A self-assembled clavanin A-coated amniotic membrane scaffold for the prevention of biofilm formation by ocular surface fungal pathogens

Amniotic membrane (AM) is frequently used in ophthalmologic surgery for rapid ocular surface reconstruction. Sometimes it may create a major problem with associated infections after biofilm formation over the membrane. To overcome this problem, AM was coated with the antimicrobial peptide clavanin A. The antifungal activity of clavanin A in the native and self-assembled form was determined against the common ocular surface pathogens Candida albicans, Aspergillus fumigatus, Alternaria sp. and Fusarium sp. Biofilm formation over the coated surface was significantly reduced in comparison with the uncoated membrane. The coated membrane revealed effectiveness in terms of biocompatibility, cell attachment colonization when tested in non-cancerous 3T3 and human embryonic kidney (HEK)-293 cell lines. Clavanin A-coated AM also exhibited excellent physical, morphological and antifungal characteristics, indicating potential applicability for ocular surface infection control.

Neutrophil Extracellular Traps in the Amniotic Cavity of Women with Intra-Amniotic Infection: A New Mechanism of Host Defense

OBJECTIVE

Neutrophil extracellular traps (NETs) control microbial infections through their antimicrobial activities attributed to DNA, histones, granules, and cytoplasmic proteins (eg, elastase). Intra-amniotic infection is characterized by the influx of neutrophils into the amniotic cavity; therefore, the aim of this study was to determine whether amniotic fluid neutrophils form NETs in this inflammatory process.

METHODS

Amniotic fluid samples from women with intra-amniotic infection (n = 15) were stained for bacteria detection using fluorescent dyes. Amniotic fluid neutrophils were purified by filtration. As controls, neutrophils from maternal blood samples (n = 3) were isolated by density gradients. Isolated neutrophils were plated onto glass cover slips for culture with and without 100 nM of phorbol-12-myristate-13-acetate (PMA). NET formation was assessed by 4',6-diamidino-2-phenylindole (DAPI) staining and scanning electron microscopy. Different stages of NET formation were visualized using antibodies against elastase and histone H3, in combination with DAPI staining, by confocal microscopy. Finally, maternal or neonatal neutrophils were added to amniotic fluid samples from women without intra-amniotic infection (n = 4), and NET formation was evaluated by DAPI staining.

RESULTS

(1) NETs were present in the amniotic fluid of women with intra-amniotic infection; (2) all of the amniotic fluid samples had detectable live and dead bacteria associated with the presence of NETs; (3) in contrast to neutrophils from the maternal circulation, amniotic fluid neutrophils did not require PMA stimulation to form NETs; (4) different stages of NET formation were observed by co-localizing elastase, histone H3, and DNA in amniotic fluid neutrophils; and (5) neither maternal nor neonatal neutrophils form NETs in the amniotic fluid of women without intra-amniotic infection.

CONCLUSION

NETs are detectable in the amniotic fluid of women with intra-amniotic infection.

Intrapartum chlorhexidine vaginal irrigation and chorioamnion and placental microbial colonization

OBJECTIVES

To determine whether intrapartum chlorhexidine vaginal irrigation reduces microbial colonization of the chorioamnion or placenta.

METHODS

Secondary analysis was made of a randomized trial. Cultures for aerobic and anaerobic bacteria, Mycoplasma species and Ureaplasma urealyticum were performed using standard isolation techniques.

RESULTS

The placentas of 83 trial participants allocated to chlorhexidine and 93 allocated to placebo underwent evaluation. These two groups were statistically balanced for risk factors for infection. Aerobic bacteria were isolated from 47% of the chlorhexidine placentas vs. 51% of the placebo placentas (relative risk 0.9, 95% confidence interval 0.7-1.3), anaerobic bacteria from 30% and 35%, respectively (0.8, 0.5-1.3), group B streptococcus from 12% and 15% (0.8, 0.4-1.7), U. urealyticum from 18% and 29% (0.6, 0.4-1.1), Mycoplasma species from 6% and 11% (0.6, 0.2-1.6), and any organism from 57% and 67%, respectively (0.8, 0.7-1.1).

CONCLUSIONS

Intrapartum chlorhexidine vaginal irrigation was associated with non-significant reductions in the rates of placental microbial isolation.

Cervical microbiota in women with preterm prelabor rupture of membranes

OBJECTIVE

To analyze the cervical microbiota in women with preterm prelabor rupture of membranes (PPROM) by pyrosequencing and to document associations between cervical microbiota, cervical inflammatory response, microbial invasion of the amniotic cavity (MIAC), histological chorioamnionitis, and intraamniotic infection (IAI).

STUDY DESIGN

Sixty-one women with singleton pregnancies complicated by PPROM were included in the study. Specimens of cervical and amniotic fluid were collected on admission. The cervical microbiota was assessed by 16S rRNA gene sequencing by pyrosequencing. Interleukin (IL)-6 concentration in the cervical fluid and amniotic fluid was measured by ELISA and lateral flow immunoassay, respectively.

RESULTS

Four bacterial community state types [CST I (Lactobacillus crispatus dominated), CST III (Lactobacillus iners dominated), CST IV-A (non-Lactobacillus bacteria dominated), and CST IV-B (Gardnerella vaginalis and Sneathia sanguinegens dominated)] were observed in the cervical microbiota of women with PPROM. Cervical fluid IL-6 concentrations differed between CSTs (CST I = 145 pg/mL, CST III = 166 pg/mL, CST IV-A = 420 pg/mL, and CST IV-B = 322 pg/mL; p = 0.004). There were also differences in the rates of MIAC, of both MIAC and histological chorioamnionitis, and of IAI among CSTs. No difference in the rate of histological chorioamnionitis was found among CSTs.

CONCLUSIONS

The cervical microbiota in PPROM women in this study was characterized by four CSTs. The presence of non-Lactobacillus CSTs was associated with a strong cervical inflammatory response and higher rates of MIAC, both MIAC and histological chorioamnionitis, and IAI representing a PPROM subtype with pronounced inflammation. CST I represents the dominant type of PPROM with a low rate of MIAC, IAI, and the combination of MIAC and histological chorioamnionitis.

Escherichia coli-induced temporal and differential secretion of heat-shock protein 70 and interleukin-1β by human fetal membranes in a two-compartment culture system

INTRODUCTION

Escherichia coli is recognized as an etiological bacteria associated with chorioamnionitis and the preterm premature rupture of fetal membranes. This pathological condition induces pro-inflammatory cytokines and degradative metalloproteinases, which are considered biological markers secreted in an acute stage of infection. Heat-shock proteins (HSPs) are an important component of the innate immunity response and are found in different pathological conditions. They have not been previously measured in human fetal membranes in response to infectious conditions. We hypothesized that the choriodecidual tissue and amniotic epithelium secreted temporal and differential Hsp-60, Hsp-70, and interleukin (IL)-1β mediated by E. coli infection.

METHODS

Fetal membranes were mounted in a two-compartment culture system and infected with two passes of live E. coli at different doses (10², 10⁴, 10⁵, and 10⁶ colony-forming units (CFU)/mL) and intervals of incubation (3, 6, and 24 h). The culture medium was collected, and Hsp-60, Hsp-70, and IL-1β were assessed using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

After 3 and 6 h of infection, E. coli induced an increase in Hsp-70 secretion in the choriodecidual tissue. However, after 24 h of incubation, Hsp-70 was downregulated and we observed an increase in IL-1β secretion. By contrast, E. coli induced a lower Hsp-60 secretion in the amnion compared to Hsp-70.

DISCUSSION

Human fetal membranes responded actively to E. coli infection, with an increase in Hsp-70 during the first hours of infection. After 24 h, there was an increase in the liberation of IL-1β.

Silent chorioamnionitis and associated pregnancy outcomes: a review of clinical data gathered over a 16-year period

OBJECTIVE

To assess neonatal outcomes and associated findings in pregnant women identified after delivery as having had underlying subclinical chorioamnionitis by either histology or bacterial culture.

METHODS

In 16 years, 8974 clinical, histological, and bacterial culture data were obtained retrospectively.

RESULTS

Placental histology was analyzed in 4237 pregnancies (2785 term and 1452 preterm) and 4737 amniotic cavity cultures were obtained during 5446 cesarean deliveries (3268 term and 1469 preterm). Histological results and bacterial cultures were both available in 1270 of the preterm deliveries. Histology revealed inflammation, suggestive of infection, in 13.6% of placentas. Subclinical acute chorioamnionic inflammation was confirmed in 142 out of 2785 term pregnancies (5.1%) and in 436 out of 1452 preterm pregnancies (30.0%, P<0.001). Bacteriological culture of the intrauterine cavity was obtained from the lower uterine segment of the uterus during cesarean section. A positive culture was found in 19.9% of all cases (941/4737), this proportion was significantly higher in preterm deliveries (343/1273, 26.9%) than in term (17.3%, P<0.001). The lower the birth-weight or gestational age, the higher the frequency of silent infections in the uterine cavity.

CONCLUSIONS

Our study findings support the association between intra-amniotic infections and preterm delivery.

The diagnostic performance of the Mass Restricted (MR) score in the identification of microbial invasion of the amniotic cavity or intra-amniotic inflammation is not superior to amniotic fluid interleukin-6

OBJECTIVE

Intra-amniotic infection/inflammation are major causes of spontaneous preterm labor and delivery. However, diagnosis of intra-amniotic infection is challenging because most are subclinical and amniotic fluid (AF) cultures take several days before results are available. Several tests have been proposed for the rapid diagnosis of microbial invasion of the amniotic cavity (MIAC) or intra-amniotic inflammation. The aim of this study was to examine the diagnostic performance of the AF Mass Restricted (MR) score in comparison with interleukin-6 (IL-6) and matrix metalloproteinase-8 (MMP-8) for the identification of MIAC or inflammation.

