Fighting the spread of AmpC-hyperproducing Enterobacteriaceae: beneficial effect of replacing ceftriaxone with cefotaxime

Results: The incidence of HL-CASE increased significantly from 0.32 to 0.69/1000 PD during Period 1 (coefficient¼0.082, P,0.01). A significant inflection of the slope in the incidence curve occurred in Period 2 (coefficient ¼20.061, P¼0.05), mainly owing to the stabilization of the HL-CASE incidence of Enterobacteriaceae harbouring chromosomally inducible cephalosporinase (Period 1, 0.27 to 0.64/1000 PD; Period 2, 0.58 to 0.61/1000 PD) and especially for Enterobactercloacae (Period 1, 0.09 to 0.30/1000 PD; Period 2, 0.26 to 0.27/1000 PD). This deceleration was observed despite a significant increase in the slope of cefotaxime consumption over Period 2 (coefficient ¼2.97, P,0.01). Conclusion: Despite the disadvantages of using cefotaxime compared with ceftriaxone (administration three times daily versus once a day), the ecological benefits of this substitution seem sufficiently convincing to preferentially use cefotaxime. Control of HL-CASE incidence is crucial to limiting carbapenem use and preventing the selection of carbapenemase-producing Enterobacteriaceae.