Intra-amniotic infection with genital mycoplasmas is characterized by an intense inflammatory response in the amniotic cavity and in the maternal compartment

Abstract

OBJECTIVE: Genital mycoplasmas are the most frequent organisms responsible for intra-amniotic infection. Yet, they are considered to be less virulent than other bacteria. The purpose of this study was to compare the intensity of intra-amniotic and maternal inflammatory responses between cases of intra-amniotic infection (IAI) caused by genital mycoplasmas and IAI caused by other microorganisms. STUDY DESIGN: We studied the magnitude of the inflammatory response in 93 patients with preterm PROM and a positive amniotic fluid (AF) culture for microorganisms. Patients were divided into 2 groups: 1) those with genital mycoplasmas in the AF (ureaplasmas and/or Mycoplasma hominis, n 62); and 2) cases with other microorganisms (n 31). Patients with mixed infections (genital mycoplasmas and other microorganisms) were excluded. The intensity of intraamniotic inflammatory response was determined by the AF white blood cell (WBC) count, and that of the maternal inflammatory response was assessed by the concentration of C-reactive protein (CRP) and WBC count in maternal blood at the time of amniocentesis. RESULTS: 1) The median AF WBC count, maternal blood WBC count and plasma CRP concentration were significantly higher in cases with IAI caused by genital mycoplasmas than in those with IAI with other microorganisms (p 0.05 for each); and 2) there were no significant differences in maternal age, parity, gestational age at amniocentesis, rupture of membranes-to-amniocentesis interval, and use of corticosteroids and antibiotics before amniocentesis between the two groups. CONCLUSION: 1) Intra-amniotic infection caused by genital mycoplasmas results in a more intense inflammatory response in the amniotic cavity as well as in the maternal compartment than those caused by other microorganisms; 2) it is possible that chronicity can account for the more severe magnitude of intra-amniotic and maternal inflammatory response reported herein.