Emergence of extensively drug-resistant and pandrug-resistant Gram-negative bacilli in Europe

International and local surveillance networks as well as numerous reports in the biomedical literature provide evidence that the prevalence of antibiotic resistant Gram-negative bacteria is escalating in many European countries. Furthermore, isolates characterised as multidrug-resistant (i.e. resistant to three or more classes of antimicrobials), extensively drug resistant (i.e. resistant to all but one or two classes) or pandrug-resistant (i.e. resistant to all available classes) are increasingly frequently isolated in hospitalised patients causing infections for which no adequate therapeutic options exist. Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae are specifically addressed in this review as the most problematic and often extensively or pandrug-resistant pathogens. According to the available multicentre surveillance studies, the proportion of imipenem-resistant A. baumannii strains is reported to be as high as 85% in bloodstream isolates from intensive care unit patients in Greece and 48% in clinical isolates from hospitalised patients in Spain and Turkey. Among 33 European countries participating in the European Antimicrobial Resistance Surveillance System (EARSS) in 2007, six countries reported carbapenem resistance rates of more than 25% among P. aeruginosa isolates, the highest rate reported from Greece (51%). According to EARSS, Greece has also the highest resistance rates among K. pneumoniae; 46% to carbapenems, 58% to quinolones and 63% to third generation cephalosporins. This review describes the magnitude of antimicrobial resistance in Gram-negative bacteria in Europe highlighting where the efforts of the scientific communities, the academia, the industry and the government should focus in order to confront this threat.