The spread of carbapenemase-producing gram-negative bacteria is one of the major 
challenges of the present. Since 2009, the National Reference Laboratory for 
gram-negative nosocomial pathogens has observed the molecular epidemiology of 
carbapenemases in Germany. In 2011, 1,454 referred bacterial isolates were 
tested for the presence of carbapenemases. Carbapenemase was found in 34.4% of 
Enterobacteriaceae isolates, in 19.9% of Pseudomonas aeruginosa isolates and in 
96.3% of Acinetobacter baumannii isolates. The most frequent carbapenemases in 
Enterobacteriaceae were OXA-48, KPC and VIM-1; in P. aeruginosa it was VIM-2 and 
in A. baumannii OXA-23.