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Nonhuman primate model for Listeria monocytogenes-induced stillbirths
Mary Alice Smith1, Kazue Takeuchi, Robert E Brackett
1Department of Environmental Health Science, University of Georgia, Athens, Georgia 30602, USA. masmith@uga.edu
Abstract:
Listeria monocytogenes, isolated from outbreaks in either human or nonhuman primate populations, was administered orally at doses ranging from 10(6) to 10(10) CFU. Four of 10 treated animals delivered stillborn infants. L. monocytogenes was isolated from fetal tissue, and the pathology was consistent with L. monocytogenes infection as the cause of pregnancy loss. For all pregnancies resulting in stillbirths, L. monocytogenes was isolated from maternal feces, indicating that L. monocytogenes had survived and had probably colonized the gastrointestinal tract. Antibodies and antigen-specific lymphocyte proliferation against Listeria increased in animals that had stillbirths.
Insights
Oral administration of Listeria monocytogenes caused pregnancy loss in nonhuman primates. The bacteria were found in fetal tissues and maternal feces, indicating infection and gastrointestinal colonization led to stillbirths.
Area of Science:
- Veterinary Medicine
- Microbiology
- Reproductive Science
Background:
- Listeria monocytogenes is a foodborne pathogen causing listeriosis in humans and animals.
- Pregnancy loss is a significant concern in both human and nonhuman primate populations.
- Previous studies have linked Listeria monocytogenes to abortions in various animal species.
Purpose of the Study:
- To investigate the effects of oral Listeria monocytogenes infection on pregnancy outcomes in nonhuman primates.
- To determine if Listeria monocytogenes can cause fetal infection and pregnancy loss in this model.
- To assess the immune response in animals experiencing pregnancy loss due to Listeria monocytogenes.
Main Methods:
- Nonhuman primates were orally administered varying doses of Listeria monocytogenes (10^6 to 10^10 CFU).
- Pregnancy outcomes were monitored, and stillborn infants were examined for the presence of Listeria monocytogenes.
- Fetal tissues and maternal fecal samples were analyzed for bacterial isolation and identification.
- Antibody levels and antigen-specific lymphocyte proliferation were measured in exposed animals.
Main Results:
- Four out of ten treated animals delivered stillborn infants.
- Listeria monocytogenes was successfully isolated from the fetal tissues of stillborn infants.
- The pathology observed was consistent with Listeria monocytogenes infection causing pregnancy loss.
- Listeria monocytogenes was consistently found in the feces of mothers experiencing stillbirths, suggesting gastrointestinal colonization.
- Increased antibodies and lymphocyte proliferation against Listeria were detected in animals with stillbirths.
Conclusions:
- Oral Listeria monocytogenes infection can lead to pregnancy loss and stillbirths in nonhuman primates.
- The gastrointestinal tract appears to be a reservoir for Listeria monocytogenes during pregnancy, facilitating fetal infection.
- The study demonstrates the utility of nonhuman primates as a model for investigating Listeria monocytogenes-induced reproductive failure.