Characterization of /F1:A2:B20 Plasmids Harbored by Escherichia coli Sequence Type 131 Sublineage C1/30R Isolates Spreading among Elderly Japanese in Nonacute-Care Settings.

We characterized 29 -harboring plasmids of sequence type 131 (ST131) sublineage C1/30R isolates from healthy individuals and long-term-care facility (LTCF) residents. Most (27/29) plasmids were of the FIA, FIB, and FII multireplicon type with the same plasmid multilocus sequence typing (pMLST). Several plasmids (7/23) from LTCF residents harbored only as the resistance gene; however, their fundamental structures were very similar to those of previously isolated /F1:A2:B20 plasmids, suggesting their prevalence as a newly arising public health concern.