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

Kim, Mi Jeong; Romero, Roberto; Gervasi, Maria Teresa; Kim, Jung Sun; Yoo, Wonsuk; Lee, Deug Chan; Mittal, Pooja; Erez, Offer; Kusanovic, Juan Pedro; Hassan, Sonia S.; Kim, Chong Jai

doi:10.1038/labinvest.2009.49

Cited by 135 publications

(106 citation statements)

References 58 publications

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“…Moreover, the TLR5 and TLR6/2 responses that we observed in amniotic epithelial cells were somewhat predictable. Genital Mycoplasma (and in particular Ureaplasma urealyticum), Streptococcus agalactiae, as well as other Gram-positive and Gram-negative aerobic and anaerobic organisms are known to be associated with chorioamnionitis and PTB (9,41,42). Both TLR2 and TLR6 are necessary for responding to Mycoplasma-associated protein (43), and flagellin, the TLR5 ligand, is a highly immunogenic molecule expressed in flagellated Gram-positive and Gram-negative bacteria.…”

Section: Discussionmentioning

confidence: 99%

“…The association of PTB and colonization of the cervicovaginal tract with specific microorganisms, especially before 32 wk of pregnancy, has long been recognized (6)(7)(8)(9). Many infections are polymicrobial and most commonly involve commensal bacterial species found in the vaginal tract, such as genital Mycoplasma, in particular Ureaplasma urealyticum and Streptococcus agalactiae, other Gram-positive and -negative organisms, and commensal species of the oral cavity, although a causal link rather than an opportune commensality has yet to be ascertained.…”

mentioning

confidence: 99%

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Functional Screening of TLRs in Human Amniotic Epithelial Cells

Gillaux

Méhats

Vaiman

et al. 2011

The Journal of Immunology

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Intrauterine infection is a major cause of spontaneous preterm birth. Amniotic epithelial cells represent the first line of defense against intra-amniotic bacteria. We hypothesize that this epithelial cell barrier is able to recognize and respond to pathogens through the function of TLRs, which are crucial regulators of the innate immune system. In this study, we describe the expression of transcripts for TLR1–TLR10 in human amniotic epithelial cells. We show that amniotic epithelial cells express functional TLR5, TLR6/2, and TLR4. Activation by TLR5 and TLR6/2 agonists produces IL-6 and IL-8, concomitantly with the activation of NF-κB signaling pathway, matrix metalloproteinase-9 induction, and PTGS2 expression. In contrast, TLR4 activation reduced amniotic epithelial cell viability and induced cell apoptosis evidenced by an elevated Bax/Bcl-2 ratio and cleavage of caspase-3. These data suggest specific TLR-mediated functions in human amniotic epithelial cells for initiating different immune responses, which ultimately may lead to preterm birth.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Functional Screening of TLRs in Human Amniotic Epithelial Cells

Gillaux

Méhats

Vaiman

et al. 2011

The Journal of Immunology

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“…Additionally, the molecular characteristics and AST results of the isolates from different specimens revealed 100% consistency, and the three isolates belonged to a new sequence typing. Furthermore, in our case, the fetal membrane was found intact before Csection, which might be explained by the ability of the microorganism to cross the intact membranes [13][14][15]. Despite the fact that SDSE has been rarely documented either to colonize the vaginal tract or as a cause of maternal infections [19], this case suggests that SDSE colonized in the lower genital tract may be a potential, if rare, cause of maternal IAI via the ascending route during pregnancy.…”

Section: Discussionmentioning

confidence: 67%

“…The organisms frequently found in IAI and SSI after cesarean section are those normally present in the lower genital tract, indicating that the lower genital tract is the most likely reservoir for causative microorganisms for maternal infections via the ascending pathway under the appropriate circumstances [13][14][15][16]. SDSE, increasingly recognized as an important human pathogen, is a group C or G pyogenic β-hemolytic streptococcus sharing similar virulence factors and disease spectrum with GAS [17].…”

Section: Discussionmentioning

confidence: 99%

First molecular evidence of intrauterine and surgical-site infections caused by Streptococcus dysgalactiae subsp. equisimilis

Diao

Fang

et al. 2016

J Infect Dev Ctries

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S. dysgalactiae subsp. equisimilis (SDSE) is infrequently associated with maternal infections during delivery in pregnant women. A rare case is presented of a woman with intrauterine infection and surgical-site infection due to SDSE after cesarean section, which had colonized her genital tract and, via the ascending pathway, reached her intact fetal membrane. All isolates were identified as Streptococcus Lancefield group G, and their emm genes that coded M protein belonged to stG6.1. The isolates tested negative for a series of streptococcal superantigen virulence genes but positive for nonsuperantigenic virulence genes. In particular, molecular typing using pulsed-field gel electrophoresis analysis disclosed that the three isolates from the different infection sites had identical profiles. Furthermore, multilocus sequence typing indicated that the three isolates belonged to a new sequence typing. Our results indicated that SDSE is potentially pathogenic for pregnant women and newborns if colonized.

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“…The most common route is the ascension of microorganisms from the vagina through the cervix and into the uterus. The infection can ultimately gain access to the amniotic fluid thereby exposing the fetus to infection (Kim, Romero et al 2009). Other routes of infection include hematogenous spread through the placenta of non-genital tract infections such as those from the oral cavity (Bearfield, Davenport et al 2002).…”

Section: Cervical Ripeningmentioning

confidence: 99%