Genetic stability of Brucella abortus S19 and RB51 vaccine strains by multiple locus variable number tandem repeat analysis (MLVA16).
The aims of the present study were (i) to assess the in vitro genetic stability of S19 and RB51 Brucella abortus vaccines strains and (ii) to evaluate the ability of multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) as a tool to be used in the quality control of live vaccines against brucellosis. Sixty-three batches of commercial S19 (n=53) and RB51 (n=10) vaccines, produced between 2006 and 2009, were used in this study. S19 and RB51 vaccines were obtained from, respectively, seven and two different manufacturers. Ten in vitro serial passages were performed on reference strains and on selected batches of commercial vaccines. All batches, reference strains and strains of serial passages were typed by the MLVA16. The results demonstrated that B. abortus S19 and RB51 vaccine strains are genetically stable and very homogeneous in their respective groups. Anyway, batches of S19 from one manufacturer and batches of RB51 from another presented genotypes distincts from the reference vaccine strains. In both cases, differences were found on locus Bruce07, which had addition of one repeat unit in the case of S19 batches and the deletion of one repeat unit in the case of RB51 batches. In summary, MLVA16 proved to be a molecular tool capable of discriminating small genomic variations and should be included in in vitro official tests.
Laboratório de Bacteriologia Aplicada, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Elaine Maria Seles
EM
Dorneles
Ana Paula Paiva
AP
de Faria
Rebeca Barbosa
RB
Pauletti
Jordana Almeida
JA
Santana
George Afonso Vítor
GA
Caldeira
Marcos Bryan
MB
Heinemann
Ricardo
R
Titze-de-Almeida
Andrey Pereira
AP
Lage
D002004:Brucella Vaccine / Q000235:genetics*; D002003:Brucella abortus / Q000235:genetics*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics*; D004355:Drug Stability; D042822:Genomic Instability; D005838:Genotype; D018598:Minisatellite Repeats
D002004:Brucella Vaccine; D004269:DNA, Bacterial
Brucellosis; Genotyping; MLVA16; Vaccines