Ureaplasma parvum undergoes selection in utero resulting in genetically diverse isolates colonising the chorioamnion of fetal sheep

Dando, Samantha J., Nitsos, Ilias, Polglase, Graeme R., Newnham, John P., Jobe , Alan H., & Knox, Christine L. (2014) Ureaplasma parvum undergoes selection in utero resulting in genetically diverse isolates colonising the chorioamnion of fetal sheep. Biology of Reproduction, 90(2), pp. 1-10.

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Abstract

Ureaplasmas are the microorganisms most frequently isolated from the amniotic fluid of pregnant women and can cause chronic intrauterine infections. These tiny bacteria are thought to undergo rapid evolution and exhibit a hypermutatable phenotype; however, little is known about how ureaplasmas respond to selective pressures in utero. Using an ovine model of chronic intra-amniotic infection, we investigated if exposure of ureaplasmas to sub-inhibitory concentrations of erythromycin could induce phenotypic or genetic indicators of macrolide resistance. At 55 days gestation, 12 pregnant ewes received an intra-amniotic injection of a non-clonal, clinical U. parvum strain, followed by: (i) erythromycin treatment (IM, 30 mg/kg/day, n=6); or (ii) saline (IM, n=6) at 100 days gestation. Fetuses were then delivered surgically at 125 days gestation. Despite injecting the same inoculum into all ewes, significant differences between amniotic fluid and chorioamnion ureaplasmas were detected following chronic intra-amniotic infection. Numerous polymorphisms were observed in domain V of the 23S rRNA gene of ureaplasmas isolated from the chorioamnion (but not the amniotic fluid), resulting in a mosaic-like sequence. Chorioamnion isolates also harboured the macrolide resistance genes erm(B) and msr(D) and were associated with variable roxithromycin minimum inhibitory concentrations. Remarkably, this variability occurred independently of exposure of ureaplasmas to erythromycin, suggesting that low-level erythromycin exposure does not induce ureaplasmal macrolide resistance in utero. Rather, the significant differences observed between amniotic fluid and chorioamnion ureaplasmas suggest that different anatomical sites may select for ureaplasma sub-types within non-clonal, clinical strains. This may have implications for the treatment of intrauterine ureaplasma infections.

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4 citations in Web of Science®
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ID Code: 66210
Item Type: Journal Article
Refereed: Yes
Additional URLs:
Keywords: Amniotic fluid, Chorioamnion, minimum inhibitory concentration, ribosomal RNA, Ureaplasma parvum, ovine model
DOI: 10.1095/biolreprod.113.113456
ISSN: 1529-7268
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > EVOLUTIONARY BIOLOGY (060300) > Host-Parasite Interactions (060307)
Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > MICROBIOLOGY (060500)
Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > MICROBIOLOGY (060500) > Infectious Agents (060502)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > PAEDIATRICS AND REPRODUCTIVE MEDICINE (111400) > Reproduction (111404)
Divisions: Current > Schools > School of Biomedical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Funding:
Copyright Owner: Copyright 2013 by The Society for the Study of Reproduction.
Copyright Statement: The above signed authors, jointly and severally, relinquish to the Society for the Study of Reproduction, Inc. (SSR), all control over this material such as rights to make or authorize reprints, to reproduce the materials in other association publications, and to grant the material to others with or without charge. The above signed grant and assign exclusively to SSR for its use any and all rigths of what-so-ever kind or nature now or hereafter protected by the copyright laws (common or statutory) in the United States and all foreign countries in all languages in and to the above-named article, including all subsidary rights. The SSR, in turn, grants to each author the right of republication in any work of which she/he is the author or editor, subject only to giving proper credit to the original journal publication of the article. If the manuscript is not accepted for publication, this copyright transfer has no legal effect and will be returned upon request.
Deposited On: 15 Jan 2014 23:19
Last Modified: 09 Sep 2014 04:00

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