. This study aimed to evaluate the PCR assays targeting the ۱۶S ribosomal RNA gene (۱۶S rDNA) for detection of the GBS in comparison with a specific culture method. Materials and Methods Two swabs were used to obtain vaginal specimens from the ۳۳۰ pregnant women attended delivery room at Hedayat hospital, Tehran, Iran. One swab was analyzed by direct plating onto selective GBS agar medium (ISLAM) and the other swab was used for a PCR assay, which amplified the ۱۶S rDNA of S. agalactiae. Comparative study between the selective culture and the PCR assay was done among the ۳۳۰ tested women. Results The GBS colonization rate based on the culture results was ۲۰.۶% (۶۸/۳۳۰). Both culture and PCR methods were positive for ۵۶ and negative for ۲۵۳ women. The culture method was positive and PCR was negative in ۱۲ women. The culture was negative and the PCR positive for ۹ women. Sensitivity of the PCR assay was ۸۲.۳% and specificity was ۹۶.۵%. The positive predictive value was ۸۶.۱۵% and negative predictive value was ۹۵.۴%. Conclusion ISLAM diagnostic procedure and PCR are rapid and reliable analyzing methods, which might be useful for accurate diagnosis of GBS colonization in pregnant women at the time of delivery.

کلیدواژه ها:

Early diagnosis ، PCR ، rRNA gene ، Streptococcus agalactiae ، Streptococcal infection