Infection-stage adjusted dose of beta-lactams for parsimonious and efficient antibiotic treatments: A Pasteurella multocida experimental pneumonia in mice.

In this study, the impact of infection stage on clinically and microbiologically efficacious doses and on antibiotic consumption was assessed during a naturally evolving infectious disease, using an original mouse model of pulmonary infection produced by air-borne contamination. When Pasteurella multocida was administered as pathogenic agent to immunocompetent mice, 60% of the animals exhibited clinical symptoms of pneumonia 2 to 4 days after bacterial contamination of the lungs. Two beta-lactam antibiotics were evaluated: amoxicillin and cefquinome, a fourth generation cephalosporin developed for food animals.

Low or high doses of cefquinome targeting low or high bacterial inocula cure Klebsiella pneumoniae lung infections but differentially impact the levels of antibiotic resistance in fecal flora.

The combination of efficacious treatment against bacterial infections and mitigation of antibiotic resistance amplification in gut microbiota is a major challenge for antimicrobial therapy in food-producing animals. In rats, we evaluated the impact of cefquinome, a fourth-generation cephalosporin, on both Klebsiella pneumoniae lung infection and intestinal flora harboring CTX-M-producing Enterobacteriaceae. Germfree rats received a fecal flora specimen from specific-pathogen-free pigs, to which a CTX-M-producing Escherichia coli strain had been added.