Archive for June 22, 2012

Detection and differentiation of the six Brucella species by polymerase chain reaction.

Mol Med. Nov. 1997  V.3 N.11 P.734-9.

Sifuentes-Rincón AM, Revol A, Barrera-Saldaña HA.

Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, México.



Brucelosis is a severe acute febrile disease caused by bacteria of the genus Brucella. Its current diagnosis is based on clinical observations that may be complemented by serology and microbiological culture tests; however, the former is limited in sensitivity and specificity, the latter is time consuming. To improve brucelosis diagnosis we developed a test which is specific and sensitive and is capable of differentiating the six species of Brucella.


Four primers were designed from B. abortus sequences at the well-conserved Omp2 locus that are able to amplify the DNAs of all six species of Brucella.


Our test detected all six species of Brucella. Their differentiation resulted directly from differences in the amplification patterns or was achieved indirectly using a RFLP present in one of the PCR products. The sensitivity and specificity of the new test were then determined; it was applied successfully in confirming the diagnosis of a patient whose clinical history and serology indicated infection with Brucella.


The results make possible the use of a PCR test for Brucella detection and differentiation without relying on the measurement of the antibodies or microorganism culture. Our first results showed that the PCR test can confirm the presence of Brucella in blood samples of infected patients.


June 22, 2012 at 2:37 pm

In vitro and in vivo activities of linezolid alone and combined with vancomycin and imipenem against Staphylococcus aureus with reduced susceptibility to glycopeptides.

Eur J Clin Microbiol Infect Dis. 2010 Nov  V.29 N.11 P.1361-7.

Ribes S, Pachón-Ibáñez ME, Domínguez MA, Fernández R, Tubau F, Ariza J, Gudiol F, Cabellos C.

Laboratory of Experimental Infection, Infectious Diseases Department, IDIBELL-Hospital Universitari de Bellvitge, Feixa Llarga s/n, 08907 L’Hospitalet de Llobregat, Barcelona, Spain.


The objective of this study was to evaluate the in vitro and in vivo efficacies of linezolid (35 mg/kg/5 h), vancomycin (60 mg/kg/5 h), imipenem (30 mg/kg/5 h), linezolid+imipenem, linezolid+vancomycin and vancomycin+imipenem against two clinical Staphylococcus aureus isolates with reduced susceptibility to glycopeptides using time-kill curves and the murine peritonitis model. Time-kill curves were performed over 24 h. For the murine peritonitis model, peritonitis was induced by the intraperitoneal inoculation of 10(8) CFU/ml of each bacterial strain. Four hours later (0 h), the mice were randomly assigned to a control group or to therapeutic groups receiving subcutaneous treatment for 25 h. Bacterial counts in peritoneal fluid, bacteraemia and mortality rates were determined. The time-kill curves showed that the addition of linezolid to imipenem yielded synergistic results after 24 h. The addition of linezolid decreased vancomycin activity. In the animal model, vancomycin and linezolid monotherapies produced comparable bacterial decreases in mice infected with each strain but linezolid achieved higher rates of blood sterilisation. Linezolid tested either in monotherapy or in combination showed similar efficacy against both strains in terms of bacterial killing, number of negative blood cultures and survival. Linezolid and vancomycin were moderately bactericidal and similar in efficacy against glycopeptide-intermediate or -resistant S. aureus. Linezolid combinations, as effective as linezolid tested alone, could be considered as alternative options for the treatment of glycopeptide-intermediate S. aureus (GISA) infections.



June 22, 2012 at 2:35 pm


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