Practical Use of Temocillin in Enterobacteriaceae Resistant to Third Generation of Cephalosporins: Experience of Two French University Hospitals

We will retrospectively include every patient who received at least 24 hours of temocillin for the treatment of an extended-spectrum beta-lactamase Enterobacteriaceae (ESBL-E) infection from January to December 2016 in two university hospitals (centres 1 and 2). Each treatment indication will be recorded including off-label prescriptions. Patients will be classified in 2 treatment groups: group 1 received a probabilistic antibiotherapy first (3GC or carbapenem or piperacillin/tazobactam or fluoroquinolones) followed by temocillin as second line treatment. Group 2 was defined by the use of temocillin as first line treatment or as prophylaxis.

Data collection : Clinical, biological and pharmaceutical data will be retrieved from medical chart. The patient's referring physician and/or the department will be contacted for further information on missing data. Remote outcomes will be retrieved either by hospital records if the patient is rehospitalized in the meantime or by contacting directly the patient by phone or e-mail. Demographic characteristics, comorbidities, type and location of infection, treatment, side effects, biological results, follow-up duration, treatment and outcome will be collected. For all antibiotics, doses, route and scheme administration, duration, first, second and third line of antibiotic (after temocillin) will be retrieved from medical chart.

Case definition and outcome: Treatment failure in curative use is defined by the persistence of clinical symptoms 72h after starting the antibiotic and/or clinical worsening leading to a switch to broad-spectrum antibiotic and/or recurrence of initial symptoms and/or identification of the same bacterial species with the same susceptibility pattern as initially observed (same or new location). Treatment failure in prophylactic use is defined by the persistence of the enterobacteria according to the indication of prophylaxis (e.g. urine). All deaths and lost-to-follow-up will be considered as failures (worst case scenario). Treatment success is defined by the absence of failure in the four weeks after treatment. We will use the Sequential Organ Failure Assessment (SOFA) score in predicting mortality in patients with ESBL-E infections included in our study.

Microbiological definitions : The susceptibility of the isolates to temocillin wil be determined by disc diffusion method (Biorad®, Marnes-la-Coquette, France) according to the guidelines of the CA-SFM ("Comité de l'Antibiogramme - Société Française de Microbiologie", Antibiogram Committee - French Society of Microbiology ). The Minimum Inhibitory Concentration (MIC) of temocillin will be determined by E-test (bioMérieux®, Marcy l'Étoile, France) on Mueller-Hinton agar using the manufacturer's instructions. MIC results will be also interpreted according to the 2016 guidelines of the CA-SFM.18