Negative Amniotic Fluid Culture Research Articles

EP459: Rare clinical gene variant of SOX9: Acampomelic campomelic dysplasia

eP459: Rare clinical gene variant of SOX9: Acampomelic campomelic dysplasia

The frequency and clinical significance of intra-amniotic inflammation in twin pregnancies with preterm labor and intact membranes

Objective: The objective of this study is to evaluate the frequency and clinical significance of intra-amniotic inflammation in twin pregnancies with preterm labor and intact membranes.Study design: Amniotic fluid (AF) was retrieved from both sacs in 90 twin gestations with preterm labor and intact membranes (gestational age between 20 and 34 6/7 weeks). Preterm labor was defined as the presence of painful regular uterine contractions, with a frequency of at least 2 every 10 min, requiring hospitalization. Fluid was cultured and assayed for matrix metalloproteinase-8. Intra-amniotic inflammation was defined as an AF matrix metalloproteinase-8 concentration >23 ng/mL.Results: The prevalence of intra-amniotic inflammation for at least 1 amniotic sac was 39% (35/90), while that of proven intra-amniotic infection for at least one amniotic sac was 10% (9/90). Intra-amniotic inflammation without proven microbial invasion of the amniotic cavity was found in 29% (26/90) of the cases. Intra-amniotic inflammation was present in both amniotic sacs for 22 cases, in the presenting amniotic sac for 12 cases, and in the non-presenting amniotic sac for one case. Women with intra-amniotic inflammation observed in at least one amniotic sac and a negative AF culture for microorganisms had a significantly higher rate of adverse pregnancy outcome than those with a negative AF culture and without intra-amniotic inflammation (lower gestational age at birth, shorter amniocentesis-to-delivery interval, and significant neonatal morbidity). Importantly, there was no significant difference in pregnancy outcome between women with intra-amniotic inflammation and a negative AF culture and those with a positive AF culture.Conclusion: Intra-amniotic inflammation is present in 39% of twin pregnancies with preterm labor and intact membranes and is a risk factor for impending preterm delivery and adverse outcome, regardless of the presence or absence of bacteria detected using cultivation techniques.

Clinical significance of histologic chorioamnionitis with a negative amniotic fluid culture in patients with preterm labor and premature membrane rupture.

ObjectiveTo evaluate the effect of histological chorioamnionitis (HCA) with a negative amniotic fluid (AF) culture on adverse pregnancy and neonatal outcomes and inflammatory status in the AF compartment in women with preterm labor or preterm premature rupture of membranes (PPROM).MethodsThis is a retrospective cohort study of 153 women diagnosed as having a preterm labor or PPROM (20–34 weeks) who delivered singleton gestations within 48 hours of amniocentesis. AF obtained through amniocentesis was cultured, and interleukin (IL)-6, IL-8, and metalloproteinase-9 (MMP-9) levels were determined. The placentas were examined histologically.ResultsThe prevalence of HCA with negative AF culture was 23.5% (36/153). The women with HCA but with a negative AF culture (group 2) and those with a positive AF culture (group 3) had a significantly lower mean gestational age at amniocentesis and delivery than those with a negative AF culture and without HCA (group 1). Women in group 3 had the highest levels of AF IL-6, IL-8, and MMP-9, followed by those in group 2, and those in group 1. Composite neonatal morbidity was significantly higher in groups 2 and 3 than in group 1, but this was no longer significant after adjusting for confounders caused mainly by the impact of gestational age.DiscussionIn the women who delivered preterm neonates, HCA with a negative AF culture was associated with increased risks of preterm birth, intense intra-amniotic inflammatory response, and prematurity-associated composite neonatal morbidity, and its risks are similar to the risk posed by positive AF culture.

