Abstract

BARONI, E et al. In vitro antibacterial activity of ciprofloxacin on Escherichia coli: effect of bovine serum and inoculum size. InVet [online]. 2014, vol.16, n.1, pp.07-14. ISSN 1668-3498.

The in vitro assays used to evaluate the activity of antibacterial drugs do not consider the patient immune response, which is necessary for the successful recovery from infectious disease. In this study the effect of the bovine serum and the bacterial concentration on the activity of ciprofloxacin on a strain of Escherichia coli (ATCC 25922) was evaluated in vitro. The minimum inhibitory concentrations on Mueller Hinton broth and in presence of bovine serum were 0.0188 and 0.0047 μg/ml respectively, while the value of the mutant prevention concentration estimated on Mueller Hinton agar was 0.60μg/ml. In the time-killing curve constructed on Mueller Hinton broth, no concentration achieved an efficacy of 99.9% at the end of the assay, whereas in presence of bovine serum the bactericidal activity increased directly with the increasing concentrations, attaining efficacy values of 99,9% (bactericidal effect) y del 99,99% (bacterial eradication). No concentrations reduced the viable bacteria at levels of bactericidal effect when the time-kill curves where constructed in Muller-Hinton broth. The results obtained in this study showed that the optima efficacy of ciprofloxacin on Escherichia coli depends on the inoculum size ant the factors of the immune response present in bovine serum.

Keywords : Ciprofloxacin; Bovine serum; Bacterial concentration; Time-kill curve.

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