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Updated: May 13, 2025
Detection of Bacteria Using Fluorogenic DNAzymes
Published on: May 28, 2012
An improved procedure based on fluorescence immunochromatography for rapid detection of group B streptococcus from
Xiaoli Chen1, Sijia Cao1, Yan Ni2,3,4
1Department of Laboratory Medicine, Fujian Key Clinical Specialty of Laboratory Medicine, Department of Gynecology and Obstetrics, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China.
Insights
A new rapid test detects Group B Streptococcus (GBS) in under 15 minutes. This fluorescence immunochromatographic test (FICT) offers a faster alternative for GBS screening, improving timely treatment for pregnant individuals.
Area of Science:
- Microbiology
- Medical Diagnostics
- Perinatal Health
Background:
- Group B Streptococcus (GBS) poses significant risks for perinatal infectious morbidity and mortality.
- Current culture-based GBS screening methods require 24-72 hours, delaying intrapartum antibiotic prophylaxis (IAP).
- There is a critical need for rapid GBS detection strategies to improve neonatal outcomes.
Purpose of the Study:
- To develop and evaluate a rapid fluorescence immunochromatographic test (FICT) for GBS detection.
- To assess the efficacy of FICT with and without enrichment culture compared to established methods.
- To establish a faster screening protocol for GBS to guide IAP administration.
Main Methods:
- Developed a novel fluorescence immunochromatographic test (FICT) strip for rapid GBS identification.
- Evaluated FICT's detection limit, analytical sensitivity, and cross-reactivity.
- Compared FICT performance on vaginal-rectal swabs (direct vs. 4-hour enrichment) against qPCR and GIC assays.
Main Results:
- The FICT strip detects GBS within 15 minutes with a detection limit of 10^4-10^6 CFU/mL.
- Sensitivity increased from 34.48% (direct samples) to 90.91% with a 4-hour LIM broth enrichment.
- Specificity remained high at 95.35% with enrichment, showing no false positives in cross-reactivity tests.
Conclusions:
- A rapid GBS detection strategy using FICT combined with short-term LIM broth enrichment is effective.
- This improved procedure significantly enhances GBS screening efficiency.
- The rapid FICT method is poised to guide timely IAP administration, especially in obstetric emergencies.
Background:
Group B streptococcus (GBS) is a major cause of perinatal infectious morbidity and mortality. Although intrapartum antibiotic prophylaxis (IAP) administration for ≥ 4 h is effective in preventing neonatal early-onset GBS diseases, the conventional culture-based approach to identify GBS often takes 24-72 h. This study aimed to find a strategy to improve the efficacy of GBS screening.
Methods:
We developed a fluorescence immunochromatographic test (FICT) strip to detect GBS within 15 min. The detection limit, analytical sensitivity, cross-reactivity and performance of the strip were evaluated. The performance of the strip on vaginal-rectal swabs with or without enrichment culture was compared with real-time quantitative polymerase chain reaction (qPCR) and colloidal gold immunochromatography (GIC) assay with conventional enrichment culture method as the reference method.
Results:
The detection limit of the strip ranges from 104 CFU/mL to 106 CFU/mL. Additionally, the strip has detected all of the positives from 48 h enrichment cultures (175/175). and 30 GBS strains representing different serotypes at cell density of 106 CFU/mL yielded positive results. Cross-reactivity test indicated no false-positive results. The sensitivity on direct samples was 34.48%, while 4 h enrichment in LIM broth prior to FICT has greatly increased the sensitivity to 90.91% with the specificity being 95.35%.
Conclusions:
The improved procedure based on the FICT for GBS detection from short-term LIM broth cultures was expected to guide IAP administration in obstetrical emergencies.
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