Isolation of Ureaplasma urealyticum from amniotic fluid by polymerase chain reaction and intraamniotic inflammation and adverse outcome in preterm premature rupture of membranes

Lee, Hee Sun; Yoon, Bo Hyun

Abstract

OBJECTIVE
The aim of this study was 1) to determine the clinical significance of isolation of Ureaplasma urealyticum (U urealyticum) by polymerase chain reaction (PCR) in amniotic fluid and 2) to identify the association of positive result of PCR for U urealyticum with maternal and intraamniotic inflammatory response in patients with preterm premature rupture of membrane (PROM).
METHODS
Amniocentesis was done in 131 patients with preterm PROM during the period from January, 1994 to January, 1998. Amniotic fluid was cultured for bacteria and mycoplasmas. PCR with primer for U urealyticum was performed. Patients were divided three groups according to the results of amniotic fluid culture and PCR for U urealyticum: those with a negative amniotic fluid culture and negative PCR (group 1, n=84), those with a negative amniotic fluid culture but positive PCR (group 2, n=12) and those with a positive amniotic fluid culture (group 3, n=35).
RESULTS
1) U urealyticum was isolated in 18.3% (24/131) by conventional culture method and in 26.7% (35/131) by PCR. 2) Patients with a negative amniotic fluid culture but positive PCR for U urealyticum (group 2) had significantly higher amniotic fluid white blood cell (WBC) count and higher rate of funisitis than those with a negative amniotic fluid culture and negative PCR (group 1) (amniotic fluid WBC: median 169 [1-2,295] cells/mm3 vs median 1 [0-7,956] cells/mm3 p<.001; funisitis: 71.4%[5/7] vs 24.6%[15/61], p=0.02). 3) Patients with a negative culture but positive PCR for U urealyticum (group 2) had higher rate of congenital infectious morbidity and bronchopulmonary dysplasia in their babies than those with a negative culture and negative PCR (group 1) (congenital infectious morbidity: 36.4% [4/11] vs 11.4% [9/79]; bronchopulmonary dysplasia: 27.3% [3/11] vs 2.5%[2/79], p<0.05 for each). 4) No significant differences in perinatal outcome were observed between patients with a negative culture but positive PCR (group 2) and those with a positive amniotic fluid culture (group 3).
CONCLUSION
Isolation of U urealyticum by PCR in amniotic fluid is associated with an intense intra-amniotic inflammatory response and adverse perinatal outcomes in patients with preterm premature rupture of membranes.