A new variant of Brucella melitensis

ABSTRACTBrucella melitensis is highly pathogenic and constitutes a serious risk to public health. In Argentina, biovar 1 has been isolated from infected animals, but the Rev.1 strain vaccine is not authorised for use. This report describes nine atypical B. melitensis isolates obtained from humans. These isolates grew slowly, produced small colonies and were susceptible to penicillin and dyes, similar to the B. melitensis Rev.1 vaccine strain, but were inhibited by streptomycin 2.5 mg/L. The isolation of such atypical B. melitensis variants has never been reported from animals in Argentina, and could indicate the emergence of a new mutant variant

Brucella abortus d'origine bovine au Sénégal : identification et typage

Cent quatre-vingt une souches de Brucella d'origine bovine, isolées au Sénégal, de 1976 à 1978, ont été identifiées par l'ensemble des épreuves recommandées par le sous-Comité de la Taxonomie de ce genre bactérien. Leurs caractères sont, pour l'essentiel, conformes à la définition de l'espèce Brucella abortus au sein de laquelle 180 souches appartiennent au biotype 3 et une au biotype 1. Deux caractères inhabituels pour cette espèce distinguent toutefois les souches sénégalaises: leur réponse négative - à une exception près - à l'épreuve de l'oxydase et leur profil moyen d'oxydation métabolique modifié au niveau de 4 des substrats conventionnels (L-asparagine, L-arabinose, D-galactose et D-xylose). Ces deux caractères originaux sont discutés d'un double point de vue, épidémiologique et taxonomiqu

Evaluation of a multiplex PCR assay (Bruce-ladder) for molecular typing of all <i>Brucella</i> species, including the vaccine strains

An evaluation of a multiplex PCR assay (Bruce-ladder) was performed in seven laboratories using 625 Brucella strains from different animal and geographical origins. This robust test can differentiate in a single step all of the classical Brucella species, including those found in marine mammals and the S19, RB51, and Rev.1 vaccine strains

Simultaneous Expression of Smooth and Rough Phase Properties Related To Lipopolysaccharide in a Strain of Brucella-melitensis

Brucella strains exhibit either a rough (R) or a smooth (S) colonial phase identifiable by bacteriological methods. This depends on the biosynthesis and translocation to the surface in S but not in R strains, of the O-polysaccharide chain of the lipopolysaccharide (LPS) molecule. B. melitensis biovar 1 strain EP exhibited simultaneously both S and R characteristics in relation to colonial morphology, agglutination by monospecific anti-M and anti-R sera, activity of bacteriophages lytic for rough Brucella spp. (phage R/C) and for smooth B. melitensis (phage Iz). B. melitensis strain EP expressed fewer O-chains with a similar distribution of molecular weights than B. melitensis reference strain 16M by SDS-PAGE and immunoblotting, but higher amounts of R-LPS. Quantitative determination of S-LPS by a turbidimetric latex inhibition immunoassay with monoclonal antibodies confirmed the limited expression of S-LPS in strain EP. As with other gram-negative bacteria, the phenomenon could be attributed to a deficiency in one step of the biosynthetic assembly of the O-chains

A new variant of Brucella melitensis

Fil: Lucero, Nidia E. ANLIS Dr. C. G. Malbrán. Instituto Nacional de Enfermedades Infecciosas (INEI). Laboratorio de Brucelosis; Argentina.Fil: Escobar, Gabriela I. ANLIS Dr. C. G. Malbrán. Instituto Nacional de Enfermedades Infecciosas (INEI). Laboratorio de Brucelosis; Argentina.Fil: Ayala, Sandra M. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas (INEI). Laboratorio de Brucelosis; Argentina.Fil: Grayon, M. Instituto Nacional de Investigaciones Agronómicas. Unidad de Patología e Inmunología Infecciosa; Nouzilly, Francia.Fil: Jacques, Isabelle. Instituto Nacional de Investigaciones Agronómicas. Unidad de Patología e Inmunología Infecciosa; Nouzilly, Francia.Brucella melitensis is highly pathogenic and constitutes a serious risk to public health. In Argentina, biovar 1 has been isolated from infected animals, but the Rev.1 strain vaccine is not authorised for use. This report describes nine atypical B. melitensis isolates obtained from humans. These isolates grew slowly, produced small colonies and were susceptible to penicillin and dyes, similar to the B. melitensis Rev.1 vaccine strain, but were inhibited by streptomycin 2.5 mg/L. The isolation of such atypical B. melitensis variants has never been reported from animals in Argentina, and could indicate the emergence of a new mutant variant