Microarray evaluation of the Listeria monocytogenes infection and amoxicillin treatment in mice

By using Affymetrix Mouse Genome Arrays and 20 biological replicates per experimental condition, the predictive value of liver and blood gene expression profiles previously identified was validated as predictive of Listeria monocytogenes infection severity (lethal and nonlethal infection). The ability of these genes to predict the outcome of antibiotic treatment was also assessed. Lethally infected BALB/c mice were treated with amoxicillin at 10 or 20 mg/kg; only the higher dose prevented death. The liver genes predicted that 70% of the animals treated at 10 mg/kg, but only 25% of the mice treated at 20 mg/kg, belonged to the lethal infection group, and this prediction was similar to the ultimate mortality outcome. These results confirm the value of microarrays as tools to predict host response to infection and efficacy of antibacterial therapy. These results might lead to applications that would help clinicians to adjust antibiotic dosages for efficient treatment but yet without toxicity.