Related Experiment Video
Updated: Aug 1, 2026
Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings
Published on: October 25, 2015
Pathogenicity and protective activity in pregnant goats of a Brucella melitensis Deltaomp25 deletion mutant
M D Edmonds1, A Cloeckaert, S D Hagius
1Department of Veterinary Microbiology and Parasitology, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA.
Abstract:
The Brucella melitensis mutant BM 25, which lacks the major 25 kDa outer membrane protein Omp25, has previously been found to be attenuated in the murine brucellosis model. In the present study, the capacity of the Deltaomp25 mutant to colonise and cause abortions in the caprine host was evaluated. The vaccine potential of BM 25 was also investigated in goats. Inoculation of nine pregnant goats in late gestation with the B. melitensis mutant resulted in 0/9 abortions, while the virulent parental strain, B. melitensis 16M, induced 6/6 dams to abort (P<0.001, n=6). BM 25 also colonised fewer adults (P<0.05, n=6) and kids (P<0.01, n=6) than strain 16M. The Deltaomp25 mutant was found capable of transient in vivo colonisation of non-pregnant goats for two weeks post-infection. Owing to the ability of BM 25 to colonise both non-pregnant and pregnant adults without inducing abortions, a vaccine efficacy study was performed. Vaccination of goats prior to breeding with either BM 25 or the current caprine vaccine B. melitensis strain Rev. 1 resulted in 100 per cent protection against abortion following challenge in late gestation with virulent strain 16M (P<0.05, n=7). However, unlike strain Rev. 1, BM 25 does not appear to cause abortions in late gestation based on this study with a small number of animals. The B. melitensis Deltaomp25 mutant, BM 25, may be a safe and efficacious alternative to strain Rev. 1 when dealing with goat herds of mixed age and pregnancy status.
Insights
The Brucella melitensis Deltaomp25 mutant BM 25 shows promise as a safe and effective vaccine candidate for goats. It colonizes goats without causing abortions and protects them from virulent Brucella melitensis.
Area of Science:
- Veterinary Microbiology
- Immunology
Background:
- Brucellosis is a significant zoonotic disease affecting livestock, particularly goats.
- Brucella melitensis is a primary cause of caprine brucellosis, leading to abortions and economic losses.
- Current vaccines may have limitations in specific host populations.
Purpose of the Study:
- To evaluate the pathogenicity and vaccine potential of the Brucella melitensis Deltaomp25 mutant (BM 25) in goats.
- To compare the efficacy of BM 25 against the virulent B. melitensis 16M strain and the current vaccine strain Rev. 1.
Main Methods:
- Infection of pregnant and non-pregnant goats with B. melitensis BM 25 and 16M strains.
- Assessment of abortion rates, colonization levels in adults and kids, and transient colonization in non-pregnant goats.
- Vaccine efficacy study involving vaccination with BM 25 or Rev. 1, followed by challenge with B. melitensis 16M.
Main Results:
- The BM 25 mutant did not induce abortions in pregnant goats, unlike the virulent 16M strain.
- BM 25 showed reduced colonization in adult goats and kids compared to strain 16M.
- Both BM 25 and Rev. 1 provided 100% protection against abortion following challenge with virulent 16M, with BM 25 not causing abortions.
- BM 25 demonstrated transient colonization in non-pregnant goats.
Conclusions:
- The Brucella melitensis Deltaomp25 mutant BM 25 is attenuated in goats, causing no abortions.
- BM 25 is a safe and efficacious vaccine candidate, offering protection against virulent B. melitensis challenge.
- BM 25 may be a suitable alternative to strain Rev. 1 for vaccinating goat herds with mixed age and pregnancy status.
Related Concept Videos
01:28Toxoplasmosis
01:25Clinical Significance of Antibiotic Resistance