Abortive Potency of<i>Chlamydophila abortus</i>in Pregnant Mice Is Not Directly Correlated with Placental and Fetal Colonization Levels

Bouakane, Amel; Benchaîeb, Ilhem; Rodolakis, Annie

doi:10.1128/iai.71.12.7219-7222.2003

Cited by 16 publications

(14 citation statements)

References 31 publications

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“…Similar results were observed after intraperitoneal or intravenous inoculation of pregnant mice (Buzoni-Gatel and Rodolakis, 1983;. Only the three C. abortus strains AB16, POS and LLG differed from other C. abortus strains in their abortive effect, placental and foetal colonisation, as well as in level of IFN- in blood (Bouakane et al, 2003), suggesting an essential role of Pmp in the virulence of Chlamydiae. Pmp have been identified as autotransported surface proteins of the Type V secretion system (Henderson and Lam, 2001) and, consequently, likely to be essential to chlamydial virulence, including the ability to evade host immune responses by antigenic variation (Grimwood et al, 2001).…”

Section: Virulence Of Strainssupporting

confidence: 84%

Chlamydiaceae and chlamydial infections in sheep or goats

Rodolakis

Laroucau

2015

Veterinary Microbiology

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Section: Virulence Of Strainssupporting

confidence: 84%

Chlamydiaceae and chlamydial infections in sheep or goats

Rodolakis

Laroucau

2015

Veterinary Microbiology

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“…Additionally, these two variant strains, which are described as homologous strains in the literature, have been shown to possess similar monoclonal reactivity and growth characteristics [9], although this and other studies indicate that there may be differences [9,15]. The reasons for these apparent discrepancies are unclear.…”

Section: Discussionmentioning

confidence: 99%

Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS

et al. 2017

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This study investigated the pathogenesis of two variant strains (LLG and POS) of Chlamydia abortus, in comparison to a typical wild-type strain (S26/3) which is known to be responsible for late term abortion in small ruminants. Challenge with the three strains at mid-gestation resulted in similar pregnancy outcomes, with abortion occurring in approximately 50–60% of ewes with the mean gestational lengths also being similar. However, differences were observed in the severity of placental pathology, with infection appearing milder for strain LLG, which was reflected in the lower number of organisms shed in vaginal swabs post-partum and less gross pathology and organisms present in placental smears. Results for strain POS were somewhat different than LLG with a more focal restriction of infection observed. Post-abortion antibody responses revealed prominent differences in seropositivity to the major outer membrane protein (MOMP) present in elementary body (EB) preparations under denaturing conditions, most notably with anti-LLG and anti-POS convalescent sera where there was no or reduced detection of MOMP present in EBs derived from the three strains. These results and additional analysis of whole EB and chlamydial outer membrane complex preparations suggest that there are conformational differences in MOMP for the three strains. Overall, the results suggest that gross placental pathology and clinical outcome is not indicative of bacterial colonization and the severity of infection. The results also highlight potential conformational differences in MOMP epitopes that perhaps impact on disease diagnosis and the development of new vaccines.

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“…The overall biological, biochemical and genotypic differentiation between LLG/POS variant and other C. abortus classical strains [13]–[18] in addition to their phylogenetic placement favor the delineation of these lineages as “subspecies”. Nevertheless, their systematics should be significantly aided by future sequence analyses of complete genomes [78].…”

Section: Resultsmentioning

confidence: 99%

Evolutionary Relationships among Chlamydophila abortus Variant Strains Inferred by rRNA Secondary Structure-Based Phylogeny

et al. 2011

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The evolutionary relationships among known Chlamydophila abortus variant strains including the LLG and POS, previously identified as being highly distinct, were investigated based on rRNA secondary structure information. PCR-amplified overlapping fragments of the 16S, 16S-23S intergenic spacer (IS), and 23S domain I rRNAs were subjected to cloning and sequencing. Secondary structure analysis revealed the presence of transitional single nucleotide variations (SNVs), two of which occurred in loops, while seven in stem regions that did not result in compensatory substitutions. Notably, only two SNVs, in 16S and 23S, occurred within evolutionary variable regions. Maximum likelihood and Bayesian phylogeny reconstructions revealed that C. abortus strains could be regarded as representing two distinct lineages, one including the “classical” C. abortus strains and the other the “LLG/POS variant”, with the type strain B577T possibly representing an intermediate of the two lineages. The two C. abortus lineages shared three unique (apomorphic) characters in the 23S domain I and 16S-23S IS, but interestingly lacked synapomorphies in the 16S rRNA. The two lineages could be distinguished on the basis of eight positions; four of these comprised residues that appeared to be signature or unique for the “classical” lineage, while three were unique for the “LLG/POS variant”. The U277 (E. coli numbering) signature character, corresponding to a highly conserved residue of the 16S molecule, and the unique G681 residue, conserved in a functionally strategic region also of 16S, are the most pronounced attributes (autapomorphies) of the “classical” and the “LLG/POS variant” lineages, respectively. Both lineages were found to be descendants of a common ancestor with the Prk/Daruma C. psittaci variant. Compared with the “classical”, the “LLG/POS variant” lineage has retained more ancestral features. The current rRNA secondary structure-based analysis and phylogenetic inference reveal new insights into how these two C. abortus lineages have differentiated during their evolution.

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Abortive Potency ofChlamydophila abortusin Pregnant Mice Is Not Directly Correlated with Placental and Fetal Colonization Levels

Cited by 16 publications

References 31 publications

Chlamydiaceae and chlamydial infections in sheep or goats

Chlamydiaceae and chlamydial infections in sheep or goats

Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS

Evolutionary Relationships among Chlamydophila abortus Variant Strains Inferred by rRNA Secondary Structure-Based Phylogeny

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