The genes
encoding OXAs may be passed on by chromosomal fragments,
plasmids and transposons and are often regulated by insertion
sequences such as ISAba1.14 Presence of OXA-23-like, OXA-40-
like, OXA-58-like and OXA-143 is often related to carbapenem
resistance. These acquired enzymes are found integrated in
the chromosome or on plasmids and the strains which produce
them may spread epidemically and exchange resistance genes
between them.30 The majority of strains tested in this study
had the acquired OXA-23-like enzyme.