Twenty-four percent of patients with clinical chorioamnionitis in preterm gestations have no evidence of either culture-proven intraamniotic infection or intraamniotic inflammation

Recent studies on clinical chorioamnionitis at term suggest that some patients with this diagnosis have neither intraamniotic infection nor intraamniotic inflammation. A false-positive diagnosis of clinical chorioamnionitis in preterm gestation may lead to unwarranted preterm delivery. We sought to determine the frequency of intraamniotic inflammation and microbiologically proven amniotic fluid infection in patients with preterm clinical chorioamnionitis. Amniocentesis was performed in singleton pregnant women with preterm clinical chorioamnionitis (<36 weeks of gestation). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8 concentration. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture; intraamniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration of >23 ng/mL. Nonparametric and survival techniques were used for analysis. Among patients with preterm clinical chorioamnionitis, 24% (12/50) had neither microbiologic evidence of intraamniotic infection nor intraamniotic inflammation. Microbial invasion of the amniotic cavity was present in 34% (18/53) and intraamniotic inflammation in 76% (38/50) of patients. The most common microorganisms isolated from the amniotic cavity were the Ureaplasma species. Finally, patients without microbial invasion of the amniotic cavity or intraamniotic inflammation had significantly lower rates of adverse outcomes (including lower gestational age at delivery, a shorter amniocentesis-to-delivery interval, acute histologic chorioamnionitis, acute funisitis, and significant neonatal morbidity) than those with microbial invasion of the amniotic cavity and/or intraamniotic inflammation. Among patients with preterm clinical chorioamnionitis, 24% had no evidence of either intraamniotic infection or intraamniotic inflammation, and 66% had negative amniotic fluid cultures, using standard microbiologic techniques. These observations call for a reexamination of the criteria used to diagnose preterm clinical chorioamnionitis.

Timing of Histologic Progression from Chorio-Deciduitis to Chorio-Deciduo-Amnionitis in the Setting of Preterm Labor and Preterm Premature Rupture of Membranes with Sterile Amniotic Fluid.

BackgroundHistologic chorio-deciduitis and chorio-deciduo-amnionitis (amnionitis) in extra-placental membranes are known to represent the early and advanced stages of ascending intra-uterine infection. However, there are no data in humans about the time required for chorio-deciduitis to develop and for chorio-deciduitis without amnionitis to progress to chorio-deciduitis with amnionitis, and the effect of prolongation of pregnancy on the development of chorio-deciduitis and amnionitis in patients with preterm labor and intact membranes (PTL) and preterm premature rupture of membranes (preterm-PROM). We examined these issues in this study.MethodsThe study population consisted of 289 women who delivered preterm (133 cases with PTL, and 156 cases with preterm-PROM) and who had sterile amniotic fluid (AF) defined as a negative AF culture and the absence of inflammation as evidenced by a matrix metalloproteinase-8 (MMP-8) level <23 ng/ml. We examined the association between amniocentesis-to-delivery interval and inflammatory status in the extra-placental membranes (i.e., inflammation-free extra-placental membranes, choroi-deciduitis only, and chorio-deciduitis with amnionitis) in patients with PTL and preterm-PROM.ResultsAmniocentesis-to-delivery interval was longer in cases of chorio-deciduitis with amnionitis than in cases of chorio-deciduitis only in both PTL (median [interquartile-range (IQR)]; 645.4 [319.5] vs. 113.9 [526.9] hours; P = 0.005) and preterm-PROM (131.3 [135.4] vs. 95.2 [140.5] hours; P<0.05). Amniocentesis-to-delivery interval was an independent predictor of the development of both chorio-deciduitis and amnionitis after correction for confounding variables such as gestational age at delivery in the setting of PTL, but not preterm-PROM.ConclusionsThese data confirm for the first time that, in cases of both PTL and preterm-PROM with sterile AF, more time is required to develop chorio-deciduitis with amnionitis than chorio-deciduitis alone in extra-placental membranes. Moreover, prolongation of pregnancy is an independent predictor of the development of both chorio-deciduitis and amnionitis in cases of PTL with sterile AF.

Prevalence and clinical significance of sterile intra-amniotic inflammation in patients with preterm labor and intact membranes.

