Relationship between Antenatal Inflammation and Antenatal Infection Identified by Detection of Microbial Genes by Polymerase Chain Reaction

Abstract

Although antenatal infection is thought to play an important role in the pathogenesis of preterm labor and neonatal diseases, the exact mechanisms are largely unknown. We sought to clarify the relationship between antenatal infection and intrauterine and neonatal inflammation. Samples were obtained from 41 preterm infants of Ͻ33 wk gestation delivered to 36 mothers and analyzed for the presence of 16s ribosomal RNA (16s rRNA) genes using PCR and for the proinflammatory cytokines IL-6 and IL-8. In 16 (44%) mother-baby pairings, at least one sample was found to be positive for the presence of 16s rRNA genes. All but one of the positive samples were from mothers presenting with preterm prelabor rupture of membranes (pPROM) or in spontaneous idiopathic preterm labor. A strong association was found between the presence of 16s rRNA genes and chorioamnionitis and with funisitis. A marked increase in IL-6 and IL-8 was noted in all tissues positive for 16s rRNA genes, including placenta, fetal membranes, cord blood serum, and, where samples were available, in bronchoalveolar lavage fluid (BAL) and in amniotic fluid. Interestingly, gastric fluid was always positive for 16s rRNA genes if any other intrauterine or BAL sample was positive, suggesting that this sample may provide an alternative to amniotic fluid to identify antenatal infection. In conclusion, we have found that microbial genes are particularly prevalent in pPROM and spontaneous preterm labor groups and that their presence is strongly associated with a marked intrauterine inflammatory response. (Pediatr Res 57: 570-577, 2005) Abbreviations BAL, bronchoalveolar lavage CLD, chronic lung disease pPROM, preterm prelabor rupture of membranes rRNA, ribosomal RNA Preterm birth is the most common cause of neonatal death (1) and is associated with increased neonatal morbidity and childhood disability (2,3). Evidence from studies over the past two decades suggests that subclinical infection and inflammation of the amnion/chorion/decidua is implicated in the pathogenesis of pPROM and "spontaneous" preterm labor (4,5). More recently, intrauterine infection/inflammation has been associated with neonatal morbidity, including white matter cerebral lesions (6 -8) and CLD (9 -11). It has been estimated that as many as 40% of spontaneous preterm births may be attributed to antenatal infection (12). Furthermore, because many infections are subclinical and the women have often been treated with antibiotics, culture results may underestimate the "true" infection rates.Many studies have used amniotic fluid to identify antenatal intrauterine infection. The organisms commonly identified are vaginal commensals, suggesting ascending infection as a route of entry to the uterine cavity (13). Few studies have investigated other components of the uterine cavity to accurately identify the presence of infection and the nature of the relationship between such infection and inflammation. A clear association has been demonstrated between chorioamnionitis and intrauterine infection (14 -16). Oft...

Antenatal exposure to Ureaplasma species exacerbates bronchopulmonary dysplasia synergistically with subsequent prolonged mechanical ventilation in preterm infants

“…Because their study design allowed them to enroll more infants with a low risk for BPD, it is likely that it underestimated the impact of Ureaplasma species in increasing the risk of developing BPD. Miralles et al reported in their preliminary study that there was no association between the presence of microbes in neonatal and/or placental specimens and the development of BPD (15). This study has some similarities with ours, but differed in that it was designed to investigate the significance of microbes and not Ureaplasma species.…”

“…The bacterial 16S rRNA gene was detected using the methods described previously (15,16). Briefly, the extracted DNA was amplified by PCR using the FD1 (AGA GTT TGA TCC TGG CTC AG) and rP1 (ACG G(T/A/C)T ACC TTG TTA CGA CTT) primers.…”

“…In an experimental model, the intra-amniotic injection of lipopolysaccharide induced an inflammatory response that caused deterioration in the lung architecture of premature animals in combination with mechanical ventilation (MV) (14). Miralles et al reported that the presence of a bacterial 16S ribosomal RNA (rRNA) gene in gastric fluid at birth was correlated with antenatal infection, thereby indicating that gastric fluid samples obtained from neonates soon after birth could be used as an alternative specimen to reflect antenatal infection (15). We recently found that the presence of a bacterial 16S rRNA gene in gastric fluid in infants was associated with the development of severe BPD (16).…”

Molecular Study for Diagnosis of Ureaplasma parvum in Women with Recurrent Miscarriage

“…The proposed mechanisms for infectious causes of recurrent abortion include: direct infection of the uterus, fetus, or placenta; placental insufficiency; chronic endometritis or endocervicitis; amnionitis; infected intrauterine device [18,19]. Ureaplasma can be detected in the cervix or vagina of 40-80% of sexually mature asymptomatic women [20]. U. parvum may play important role in pregnancy and eliciting conditions associated with prematurity [21].…”

Maternal oral origin of Fusobacterium nucleatum in adverse pregnancy outcomes as determined using the 16S–23S rRNA gene intergenic transcribed spacer region

“…In terms of bacterial presence, the aspirates were shown to contain swallowed amniotic fluid, and thus have been proposed as an alternative to investigate fetal infections associated with adverse pregnancy outcomes (Miralles et al, 2005;GonzalesMarin et al, 2012). In our previous studies, F. nucleatum was observed at high levels in the neonatal samples (up to 2.32610 3 cells ml…”