Multidrug Resistant Uropathogenic ST405 With a Novel, Composite IS Transposon in a Unique Chromosomal Location.

ST405 is an emerging urosepsis pathogen, noted for carriage of , , and a repertoire of virulence genes comparable with O25b:H4-ST131. Extraintestinal and multidrug resistant ST405 are poorly studied in Australia. Here we determined the genome sequence of a uropathogenic, multiple drug resistant ST405 (strain 2009-27) from the mid-stream urine of a hospital patient in Sydney, Australia, using a combination of Illumina and SMRT sequencing. The genome of strain 2009-27 assembled into two unitigs; a chromosome comprising 5,287,472 bp and an IncB/O plasmid, pSDJ2009-27, of 89,176 bp. and phenotypic analyses showed that strain 2009-27 is a serotype O102:H6, phylogroup D ST405 resistant to ampicillin, azithromycin, kanamycin, streptomycin, trimethoprim, and sulphafurazole. The genes encoding resistance to these antibiotics reside within a novel, mobile IS-flanked transposon, identified here as Tn, in the chromosomal gene . Tn comprises four modules that each carries resistance genes flanked by IS, including a class 1 integron with and gene cassettes, a variant of Tn, and . We exploited unique genetic signatures located within Tn to identify strains of ST405 from Danish patients that also carry the transposon in the same chromosomal location. The acquisition of Tn into in ST405 is significant because it (i) is vertically inheritable; (ii) represents a reservoir of resistance genes that can transpose onto resident/circulating plasmids; and (iii) is a site for the capture of further IS-associated resistance gene cargo.