Inflammation and infection play a major role in preterm birth. The purpose of this study was to (i) determine the prevalence and clinical significance of sterile intra-amniotic inflammation and (ii) examine the relationship between amniotic fluid (AF) concentrations of high mobility group box-1 (HMGB1) and the interval from amniocentesis to delivery in patients with sterile intra-amniotic inflammation. AF samples obtained from 135 women with preterm labor and intact membranes were analyzed using cultivation techniques as well as broad-range PCR and mass spectrometry (PCR/ESI-MS). Sterile intra-amniotic inflammation was defined when patients with negative AF cultures and without evidence of microbial footprints had intra-amniotic inflammation (AF interleukin-6 ≥ 2.6 ng/mL). (i) The frequency of sterile intra-amniotic inflammation was significantly greater than that of microbial-associated intra-amniotic inflammation [26% (35/135) versus 11% (15/135); (P = 0.005)], (ii) patients with sterile intra-amniotic inflammation delivered at comparable gestational ages had similar rates of acute placental inflammation and adverse neonatal outcomes as patients with microbial-associated intra-amniotic inflammation, and (iii) patients with sterile intra-amniotic inflammation and high AF concentrations of HMGB1 (≥8.55 ng/mL) delivered earlier than those with low AF concentrations of HMGB1 (P = 0.02). (i) Sterile intra-amniotic inflammation is more frequent than microbial-associated intra-amniotic inflammation, and (ii) we propose that danger signals participate in sterile intra-amniotic inflammation in the setting of preterm labor.

Amniotic fluid inflammation with negative culture and outcome after cervical cerclage

Objective: To determine whether amniotic fluid (AF) inflammation, in the absence of infection, is associated with adverse pregnancy outcomes in nonelective cervical cerclage patients. Methods: A retrospective case-control study was carried out. The patient population included 82 singleton pregnancies with negative AF cultures. The variables used to define AF inflammation were white blood cell count (WBC) >50 cell/mm3, glucose <14 mg/dl or interleukin-6 (IL-6) >11.3 ng/ml. The study group consisted of cases with intra-amniotic inflammation. Sub-analysis was performed for the groups in which IL-6 concentrations were measured. Adverse outcomes were evaluated with variables such as gestational age at delivery, interval from cerclage to delivery, chorioamnionitis and cumulative neonatal morbidity. Results: Elevated AF WBC was correlated with severe and extreme preterm delivery (p < 0.05). Decreased AF glucose was associated with histological chorioamnionitis and a decreased cerclage to delivery interval (p < 0.05). Elevated AF IL-6 correlated significantly with decreased gestational age at delivery (p < 0.012) and decreased cerclage to delivery interval (p < 0.001). Elevated IL-6 concentrations were associated with severe, extreme preterm delivery (p < 0.001) and neonatal death (p < 0.001). Conclusion: Elevated AF IL-6, elevated WBC and low AF glucose, in the absence of a positive AF culture, are significantly associated with adverse pregnancy outcomes in patients undergoing nonelective cerclage.

Patients with an asymptomatic short cervix (≤15 mm) have a high rate of subclinical intraamniotic inflammation: implications for patient counseling

The objective of the study was to determine the frequency and clinical significance of intraamniotic inflammation in asymptomatic women with a sonographic short cervix (SCX) in the midtrimester. This cohort study included 47 asymptomatic women (14-24 weeks) with an SCX (<or=15 mm) who underwent amniocentesis. Women with multiple gestation, cerclage, or cervical dilatation greater than 2 cm were excluded. Intraamniotic inflammation was defined as an elevated amniotic fluid (AF) matrix metalloproteinase-8 concentration (>23 ng/mL). (1) intraamniotic infection was found in 4.3% of patients; (2) among patients with a negative AF culture, the prevalence of intraamniotic inflammation was 22.2%; and (3) patients with a negative AF culture, but with intraamniotic inflammation, had a higher rate of delivery within 7 days (40% vs 5.7%; P=.016) and a shorter median diagnosis-to-delivery interval than those without intraamniotic inflammation (18 vs 42 days; P=.01). Twenty-two percent of patients with a midtrimester SCX have intraamniotic inflammation. The risk of preterm delivery within 7 days for these patients is 40%.

