Carbapenemase-producing Enterobacteriaceae: overview of a major public health challenge.

Bacterial resistance to antibiotics has become a major source of concern for public health. Enterobacteriaceae are among the most common human pathogens, causing community-acquired as well as hospital-acquired infections. Carbapenem-resistant Enterobacteriaceae have been increasingly reported worldwide since their first identification more than 20 years ago. Three main classes of carbapenemases have been identified: Ambler class A beta-lactamase (KPC), class B (metallo-enzymes), and class D (OXA-48 type). Klebsiella pneumoniae carbapenemases (KPC) was first reported in the United States in the late 1990s and since then worldwide, with a marked endemicity in the United States, Greece, and now Italy. Carbapenemase NDM-1 (New Delhi metallo-beta-lactamase-1) is one of the most recently reported metallo-enzymes. It has spread widely in the Indian sub-continent and now worldwide. Carbapenemases of the oxacillinase-48 type (OXA-48) have been identified mostly in Mediterranean and southern European countries with a rapid spread. An early and quick identification of carbapenemase-producing infected patients, but also of carriers, is mandatory to prevent the spread of these highly resistant pathogens. The early identification of carriers and implementing of cohorting strategies is the only means to prevent nosocomial outbreaks caused by carbapenemase, with very few, if any, therapeutic options.