Limitation of Acinetobacter baumannii treatment by plasmid-mediated carbapenemase ARI-2. Susan Brown, Carlos Bantar, Hilary-Kay Young, Sebastian G B Amyes. Acinetobacter species now account for 10% of nosocomial infections in intensive therapy units (ITU) in Europe. They are invariably multiresistant, and one major concern is the increasing incidence of carbapenem-resistant isolates since these antibiotics are frequently the therapeutic choice for these infections. Carbapenem resistance in South America has already reached levels that significantly influence therapeutic choices (Carlos Bantar, unpublished data), and this looks set to be a problem in some European countries. ARI-1, a plasmid-mediated enzyme capable of hydrolysing imipenem, was the first carbapenemase to be isolated from this genus. We report a novel plasmid-mediated carbapenemase (ARI-2)