Since effective empirical antibiotic therapy is a key factor for survival, local antibiotic resistance epidemiology is critical. We aimed to identify current trends in antibiotic resistance for key antibiotics obtained over 16 years (2001-2016) for invasive infections corresponding to empirical treatment in a large hospital centre in Marseille, France.From January 2014 to December 2016, we have collected all data on antibiotic susceptibility from public laboratory hospitals, and a retrospective analysis was performed on key antibiotics in blood cultures since 2001. A total of 99,932 antibiotic susceptibility testings (ASTs) were analysed, and proportion of pan-drug resistant (PDR = resistant to all antibiotics tested) and extensively drug-resistant (XDR = resistant to all except for two classes) strains were < 0.03 and 0.5%, respectively. Between 2001 and 2016, we found an increase of resistance to third-generation cephalosporins for E. coli invasive strains (0% vs 17.8%; p < 10-5) and K. pneumoniae (8% vs 35.4%; p = 0.001) along with a decrease of methicillin-resistant S. aureus strains (31% vs 19.8%; p = 0.006). Moreover, during the 3-year period, a significant increase of wild-type strains, susceptible to all antibiotics tested, was observed in invasive infections. Regarding bacteraemia involving Enterobacteriaceae and S. aureus, empirical therapy is effective in > 99% cases. Active epidemiological surveillance is necessary because antibiotic resistance remains unpredictable.
Keywords: Antibiotic resistance; Epidemiology; Marseille; Snapshot.