Acquired Carbapenemases in Gram-Negative Bacilli in Singapore

Abstract

This thesis hypothesised that the increase in carbapenem-resistance in Gram-negative bacilli in Singapore is due to the introduction of global clones of carbapenemase-producing strains with the potential to cause outbreaks. The diversity of acquired carbapenemase genes in Singapore, their distribution among different species, and some idea of the mechanisms underlying their spread locally are demonstrated. Global clones were found to be present among carbapenemase-producing P. aeruginosa, A. baumannii, and Enterobacteriaceae. They are likely to be responsible for the increase in carbapenem-resistant A. baumannii but not P. aeruginosa. However, the global clones of carbapenemase-producing P. aeruginosa and Enterobacteriaceae are recently introduced and the situation may change in the future.