Bacteria in the amniotic fluid without inflammation: Early colonization vs. contamination

Eunjung Jung, Roberto Romero, Bo Hyun Yoon, Kevin R. Theis, Dereje W. Gudicha, Adi L. Tarca, Ramiro Diaz-Primera, Andrew D. Winters, Nardhy Gomez-Lopez, Lami Yeo, Chaur Dong Hsu

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Objectives: Intra-amniotic infection, defined by the presence of microorganisms in the amniotic cavity, is often accompanied by intra-amniotic inflammation. Occasionally, laboratories report the growth of bacteria or the presence of microbial nucleic acids in amniotic fluid in the absence of intra-amniotic inflammation. This study was conducted to determine the clinical significance of the presence of bacteria in amniotic fluid samples in the absence of intra-amniotic inflammation. Methods: A retrospective cross-sectional study included 360 patients with preterm labor and intact membranes who underwent transabdominal amniocentesis for evaluation of the microbial state of the amniotic cavity as well as intra-amniotic inflammation. Cultivation techniques were used to isolate microorganisms, and broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was utilized to detect the nucleic acids of bacteria, viruses, and fungi. Results: Patients whose amniotic fluid samples evinced microorganisms but did not indicate inflammation had a similar perinatal outcome to those without microorganisms or inflammation [amniocentesis-to-delivery interval (p=0.31), spontaneous preterm birth before 34 weeks (p=0.83), acute placental inflammatory lesions (p=1), and composite neonatal morbidity (p=0.8)]. Conclusions: The isolation of microorganisms from a sample of amniotic fluid in the absence of intra-amniotic inflammation is indicative of a benign condition, which most likely represents contamination of the specimen during the collection procedure or laboratory processing rather than early colonization or infection.

Original languageEnglish (US)
Pages (from-to)1103-1121
Number of pages19
JournalJournal of Perinatal Medicine
Issue number9
StatePublished - Nov 1 2021
Externally publishedYes


  • Acinetobacter
  • Propionibacterium acnes
  • acute funisitis
  • acute histologic chorioamnionitis
  • amniocentesis
  • interleukin-6
  • intra-amniotic infection
  • intra-amniotic inflammation
  • microbial burden
  • preterm labor with intact membranes

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Obstetrics and Gynecology


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