Background Intra-amniotic infection has long been recognized as the leading cause of preterm delivery. Microbial culture is the gold standard for the detection of intra-amniotic infection, but several days are required, and many bacterial species in the amniotic fluid are difficult to cultivate. Methods We developed a novel nested-PCR-based assay for detecting Mycoplasma, Ureaplasma, other bacteria and fungi in amniotic fluid samples within three hours of sample collection. To detect prokaryotes, eukaryote-made thermostable DNA polymerase, which is free from bacterial DNA contamination, is used in combination with bacterial universal primers. In contrast, to detect eukaryotes, conventional bacterially-made thermostable DNA polymerase is used in combination with fungal universal primers. To assess the validity of the PCR assay, we compared the PCR and conventional culture results using 300 amniotic fluid samples. Results Based on the detection level (positive and negative), 93.3% (280/300) of Mycoplasma, 94.3% (283/300) of Ureaplasma, 89.3% (268/300) of other bacteria and 99.7% (299/300) of fungi matched the culture results. Meanwhile, concerning the detection of bacteria other than Mycoplasma and Ureaplasma, 228 samples were negative according to the PCR method, 98.2% (224/228) of which were also negative based on the culture method. Employing the devised primer sets, mixed amniotic fluid infections of Mycoplasma, Ureaplasma and/or other bacteria could be clearly distinguished. In addition, we also attempted to compare the relative abundance in 28 amniotic fluid samples with mixed infection, and judged dominance by comparing the Ct values of quantitative real-time PCR. Conclusions We developed a novel PCR assay for the rapid detection of Mycoplasma, Ureaplasma, other bacteria and fungi in amniotic fluid samples. This assay can also be applied to accurately diagnose the absence of bacteria in samples. We believe that this assay will positively contribute to the treatment of intra-amniotic infection and the prevention of preterm delivery.
Eukaryote-Made Thermostable DNA Polymerase Enables Rapid PCR-Based Detection of Mycoplasma, Ureaplasma and Other Bacteria in the Amniotic Fluid of Preterm Labor Cases
Tomohiro Ueno,H. Niimi,N. Yoneda,S. Yoneda,M. Mori,H. Tabata,H. Minami,S. Saito,I. Kitajima
Published 2015 in PLoS ONE
ABSTRACT
PUBLICATION RECORD
- Publication year
2015
- Venue
PLoS ONE
- Publication date
2015-06-04
- Fields of study
Biology, Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- amniotic fluid samples
The clinical specimen collected from the amniotic cavity and tested for microbial DNA in this work.
Aliases: amniotic fluid
- bacterial universal primers
A primer set used in the assay to amplify bacterial targets from amniotic fluid DNA.
Aliases: universal bacterial primers, bacterial primer set
- conventional culture
A standard cultivation-based laboratory test used as the comparison reference for PCR results in the sample set.
Aliases: microbial culture, culture method
- ct values
The PCR threshold-cycle measurements used as a proxy for relative target abundance in mixed infections.
Aliases: cycle threshold values, Cq values
- eukaryote-made thermostable dna polymerase
A thermostable DNA polymerase produced in eukaryotic cells and used here because it is described as free from bacterial DNA contamination.
Aliases: eukaryotic-made thermostable DNA polymerase, eukaryote-made polymerase
- fungal universal primers
A primer set used in the assay to amplify fungal targets from amniotic fluid DNA.
Aliases: universal fungal primers, fungal primer set
- nested-pcr-based assay
A nested PCR workflow designed in this paper to detect microbial DNA from amniotic fluid using separate primer and polymerase combinations for different target groups.
Aliases: nested PCR-based assay, nested PCR assay
- quantitative real-time pcr
A PCR measurement approach used here to compare amplification signals across mixed-infection samples.
Aliases: qPCR, real-time PCR
REFERENCES
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