Amniotic fluid volume in intra-amniotic inflammation with and without culture-proven amniotic fluid infection in preterm premature rupture of membranes

Previous studies reported that the clinical significance of intra-amniotic inflammation with a negative amniotic fluid (AF) culture is similar to that of intra-amniotic inflammation with microbiologically-proven AF infection. However, the magnitude of the fetal inflammatory response in these two conditions is different as gauged by umbilical cord C-reactive protein (CRP) concentrations. We undertook this study to determine if the frequency of oligohydramnios is different in these two conditions. The amniotic fluid index (AFI) was measured in 205 patients with preterm premature rupture of membranes (PROM) (<or=35 weeks). AF was cultured for aerobic and anaerobic bacteria and genital mycoplasmas. Intra-amniotic inflammation was defined as an elevated AF matrix metalloproteinase-8 (MMP-8) concentration (>23 ng/mL). Patients were divided into three groups according to the results of AF culture and the presence or absence of intra-amniotic inflammation: 1) without intra-amniotic inflammation and a negative culture (n=109); 2) with intra-amniotic inflammation and a negative culture (n=44); and 3) a positive culture (n=52). Patients with a positive culture had a higher frequency of oligohydramnios and a lower median AFI than those with a negative culture but with intra-amniotic inflammation (P<0.01). However, there was no significant difference in the median AFI or in the frequency of oligo-hydramnios according to the presence or absence of intra-amniotic inflammation among patients with a negative culture (P>0.1). Oligohydramnios was more frequent in patients with culture-proven AF infection than in those with intra-amniotic inflammation and a negative AF culture.

Widespread microbial invasion of the chorioamniotic membranes is a consequence and not a cause of intra-amniotic infection

Acute chorioamnionitis is a response to amniotic fluid (AF) infection. However, it remains unclear whether substantial bacterial propagation in the chorioamniotic membranes (CAMs) precedes microbial invasion of the amniotic cavity (MIAC), which is inconsistent with characteristic ‘amniotropic neutrophil migration' in acute chorioamnionitis. This study was performed to determine whether CAMs have widespread bacterial infection during MIAC and whether bacteria normally colonize CAMs. AF pellets and CAMs from the following groups were studied: group 1, patients with positive (n=18) or negative (n=22) AF cultures; group 2, patients with or without acute chorioamnionitis in which the amnion and chorion were studied separately (n=60); and group 3, patients at term who underwent a cesarean delivery (n=30). SYTO 9/propidium iodide fluorescent staining and fluorescent in situ hybridization for 16S rRNA were performed. Real-time quantitative PCR for 16S rDNA and PCR for genital mycoplasmas were also conducted. Bacteria were more frequently detected in AF than in CAMs of patients with positive AF culture (100 vs. 33%; P<0.0001). Bacteria were detected more frequently in CAMs as the severity of chorioamnionitis increased (P<0.01). The median 16S rRNA gene copy number in the amnion was significantly greater than in the chorion (group 2; P<0.0001). Bacteria were not detected in CAMs or AF in women at term before labor (group 3). A fraction of patients with chorioamnionitis or MIAC did not have bacteria in CAMs. Collectively, the findings herein indicate that MIAC does not follow widespread infection of CAMs, but precedes it. We propose a model of MIAC: the initial stage is intra-amniotic bacterial invasion through a discrete region of the CAMs, followed by intra-amniotic proliferation, and bacterial invasion of CAMs primarily extends from the amniotic fluid. This study emphasizes the importance of assessing the intra-amniotic compartment for diagnosis and treatment of preterm birth.

Transvaginal ultrasonographic measurement of cervical length in predicting intra-amniotic infection and impending preterm delivery in preterm labor: a comparison with amniotic fluid white blood cell count

To determine whether sonographic measurement of cervical length predicts intra-amniotic infection and impending preterm delivery (within 7 days of amniocentesis) in women with preterm labor and intact membranes, and to compare the predictability with that of amniotic fluid (AF) white blood cell (WBC) count. Transvaginal ultrasonographic assessment of cervical length was performed immediately after amniocentesis in 67 consecutive women with preterm labor. AF obtained by amniocentesis was cultured for aerobic and anaerobic bacteria and for Mycoplasmas, and WBC count was determined. Patients with a positive AF culture had a significantly shorter median cervical length, higher median AF WBC count, and lower median gestational age at delivery than did those with a negative AF culture. Multivariate analysis indicated that only the AF WBC count bears a significant relationship with the presence of intra-amniotic infection, whereas only cervical length correlates with impending preterm delivery. Transvaginal sonographic measurements of cervical length are a valuable method for predicting intra-amniotic infection as well as impending preterm delivery in women with preterm labor. However, in comparison with AF WBC, cervical length is less predictive for intra-amniotic infection, whereas cervical length demonstrates better predictability of impending preterm delivery.