METHODS

AF samples were collected from patients with singleton gestations and symptoms of preterm labor (n = 100). Intra-amniotic inflammation was defined as >100 white blood cells/mm(3) (WBCs) in AF; MIAC was defined as a positive AF culture. AF IL-6 and MMP-8 were determined using ELISA. The MR score was obtained using the Surface-Enhanced Laser Desorption Ionization Time of Flight (SELDI-TOF) mass spectrometry. Sensitivity and specificity were calculated and logistic regression models were fit to construct receiver-operating characteristic (ROC) curves for the identification of each outcome. The McNemar's test and paired sample non-parametric statistical techniques were used to test for differences in diagnostic performance metrics.

RESULTS

(1) The prevalence of MIAC and intra-amniotic inflammation was 34% (34/100) and 40% (40/100), respectively; (2) there were no significant differences in sensitivity of the three tests under study (MR score, IL-6 or MMP-8) in the identification of either MIAC or intra-amniotic inflammation (using the following cutoffs: MR score >2, IL-6 >11.4 ng/mL, and MMP-8 >23 ng/mL); (3) there was no significant difference in the sensitivity among the three tests for the same outcomes when the false positive rate was fixed at 15%; (4) the specificity for IL-6 was not significantly different from that of the MR score in identifying either MIAC or intra-amniotic inflammation when using previously reported thresholds; and (5) there were no significant differences in the area under the ROC curve when comparing the MR score, IL-6 or MMP-8 in the identification of these outcomes.

CONCLUSIONS

IL-6 and the MR score have equivalent diagnostic performance in the identification of MIAC or intra-amniotic inflammation. Selection from among these three tests (MR score, IL-6 and MMP-8) for diagnostic purposes should be based on factors such as availability, reproducibility, and cost. The MR score requires a protein chip and a SELDI-TOF instrument which are not widely available or considered "state of the art". In contrast, immunoassays for IL-6 can be performed in the majority of clinical laboratories.

Effects of gamma irradiation on bacterial microflora associated with human amniotic membrane

Human amniotic membrane is considered a promising allograft material for the treatment of ocular surface reconstruction, burns, and other skin defects. In order to avoid the transmission of any diseases, grafts should be perfectly sterile. Twenty-five amniotic sacs were collected to determine the microbiological quality of human amniotic membrane, to analyze the radiation sensitivity pattern of the microorganism, and to detect the radiation decimal reduction dose (D₁₀) values. All the samples were found to be contaminated, and the bioburden was ranged from 3.4 × 10² to 1.2 × 10⁵ cfu/g. Initially, a total fifty bacterial isolates were characterized according to their cultural, morphological, and biochemical characteristics and then tested for the radiation sensitivity in an incremental series of radiation doses from 1 to 10 KGy. The results depict gradual decline in bioburden with incline of radiation doses. Staphylococcus spp. were the most frequently isolated bacterial contaminant in tissue samples (44%). The D₁₀ values of the bacterial isolates were ranged from 0.6 to 1.27 KGy. Streptococcus spp. were found to be the highest radioresistant strain with the radiation sterilization dose (RSD) of 11.4 KGy for a bioburden level of 1000. To compare the differences, D₁₀ values were also calculated by graphical evaluations of the data with two of the representative isolates of each bacterial species which showed no significant variations. Findings of this study indicate that lower radiation dose is quite satisfactory for the sterilization of amniotic membrane grafts. Therefore, these findings would be helpful to predict the efficacy of radiation doses for the processing of amniotic membrane for various purposes.

Antimicrobial peptide response to group B Streptococcus in human extraplacental membranes in culture

OBJECTIVE

Streptococcus agalactiae (GBS) is an important cause of chorioamnionitis. This study characterizes GBS colonization and stimulation of antimicrobial responses in human extraplacental membranes using an ex vivo transwell two-compartment system of full-thickness membranes and live GBS.

STUDY DESIGN

Human extraplacental membranes were affixed to transwell frames (without synthetic membranes). Live GBS was added to the decidual side of membranes in transwell cultures, and cocultures were incubated for 4, 8 and 24 h. GBS recovery from homogenized membranes and culture medium was determined by enumerating colony forming units (CFU) on blood agar. Antimicrobial peptide expression was identified using immunohistochemistry and ELISA. GBS killing by HBDs was assessed in vitro by incubating GBS with different human beta defensins (HBDs) for 3 h, then enumerating CFU.

RESULTS

GBS recovery from membranes markedly decreased over time (P < 0.05). The antimicrobial peptides HBD-1, HBD-2, HBD-3, and lactoferrin were expressed in both GBS-exposed and non-exposed tissues. Notably, a pattern of localized increased HBD-2 in the amnion of GBS-infected tissue was observed. Moreover, GBS-treated membranes released increased amounts of HBD-2 into the amniotic and decidual compartments of the transwell cultures after 24 h (P < 0.05). In bacterial cultures, HBD-2 decreased GBS viability in a concentration-dependent manner (P < 0.05).

CONCLUSION

Innate immune responses in ex vivo human extraplacental membranes suppress GBS growth. HBD-2 was implicated in this GBS suppression with evidence of signal transduction across the tissue. Antimicrobial peptides may be important for innate immune defense against intrauterine GBS infections during pregnancy.

Ureaplasma parvum serovar 3 multiple banded antigen size variation after chronic intra-amniotic infection/colonization

Ureaplasma species are the microorganisms most frequently associated with adverse pregnancy outcomes. The multiple banded antigen (MBA), a surface-exposed lipoprotein, is a key virulence factor of ureaplasmas. The MBA demonstrates size variation, which we have shown previously to be correlated with the severity of chorioamnion inflammation. We aimed to investigate U. parvum serovar 3 pathogenesis in vivo, using a sheep model, by investigating: MBA variation after long term (chronic) and short term (acute) durations of in utero ureaplasma infections, and the severity of chorioamnionitis and inflammation in other fetal tissues. Inocula of 2×10⁷ colony-forming-units (CFU) of U. parvum serovar 3 (Up) or media controls (C) were injected intra-amniotically into pregnant ewes at one of three time points: day 55 (69d Up, n = 8; C69, n = 4); day 117 (7d Up, n = 8; C7, n = 2); and day 121 (3d Up, n = 8; C3, n = 2) of gestation (term = 145–150d). At day 124, preterm fetuses were delivered surgically. Samples of chorioamnion, fetal lung, and umbilical cord were: (i) snap frozen for subsequent ureaplasma culture, and (ii) fixed, embedded, sectioned and stained by haematoxylin and eosin stain for histological analysis. Selected fetal lung clinical ureaplasma isolates were cloned and filtered to obtain cultures from a single CFU. Passage 1 and clone 2 ureaplasma cultures were tested by western blot to demonstrate MBA variation. In acute durations of ureaplasma infection no MBA variants (3d Up) or very few MBA variants (7d Up) were present when compared to the original inoculum. However, numerous MBA size variants were generated in vivo (alike within contiguous tissues, amniotic fluid and fetal lung, but different variants were present within chorioamnion), during chronic, 69d exposure to ureaplasma infection. For the first time we have shown that the degree of ureaplasma MBA variation in vivo increased with the duration of gestation.

Amniotic fluid protein profiles of intraamniotic inflammatory response to Ureaplasma spp. and other bacteria

OBJECTIVE

This study aimed to evaluate the amniotic fluid protein profiles and the intensity of intraamniotic inflammatory response to Ureaplasma spp. and other bacteria, using the multiplex xMAP technology.

METHODS

A retrospective cohort study was undertaken in the Department of Obstetrics and Gynecology, University Hospital Hradec Kralove, Czech Republic. A total of 145 pregnant women with preterm prelabor rupture of membranes between gestational age 24+0 and 36+6 weeks were included in the study. Amniocenteses were performed. The presence of Ureaplasma spp. and other bacteria was evaluated using 16S rRNA gene sequencing. The levels of specific proteins were determined using multiplex xMAP technology.

RESULTS

The presence of Ureaplasma spp. and other bacteria in the amniotic fluid was associated with increased levels of interleukin (IL)-6, IL-8, IL-10, brain-derived neurotropic factor, granulocyte macrophage colony stimulating factor, monocyte chemotactic protein-1, macrophage inflammatory protein-1, and matrix metalloproteinasis-9. Ureaplasma spp. were also associated with increased levels of neurotropin-3 and triggering receptor expressed on myeloid cells-1.

CONCLUSIONS

The presence of Ureaplasma spp. in the amniotic fluid is associated with a slightly different protein profile of inflammatory response, but the intensity of inflammatory response to Ureaplasma spp. is comparable with the inflammatory response to other bacteria.

[Intraamniotic infection--cause and satellite of preterm birth]

Intraamniotic infection (IAI), most commonly presented as chorioamniotitis, plays a major role in the pathogenesis of preterm birth (PTB). In this study, we sought for signs of IAI through clinical and laboratory parameters (leukocyte count, CRP concentration and IL-6 in maternal blood), and compared those to the newborns' infectious condition. Using cervical and vaginal secretion cultures, we determined the probable causing agents of IAI. We also followed up the therapeutic effect from the use of corticosteroids, tocolitics and antibiotics for the treatment of PTB. The results demonstrated that over 46% of the pregnant women with PTB presented with evidence of IAI. The best diagnostic option to detect an IAI provides maternal blood IL-6, and the combination between leukocyte count and CRP is a must for routine examinations. We did not isolate a single vaginal pathogen but a combination of harmful microbes which provided evidence of a vaginal ecosystem disorder. The combination therapy in over 50% of women had a positive effect on PTB for the period of corticosteroid prophylaxis (72 hrs). From hour 84, antibiotic therapy can no longer control IAI development.

