Study design
Mice were randomly divided into 2 independent experiment studies, early sepsis stage experiment and late sepsis stage experiment. Early sepsis stage was defined as 3 days after CLP procedure and late sepsis stage was defined as 6 days or more in terms of antibiotics recommendation in sepsis and study design [4, 12, 13].
In early sepsis experiment, mice were randomly divided into 5 groups, as followed: DE for de-escalation group, ES for escalation group, DNase+DE for DNaseI+ de-escalation group, Sham group and Control group. In DE, ES and DNase+DE group, imipenem (Merck & Co., New Jersey, USA) (ip.,25mg/kg, twice a day), ceftriaxone (Pfizer, New York, USA) (ip.,75mg/kg, twice a day) and imipenem (ip.,25mg/kg, twice a day) + DNaseI (Thermo Fisher, Waltham, MA, USA )(ip.,5mg/kg, once a day) were used during all 3 days after CLP procedure and no antibiotics or DNaseI were used in control group. There was no CLP procedure for sham group. Animal were euthanized at day 4 morning. Blood and organs were collected for further analysis.
In late sepsis experiment, mice were randomly divided into 4 groups as DE for de-escalation group, ES for escalation group, Sham group and Control group. In the first 3 days, the antibiotics usage was the same as the early sepsis experiment. At day 4 after CLP procedure, ceftriaxone (ip.,75mg/kg, twice a day) was used in DE group while imipenem (ip.,25mg/kg, twice a day) was used in ES group. Namely, imipenem-initial and ceftriaxone-initial strategy were evaluated. Animals were euthanized at day 7 morning. Blood and organs were collected for further analysis.