Comparison of polymerase chain reaction technique and culture method in antenatal group B streptococcus screening of pregnants

Purpose: The aim of this study; is to determine the colonization prevalence of Group B Streptococcus (GBS), which is one of the leading causes of neonatal infections, in pregnant women between 35-37 weeks gestation and to investigate the effectiveness of polymerase chain reaction (PCR) in general use by comparing PCR and culture methods used for the detection of GBS colonization in pregnant women Materials and Methods: Our prospective study was completed with 106 patients at 35-37 weeks gestation who applied to Akdeniz University Medical Faculty Hospital Clinic of Gynecology and Obstetrics between January 2022 and August 2022. Pregnant women who received antibiotic treatment in the last month were not included in the study. Samples were taken from the vagina and then the rectum with the same swab for culture and PCR testing. The prevalence was determined by evaluating the swab sample by culture and PCR methods. The sensitivity, specificity, negative and positive predictive value, and consistency of the PCR method were calculated. Ages, weights, heights, body mass indexes, gravidities, parities, number of abortions, previous cesarean and normal deliveries, weeks of gestation, presence of gestational hypertension, presence of gestational and type 2 diabetes, smoking and alcohol use, education levels, employment status of pregnant women were compared between culture positive and negative groups, PCR positive and negative groups, culture and PCR positive and culture and PCR negative groups, only PCR positive and both culture and PCR positive groups. If the PCR and/or culture of the samples showed positive results for GBS, the patient was informed about intrapartum antibiotic prophylaxis and was added to the examination notes in our hospital. Results: In the results of 106 patients at 35-37 weeks gestation who applied to Akdeniz University Medical Faculty Hospital Clinic of Gynecology and Obstetrics between January 2022 and August 2022, the mean age was 29.14±5.41, 62 gravidity 2.42±1.44, parity 1.08±1.12 found. The prevalence was determined as 10.4% by the culture method, which is the gold standard. A total of 23 (21.69%) pregnant women were found to be positive by PCR method. Compared with culture, the sensitivity of the PCR method was 100%, the specificity was 87%, the positive predictive value was 47%, the negative predictive value was 100%, and the consistency was 88%. As a result, PCR correctly detected 100% of positive patients and 87% of patients who were negative by culture. In our study, it was determined that the frequency of GBS positivity in culture and PCR increased statistically with the increase in body mass index, and the data are compatible with the literature. Conclusion: In this study, the PCR test for the detection of GBS is a rapid test with high sensitivity, specificity, and negative predictive value. PCR can be used effectively for GBS screening in pregnant women. Key Words: Antepartum, Culture, Group B Streptococcus, Intrapartum, PCR, Screening