Diversity of microbes in amniotic fluid

Recent polymerase chain reaction (PCR)-based studies estimate the prevalence of microbial invasion of the amniotic cavity (MIAC) to be ≥30-50% higher than that detected by cultivation-based methods. Some species that have been long implicated in causing MIAC remain among the common invaders (e.g. Ureaplasma spp., Mycoplasma spp., Fusobacterium spp. Streptococcus spp., Bacteroides spp. and Prevotella spp.). Yet we now know from studies based on PCR of the 16S ribosomal DNA that cultivation-resistant anaerobes belonging to the family Fusobacteriaceae (particularly Sneathia sanguinegens, and Leptotrichia spp.) are also commonly found in amniotic fluid. Other diverse microbes detected by PCR of amniotic fluid include as-yet uncultivated and uncharacterized species. The presence of some microbial taxa is associated with specific host factors (e.g. Candida spp. and an indwelling intrauterine device). It appears that MIAC is polymicrobial in 24-67% of cases, but the potential role of pathogen synergy is poorly understood. A causal relationship between diverse microbes, as detected by PCR, and preterm birth is supported by types of association (e.g. space, time and dose) proposed as alternatives to Koch's postulates for inferring causality from molecular findings. The microbial census of the amniotic cavity remains unfinished. A more complete understanding may inform future research directions leading to improved strategies for preventing, diagnosing and treating MIAC.

The role of the multiple banded antigen of Ureaplasma parvum in intra-amniotic infection: major virulence factor or decoy?

The multiple banded antigen (MBA) is a predicted virulence factor of Ureaplasma species. Antigenic variation of the MBA is a potential mechanism by which ureaplasmas avoid immune recognition and cause chronic infections of the upper genital tract of pregnant women. We tested whether the MBA is involved in the pathogenesis of intra-amniotic infection and chorioamnionitis by injecting virulent or avirulent-derived ureaplasma clones (expressing single MBA variants) into the amniotic fluid of pregnant sheep. At 55 days of gestation pregnant ewes (n = 20) received intra-amniotic injections of virulent-derived or avirulent-derived U. parvum serovar 6 strains (2×10⁴ CFU), or 10B medium (n = 5). Amniotic fluid was collected every two weeks post-infection and fetal tissues were collected at the time of surgical delivery of the fetus (140 days of gestation). Whilst chronic colonisation was established in the amniotic fluid of animals infected with avirulent-derived and virulent-derived ureaplasmas, the severity of chorioamnionitis and fetal inflammation was not different between these groups (p>0.05). MBA size variants (32–170 kDa) were generated in vivo in amniotic fluid samples from both the avirulent and virulent groups, whereas in vitro antibody selection experiments led to the emergence of MBA-negative escape variants in both strains. Anti-ureaplasma IgG antibodies were detected in the maternal serum of animals from the avirulent (40%) and virulent (55%) groups, and these antibodies correlated with increased IL-1β, IL-6 and IL-8 expression in chorioamnion tissue (p<0.05). We demonstrate that ureaplasmas are capable of MBA phase variation in vitro; however, ureaplasmas undergo MBA size variation in vivo, to potentially prevent eradication by the immune response. Size variation of the MBA did not correlate with the severity of chorioamnionitis. Nonetheless, the correlation between a maternal humoral response and the expression of chorioamnion cytokines is a novel finding. This host response may be important in the pathogenesis of inflammation-mediated adverse pregnancy outcomes.

In utero exposure to Ureaplasma spp. is associated with increased rate of bronchopulmonary dysplasia and intraventricular hemorrhage in preterm infants

AIMS

We determined the association between short-term neonatal morbidities, such as bronchopulmonary dysplasia (BPD) and intraventricular hemorrhage (IVH), and Ureaplasma spp. in amniotic fluid, placental and amniotic membrane of preterm infants.

METHODS

This study enrolled 257 patients who were born by cesarean section at <34 weeks' gestation. Patients were divided into two groups according to detection of Ureaplasma spp. by culture-based and/or polymerase chain reaction (PCR) techniques.

RESULTS

Significant differences were observed between both groups for all IVH (P=0.032) and IVH grades III or IV (P=0.013), as wells as for BPD [odds ratio (OR) 5.46, 95% confidence interval (CI) 2.02-14.77], oxygen requirement at 28 days postnatal age (OR 1.93, 95% CI 1.00-3.70), and for death between 28 days and 36 postmenstrual weeks or BPD (OR 4.20, 95% CI 1.77-9.96). Ureaplasma spp. was a significant predictor (P<0.001) of BPD after correcting for birth weight (P=0.003) and positive pressure ventilation (P=0.001).

CONCLUSIONS

In our study population Ureaplasma spp. was associated with BPD and IVH in preterm infants even after adjustment for multiple risk factors.

Microbial invasion of the amniotic cavity in preeclampsia as assessed by cultivation and sequence-based methods

OBJECTIVE

Infection has been implicated in the pathogenesis of preeclampsia, yet the association between microbial invasion of the amniotic cavity (MIAC) and preeclampsia has not been determined. The aim of this study was to determine the prevalence, and microbial diversity associated with MIAC, as well as the nature of the host response to MIAC in patients with preeclampsia.

METHOD OF STUDY

Amniotic fluid (AF) from 62 subjects with preeclampsia, not in labor, was analyzed with both cultivation and molecular methods. Broad-range and group-specific PCR assays targeting small subunit ribosomal DNA, or other gene sequences, from bacteria, fungi and archaea were used. Results were correlated with measurements of host inflammatory response, including AF white blood cell count and AF concentrations of glucose, interleukin-6 (IL-6) and MMP-8.

RESULTS

1) The rate of MIAC in preeclampsia was 1.6% (1/62) based on cultivation techniques, 8% (5/62) based on PCR, and 9.6% (6/62) based on the combined results of both methods; 2) among the six patients diagnosed with MIAC, three had a positive PCR for Sneathia/Leptotrichia spp.; and 3) patients with MIAC were more likely to have evidence of an inflammatory response in the amniotic cavity than those without MIAC, as determined by a higher median AF IL-6 [1.65 ng/mL interquartile range (IQR): 0.35-4.62 vs. 0.22 ng/mL IQR: 0.12-0.51; P=0.002).

CONCLUSION

The prevalence of MIAC in preeclampsia is low, suggesting that intra-amniotic infection plays only a limited role in preeclampsia. However, the unexpectedly high number of positive AF specimens for Sneathia/Leptotrichia warrants further investigation.

Clinical and histopathological correlations of the modifications of fetal membranes in amniochorial infection

The paper aims at analyzing the histopathological modifications induced by the amniotic infection on present fetal membranes and in the absence of clinical signs of chorioamnionitis. Such an evaluation is important in the context of postpartum fetomaternal complications. The objective was to determine the relation between the microbial invasion in the amniotic cavity and the severity of inflammatory lesions of the placenta, of the membranes and the umbilical chord.

Microbial prevalence, diversity and abundance in amniotic fluid during preterm labor: a molecular and culture-based investigation

Background

Preterm delivery causes substantial neonatal mortality and morbidity. Unrecognized intra-amniotic infections caused by cultivation-resistant microbes may play a role. Molecular methods can detect, characterize and quantify microbes independently of traditional culture techniques. However, molecular studies that define the diversity and abundance of microbes invading the amniotic cavity, and evaluate their clinical significance within a causal framework, are lacking.

Methods and Findings

In parallel with culture, we used broad-range end-point and real-time PCR assays to amplify, identify and quantify ribosomal DNA (rDNA) of bacteria, fungi and archaea from amniotic fluid of 166 women in preterm labor with intact membranes. We sequenced up to 24 rRNA clones per positive specimen and assigned taxonomic designations to approximately the species level. Microbial prevalence, diversity and abundance were correlated with host inflammation and with gestational and neonatal outcomes. Study subjects who delivered at term served as controls. The combined use of molecular and culture methods revealed a greater prevalence (15% of subjects) and diversity (18 taxa) of microbes in amniotic fluid than did culture alone (9.6% of subjects; 11 taxa). The taxa detected only by PCR included a related group of fastidious bacteria, comprised of Sneathia sanguinegens, Leptotrichia amnionii and an unassigned, uncultivated, and previously-uncharacterized bacterium; one or more members of this group were detected in 25% of positive specimens. A positive PCR was associated with histologic chorioamnionitis (adjusted odds ratio [OR] 20; 95% CI, 2.4 to 172), and funisitis (adjusted OR 18; 95% CI, 3.1 to 99). The positive predictive value of PCR for preterm delivery was 100 percent. A temporal association between a positive PCR and delivery was supported by a shortened amniocentesis-to-delivery interval (adjusted hazard ratio 4.6; 95% CI, 2.2 to 9.5). A dose-response association was demonstrated between bacterial rDNA abundance and gestational age at delivery (r² = 0.42; P<0.002).

Conclusions

The amniotic cavity of women in preterm labor harbors DNA from a greater diversity of microbes than previously suspected, including as-yet uncultivated, previously-uncharacterized taxa. The strength, temporality and gradient with which these microbial sequence types are associated with preterm delivery support a causal relationship.

Patterns of cytokine profiles differ with pregnancy outcome and ethnicity

BACKGROUND

Preterm birth (PTB) is hypothesized to be an inflammatory response disease. However, no single factor alone is likely to explain PTB risk. It is more probable that coordinated networks of cytokines affect risk.