689: Evidence supporting that a culture-proven infection has clinical implications beyond the presence of intra-amniotic inflammation with a negative amniotic fluid culture in preterm PROM

689: Evidence supporting that a culture-proven infection has clinical implications beyond the presence of intra-amniotic inflammation with a negative amniotic fluid culture in preterm PROM

Interleukin 6 determination in the detection of microbial invasion of the amniotic cavity.

A growing body of evidence suggests a role for cytokines in the mechanisms responsible for preterm parturition associated with intrauterine infection. Interleukin 6, a polyfunctional cytokine that is secreted by tissues in the feto-maternal interface in response to microbial products, has been implicated in the host response to intrauterine infection. The purpose of this study was to establish whether measurement of amniotic fluid concentrations of interleukin 6 could be of value in the diagnosis of microbial invasion of the amniotic cavity. Fluid was obtained by transabdominal amniocentesis from patients with preterm labour and intact chorioamniotic membranes and cultured for aerobic and anaerobic bacteria and mycoplasmas. Interleukin 6 concentrations were determined by an ELISA validated for human amniotic fluid. An interleukin 6 concentration above 11.2 ng/ml had a 93.7% sensitivity and a 92.3% specificity in the diagnosis of intra-amniotic infection. Moreover, patients with an amniotic fluid interleukin 6 level above 11.2 ng/ml and a negative amniotic fluid culture failed to respond to tocolysis, delivered a preterm infant and showed histological evidence of chorioamnionitis, and their neonates were at risk for congenital infections.

The intensity of the fetal inflammatory response in intraamniotic inflammation with and without microbial invasion of the amniotic cavity

Intraamniotic inflammation is a risk factor for adverse pregnancy and neonatal outcome, regardless of the presence or absence of a positive amniotic fluid (AF) culture. The purpose of this study was to determine whether the intensity of a fetal inflammatory response (FIR) differs between cases of intraamniotic inflammation with microbiologically proven infection and cases with negative AF cultures. The FIR was examined in 89 cases of women with preterm premature rupture of membranes who delivered singleton preterm newborn infants within 48 hours of amniocentesis. AF was cultured for aerobic and anaerobic bacteria and for genital mycoplasmas. AF white blood cell (WBC) count and matrix metalloproteinase-8 (MMP-8) determinations were performed to assess the presence of intraamniotic inflammation. Intraamniotic inflammation was defined as an elevated AF MMP-8 concentration (>23 ng/mL). The intensity of the FIR was determined by the umbilical cord plasma concentrations of C-reactive protein (CRP). Patients were divided into 3 groups according to the presence or absence of intraamniotic inflammation and AF culture results: group 1, without intraamniotic inflammation and with a negative AF culture (n = 28); group 2, with intraamniotic inflammation and with a negative AF culture (n = 26); group 3, with a positive AF culture (n = 35). Neonates who were born to mothers with intraamniotic inflammation and negative AF cultures had a significantly higher median umbilical cord plasma CRP concentration than did those without intraamniotic inflammation and a negative AF culture (P < .005) but a significantly lower median cord plasma CRP concentration than did those with proven AF infection (P < .05). Patients with intraamniotic inflammation and a negative AF culture had significantly higher median AF MMP-8 concentrations and WBC count than did those without intraamniotic inflammation and a negative AF culture (P < .001). However, there was no significant difference in the median AF MMP-8 and WBC count between patients with intraamniotic inflammation and a negative AF culture and those with proven AF infection (MMP-8, P > .1, and WBC, P = .09). Intraamniotic inflammation without documented AF infection is a risk factor for a systemic FIR. However, the magnitude of the FIR in those cases was lower than in those with documented AF infection.

