Guidance: Infection Prevention and Control Measures for Healthcare Workers in All Healthcare Settings

"Gram-negative bacilli commonly encountered in healthcare settings include species such as Pseudomonas aeruginosa, Acinetobacter spp. and Stenotrophomonas maltophilia, and species belonging to the Enterobacteriaceae family, such as Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae. Recent events indicate an increasing occurrence of antimicrobial resistance in Gram-negative bacteria. The carbapenem group of antimicrobials is a safe and generally effective treatment for severe Gram-negative bacterial infections when resistance to other classes of antimicrobials is present. When resistance to carbapenems occurs, there are often few alternative treatments available. Carbapenem-resistance in Gram-negative bacteria can occur by a number of different mechanisms. Identifying carbapenem resistance and distinguishing between these different mechanisms of resistance can be challenging for clinical microbiology laboratories. Carbapenem resistance develops as a result of the production of carbapenem-hydrolysing enzymes. These enzymes are usually encoded by genes carried on mobile genetic elements such as plasmids which can rapidly spread amongst related bacterial genera. Some notable examples of recently identified carbapenemases are: •Klebsiella pneumoniae carbapenemase (KPC) which is found mostly in K. pneumoniae but also in other Enterobacteriaceae. KPC producing microorganisms have caused major healthcare related outbreaks in Greece, Israel and north eastern USA; •The OXA-type resistance genes found in Acinetobacter spp. Carbapenem-resistant Acinetobacter has been identified worldwide but is currently rarely seen in Canadian hospitals. •Metallo-ß-lactamases which are mostly found in P. aeruginosa and Acinetobacter spp., and rarely in other Enterobacteriaceae; and include the New Delhi metallo beta-lactamase (NDM-1 enzyme) found mostly in Escherichia coli and K. pneumoniae, but also seen in other Enterobacteriaceae. The New Delhi metallo beta-lactamase (NDM-1 enzyme) has recently been identified in India and Pakistan and in patients hospitalized in other countries after receiving health care in India and Pakistan. "