METHODS

Therefore, we examined the relationships between amniotic fluid (AF) cytokines/chemokines and related biomarkers in PTB and normal term deliveries in African Americans and Caucasians. Data were obtained from African American (41 preterm labor and 91 term labor) and Caucasian (105 preterm labor and 100 term labor) pregnant mothers. Pro-inflammatory cytokines and related molecules interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor- (TNF)-alpha, TNF soluble receptors (sTNFR1 and sTNFR2), and anti-inflammatory cytokine IL-10 that were all previously associated with PTB were studied. Correlations between biomarkers were calculated; differences of correlation coefficients between AF from African American and Caucasian samples in preterm labor and term labor were measured.

RESULTS

Multiple differences were observed between African American and Caucasian preterm and term birth groups. In term birth the strongest differences were between pro- and anti-inflammatory correlations, whereas in PTB differences were equally distributed between pro-inflammatory/anti-inflammatory and pro-inflammatory/pro-inflammatory correlations. Three correlation patterns differed significantly between AF from PTB African Americans with and without microbial invasion of the intra-amniotic cavity (MIAC); no differences were observed in Caucasians with MIAC.

CONCLUSION

Correlation analyses of cytokine measurements suggest coordinated interplay during pregnancy; significant differences exist between African Americans and Caucasians. Such analyses can serve as a means of understanding risk factors in these populations.

Invasive pathway of Listeria ivanovii in human amnion-derived WISH cells

Among Listeria genus, only two species, Listeria ivanovii and Listeria monocytogenes, are pathogenic. L. ivanovii is almost only associated with infections in animals, mainly sheep and cattle, and has rarely been associated with human infections, whereas L. monocytogenes causes severe illnesses in both humans and animals. To further investigate the pathogenetic features of L. ivanovii in humans, we undertook a study in which the intracellular behaviour of this pathogen was analysed in WISH cells, a cell line derived from human amniotic tissue, and compared to that of L. monocytogenes. Using microbiological, biochemical, and ultrastructural approaches, we demonstrate that L. ivanovii can adhere to and invade human amniotic cells, lyse the phagosomal membrane, polymerize host cell actin, and spread from cell to cell more efficiently than L. monocytogenes. However, although L. ivanovii is capable of specifically infecting and replicating in human amnion cells, its survival in cytoplasm is limited compared to that of L. monocytogenes.

The role of inflammation and infection in preterm birth

Inflammation has been implicated in the mechanisms responsible for preterm and term parturition, as well as fetal injury. Out of all of the suspected causes of preterm labor and delivery, infection and/or inflammation is the only pathological process for which both a firm causal link with preterm birth has been established and a molecular pathophysiology defined. Inflammation has also been implicated in the mechanism of spontaneous parturition at term. Most cases of histopathological inflammation and histological chorioamnionitis, both in preterm and term labor, are sub-clinical in nature. The isolation of bacteria in the amniotic fluid, known as microbial invasion of the amniotic cavity, is a pathological finding; the frequency of which is dependent upon the clinical presentation and gestational age. This article reviews the role of inflammation in preterm and term parturition.

Microbiological safety and clinical efficacy of radiation sterilized amniotic membranes for treatment of second-degree burns

Amniotic membranes collected from the placentae of screened donors were processed and sterilized by gamma irradiation at 25 kGy. The sterility assurance level (SAL) of gamma irradiated amniotic membranes and clinical efficacy in second-degree burn wound healing were evaluated. Processed air-dried amniotic tissue from 159 batches of processing was checked for the bioburden level before sterilization. About 39% of the tissues had bioburden in the range of 10(1)-10(2)/100 cm(2) and 54.8% in the range of 10(2)-10(3)/100 cm(2). Based on the bioburden of the processed tissue prior to sterilization and the D(10) value of 2.3 kGy for the radiation resistant reference strain Bacillus pumilus, the sterility assurance level of the amniotic membranes irradiated at 25 kGy is found to be 10(-7) to 10(-11). The burn wound healing rate was compared between the radiation sterilized amniotic membranes and glycerol preserved amniotic membranes. Fifty patients with partial-thickness burns (up to 70% TBSA) were selected for the study. The scalds constituted 82% (41 patients) whereas flame burns accounted for 18% (9 patients). Various aspects like ease of application, patient comfort, development of fluid under the membrane, bacterial culture of drained fluid, rate of epithelialization, development of hypertrophic scars, keloids, unstable scars and restriction of joint movements were recorded with the application of gamma irradiated and glycerol preserved membranes. Radiation sterilized amniotic membranes had advantage over the glycerolized membranes with respect to the ease of application. Five patients with glycerol preserved membranes and four with gamma irradiated membranes developed fluid. The bacteriology of fluid showed Pseudomonas aeruginosa in four cases, Staphylococcus aureus in two cases, Escherichia coli in two cases and Acinetobacter in one case. The application of radiation sterilized amniotic membranes on the burn wound favoured epithelialization. In all the patients, membranes dessicated and separated in 10-14 days time leaving behind an epithelialized surface.

Inflammation in preterm and term labour and delivery

Inflammation has been implicated in the mechanisms responsible for preterm and term parturition, as well as fetal injury. Out of all of the suspected causes of preterm labour and delivery, infection and/or inflammation is the only pathological process for which both a firm causal link with preterm birth has been established and a molecular pathophysiology defined. Inflammation has also been implicated in the mechanism of spontaneous parturition at term. Most cases of histopathological inflammation and histological chorioamnionitis, both in preterm and term labour, are sub-clinical in nature. The isolation of bacteria in the amniotic fluid, known as microbial invasion of the amniotic cavity, is a pathological finding; the frequency of which is dependent upon the clinical presentation and gestational age. There is a window of time during which it may be possible to detect a 'molecular signature of inflammation' by analysis of the transcriptome before histological evidence is observed. This article reviews the role of inflammation in preterm and term parturition. It is possible that modulation of inflammation using anti-inflammatory cytokines, corticoids, antioxidants and/or other factors may complement antibiotic therapy and limit fetal injury.

Validation and Substantiation of 25 kGy as Sterilization Dose for Lyophilized Human Amnion Membrane

The validation and substantiation of sterilization dose for lyophilized human amnion membrane by gamma irradiation delivered by Co60 source were investigated. The validation experiments were conducted according to ISO 13409 method B. A total of 120 human amnion membranes were collected. Of these, 10 membranes were used for estimation of bioburden and 20 membranes were used for the individual sterility test at verification dose. The average bioburden per product unit with sample item portion (SIP = 1) for lyophilized human amnion membrane was 572 cfu. The verification dose experiments were done at dose of 8.1 kGy and the results of sterility tests showed that human amnion membrane got one positive. Consequently, the sterilization dose of 25 kGy was confirmed and substantiated.

Pregnancy loss after first-trimester viability in women with sickle cell trait: time for a reappraisal?

OBJECTIVE

The purpose of this study was to evaluate the obstetric outcomes and pathologic findings in women with sickle cell trait.

STUDY DESIGN

In this retrospective case control study, pregnant women with sickle cell trait were studied over a 4-year period (2001-2005). The women who were delivered at > 16 weeks of gestation were compared with a cohort group of subjects with normal hemoglobin levels, and the placentas were sent for pathologic evaluation.

RESULTS

A total of 180 pregnancies were studied with a like number of control patients. Subjects who had sickle cell trait demonstrated shorter average duration of pregnancy (233 +/- 45 days vs 255 +/- 34 days; P < .001) and lower birth weight (2114 +/- 1093 g vs 2672 +/- 942 g; P < .001). The rate of fetal death was significantly higher among study group patients (3.5% vs 9.7%; P = .015) when compared with the control group. Additionally, in study women, acute ascending amniotic infection and meconium histiocytosis were noted much more frequently. Sickling in the intervillous space and decidual vessels that were not associated with artifactual change was also found among patients sickle cell trait.

CONCLUSION

Patients with sickle cell trait appear to be at increased risk for fetal loss compared with women with normal hemoglobin levels, and placental abnormalities may play a causal role.

Effect of bacterial virulence on IL-18 expression in the amnion infected with Escherichia coli

PROBLEM

The upregulation of inflammatory substances threatens pregnancy. Interleukin-18 (IL-18) is elevated in women who miscarried. The purpose of this study was to develop a pig model of chorioamnionitis to study the effect of bacterial virulence on IL-18 response in experimentally infected amnion.

METHOD OF STUDY

A total of 20,000 colony-forming units of Escherichia coli (an enteropathogenic O55 strain, EPEC or O86 non-pathogenic strain) were administered into the amniotic cavity of pig fetuses at 70% of gestation for 10 hr. Fetal amniotic fluid samples were analyzed for IL-18 levels by enzyme-linked immunosorbent assay. The expression of IL-18 was studied also by immunohistochemistry on cryostat sections through amniotic membranes and pathological changes were observed by electron microscopy.

RESULTS

Both E. coli strains propagated in amniotic fluids and reached similar counts. Only EPEC, however, caused a significant increase of IL-18 amniotic fluid levels (P < 0.001) and cytokine expression in the amniotic epithelium.

CONCLUSIONS

The levels of IL-18 in infected amniotic fluids correlated with bacterial virulence and pathological changes in the amnion.

Interleukin-6 and interleukin-8 in cervical and amniotic fluid: relationship to microbial invasion of the chorioamniotic membranes

OBJECTIVE

To evaluate the levels of interleukin (IL)-6 and IL-8 in cervical and amniotic fluid in relation to the presence of bacteria in the membranes in women in preterm labour (PTL).

DESIGN

A prospective follow up study.

SETTING

Sahlgrenska University Hospital, Göteborg, Sweden. Sample Women with singleton pregnancies (<34 weeks) presenting with PTL (n = 30).

METHODS

Amniotic fluid was retrieved transabdominally and cervical fluid was sampled from the uterine cervix at admission and analysed for IL-6 and IL-8 with enzyme-linked immunosorbent assay (ELISA). At birth, the chorioamniotic membranes were separated and samples for polymerase chain reaction (PCR) for Ureaplasma urealyticum and Mycoplasma hominis and general culture were obtained.