Value of Placental Microbial Evaluation in Diagnosing Intra-amniotic Infection

To evaluate the ability of microbiologic and pathologic examination of the placenta to accurately diagnose intraamniotic infection and inflammation. One hundred eighty-three women with a clinically indicated amniocentesis were enrolled prospectively. We applied our analysis to 56 women with evidence of preterm labor or preterm premature rupture of membranes who delivered within 48 hours of amniotic fluid testing results. Twenty-three patients, assessed for fetal lung maturity in the third trimester, served as controls. Amniotic fluid was cultured for aerobic, anaerobic, Ureaplasma, and Mycoplasma species. We used mass spectrometry to assess the degree of intraamniotic inflammation (Mass Restricted scoring). After delivery, microbiologic and histologic studies of the placenta were performed. These results were interpreted in comparison with the direct microbiologic and inflammatory analysis of the amniotic fluid. A sample size of 45 patients was required to show a test accuracy of 80% or more. Ninety-two percent of women with positive amniotic fluid cultures tested with at least one positive placenta culture. Eighty percent of women who had negative amniotic fluid cultures also tested with a positive placenta culture. The accuracy of placental cultures in predicting amniotic fluid infection varied from 44% to 57%. Placental pathology showed an accuracy of only 58% in diagnosing intraamniotic inflammation. Placental microbiologic and histologic studies poorly reflect the infectious and inflammatory status of the amniotic fluid. Results of such studies should be interpreted with caution in the management and future counseling of women with preterm labor or preterm premature rupture of membranes. II.

The receptor for advanced glycation end products (RAGE) system in women with intraamniotic infection and inflammation

Receptor for advanced glycation end products (RAGE) is a multiligand cell-surface receptor part of the immunoglobulin superfamily with crucial roles in inflammation. S100A12/ENRAGE, a biomarker of amniotic fluid (AF) inflammation, is a ligand for RAGE. sRAGE, a competitive soluble RAGE receptor, inhibits RAGE ligands. Here we aimed to investigate the presence and changes in components of the RAGE system in women with intra-amniotic infection and inflammation. AF was retrieved by amniocentesis in 113 women stratified as follows: (1) positive AF culture (+AFC; GA = 27 [20-33] wk; n = 27); (2) negative AF culture (-AFC; GA = 30 [20-36] wk; n = 27); (3) second trimester control (2T-CRL; GA = 19 [15-25] wk; n = 31); (4) third trimester control (3T-CRL; GA = 36 [31-38] wk; n = 28). We used mass spectrometry (SELDI) to detect S100A12/ENRAGE in AF. sRAGE levels were measured using specific immunoassays. Placental pathology was interpreted in relationship to the presence or absence of histologic acute inflammation and immunoreactivity of S100A12/ENRAGE and RAGE. mRNA expression of S100A12/ENRAGE, sRAGE, and RAGE in amniochorion and placental villous tissue was investigated using quantitative real-time polymerase chain reaction (PCR). Presence of the S100A12/ENRAGE biomarker SELDI peak was confirmed in 70% of the +AFC but in only 10% of the -AFC samples (P < .001). The inflammatory biomarker was absent in all control samples. We further determined that the competitive inhibitor sRAGE is temporally regulated during gestation and that its AF levels are not influenced by the presence of either intra-amniotic infection or inflammation. Histologic choriamnionitis associated with intense staining for S100A12/ENRAGE, particularly in inflammatory cells. The immunoreactivity for extracellular domain of RAGE was localized exclusively to amnion epithelial, decidual, and extravillous trophoblast cells. Yet, acute histologic chorioamnionitis was related to increased gene expression of S100A12/ENRAGE in fetal membranes and decreased sRAGE and RAGE in the placenta. The S100A12/ENRAGE system is markedly upregulated in women with intra-amniotic infection and correlates with the degree of inflammation. Further studies remain to elucidate whether the gestational age dependence of the inhibitor molecule sRAGE may explain the higher incidence of infection-related preterm deliveries and especially rupture of the membranes at earlier gestational age.

