Detection of bacteria in placental tissues obtained from extremely low gestational age neonates

Am J Obstet Gynecol. 2008 Jan;198(1):110.e1-7. doi: 10.1016/j.ajog.2007.05.044.


Objective: The objective of the study was to quantify and identify aerobic and anaerobic bacteria as well as Mycoplasma and Ureaplasma in the chorionic parenchyma.

Study design: A sample of the chorionic parenchyma from neonates delivered between 23-27 completed weeks was cultured and tested by polymerase chain reaction (PCR) methods using universal bacterial primers for the presence of bacteria and mycoplasmas.

Results: The culture positive rate was higher for vaginal deliveries (333/489; 68%) than for cesarean sections (363/876; 41%). Thirty percent of all culture-positive samples had only aerobic bacteria, 21% of the samples had only anaerobic bacteria, and 9% of the samples had only Mycoplasma/Ureaplasma. The mean concentration of Mycoplasma/Ureaplasma (4.00 +/- 1.11 log10 CFU/g) was significantly higher (P < .001) than the total count of either aerobes (3.24 +/- 1.12 log10 CFU/g) or anaerobes (2.89 +/- 0.99 log10 CFU/g). Staphylococcus sp. and Corynebacterium sp. as well as organisms associated with bacterial vaginosis were the most frequently recovered. A PCR product was not detected from either randomly selected or known culture-positive samples.

Conclusion: Approximately half of second-trimester placentas harbor organisms within the chorionic plate. The chorion parenchyma appears to harbor constituents that prevent the identification of bacterial deoxyribonucleic acid by PCR methods.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Bacteria, Aerobic / isolation & purification
  • Bacteria, Anaerobic / isolation & purification
  • Cohort Studies
  • Colony Count, Microbial
  • DNA, Bacterial / analysis
  • Female
  • Humans
  • Infant, Newborn
  • Infant, Premature*
  • Infant, Very Low Birth Weight*
  • Middle Aged
  • Mycoplasma / isolation & purification*
  • Placenta / microbiology*
  • Polymerase Chain Reaction
  • Pregnancy
  • Pregnancy Trimester, Second
  • Sampling Studies
  • Sensitivity and Specificity
  • Ureaplasma urealyticum / isolation & purification*


  • DNA, Bacterial