MAIN OUTCOME MEASURE

IL-6 and IL-8 in relation to microbial invasion of the chorioamniotic membranes.

RESULTS

Bacteria were found in the membranes in 8 of 21 patients in PTL for whom chorioamnion as well as amniotic fluid PCR and cultures were available. Cervical IL-6 was associated with detectable bacteria in the chorioamniotic membranes in women in PTL (median 8.2 ng/mL vs 0.73 ng/mL; P = 0.01). The IL-6 (median 13 ng/mL vs 1.7 ng/mL; P = 0.004) and IL-8 (median 7.2 ng/mL vs 0.28 ng/mL; P = 0.01) levels in amniotic fluid were higher in PTL cases in which bacteria were found in the chorioamniotic membranes.

CONCLUSION

IL-6 in cervical fluid and IL-6 and IL-8 in amniotic fluid were higher in those PTL cases in which bacteria were found in the chorioamniotic membranes.

Expression of inflammatory markers in pig amnion after intraamniotic infection with nonpathogenic or enteropathogenic Escherichia coli

The pig amnion was in vivo intraamniotically infected with E. coli for 10 h at 80-85 d of gestation either with the nonpathogenic O86 strain or enteropathogenic O55 strain. TNF-alpha, IL-10, IL-1beta and IFN-gamma were determined in amniotic fluids by ELISA, the expression of cytokines and some other inflammatory markers was determined by immunohistochemistry. Intraamniotic infection induced high levels of TNF-alpha in amniotic fluids which correlated with bacterial virulence whereas IL-10 was induced only by O86. The IL-1beta level did not increase significantly and was expressed in all infected membranes. IFN-gamma was negligible or absent. TNF-alpha, IL-12p40, calprotectin, HSP65 and gp91phox were found by immunohistochemistry only in amnion membranes infected with the enteropathogenic strain 055.

Amniotic cavity cultures, blood cultures, and surface swabs in preterm infants--useful tools for the management of early-onset sepsis?

AIMS

To evaluate the potential benefit of amniotic fluid and amniotic/placental membrane cultures for the management of early-onset sepsis in preterm infants.

METHODS

The results of amniotic cavity cultures obtained during cesarean section and of peripheral blood cultures and surface swabs obtained from the preterm infant at the time of admission were analyzed with respect to the diagnosis of clinical sepsis in 221 preterm infants <34 weeks of gestation.

RESULTS

136 (61.5%) patients had negative amniotic cavity culture results or growth of contaminants, 56 (25.3%) had growth of Ureaplasma urealyticum, and 29 (13.1%) of other pathogens. The corresponding numbers for surface swabs were 82.8%, 11.6%, and 5.6%. A positive blood culture was found in only two neonates. Fifty-four patients (24.4%) had clinical early-onset sepsis. Patients with amniotic cavity culture results that were positive for other pathogens were significantly more likely to experience clinical sepsis than patients with negative culture results (51.7% vs 15.1%, OR 6.1, p<0.0001). Regarding surface swabs, this correlation did not reach statistical significance.

CONCLUSION

The strong association between positive amniotic cavity culture results and clinical early-onset sepsis supports the existence of a causal relation and provides evidence for the potential value of amniotic and/or placental membrane sampling in the management of early-onset sepsis in preterm infants. Surface swabs add no additional information and hence should not be performed routinely.

Secretions of interleukin-1beta and tumor necrosis factor alpha by whole fetal membranes depend on initial interactions of amnion or choriodecidua with lipopolysaccharides or group B streptococci

The present study evaluated the secretions of interleukin (IL)-1beta and tumor necrosis factor (TNF) alpha by fetal membranes stimulated with group B streptococci (GBS) and lipopolysaccharide (LPS). The aim was to evaluate the initial response of full-thickness membranes to the microbial insult using an in vitro experimental model that allowed testing of the individual contributions of amnion and choriodecidua to stimulation. Full-thickness membranes were obtained after delivery by elective cesarean section from women at 37-40 wk of gestation without evidence of active labor. The membranes were mounted in Transwell devices, physically separating the upper and lower chambers. The LPS (500 ng/ml) or GBS (1 x 10(6) colony-forming units/ml) was added to either the amniotic or choriodecidual surface, and accumulation of IL-1beta and TNFalpha were measured in both compartments using a specific ELISA. Fetal membranes followed different patterns of secretion of proinflammatory cytokines that depended on the side to which the stimulus was added or the nature of the stimulus itself. The TNFalpha was secreted by amnion and choriodecidua in the presence of LPS or GBS, and stimulation with GBS induced a greater synthesis of IL-1beta than did stimulation with LPS. Choriodecidual tissue was more responsive than amniotic tissue, and this response tended to be higher even when the stimulation was only on the amniotic side. However, the amnion plays an active role in recognizing LPS or GBS, contributing a significant amount of TNFalpha. Thus, cooperative and bidirectional communications occur between amnion and choriodecidua in response to bacterial products, which include intermembranous cytokine traffic and signaling between tissues.

Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks

OBJECTIVE

To evaluate the efficacy of transabdominal amnioinfusion on feto-neonatal and maternal morbidity and feto-neonatal mortality.

METHODS

We studied 71 patients with preterm premature rupture of membranes (pPROM) at <26 weeks of gestational age. Thirty-four patients were managed expectantly and 37 underwent serial transabdominal amnioinfusion with saline every 7 days in case of persistent oligohydramnios.

RESULTS

Latency period pPROM delivery, week of delivery (26.0 vs. 22.4, p<0.001), neonatal weight (922 vs. 602, p<0.01) and the percentage of intrauterine fetal survival were higher in treated than in control groups (64.8 vs. 32.3%, p<0.01). In amnioinfusion-treated patients, we did not note a higher rate of complications from infection during both pregnancy and puerperium. In the amnioinfusion group, fluid loss within 6 h after infusion is the main variable in predicting pulmonary hypoplasia and neonatal survival.

CONCLUSIONS

Our data suggest that amnioinfusion seems to be a low fetal and maternal risk technique that modifies the natural history of pPROM, improving fetal intrauterine stay and survival.

Matrix metalloproteinase 3 in parturition, premature rupture of the membranes, and microbial invasion of the amniotic cavity

OBJECTIVE

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that are expressed in many inflammatory conditions and contribute to connective tissue breakdown. Stromelysin 1 [matrix metalloproteinase 3 (MMP-3)], a novel member of this family, is produced in the context of infection and is able to activate the latent forms of other MMPs. The purpose of this study was to determine if parturition (either term or preterm), premature rupture of the membranes (PROM), and microbial invasion of the amniotic cavity are associated with changes in amniotic fluid concentrations of MMP-3.

STUDY DESIGN

A cross-sectional study was conducted, which included women who underwent transabdominal amniocentesis (n = 365) in the following categories: (1) mid-trimester with a subsequent normal pregnancy outcome (n = 84) and a subsequent fetal loss (n = 10); (2) preterm labor with intact membranes without microbial invasion of the amniotic cavity who delivered at term (n = 36), or prematurely (n = 50), and preterm labor with microbial invasion of the amniotic cavity (n = 25); (3) preterm PROM with (n = 25) and without (n = 26) microbial invasion of the amniotic cavity; (4) term with intact membranes in the absence of microbial invasion of the amniotic cavity, in labor (n = 52) and not in labor (n = 31); and (5) term with PROM in the absence of microbial invasion of the amniotic cavity and not in labor (n = 26). MMP-3 concentrations in amniotic fluid were measured by a sensitive and specific immunoassay that was validated for amniotic fluid. MMP-3 concentrations were normalized using logarithmic transformation for statistical analysis. Parametric statistics were used and a p value < 0.05 was considered statistically significant.

RESULTS

(1) MMP-3 was detected in 99.5% (363/365) of amniotic fluid samples, and its concentration did not change with advancing gestational age. (2) Spontaneous parturition at term and preterm was associated with a significant increase in amniotic fluid MMP-3 concentrations (p = 0.04 and p = 0.002, respectively). (3) Spontaneous rupture of membranes in term and preterm gestations was not associated with significant changes in amniotic fluid MMP-3 concentrations. (4) Intra-amniotic infection was associated with a significant increase in amniotic fluid MMP-3 concentrations in both women with preterm labor and intact membranes (p = 0.03), and women with preterm PROM (p = 0.02). (5) Subsequent fetal loss after genetic amniocentesis was not associated with significant changes in mid-trimester concentrations of amniotic fluid MMP-3.

CONCLUSIONS

(1) MMP-3 is a physiologic constituent of amniotic fluid. (2) MMP-3 may play a role in the mechanisms of human parturition and in the regulation of the host response to intrauterine infection.

Interleukin-18 in cervical mucus and amniotic fluid: relationship to microbial invasion of the amniotic fluid, intra-amniotic inflammation and preterm delivery

OBJECTIVE

To evaluate the relationship between interleukin (IL)-18 in cervical mucus and amniotic fluid and microbial invasion of amniotic fluid, preterm delivery and intra-amniotic inflammation in women in preterm labour, with preterm prelabour rupture of membranes and at term.

DESIGN

A prospective follow up study.

SETTING

Sahlgrenska University Hospital, Göteborg, Sweden.

SAMPLE

Women with singleton pregnancies (<34 weeks) presenting with preterm labour (n = 87) or preterm prelabour rupture of membranes (n = 47) and women, not in labour, at term (n = 28).

METHODS

Amniotic fluid was retrieved transabdominally. Cervical mucus was taken from the uterine cervix of women in preterm labour and at term. IL-18 was analysed with enzyme-linked immunosorbent assay.

