Antimicrobial resistance changing trends of Klebsiella pneumoniae isolated over the last 5 years.

The aim of this study was to describe the prevalence and epidemiology distribution of K. pneumoniae isolated at University Hospital of Campania "Luigi Vanvitelli," including the susceptibility evolution profile. Data on resistant phenotype strains, such as extended-spectrum-β-lactamase (ESBL) producers and carbapenem-resistant K. pneumoniae (CRE) isolates, were also reported. K. pneumoniae strains were collected at the Complex Operative Unit (UOC) of Virology and Microbiology from different colonization and infection sites from January 2016 to December 2020. The highest rates of isolation were in urinary samples and in respiratory and wound swabs. Antibiotics susceptibility patterns showed more than 50% of the isolates resistant to cephalosporins, fluoroquinolones and penicillin. On the other hand, from 20% to 40% of K. pneumoniae strains were resistant to carbapenems and aminoglycosides. Based on our analysis, fosfomycin, ceftazidime/avibactam and ceftolozane/tazobactam are still therapeutic alternatives. Data analysis on carbapenem class evolution in 2016-2020 showed a significant increase in resistance rates (p<0.05). Increased rates in CRE and ESBL producing K. pneumoniae since 2017 were reported. Providing information on clinical characteristics and epidemiology data on contemporary K. pneumoniae evolution could help mitigate the spread of these isolates in our hospital and avert the endemic levels that have been observed in Southern Italy and in other European countries.