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Updated: Aug 6, 2026
08:23
Feeding of Ticks on Animals for Transmission and Xenodiagnosis in Lyme Disease Research
Published on: August 31, 2013
A new variant of Brucella melitensis
N E Lucero1, S M Ayala, G I Escobar
1Brucellosis Laboratory, Administración Nacional de Laboratorios e Institutos de Salud Dr C.G. Malbrán, ANLIS, Buenos Aires, Argentina. nidia@elsitio.net
Summary
Nine atypical Brucella melitensis strains were identified in humans in Argentina. These isolates exhibit unique characteristics, suggesting a potential new mutant variant emergence in the region.
Area of Science:
- Microbiology
- Infectious Diseases
- Public Health
Background:
- Brucella melitensis is a highly pathogenic bacterium posing significant public health risks.
- Biovar 1 Brucella melitensis has been previously isolated from animals in Argentina.
- The B. melitensis Rev.1 vaccine strain is not authorized for use in Argentina.
Purpose of the Study:
- To describe nine atypical Brucella melitensis isolates recovered from human cases in Argentina.
- To characterize the phenotypic and genotypic properties of these novel isolates.
- To assess the potential public health implications of these atypical strains.
Main Methods:
- Isolation and cultivation of Brucella melitensis from human samples.
- Phenotypic characterization including growth rate, colony morphology, and antimicrobial susceptibility testing (penicillin, streptomycin).
- Dye sensitivity testing.
Main Results:
- Nine atypical Brucella melitensis isolates were obtained from human patients.
- These isolates displayed slow growth and small colony formation.
- Susceptibility to penicillin and dyes was observed, similar to the B. melitensis Rev.1 vaccine strain.
- Inhibition by streptomycin (2.5 mg/L) was noted, differentiating them from typical B. melitensis strains.
- No similar atypical variants have been reported in animals in Argentina.
Conclusions:
- The identified atypical Brucella melitensis isolates possess distinct characteristics.
- These findings may indicate the emergence of a novel mutant variant in Argentina.
- Further investigation is warranted to understand the origin and implications of these atypical strains for public health and animal health surveillance.
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