MAIN OUTCOME MEASURES

IL-18 in relation to microbial invasion of the amniotic fluid, delivery within seven days or <34 weeks of gestation and intra-amniotic inflammation.

RESULTS

The levels of IL-18 in cervical mucus and amniotic fluid were higher in women with preterm labour than in those not in labour at term. In the preterm labour group, significant associations were found between elevated IL-18 in amniotic fluid and microbial invasion of the amniotic fluid, as well as between delivery within seven days or <34 weeks of gestation and intra-amniotic inflammation. Delivery was delayed longer in the preterm prelabour rupture of membranes subgroup with IL-18 >or=1.0 ng/mL than in that with IL-18 <1.0 ng/mL.

CONCLUSIONS

In the preterm labour group, high IL-18 in amniotic fluid (but not in the cervix) was associated with microbial invasion of the amniotic fluid, intra-amniotic inflammation and prompt delivery. On the other hand, elevated IL-18 in preterm prelabour rupture of the membranes group correlated with a longer interval to delivery.

Staphylococcus epidermidis adherence to human amniotic membrane and to human, rabbit, and cat conjunctiva

PURPOSE

To evaluate Staphylococcus epidermidis adherence to human amniotic membrane (HAM) and compare it with S epidermidis adherence to human, rabbit, and cat conjunctiva in vitro.

SETTING

Research laboratory, Loyola University Medical Center, Maywood, Illinois, USA.

METHODS

Commercially available HAM (N = 3) was used. Conjunctival specimens from humans, rabbits, and cats (n = 3 each) were processed similarly to HAM. The tissues were exposed to S epidermidis (3 x 10(8) colony-forming units per milliliter) for 0, 5, 30, and 90 minutes, rinsed in sterile saline, and processed for light, scanning (SEM), and transmission (TEM) electron microscopy. Scanning electron microscopy (x2000) was used to quantify adherent bacteria/mm(2) of tissue (SEM photographs = 144).

RESULTS

The following mean levels (+/- SD) of adherent S epidermidis/mm(2) were found at 0, 5, 30, and 90 minutes: HAM, 3833 +/- 1570, 9060 +/- 2512, 15,431 +/- 10,752, and 30,315 +/- 14,803, respectively; human conjunctiva, 1493 +/- 672, 7218 +/- 3179, 17,273 +/- 7168, and 19,861 +/- 9624, respectively; rabbit conjunctiva, 3385 +/- 5074, 14,386 +/- 14,569, 15,283 +/- 13,679, and 20,113 +/- 24,016, respectively; and cat conjunctiva, 4032 +/- 2240, 12,345 +/- 3413, 8512 +/- 4032, and 19,214 +/- 5584, respectively. No statistically significant differences were found at any time point (P>.16).

CONCLUSION

There was no statistically significant difference in the adherence of S epidermidis to HAM and to human, rabbit, and cat conjunctiva. Bacterial adherence to HAM may be clinically significant.

Differences in the fetal interleukin-6 response to microbial invasion of the amniotic cavity between term and preterm gestation

BACKGROUND/OBJECTIVE

Fetal inflammatory response has been implicated as a mechanism of multi-system organ injury in preterm and term neonates. Microbial invasion of the amniotic cavity (MIAC) is frequently associated with a fetal inflammatory response. However, there are no studies comparing the fetal response to MIAC in term and preterm gestations. The purpose of this study was to compare the umbilical cord plasma interleukin-6 (IL-6) concentrations in term and preterm neonates in the presence or absence of MIAC.

STUDY DESIGN

Umbilical cord blood was obtained at birth from 252 neonates whose mothers had an amniocentesis within 48 h of delivery (preterm delivery, n = 62; term delivery, n = 190). MIAC was defined as a positive amniotic fluid culture for bacteria or genital mycoplasmas. IL-6 was measured by a sensitive and specific immunoassay.

RESULTS

The median IL-6 concentration in umbilical cord plasma was significantly higher in preterm neonates than in term neonates (median 13.4 pg/ml, range 0.1-676 pg/ml vs. median 3.2 pg/ml, range 0.1-408 pg/ml; p < 0.0001). In the context of MIAC, the median umbilical cord plasma IL-6 concentration was significantly higher in preterm than in term neonates (median 31.6 pg/ml, range 1.4-676 pg/ml vs. median 11.7 pg/ml, range 1.3-82 pg/ml, respectively; p < 0.05). Neonates born to mothers with a positive amniotic fluid culture had a significantly higher median IL-6 concentration than neonates born to mothers with a negative amniotic fluid culture (preterm: median 31.6, range 1.4-676 pg/ml vs. median 8.0, range 0.1-656 pg/ml; p < 0.05 and term: median 11.7, range 1.3-82 pg/ml vs. median 3.1, range 0.1-408 pg/ml; p < 0.01, respectively).

CONCLUSIONS

The preterm fetus is capable of mounting a systemic cytokine response as measured by IL-6 in its peripheral blood. In the setting of MIAC, a fetal IL-6 response is higher in preterm than in term gestation.

Antimicrobial peptides in amniotic fluid: defensins, calprotectin and bacterial/permeability-increasing protein in patients with microbial invasion of the amniotic cavity, intra-amniotic inflammation, preterm labor and premature rupture of membranes

OBJECTIVE

Neutrophil defensins (HNP 1-3), bactericidal/permeability-increasing protein (BPI) and calprotectin (MRP8/14) are antimicrobial peptides stored in leukocytes that act as effector molecules of the innate immune response. The purpose of this study was to determine whether parturition, premature rupture of the membranes (PROM) and microbial invasion of the amniotic cavity (MIAC) are associated with changes in amniotic fluid concentrations of these antimicrobial peptides.

STUDY DESIGN

Amniotic fluid was retrieved by amniocentesis from 333 patients in the following groups: group 1, mid-trimester with a subsequent normal pregnancy outcome (n = 84); group 2, preterm labor and intact membranes without MIAC who delivered at term (n = 36), or prematurely (n = 52) and preterm labor with MIAC (n = 26); group 3, preterm PROM with (n = 26) and without (n = 26) MIAC; and group 4, term with intact membranes in the absence of MIAC, in labor (n = 52) and not in labor (n = 31). The concentrations of HNP 1-3, BPI and calprotectin in amniotic fluid were determined by specific and sensitive immunoassays. Placentae of patients in both preterm labor with intact membranes and preterm PROM groups who delivered within 72 h of amniocentesis were examined. Non-parametric statistics, receiver-operating characteristic (ROC) curves and Cox regression models were used for analysis. A p value of < 0.05 was considered statistically significant.

RESULTS

Intra-amniotic infection was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin in both women with preterm labor and intact membranes, and women with preterm PROM. Preterm PROM was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin. Preterm parturition was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin, while parturition at term was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3. Among patients with preterm labor and intact membranes, elevation of amniotic fluid HNP 1-3, BPI and calprotectin concentrations was associated with intra-amniotic inflammation, histological chorioamnionitis and a shorter interval to delivery.

CONCLUSION

MIAC, preterm parturition and preterm PROM are associated with increased amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin. Moreover, elevated amniotic fluid concentrations of BPI, immunoreactive HNP 1-3 and calprotectin are associated with intra-amniotic inflammation, histological chorioamnionitis and shorter amniocentesis-to-delivery interval in patients presenting with preterm labor with intact membranes.

Evidence of participation of soluble CD14 in the host response to microbial invasion of the amniotic cavity and intra-amniotic inflammation in term and preterm gestations

OBJECTIVE

Endotoxin has been implicated in the mechanism responsible for the setting of infection in preterm labor. To exert its biological effects, endotoxin binds to a circulating protein known as lipopolysaccharide binding protein (LBP) and presents endotoxin monomers to CD14, which may be a membrane-bound receptor or a soluble molecule. The endotoxin-LBP-CD14 complex interacts with Toll-like receptor 4 and other regulatory proteins leading to cellular activation and an inflammatory response. The purpose of this study was to determine whether microbial invasion of the amniotic cavity (MIAC)/intra-amniotic inflammation (both preterm and term) and parturition at term are associated with changes in the amniotic fluid and umbilical plasma soluble concentrations of CD14 (sCD14).

STUDY DESIGN

Amniotic fluid was retrieved by amniocentesis from 88 patients in the following groups: group 1, preterm labor with intact membranes with MIAC/intra-amniotic inflammation (n = 18) and without these conditions (n = 26); group 2, term gestations not in labor without MIAC/intra-amniotic inflammation (n = 11), in labor without MIAC/intra-amniotic inflammation (n = 12) and in labor with MIAC/intra-amniotic inflammation (n = 13); and group 3, patients who underwent genetic amniocentesis at mid-trimester (n = 8). A sample of cord blood was obtained after delivery in all patients except those in group 3. sCD14 was assayed with a sensitive and specific immunoassay. Non-parametric statistics were used for analysis. A p value of < 0.05 was considered significant.

RESULTS

sCD14 was detectable in 97% (85/88) of the amniotic fluid samples. Amniotic fluid sCD14 concentrations were lower in patients at term than in the mid-trimester of pregnancy (mid-trimester: median 482 ng/ml, range 258-838 ng/ml vs. term no labor: median 7 ng/ml, range 2-274 ng/ml, p = 0.01). Among patients with preterm labor with intact membranes, the median amniotic fluid sCD14 level of patients with MIAC/intra-amniotic inflammation was higher than in patients without these conditions (median 1568 ng/ml, range 98-5887 ng/ml vs. median 645 ng/ml, range 0-3961 ng/ml, respectively; p = 0.01). Among women at term in labor, those with MIAC/intra-amniotic inflammation had a higher median amniotic fluid sCD14 concentration than those without these conditions (median 85 ng/ml, range 2-1113 ng/ml vs. median 17 ng/ml, range 0-186 ng/ml; p = 0.01). MIAC/intra-amniotic inflammation in women with preterm labor with intact membranes was associated with a higher median umbilical venous plasma sCD14 concentration (median 744 ng/ml, range 0-3620 ng/ml vs. median 0 ng/ml, range 0-2060 ng/ml; p = 0.04). sCD14 was undetectable in plasma from umbilical cords of all neonates born to women at term. An increase in amniotic fluid concentration of sCD14 was observed in cases of intrauterine infection, not only by gram-negative bacteria, but also gram-positive bacteria and Ureaplasma spp.