Amnionitis with Ureaplasma urealyticum or other microbes leads to increased morbidity and prolonged hospitalization in very low birth weight infants

Objective To investigate the influence of culture proven intrauterine infection on preterm morbidity and to test the effect of antimicrobial treatment. Methods Retrospective cohort study conducted between October 1997 and February 2001 in patients with preterm premature rupture of membranes or preterm labor. Vaginal swabs were sampled and amniocentesis for microbiologic culture of the amniotic fluid was performed. Patients with Ureaplasma urealyticum in the amniotic fluid were treated with josamycin. Infants were followed post partum according to birth weight, gestational age, APGAR score and infant morbidity. Results In 49 eligible patients, 40% of cultures were positive, 22% for Ureaplasma urealyticum, 12% for other bacteria and 6% for candida. Children of mothers with positive amniotic fluid cultures had significantly lower gestational ages (26 + 4 weeks for Ureaplasma urealyticum [ p = 0.04] and 25 + 5 weeks for other microorganisms [ p = 0.0017] versus 28 + 6 weeks for mothers with negative amniotic fluid cultures) and lower birth weights (975 g [n.s.] and 828 g [ p = 0.0072] versus 1041 g) but were appropriate for their gestational ages. 33.3% and 66.7% versus 24% of the children were mechanically ventilated [n.s.], duration of mechanical ventilation was 5.3 [ p = 0.02] and 10.1 days [ p = 0.04] versus 1.4 days, and prevalence of chronic lung disease was 38% and 33% versus 11% [n.s.]. Prevalence of severe intraventricular hemorrhage (12.5% [n.s.] and 33% [ p = 0.04] versus 3.4%) and nosocomial infections (50% for both groups of positive cultures versus 10.3% for negative cultures, p = 0.02 and 0.03, respectively) was higher and median length of stay was significantly longer (121 [ p = 0.02] and 107 days [ p = 0.03] versus 60 days) in these patients. Maternal positive vaginal swab cultures were not associated with any of the above-mentioned factors. In none of the patients treated with macrolids for proven Ureaplasma urealyticum amnionitis could the microbes be eradicated. Conclusion Maternal positive amniotic fluid cultures have been associated with lower gestational age and lower birth weight. Rate of infant morbidity was higher and length of stay was significantly longer in this group. Positive vaginal swabs were not predictive for infant morbidity. Treatment of mothers showing positive amniotic fluid cultures with macrolids was not effective.

A rapid MMP-8 bedside test for the detection of intra-amniotic inflammation identifies patients at risk for imminent preterm delivery

Matrix metalloproteinase-8 (MMP-8) is an enzyme that is released during neutrophil activation. MMP-8 amniotic fluid concentrations are elevated not only in patients with intra-amniotic infection, but also in patients with negative amniotic fluid cultures who deliver preterm neonates. The objective of this study was to determine whether the results of a rapid MMP-8 bedside test predict imminent preterm delivery. This test can be performed in 15 minutes and without laboratory equipment. Amniotic fluid was retrieved from 331 patients admitted with increased preterm uterine contractions and intact membranes who met the inclusion criteria. Amniotic fluid was processed for microbial cultures, Gram stain, glucose concentration, and white blood cell count. Amniotic fluid samples were stored, and the MMP-8 rapid test was performed after delivery. End points included spontaneous preterm delivery within 48 hours, 7 days, and 14 days. Diagnostic indices, predictive values, and likelihood ratios were calculated. The prevalence of spontaneous preterm delivery within 48 hours, 7 days, and 14 days was 11.6% (38/327), 20.2% (66/327), and 24.5% (80/327), respectively (4 patients with augmentation of labor were excluded). A positive MMP-8 rapid test had a positive predictive value of 70% (23/33) for the identification of patients who delivered spontaneously within 48 hours, and 94% (31/33) for patients who were delivered within 7 days and 14 days (likelihood ratios: 17.5 [95% CI, 9-33.9], 61.3 [95% CI, 15.1-250], and 50 [95% CI, 12-196], respectively). The MMP-8 rapid test can identify patients at risk for preterm delivery within 7 days and 14 days. Moreover, a positive MMP-8 rapid test result can identify patients with intra-amniotic infection/inflammation with a high sensitivity and specificity. This rapid test will give clinicians a fast and accurate assessment of the inflammatory status of the amniotic cavity and allow for better identification of patients at risk for impending preterm delivery.

