[Multidrug resistant Acinetobacter baumannii].

Acinetobacter baumannii is a well recognized cause of nosocomial infections, particularly in intensive care units. Strains of this species can be resistant to multiple antimicrobial agents, leaving limited therapeutic options. It has been shown that multidrug resistance in A. baumannii is, although not exclusively, associated with some lineages (EU clones) spread in many European countries. Since 1991, the population structure and antimicrobial resistance of Acinetobacter hospital isolates in the Czech Republic have been systematically studied in our laboratory. It has been shown that the vast majority of Czech multidrug resistant isolates from 1991 to 2006 belonged to EU clone I or II. While clone I largely predominated among the isolates in the 1990s, a prospective study 2005-2006 has shown a recent shift towards clone II. This change was associated with the emergence of resistance to carbapenems in the Czech Acinetobacter population. As similar observations have been recently reported from other European countries, EU clone II is likely to play an important role in the spread of carbapenem resistance.