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Case Reports
. 2025 Jul 12;17(7):e87792.
doi: 10.7759/cureus.87792. eCollection 2025 Jul.

A Case of Intrauterine Listeria Infection During Pregnancy: NanoSuit Imaging of Listeria monocytogenes in the Amniotic Membrane

Chihiro Dohshita  1 , Naomi Isomura  1 , Chizuko Yaguchi  1 , Akira Ohishi  2 , Hiroaki Itoh  3   4 , Tomomi Kotani  1 , Hideya Kawasaki  5
Affiliations
Case Reports

A Case of Intrauterine Listeria Infection During Pregnancy: NanoSuit Imaging of Listeria monocytogenes in the Amniotic Membrane

Chihiro Dohshita et al. Cureus. .

Abstract

Listeriosis during pregnancy is rare but can lead to premature miscarriage and intrauterine fetal death. A 29-year-old pregnant woman at 29 weeks of gestation was transferred to our hospital because of mild fever and abdominal pain. Emergency cesarean section was performed due to non-reassuring fetal status concomitant with suspected intrauterine infection. An unusually bright yellow amniotic fluid was observed. The oropharyngeal cavity of the neonate was occupied by thick, tenacious yellow mucus, making its removal challenging. The neonate was intubated due to poor oxygenation. Neonatal blood cultures revealed Listeria monocytogenes. Gram staining of cerebrospinal fluid was negative. The neonate was treated and discharged on the 65th day after birth. The mother had a fever of 39.4°C on the first day after surgery; however, no other significant incident occurred. She was discharged on the 10th day after surgery. Placental pathology revealed funisitis, chorioamnionitis, and marginal deciduitis without evidence of villitis, suggesting predominant transvaginal rather than hematogenous infection. Scanning electron microscopy using NanoSuit imaging revealed Listeria monocytogenes in the amniotic epithelium. The presence of Listeria monocytogenes has been reported in foods stored in refrigerators for extended periods of time and in ready-to-eat meals; therefore, it is difficult for pregnant women to be aware of all potential risks. It is important for physicians to recognize that listeriosis may have a long incubation period and present with mild maternal symptoms. Nevertheless, it should be considered as a differential diagnosis. Routine and prompt identification of the causative organism through amniotic fluid and placental swab cultures is important, particularly when intrauterine infection is suspected. Moreover, pathological examination of the placenta can provide insights into the potential route of infection.

Keywords: intrauterine infection; listeria monocytogenes; nanosuit imaging; pregnancy; preterm delivery.

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Conflict of interest statement

Human subjects: Informed consent for treatment and open access publication was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Placental pathological findings
(H&E staining: scale bar 100μm) A: Umbilical artery - neutrophil infiltration extending into the muscular layer of the vascular wall, B: Umbilical vein - neutrophil infiltration extending to Wharton’s jelly, C: The infiltration of numerous neutrophils is observed on the decidual side of the marginal placental membrane, D: Neutrophil infiltration is not observed in the placental villi.
Figure 2
Figure 2. Amniotic epithelium was found to be Gram stain positive
Gram stain findings (scale bar; 20μm).
Figure 3
Figure 3. Immunohistochemical staining of Listeria monocytogenes
Anti-Listeria antibody: abcum:ab35132 (scale bar; 50μm). A: Positive (brown) is observed in the amniotic epithelium, B: Positive staining of Listeria monocytogenes is not observed in the placental villi or intervillous spaces.
Figure 4
Figure 4. NanoSuit-assisted scanning electron microscopy reveals Listeria monocytogenes in the amniotic membrane epithelium
Numerous bodies of Listeria monocytogenes (yellow arrows) are observed in the amniotic epithelium.
See this image and copyright information in PMC

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References

    1. An update review on listeria infection in pregnancy. Wang Z, Tao X, Liu S, Zhao Y, Yang X. Infect Drug Resist. 2021;14:1967–1978. - PMC - PubMed
    1. Detection of Listeria monocytogenes in humans, animals and foods. Iida T, Kanzaki M, Nakama A, Kokubo Y, Maruyama T, Kaneuchi C. J Vet Med Sci. 1998;60:1341–1343. - PubMed
    1. Overview of Listeria monocytogenes contamination in Japan. Okutani A, Okada Y, Yamamoto S, Igimi S. Int J Food Microbiol. 2004;93:131–140. - PubMed
    1. Listeriosis in pregnancy: a rare but high-risk infection. Correia de Sá A, Casanova D, Ferreira AL, Fernandes C, Cotter J. Cureus. 2023;15:0. - PMC - PubMed
    1. The NanoSuit method: a novel histological approach for examining paraffin sections in a nondestructive manner by correlative light and electron microscopy. Kawasaki H, Itoh T, Takaku Y, et al. Lab Invest. 2020;100:161–173. - PMC - PubMed

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