Carbapenemase-producing Enterobacteriaceae isolates resistant to last-line antibiotics in an Italian general hospital

The global dissemination of carbapenemase-producing Enterobacteriaceae (CPE) is of great concern for public health. These bacteria have the potential for rapid dissemination in healthcare settings and cause infections associated with high rates of morbidity and mortality. A total of 221 carbapenem non-susceptible Enterobacteriaceae isolates were collected from patients admitted to an Italian general hospital from January 2016 to March 2017. Among these isolates, 78.3% were carbapenemase producers: 96% were positive for the blaKPC gene and the remainder for the blaVIM gene (allelic variant VIM-1). CPE isolates were mainly Klebsiella pneumoniae, but we also detected carbapenemase enzymes in Citrobacter freundii, Enterobacter cloacae and Escherichia coli. Among CPE isolates, 79.2% exhibited co-resistance to two or more non-b-lactam agents and 38% of these isolates (all KPC-positive) were resistant to colistin. This percentage reached 55% among CPE isolated from the bloodstream. All patients with colistin-resistant CPE isolates recovered from blood samples showed an unfavorable outcome within 7 days from the first positive blood culture. Our data show the dissemination of a high percentage of CPE isolates co-resistant to last-line antibiotics. In addition, we report the first identification in our hospital of CPE isolates harboring the blaVIM gene and Escherichia coli harboring the blaKPC gene. These results underline the need to implement antibiotic stewardship and infection control programs, and emphasize the need for novel antimicrobial agents active against CPE.