CONCLUSION

sCD14 is a physiological constituent of amniotic fluid, and its concentrations at term are lower than in the mid-trimester. Intrauterine infection/inflammation is associated with a higher median amniotic fluid sCD14 concentration in both preterm and term parturition. Neonates born from mothers with preterm labor with intact membranes and MIAC/intra-amniotic inflammation had a higher median concentration of sCD14 in umbilical cord plasma than those without these conditions. sCD14 concentrations are increased in the amniotic fluid and umbilical cord blood even in the absence of a microbiologically proven gram-negative infection. CD14 appears to participate in the host response to intrauterine infection even in cases involving genital mycoplasmas.

Lipopolysaccharide-binding protein in microbial invasion of the amniotic cavity and human parturition

OBJECTIVE

Lipopolysaccharide-binding protein (LBP) is an acute-phase protein of predominantly hepatic origin, capable of binding the lipid A fraction of bacterial lipopolysaccharide (LPS). The complex LBP-LPS binds to CD14, and has been implicated in the host response to gram-negative infection. The purpose of this study was to determine whether microbial invasion of the amniotic cavity (MIAC) and parturition (term and preterm) are associated with changes in the amniotic fluid concentration of LBP.

STUDY DESIGN

Amniotic fluid was retrieved by amniocentesis from 343 patients in the following groups: (1) those in mid-trimester with a subsequent normal pregnancy outcome (n = 84); (2) those in mid-trimester with a fetal loss after the procedure (n = 10); (3) those with preterm labor and intact membranes without MIAC who delivered at term (n = 36) or prematurely (n = 52), and those with preterm labor with MIAC (n = 26); (4) those with preterm premature rupture of membranes (PROM) with (n = 26) and without (n = 26) MIAC; and (5) those delivering at term with intact membranes in the absence of MIAC, in labor (n = 52) and not in labor (n = 31). The concentration of LBP in amniotic fluid was determined with a specific and sensitive immunoassay. Non-parametric statistics were used. A p value of < 0.05 was considered significant.

RESULTS

LBP was detected in 98% (335/343) of the amniotic fluid samples. MIAC was associated with a significant increase in amniotic fluid concentration of LBP in women with preterm labor and intact membranes, but not in preterm PROM. Spontaneous preterm parturition was associated with a significant increase in amniotic fluid concentration of LBP. Patients who had a spontaneous fetal loss after a mid-trimester amniocentesis had a significantly higher median amniotic fluid LBP concentration than those who had a mid-trimester amniocentesis and a normal perinatal outcome.

CONCLUSION

Preterm labor with MIAC and preterm parturition are associated with higher amniotic fluid concentrations of LBP than those with sterile amniotic fluid.

[A study on ways of intrauterine infection of chlamydia trachomatis]

OBJECTIVE

To study the route of intrauterine infection of chlamydia trachomatis (CT).

METHODS

Seven hundred and seventy-two cervical samples from in women and 105 matched maternal-labom neonatal samples composed of cervical samples, cord blood, amniotic fluid, conjunctival and nasopharyngeal samples of neonate were detected by PCR-SSCP and DNA sequencing technique.

RESULTS

CT were detected in 87 of 772 (11.3%) cervical samples. In the 81 matched maternal-infant samples from pregnant women with cervical CT-positive, CT were not detected in all of the cord blood samples. In the 30 CT-positive neonatal samples, 26 were from cases of vaginal delivery and 4 from cases of caesarean section. Statistical analysis showed a significant difference between the groups of caesarean section and the vaginal delivery (P < 0.01). Four of 11 amniotic fluid samples with CT-positive were obtained during caesarean section in which 3 were without premature rupture of membranes (PROM), SSCP patients were same between maternal samples and matched neonatal samples. The sequences of amplified DNA fragments also showed the same results between maternal and match neonatal samples. No samples were found CT-positive in 24 matched maternal-infant samples from cervical CT-negative women.

CONCLUSIONS

An ascending transmission from cervix to amniotic cavity was the major route for CT intrauterine infection. Transplacental passage of chlamydial infection was not confirmed. Rates of vertical transmission were significantly lower in caesarean section group than that of vaginal delivery group with maternal cervical chlamydial positive.

Identification of matrix metalloproteinase-9 in amniotic fluid and amniochorion in spontaneous labor and after experimental intrauterine infection or interleukin-1 beta infusion in pregnant rhesus monkeys

OBJECTIVE

The purpose of this study was to examine the roles of intrauterine infection, inflammation, and spontaneous labor on the expression of matrix metalloproteinase-9 in fetal membranes and amniotic fluid of late pregnant rhesus monkeys.

STUDY DESIGN

Pregnant rhesus monkeys with timed gestations were chronically catheterized to allow serial sampling of amniotic fluid before and during experimentally induced intrauterine inflammation. Six animals received group B streptococci into the chorionic-decidual space, and 4 animals received intra-amniotic interleukin-1 beta infusions (10 microg). Three additional animals were serially sampled by amniocentesis through late pregnancy until spontaneous term labor. Amniotic fluid samples were examined by zymography for matrix metalloproteinase-9 and -2 and Western immunoblot for matrix metalloproteinase-9 and -2 and tissue inhibitors of metalloproteinase-1 and -2. Fetal membranes were obtained at cesarean delivery during labor (before rupture), formalin fixed, and embedded in paraffin for immunocytochemistry of matrix metalloproteinase-9 and in situ hybridization of matrix metalloproteinase-9 messenger RNA. Tissues from 2 additional animals were collected as age-matched non-labor controls.

RESULTS

In amniotic fluid, the 92-kd latent matrix metalloproteinase-9 was detectable in late pregnancy and increased dramatically, followed by the appearance of the 83-kd active form before spontaneous term delivery. Amniotic fluid matrix metalloproteinase-2 levels (both latent and active forms) remained relatively constant throughout pregnancy and in labor. Both bacteria and interleukin-1 beta rapidly increased the signal of latent matrix metalloproteinase-9 without a consistent increase in the active form before the onset of labor. Chorionic-decidual inoculation of group B streptococci was followed by the expression of latent matrix metalloproteinase-9 before the appearance of group B streptococci in amniotic fluid or the onset of labor. Matrix metalloproteinase-2 increased to a new steady-state level or remained unchanged after group B streptococci inoculation or interleukin-1 beta infusion, respectively. Amniotic fluid tissue inhibitors of metalloproteinase-1 declined and tissue inhibitors of metalloproteinase-2 remained unchanged during early group B streptococci infection, after interleukin-1 beta infusion and on the day of spontaneous term labor. However, both tissue inhibitors of metalloproteinase-1 and -2 levels increased after preterm labor that was induced by group B streptococci. Immunocytochemistry localized matrix metalloproteinase-9 protein to amnion and chorion epithelial and mesenchymal cells and decidual stromal cells. Granular matrix metalloproteinase-9 staining was observed in the connective tissue layer of inflamed fetal membranes. In situ hybridization for messenger RNA confirmed the production of matrix metalloproteinase-9 by amnion and chorion.

CONCLUSION

Bacterial- and interleukin-1 beta-induced preterm labor and spontaneous term labor are preceded and accompanied by progressive increases in amniotic fluid matrix metalloproteinase-9 (92 kd) in rhesus monkeys. Amniotic fluid matrix metalloproteinase-9 may serve as a clinical marker for the onset of both preterm and term labor.

Increased tumor necrosis factor-alpha production after lipopolysaccharide stimulation of whole blood in patients with previous preterm delivery complicated by intra-amniotic infection or inflammation

OBJECTIVE

To compare cytokine production after lipopolysaccharide stimulation of whole blood from women who were delivered of infants at term compared with women who were delivered of preterm infants with intra-amniotic evidence of infection or inflammation.

STUDY DESIGN

Whole blood samples from 12 women who were not pregnant and who had previously had preterm deliveries before 32 weeks complicated by intra-amniotic infection or inflammation and samples from 12 age- and race-matched control subjects were stimulated with Escherichia coli lipopolysaccharide. Tumor necrosis factor-alpha and interleukin-6 levels were quantified at 6 hours and interleukin-10 at 24 hours by enzyme immunoassay. Results were compared with use of the Wilcoxon rank sum test.

RESULTS

Tumor necrosis factor-alpha production was significantly higher in whole blood from women with histories of a preterm birth and intra-amniotic infection or inflammation (11,243 +/- 1030 pg/mL [mean +/- SEM]) compared with control subjects (3649 +/- 349 pg/mL) at a lipopolysaccharide concentration of 1 microg/mL (P =.002). There were no significant differences in interleukin-6 or interleukin-10 production.

CONCLUSION

Women with previous early preterm deliveries who had evidence of intra-amniotic infection or inflammation had significantly higher tumor necrosis factor-alpha production after lipopolysaccharide stimulation of whole blood compared with women with previous term deliveries.

Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes

OBJECTIVE

The purpose of this study was to determine the frequency and clinical significance of intraamniotic inflammation in patients with preterm labor and intact membranes.

