MICROBIAL INVASION OF THE AMNIOTIC CAVITY WITH UREAPLASMA-UREALYTICUMIS ASSOCIATED WITH A ROBUST HOST RESPONSE IN FETAL, AMNIOTIC, AND MATERNAL COMPARTMENTS

OBJECTIVE: Ureaplasma urealyticum is the microorganism most frequently isolated from the amniotic fluid of women with preterm labor and pret erm premature rupture of the membranes, yet the significance of amniot ic fluid infection exclusively caused by this microorganism is unclear . This study was conducted to examine the presence and intensity of th e inflammatory response in the fetal, amniotic, and maternal compartme nts in patients with preterm premature rupture of membranes and amniot ic fluid infection with U urealyticum. STUDY DESIGN: One hundred twent y patients with preterm premature rupture of the membranes who deliver ed preterm neonates (gestational age less than or equal to 36 weeks) w ithin 5 days of amniocentesis were included. Amniotic fluid was cultur ed for aerobic and anaerobic bacterias and mycoplasmas. The intensity of the inflammatory response was evaluated by amniotic fluid concentra tions of interleukin-6, tumor necrosis factor-alpha, interleukin-1 bet a, amniotic fluid white blood cell count, histologic chorioamnionitis, and interleukin-6 concentrations of umbilical cord plasma at birth. C ytokines were measured by sensitive and specific immunoassays. RESULTS : The prevalence of a positive amniotic fluid culture in which the onl y microbial isolate was U urealyticum was 21% (25/120) and that of pos itive cultures with other or mixed microorganisms was 9% (11/120). Int rauterine inflammatory response was significantly more intense in pati ents with positive amniotic fluid cultures limited to U urealyticum th an in those with a negative culture (median and range of amniotic flui d interleukin-6, 13.4 [0.7-115.2] ng/mL vs 0.9 [0.001-137.2] ng/mL; me dian and range of amniotic fluid tumor necrosis factor-a, 85.5 [0.9-16 00] pg/mL vs 2.4 [0-1142] pg/mL; median and range of amniotic fluid in terleukin-1 beta, 274.0 [0.3->80,000] pg/mL vs 3.4 [0-1449] pg/mL; med ian and range of amniotic fluid white blood cell count, 306 [0-19,764] cells/mm(3) vs 3 [0-7956] cells/mm3; median and range of cord interle ukin-6, 20.0 [2.3-1199.6] pg/mL vs 6.7 [0-5550] pg/mL; histologic chor ioamnionitis, 100% [22/22] vs 42% [30/72]; P < .01 for each) but was s imilar to values of patients with a positive amniotic fluid culture fo r other bacteria or mixed microorganisms. CONCLUSION: Patients with pr eterm premature rupture of membranes and microbial invasion of the amn iotic cavity with U urealyticum are associated with a robust host infl ammatory response in the fetal, amniotic, and maternal compartments.