In vivo imaging of bioluminescent Escherichia coli in a cutaneous wound infection model for evaluation of an antibiotic therapy.
A rapid, continuous method for noninvasively monitoring the effectiveness of several antibacterial agents in real time by using a model of wound infection was developed. This study was divided into three steps: (i) construction of a plasmid to transform Escherichia coli into a bioluminescent variant, (ii) study of the bioluminescent E. coli in vitro as a function of temperature and pH, and (iii) determination of the MIC and the minimal bactericidal concentration of sulfamethoxazole-trimethoprim (SMX-TMP). Finally, the efficacy of SMX-TMP was monitored in vivo in a cutaneous wound model (hairless rat) infected with this bioluminescent bacterium by using a bioluminescence imaging system. E. coli was transformed by electroporation with a shuttle vector (pRB474) containing the firefly (Photinus pyralis) luciferase gene, resulting in a bioluminescent phenotype. It was found that pH 5.0 was optimal for incorporation of the susbstrate D-luciferin for the luciferase reaction. In vitro, when the agar dilution method, standard turbidity assays, and the bioluminescence imaging system were used, E. coli(pRB474) proved to be susceptible to SMX-TMP. In vivo, at 4 h, SMX-TMP treatment was already efficient compared to no treatment (P = 0.034). At 48 h, no bioluminescence was detected in the wound, demonstrating the susceptibility of E. coli to SMX-TMP. In conclusion, this study points out the advantage of using bioluminescence imaging to evaluate the effects of antibiotics for the treatment of acute infections in vivo in a nondestructive and noninvasive manner.
UPRES EA 2689-INSERM IFR 114, Pavillon Vancostenobel, Lille University Hospital, 59037 Lille Cedex, France.
Samir
S
Jawhara
Serge
S
Mordon
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015169:Colony Count, Microbial; D017931:DNA Primers; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D004926:Escherichia coli / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D008297:Male; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D014169:Transformation, Bacterial; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use; D014946:Wound Infection / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D017931:DNA Primers; D015662:Trimethoprim, Sulfamethoxazole Drug Combination