FIG 5.

Main genera in which the presence of qnr genes has been described. This is a nonexhaustive list; the possible presence of nonreported qnr genes in genera presented in the figure or the presence of qnr genes in genera not presented in the figure should be taken into account. ^a, genera in which indigenous qnr-like genes have been described (note that when a qnr gene is present in the chromosome of a nonindigenous microorganism, it is reported as a TMQR); ^b, proposed original source of specific transferable qnr; ^c, microorganisms related to water environments; ^d, classically classified together within the family Enterobacteriaceae and classified here in separate genera according to the proposal of Adeolu et al. (347); ^e, new genus proposed in 2016, including Escherichia hermannii and Salmonella subterranea (456) (at the time of writing of this review, the genus “Atlantibacter” was not present in the List of Prokaryotic Names with Standing in Nomenclature [http://www.bacterio.net/index.html]); ^f, in none of these Gram-positive organisms are confirmatory sequences for qnrA, qnrB, qnrD, and qnrS available; ^g, Gram stain variable and phylogenetically closely related to Clostridium spp.