Enzymes, efflux pumps, and mutations expected to confer resistance to antibiotics of clinical relevancea.

aExcluding the resistance enzyme for bleomycin, an antibiotic used clinically only as an antitumor agent.bVariant number from Table 1 of Ramirez et al.[37] is used to distinguish the AAC(6′)-Ib variants.cTwo silent differences between the two copies.dProbable efflux substrates identified from literature sources including ARDB; the substrates list is not comprehensive and in many cases has been deduced from organisms other than K. pneumoniae.eMdt genes are scattered over the chromosome.