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Diversity of Tn 1546 in vanA ‐positive E nterococcus faecium clinical isolates with VanA, VanB, and VanD phenotypes and susceptibility to vancomycin
Author(s) -
Cha J.O.,
Yoo J.I.,
Kim H.K.,
Kim H.S.,
Yoo J.S.,
Lee Y.S.,
Jung Y.H.
Publication year - 2013
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12300
Subject(s) - enterococcus faecium , microbiology and biotechnology , biology , vancomycin , insertion sequence , enterococcus , ampicillin , erythromycin , ciprofloxacin , amp resistance , transposable element , genetics , antibiotics , bacteria , gene , genome , staphylococcus aureus
Aim To investigate diversity in the vanA cluster in E nterococcus faecium isolates from nontertiary hospitals. Methods and Results We identified 43 vanA ‐positive Ent. faecium isolates, including two vancomycin‐susceptible isolates, from hospitals between 2003 and 2006. Of these isolates, >85% were resistant to ampicillin, erythromycin and ciprofloxacin. The vanA cluster was classified into six types using overlapping PCR , but the prototype transposon Tn 1546 was not found. Most vanA ‐positive vancomycin‐resistant Enterococcus ( VRE ) carried IS 1216V and belonged to Type III (58·1%) or Type II (20·9%). vanY , vanZ and IS 1216V were observed in the left and right ends of Type III with long‐range PCR . IS 1216V was also observed within vanS and vanX in the two vancomycin‐susceptible isolates and in two vancomycin‐resistant isolates. No VRE isolates with VanB and VanD phenotypes contained point mutations in vanS , unlike in previous reports. Sequence types ( ST s) of all isolates belonged to clonal complex 17, and ST 78 was predominant. Conclusions Insertion sequences, especially IS 1216V, cause structural variation in the vanA cluster. We report the first observation of vanY and vanZ at the left end of Tn 1546 in clinical isolates. Significance and Impact of the Study This is the first report of the frequency of vancomycin resistance and diversity of Tn 1546 in vanA ‐positive Ent. faecium isolates from nontertiary hospitals.