A. baumannii has swiftly emerged over the past three decades as a major nosocomial opportunistic pathogen, causing infections in debilitated patients especially in the intensive care unit (ICU) setting. It is the 10th most frequently isolated pathogen in US hospitals but ranks among the top 5 pathogens in tropical hospitals including Singapore, where the number of antibiotic-resistant A. baumannii infections exceeded 700 cases in 2006. The major issue with A. baumannii is that the organism has rapidly developed resistance to many antibiotics - as an example, within a single decade (1995 to 2004) in US hospitals, carbapenem resistance in A. baumannii increased from 9% to 40%. XDR-A. baumannii (defined as A. baumannii resistant to all antibiotics - including carbapenems, beta-lactam/beta-lactamase-inhibitors, cephalosporins, aminoglycosides, fluoroquinolones, tetracyclines and sulphonamides - with the exception of the polymyxins and tigecycline) has now been described causing infections in hospitals worldwide. Mortality associated with severe infections caused by multidrug-resistant A. baumannii and other XDR-GNB has ranged between 30% and 70% depending on the clinical setting and condition of the patients. Locally, the mortality from severe XDR-GNB infections is approximately 40%. From 2006 to 2010, there was an average of 140 cases of severe XDR-GNB infections in local hospitals each year, translating to approximately 56 deaths from infections attributable to this organism alone in Singapore every year. Other local XDR-GNB includes XDR-P. aeruginosa, and carbapenemase-producing E. coli and K. pneumoniae (carriage of New Delhi metallo-beta-lactmase-1 (NDM-1), OXA-48 and Klebsiella pneumoniae carbapnemase (KPC) genes). These remain relatively rare in Singapore, with fewer than 30 severe infections in local hospitals each year.