Thus, the best results were obtained when the final concentration of the three primer sets, MgCl2, and Taq polymerase was increased respectively to 0.8 μM, 3 mM and to 1.5 U and the m-PCR was check details carried
out in a final volume of 50 μl. The thermal cycler parameters of the m-PCR were similar to those of the individual PCR using 61°C as an optimal annealing temperature. Positive and negative control DNA samples were run in each experiment. PCR products were analyzed in 1.2% agarose gel electrophoresis, stained with ethidium bromide and visualised with ultraviolet transillumination. All PCR reactions assessing limits of detection or specifiCity were performed in duplicate. Sensitivity and specifiCity of the m-PCR Sensitivity of the PCR assay was checked using serial fold dilutions of bacterial suspension Akt inhibitor of references strains AB7, iB1 and Nine-Miles at 107 bacteria per ml. Simulated positive samples were also obtained by adding
50 μl of bacterial suspension dilution to 50 μl of bacteria-free vaginal swab extract or milk sample. These preparations were then submitted to extraction procedures and to simplex and m-PCR as described above. The specifiCity of the PCR was assessed on 20 strains of Cp. abortus, 5 strains of Cp. pecorum and, 4 strains of C. burnetii VEGFR inhibitor from our laboratory bacteria collection and on some isolates suspected to be present into tested clinical samples: Brucella melitensis, Brucella abortus, Brucella suis, Escherichia coli, Bacillus cereus, Listeria monocytogenese, Salmonella abortus ovis, Salmonella Typhimurium, Staphylococcus aureus, Staphylococcus chromogenese, Staphylococcus hominis, Streptococcus dysgalactiae and Streptococcus ogalactiae, Mycobacterium avium, Legionella pneumophila. In addition, RFLP-PCR analysis was carried
out as a confirmatory test for the PCR reaction specifiCity. Thus, 10 μl of amplification products obtained from naturally infected clinical samples and those obtained from 102 genomic DNA templates of the reference strains AB7, IB 1, Nine Miles were subjected to 5 units DOCK10 of AluI restriction enzyme (Promega, Charbonnières-Les-Bains, France) in a 20 μl final volume for 3 hours at 37°C. The digested products were examined by using 2% agarose gel stained with ethidium bromide and viewed under UV illumination. In addition, PCR products amplified from clinical samples were purified with a QIAquick PCR purification Kit (Qiagen, Courtaboeuf, France) and directly sequenced with an ABI PRISM 310 genetic analyzer (Applied Biosystems). Isolation of Chlamydophila and Coxiella strains Pathogen isolation was performed to confirm the presence of the involved bacteria, on 20-different PCR positive samples showing high ethidium bromide intensity on agarose gel. Chlamydophila strains isolation were performed using both plaque assays and blind passages on McCoy monolayer cell cultures [27].