Author:
Liu Yang,Wang Yang,Schwarz Stefan,Li Yun,Shen Zhangqi,Zhang Qijing,Wu Congming,Shen Jianzhong
Abstract
ABSTRACTSeventy-seven porcineEnterococcusisolates with florfenicol MICs of ≥16 μg of were/ml screened for the presence of the multiresistance genecfr, its location on plasmids, and its genetic environment. Three isolates—Enterococcus thailandicus3-38 (from a porcine rectal swab collected at a pig farm),Enterococcus thailandicusW3, andEnterococcus faecalisW9-2 (the latter two from sewage at a different farm), carried thecfrgene. The SmaI pulsed-field gel electrophoresis patterns of the three isolates differed distinctly. In addition,E. faecalisW9-2 was assigned to a new multilocus sequence type ST469. Mating experiments and Southern blot analysis indicated thatcfris located on conjugative plasmids pW3 (∼75 kb) fromE. thailandicusW3, p3-38 (∼72 kb) fromE. thailandicus3-38, and pW9-2 (∼55 kb) fromE. faecalisW9-2; these plasmids differed in their sizes, additional resistance genes, and the analysis of the segments encompassing thecfrgene. Sequence analysis revealed that all plasmids harbored a 4,447-bp central region, in whichcfrwas bracketed by two copies of the novel insertion sequence ISEnfa4located in the same orientation. The sequences flanking the central regions of these plasmids, including the partialtragene regions and a ω-ε-ζ toxin-antitoxin module, exhibited >95% nucleotide sequence identity to the conjugative plasmid pAMβ1 fromE. faecalis. Conjugative plasmids carryingcfrappear to play an important role in the dissemination and maintenance of the multiresistance genecframong enterococcal isolates and possibly other species of Gram-positive bacteria.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
86 articles.
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