Volume 70 Number 2 March 2003	back to contents

¹Fellow, ²Assistant Professor, and ⁴Professor, Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences; ³Professor, Department of Pediatrics; and ⁵Professor, Division of Infectious Diseases, Department of Medicine, Mount Sinai School of Medicine, New York, NY.

Initially presented as abstract/poster T559 at the 45th Annual Meeting of the Society for Gynecologic Investigation in Atlanta, Georgia, (Mar 11–14, 1998); published as an abstract only in the Journal of the Society for Gynecologic Investigation, Vol. 5, #1 (Supplement), Jan/Feb 1998. This manuscript was updated as of March 7, 2002.

Address all correspondence to Sreedhar Gaddipati, M.D., Department of Obstetrics, Gynecology, and Reproductive Sciences, Box 1171, Mount Sinai School of Medicine, 100 East 100th Street, New York, NY 10029; email:sreegaddipati@mssm.edu

ABSTRACT

OBJECTIVE: To demonstrate the effects of meconium on growth of bacterial pathogens, which are common causes of intra-amniotic infection and neonatal sepsis.

METHODS: Meconium collected from 9 healthy neonates was suspended as a 20% solution using sterile saline. In experiment 1, separate test tubes of meconium solution and sterile saline (the control) were individually inoculated with 106 colony-forming units of a single species of the following test pathogens: Escherichia coli, Enterococcus faecalis, Group B Streptococcus, Staphylococcus aureus, Pseudomonas aeruginosa, and Listeria monocytogenes. After incubation at 37?C for 24 hours, 1 µL each of the bacterial-meconium and bacterial-saline solutions was inoculated onto 5% sheep blood agar. After 24 hours of incubation, the number of developing colonies was counted. In experiment 2, equal volumes of meconium and saline solutions were inoculated with 105 colony-forming units of either E. coli or Group B Streptococcus. At intervals of 6, 9, and 24 hours post-incubation, 1 µL each of the bacterial-meconium and bacterial-saline solutions was inoculated onto 5% sheep blood agar plates, and colonies were counted after overnight incubation.

RESULTS: In the first experiment, 24 hours of incubation resulted in bacterial amplification in the meconium solution from an initial inoculum of 106 colony-forming units/mL to 109 colony-forming units/mL. In contrast, the same inoculation of saline solution (control) showed no increase in colony counts over the same time interval. For E. coli and Group B Streptococcus in experiment 2, growth enhancement in meconium was seen as early as 6 hours, as colony counts of a test species increased from 105 colony-forming units/mL to 109–1010 colony-forming units/mL.

CONCLUSION: Enhanced growth of perinatal pathogens in meconium was constantly observed, and can occur as early as 6 hours after bacterial interaction of meconium.

KEYWORDS

Meconium, chorioamnionitis, intra-amniotic infection, bacterial pathogens, neonatal sepsis, amnioinfusion, Escherichia coli, group B Streptococcus.

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