Yes, it is possible.
Background:
The resistance gene for beta-lactamases, like that of, e.g., ESBL (extended-spectrum beta-lactamase), is located in the transferable segments of the genes, the so-called plasmids. Plasmids can be exchanged between bacteria of the same type as well as between different types. This exchange is called horizontal gene transfer. Horizontal gene transfer between two types can happen everywhere in a hospital environment. Gram-negative bacteria, such as the Acinetobacter baumannii and Pseudomonas aeruginosa, transfer plasmids particularly easy. They are often even combined with other resistance genes.
References:
Robert Koch-Institut: ESBL und AmpC: Beta-Laktamasen als eine Hauptursache der Cephalosporin-Resistenz bei Enterobakterien. Epidemiologisches Bulletin Nr. 28 2007.