Lactate dehydrogenase isoform activity mapping in patients with intra-amniotic infection

Five distinct lactate dehydrogenase isoenzymes have been described. We sought to illustrate the specific amniotic fluid lactate dehydrogenase isoenzyme activity profiles in women with intra-amniotic infection. Amniotic fluid was retrieved from 82 women who were stratified in the following groups: (1) positive amniotic fluid cultures (n = 23 women; gestational age, 26 weeks [range, 21-32 weeks]); (2) negative amniotic fluid cultures (n = 22 women; gestational age, 30 weeks [range, 16-36 weeks]); (3) second trimester control (normal genetic karyotype; n = 17 women; gestational age, 18 weeks [range, 16-22 weeks]); and (4) third trimester control (fetal lung maturity testing; n = 20 women; gestational age, 36 weeks [range, 31-38 weeks]). The optical density of each isoform was determined relative to a standard with 5 known lactate dehydrogenase isoenzyme activities. Total lactate dehydrogenase activity was measured by the clinical laboratory immediately after retrieval and by a kinetic UV spectrophotometric assay at the time of the isoelectric focusing. Infection increased total lactate dehydrogenase activity: positive amniotic fluid cultures (median, 762.4 [range, 169.3-3374.8]) vs negative amniotic fluid cultures (median, 203.7 [range, 57.8-1939.3]; U/L; P < .001]). Lactate dehydrogenase isoform profiling identified significant and specific increases in lactate dehydrogenase isoforms 3, 4 (P < .01), and 5 (P < .05) in positive amniotic fluid cultures compared to the negative amniotic fluid cultures group. A selective up-regulation in lactate dehydrogenase isoform 5 was identified at term in healthy subjects. Intra-amniotic infection is characterized by an increase in the activities of lactate dehydrogenase isoforms 3, 4, and 5; advancing gestational age demonstrates an up-regulation of isoform 5 only.

MMP-8 PTL: A rapid bedside test for the detection of intra-amniotic inflammation can identify patients at risk for preterm delivery within 7 days

INFLAMMATION CAN IDENTIFY PATIENTS AT RISK FOR PRETERM DELIVERY WITHIN 7 DAYS JYH KAE NIEN, BO HYUN YOON, JIMMY ESPINOZA, JUAN PEDRO KUSANOVIC, OFFER EREZ, ELEAZAR SOTO, KARINA RICHANI, RICARDO GOMEZ, ROBERTO ROMERO, Perinatology Research Branch, NICHD, NIH, DHHS, Bethesda, Maryland, Seoul National University College of Medicine, Department of Obstetrics and Gynecology, Seoul, South Korea, Wayne State University School of Medicine, Department of Obstetrics and Gynecology, Detroit, Michigan, Sotero del Rio Hospital, Center for Perinatal Diagnosis and Research, Santiago, Chile OBJECTIVE: Matrix metalloproteinase-8 (MMP-8) is an enzyme that is released during neutrophil activation. MMP-8 amniotic fluid (AF) concentrations are elevated in intra-amniotic infection, but also in patients with negative AF cultures who deliver preterm neonates. The objective of this study was to determine if the results of a rapid bedside test (MMP-8 PTL ) predicted delivery within 48 hours and 7 days. This test can be performed in 15 minutes and without laboratory equipment. STUDY DESIGN: AF was retrieved from 331 consecutive patients admitted with preterm labor and intact membranes. AF was processed for microbiology studies, as well as Gram stain, glucose, and white blood cell count. AF was stored and the MMP-8 rapid test was performed after delivery. Endpoints included spontaneous preterm delivery within 48 hours and 7 days. Diagnostic indices, predictive values and likelihood ratios were calculated. RESULTS: The prevalence of spontaneous preterm delivery within 48 hours and 7 days was 12% (41/331) and 21% (70/331), respectively. A positive MMP-8 rapid test was present in 11% (36/331) of our study population. The diagnostic indices of a positive MMP-8 rapid test in the prediction of delivery within 48 hours and 7 days are displayed in the table. CONCLUSION: The MMP-8 rapid test can identify patients at risk for preterm delivery within 7 days. Previous studies have demonstrated that this test can identify intra-amniotic infection and inflammation in preterm PROM and preterm labor with a high sensitivity and specificity.