21st European Congress of Clinical Microbiology and Infectious Diseases

Antimicrobial susceptibility patterns associated with European KPC producers

Abstract number: P732

Hackel M., Lascols C., Hawser S., Badal R., Hoban D., Bouchillon S., Johnson B., Johnson J., Dowzicky M.

Background: In recent years carbapenem resistance has emerged among Gram-negative isolates due to the acquisition of carbapenemases, which usually belong to Ambler class B metallo-b-lactamases (MBLs) or to KPC-type enzymes. Klebsiella pneumoniae carbapenemase (KPC) is an Ambler class A b-lactamase that confers resistance to all b-lactam agents, including carbapenems, cephalosporins, penicillins, and the monobactam aztreonam Although this enzyme has been found primarily in K. pneumoniae, it has also been identified in several other Gram-negative bacilli. Because the blaKPC gene is carried on a plasmid, the ease of mobility of this resistance mechanism is of concern and represents a major threat to the antimicrobial treatment of infections with Gram-negative organisms. As part of the Tigecycline European Surveillance Trial (TEST), this study investigated the incidence and susceptibility profiles of KPC producing Gram-negative isolates from Europe during 2009–10.

Methods: 11,316 Enterobacteriaceae isolated in Europe in 2009–10 had minimum inhibitory concentrations (MICs) determined using broth microdilution following CLSI guidelines and interpreted according to EUCAST breakpoints where available. A total of 148 isolates with meropenem MICs of 2 mg/L were screened for the presence of KPC genes using multiplex-PCR.

Results: Of 11,316 Enterobacteriaceae isolated in Europe in 2009–10, 148 (1.3%) had meropenem MICs of 2 mg/L. 52 (35%) of these 148 meropenem non-susceptible isolates were positive for KPC genes. All KPC positive isolates were K. pneumoniae. Susceptibility of these isolates is shown in the table.

Conclusions: The meropenem non-susceptible rate in European Enterobacteriaceae from the TEST study in 2009–10 was 1.3%, with 35% of these (0.5%) positive for KPC. The most active antimicrobial against these isolates in vitro was tigecycline with an MIC₉₀ of 1 mg/L, followed by minocycline, with an MIC₉₀ of 8 mg/L. All other antimicrobials exhibited susceptibilities of <20%.