Decreasing level of resistance in invasive Klebsiella pneumoniae strains isolated in Marseille, January 2012–July 2015

BACKGROUND Klebsiella pneumoniae is a Gram-negative bacterial species well known for its capacity to cause infections in humans, and to carry and spread a wide variety of resistance genes including extended-spectrum beta-lactamase genes, carbapenem resistance genes, and colistin resistance genes. Recently, our real-time laboratory-based surveillance system MARSS (the Marseille Antibiotic Resistance Surveillance System) allowed us to observe a intringing dramatic decrease in the beta-lactam resistance level of the K. pneumoniae strains routinely isolated from patients hospitalized in our settings since 2013. Here we study the evolution of the prevalence of K. pneumoniae infections in Marseille university hospitals, France, from January 2012 to July 2015, and study their antibiotic resistance profiles. METHODS We collected data referring to patients hostpitalized for K. pneumoniae infections in the 4 university hospitals of Marseille from January 2012 to July 2015. We then study their antibiotic resistance profiles according the clinical sites from which each strain was collected. Antibiotic consumption data from our four hospitals were also analyzed from January 2013 to July 2015. RESULTS Overall, 4868 patients were admitted in our settings for K. pneumoniae infections over the study period. Overall, 40.1, 22.3, 25.6, 0.4, 29.9, 14.8, 27.3 and 37.0 % of the strains were resistant to amoxicillin plus clavulanic acid, piperacillin-tazobactam, ceftriaxone, imipenem, ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole and furan, respectively. 447 were invasive infections. The resistance level of our invasive strains was significantly lower than that presented by 11, 7, 10 and 11 other European countries included in the 2013 European Antimicrobial Resistance Surveillance Network report for ceftriaxone, imipenem, ciprofloxacin and gentamicin, respectively, but significantly higher than that of 13, 1, 17 and 13 European countries for the same antibiotics. We also observed that the percentages of resistance of our invasive strains to three of the four antibiotics decreased over the study. In parallel, antibiotic consumption remained stable in our four hospitals from January 2013 to July 2015. CONCLUSIONS Altogether, our results underline that automated antibiotic-susceptibility testing results-based surveillance systems are crucial to better understand the evolving epidemiology of dangerous pathogenic bacterial species, like K. pneumoniae, at local scales.