Emergence of quinolone-resistant, topoisomerase-mutant Brucella after treatment with fluoroquinolones in a macrophage experimental infection model.

Aim Of The Study: To determine the activity of fluoroquinolones (FQ) and the selection of FQ-resistant mutants in a macrophage experimental infection model (MEIM).

Material And Methods: Canine macrophages were inoculated with Brucella melitensis ATCC 23457 (WT), achieving intracellular counts of around 105 CFU/mL. Cell cultures were incubated in the presence of ciprofloxacin (CIP), levofloxacin (LEV), moxifloxacin (MOX), and doxycycline (DOX).

Fluoroquinolone-resistant Brucella melitensis mutants obtained in vitro.

Three fluoroquinolone-resistant Brucella melitensis mutants were obtained after successive passages on norfloxacin-containing agar plates. The original strain was B. melitensis biovar 2 ATCC 23457.

Differential secretion of interleukin-12 (IL-12) subunits and heterodimeric IL-12p70 protein by CD-1 mice and murine macrophages in response to intracellular infection by Brucella abortus.

The secretion of interleukin-12 (IL-12) following intracellular infection with virulent Brucella abortus strain 2308 was investigated in CD-1 mice and in CD-1 cultured peritoneal macrophages. Bioactive IL-12p70 and free non-immunoactive p40 subunits (IL-12p40) were determined by enzyme-linked immunosorbent assays. In CD-1 mice, B.