Multicenter Evaluation of the Susceptibility of Enterobacteriaceae and Pseudomonas Aeruginosa to Ceftolozane/Tazobactam Combination

Currently, the probabilistic treatment of these multi-resistant bacteria involves the use of carbapenems. Unfortunately, the increasing and unreasonable use of carbapenems invariably leads to the spread of even more resistant strains, BHRe (Emerging Highly Resistant Bacteria) including enterobacteriaceae producing carbapenemases. Thus, it is strongly recommended by health authorities to limit the use of carbapenems ("carbapenem savings") by promoting the use of therapeutic alternatives. Ceftolozane/tazobactam is one of those therapeutic alternatives for which an evaluation must be carried out. Currently, in addition to complicated intra-abdominal infections and complicated urinary tract infections, ceftolozane/tazobactam combination is used in clinical practice in gram-negative infections such as upper and lower respiratory infections and bacteremia. In any case, the choice of probabilistic antibiotic therapy must take into account local and regional epidemiological data. However, published data on the in vitro activity of ceftolozane/tazobactam remain limited, particularly in France (only one French epidemiological study on Gram-negative non-fermenting bacillus strains isolated in patients with cystic fibrosis). This study does not take into account in particular multi-resistant enterobacteriaceae producing BLSE for which ceftolozane/tazobactam remains effective (particularly in E. coli and K. pneumoniae).