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A combined enrichment/polymerase chain reaction based method for the routine screening of Streptococcus agalactiae in
F M Munari1, F De-Paris, G D Salton
1Laboratório de Biologia Molecular em Doenças Auto-imunes e Infecciosas, Centro de Pesquisas, Hospital de Clínicas de Porto Alegre , Porto Alegre, RS , Brasil.
Insights
A new PCR method accurately detects Group B Streptococcus (GBS) colonization in pregnant women. This advanced screening improves early detection, leading to better intrapartum antibiotic use and reduced newborn infections.
Area of Science:
- Microbiology
- Neonatal Health
- Clinical Diagnostics
Background:
- Group B Streptococcus (GBS) is a leading cause of severe neonatal infections.
- Universal rectovaginal GBS screening in pregnant women is recommended by the CDC.
- Accurate and sensitive detection methods are crucial for effective GBS prevention strategies.
Purpose of the Study:
- To compare the performance of a combined enrichment and PCR method targeting the atr gene against the standard culture method for GBS detection in pregnant women.
- To evaluate the sensitivity, specificity, and accuracy of the novel PCR method for GBS screening.
Main Methods:
- Rectovaginal swabs were collected from 89 pregnant women at ≥36 weeks gestation.
- Samples were analyzed using two methods: standard culture with selective enrichment broth and a combined enrichment/PCR method targeting the GBS atr gene.
Main Results:
- The combined enrichment/PCR method identified a higher prevalence of GBS colonization (35.9%) compared to the standard method (22.5%).
- The PCR methodology demonstrated high sensitivity, specificity, and accuracy in detecting GBS, including in cases of light colonization.
Conclusions:
- The combined enrichment broth followed by PCR targeting the atr gene is a highly effective diagnostic tool for GBS screening in pregnant women.
- This sensitive PCR method can improve GBS detection rates, leading to more accurate intrapartum antibiotic administration and reduced neonatal mortality and morbidity.
Abstract:
Group B Streptococcus (GBS) is the most common cause of life-threatening infection in neonates. Guidelines from CDC recommend universal screening of pregnant women for rectovaginal GBS colonization. The objective of this study was to compare the performance of a combined enrichment/PCR based method targeting the atr gene in relation to culture using enrichment with selective broth medium (standard method) to identify the presence of GBS in pregnant women. Rectovaginal GBS samples from women at ≥36 weeks of pregnancy were obtained with a swab and analyzed by the two methods. A total of 89 samples were evaluated. The prevalence of positive results for GBS detection was considerable higher when assessed by the combined enrichment/PCR method than with the standard method (35.9% versus 22.5%, respectively). The results demonstrated that the use of selective enrichment broth followed by PCR targeting the atr gene is a highly sensitive, specific and accurate test for GBS screening in pregnant women, allowing the detection of the bacteria even in lightly colonized patients. This PCR methodology may provide a useful diagnostic tool for GBS detection and contributes for a more accurate and effective intrapartum antibiotic and lower newborn mortality and morbidity.