STUDY DESIGN

Amniocentesis was performed in 206 patients with preterm labor and intact membranes. Amniotic fluid was cultured for aerobic and anaerobic bacteria and mycoplasmas. The diagnosis of intraamniotic inflammation was made in patients with a negative amniotic fluid culture on the basis of amniotic fluid concentrations of interleukin-6 (>2.6 ng/mL, derived from receiver operating characteristic curve analysis). Statistical analysis was conducted with contingency tables and survival techniques.

RESULTS

Intra-amniotic inflammation (negative amniotic fluid culture but elevated amniotic fluid interleukin-6) was more common than intra-amniotic infection (positive amniotic fluid culture regardless of amniotic fluid interleukin-6 concentration; 21% [44/206 women] vs 10% [21/206 women]; P <.001). The amniocentesisto-delivery interval was significantly shorter in patients with intra-amniotic inflammation than in patients with a negative culture and without an inflammation (median, 20 hours [range, 0.1-2328 hours] vs median, 701 hours [range, 0.1-3252 hours], respectively; P <.0001). Spontaneous preterm delivery of <37 weeks was more frequent in patients with intra-amniotic inflammation than in those with a negative culture and without inflammation (98% vs 35%; P <.001). Patients with intra-amniotic inflammation had a significantly higher rate of adverse outcome than patients with a negative culture and without intra-amniotic inflammation. Adverse outcomes included clinical and histologic chorioamnionitis, funisitis, early preterm birth, and significant neonatal morbidity. There were no significant differences in the rate of adverse outcomes between patients with a negative culture but with intra-amniotic inflammation and patients with intra-amniotic infection (positive culture regardless of amniotic fluid interleukin-6 concentration).

CONCLUSION

Intra-amniotic inflammation/infection complicates one third of the patients with preterm labor (32%; 65/206 women), and its presence is a risk factor for adverse outcome. The outcome of patients with microbiologically proven intra-amniotic infection is similar to that of patients with intra-amniotic inflammation and a negative amniotic fluid culture. We propose that the treatment of patients in preterm labor be based on the operational diagnosis of intra-amniotic inflammation rather than the diagnosis of intra-amniotic infection because the latter diagnosis cannot be undertaken rapidly.

Amniotic fluid matrix metalloproteinase-8 indicates intra-amniotic infection

OBJECTIVE

This study was undertaken to determine whether matrix metalloproteinase-8, which is produced by neutrophils, is a useful marker for the detection of intra-amniotic infection.

STUDY DESIGN

We performed a case-control study using enzyme-linked immunosorbent assays to detect matrix metalloproteinase-8 in 77 amniotic fluid specimens that were obtained by amniocentesis from women with preterm contractions or preterm labor and intact fetal membranes (n = 66) and from women with preterm premature rupture of membranes (n = 11).

RESULTS

Thirty women had culture-proven intra-amniotic infection (cases), 21 of whom had intact membranes. After constructing receiver operating characteristic curves to establish the optimal threshold concentration of matrix metalloproteinase-8 for a positive test result, we detected matrix metalloproteinase-8 in 27 of 30 women with intra-amniotic infection; only 10 of 47 control specimens contained matrix metalloproteinase-8 (P <.001; odds ratio, 33.3; 95% CI, 8.4, 132.7). Matrix metalloproteinase-8 was present in 20 of 21 women with intact membranes and intra-amniotic infection and in only 10 of 45 control subjects (P <.001; odds ratio, 70.0; 95% CI, 8.3, 587.6). Among women with intact membranes, the sensitivity of the assay was 0.95 and the specificity was 0.78.

CONCLUSION

Our results indicate that matrix metalloproteinase-8 is highly correlated with intra-amniotic infection and that enzyme-linked immunosorbent assay for matrix metalloproteinase-8 may be a clinically useful test for the diagnosis of intra-amniotic infection in women with preterm contractions and preterm labor.

Support for an infection-induced apoptotic pathway in human fetal membranes

OBJECTIVE

Lipopolysaccharide and tumor necrosis factor alpha levels are both elevated in the amniotic fluid of women during infection-associated preterm labor and premature rupture of fetal membranes. Our laboratory has shown that apoptosis is associated with premature rupture of fetal membranes but is not associated with preterm labor. The exact pathway that leads to apoptosis-mediated premature rupture of fetal membranes is still unclear. Because infection and increased inflammatory cytokine response are associated with the majority of cases of premature rupture of fetal membranes, we examined the roles of bacterial lipopolysaccharide and tumor necrosis factor alpha in inducing the proapoptotic caspase pathway in fetal membranes.

STUDY DESIGN

Amniochorionic membranes collected from women undergoing elective repeat cesarean delivery at term were placed in an organ explant system. At the end of a 48-hour incubation period, membranes were stimulated with lipopolysaccharide (50 ng/mL) and recombinant tumor necrosis factor (50 ng/mL). Total ribonucleic acid extracted from these samples was subjected to reverse transcription and two separate sets of multiple polymerase chain reaction. One set studied the expression of Fas, Fas ligand, caspase 8, Fas-associated death domain, and tumor necrosis factor receptor-associated death domain genes and the second set studied the expression of caspase 2, 4, 6, 7, and 10. Caspase 2, 3, and 9 expression was also studied by reverse transcriptase-polymerase chain reaction.

RESULTS

Multiple polymerase chain reactions and reverse transcriptase-polymerase chain reactions documented the induction of Fas and caspase 2, 3, 7, 8, and 9 genes in amniochorion after lipopolysaccharide and tumor necrosis factor stimulation compared with the nonstimulated controls. Neither lipopolysaccharide nor tumor necrosis factor induced Fas ligand expression in human fetal membranes. Caspase 3, 4, and 6, Fas-associated death domain, and tumor necrosis factor receptor-associated death domain expressions were constitutive in all the tissues tested; however, tumor necrosis factor receptor-associated death domain expression appeared stronger in tumor necrosis factor-stimulated tissues.

CONCLUSION

The presence of the signal docking proteins tumor necrosis factor receptor-associated death domain and Fas-associated death domain and the induction of caspase cascade initiators (caspase 2, 8, and 10) and effector caspases (caspase 3, 6, 7, and 9) by lipopolysaccharide and tumor necrosis factor suggest that tumor necrosis factor-tumor necrosis factor receptor-mediated apoptosis may occur in the human fetal membrane.

Bacterial contamination of amniotic membrane

AIM

In the light of interest being shown in amniotic membrane grafts for use in ocular surgery, this study aims to identify the bacterial contaminants commonly found on placental membranes from both caesarean and vaginal deliveries.

METHODS

Samples of placental membrane were taken following both elective caesarean and normal vaginal deliveries. Bacterial contaminants were identified.

RESULTS

All samples were contaminated. A greater number of different species were recovered from the vaginal deliveries, including several which were actually or potentially pathogenic.

CONCLUSION

There is a greater risk of contamination from pathogenic bacteria on placentas from vaginal deliveries. It is recommended that amnion for use in ocular surface procedures should be retrieved only from placentas following elective caesarean deliveries.

Antibacterial properties of human amnion and chorion in vitro

OBJECTIVE

The purpose of the present study was to explore the direct effects of amnion and chorion on bacterial growth in vitro including the antibacterial spectrum. Chorioamniotic membranes were obtained under sterile conditions from 13 healthy women undergoing elective cesarean section at term. Likewise, chorioamniotic membranes were obtained from 10 healthy women with spontaneous vaginal delivery at term. Five strains of Hemolytic streptococci group B (GBS) were tested and one clinical isolate of the following species or bacterial groups: Hemolytic streptococcus group A, Staphylococcus aureus, Staphylococcus saprophyticus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter calcoaceticus and Lactobacillus species. Bacteriological media included (1) blood-agar medium; (2) a transparent agar medium for submerged cultures; and (3) a nutrient broth medium.

RESULTS

An inhibitory effect of fetal membranes against a range of bacteria was found. Consistent results were obtained in experiments with cultures on agar and cultures suspended in agar (membranes from eight women in both studies). In experiments with liquid cultures (seven women) only chorion showed a marginal inhibitory effect. All strains were inhibited, but the most pronounced inhibition was obtained for streptococcus group A, S. aureus and S. saprophyticus by both chorion and amnion.

CONCLUSION

This study demonstrated an inhibitory effect of the fetal membranes on a diverse panel of bacteria

The association of coagulase-negative staphylococci isolated from the chorioamnion at delivery and subsequent development of cerebral palsy

OBJECTIVE

To find out whether there is an association between cultures positive for coagulase negative staphylococci (CONS) taken from babies in the Neonatal Intensive Care Unit (NICU) and a subsequent outcome of cerebral palsy.

STUDY DESIGN

At delivery, we obtained cultures from the chorioamnion space and, when medically indicated, we obtained bacterial cultures from children in the NICU. Surviving neonates underwent final examination for cerebral palsy at age 18 months.

RESULTS

Of six children in the Magnesium and Neurologic Endpoints Trial who had cerebral palsy, chorioamnion cultures had been obtained for five of six. Four of these five children (80%) had CONS-positive cultures, whereas 26 of 102 (25%) children without cerebral palsy were CONS positive (p = 0.02). In the NICU, of children with cerebral palsy, the prevalence of culture-proven CONS was 80% (4/5); for those without cerebral palsy, the prevalence was 17% (15/86) (p = 0.01). Using multivariable logistic regression to control for confounding, CONS in the chorioamnion remained significant (adjusted odds ratio [OR] 37.7, 95% confidence interval [CI] 3.0 to +infinity; p = 0.003). However, when controlled for extremely low birth weight, nonvertex presentation, and being on a ventilator > or = 20 days, the association between culture-proven CONS in the NICU and cerebral palsy became insignificant (adjusted OR 3.0, 95% CI 0.2 to +infinity; p = 0.42).

CONCLUSION

CONS in the chorioamnion space are associated with cerebral palsy, but in these data, CONS in the NICU are not found to be associated with cerebral palsy.