OBJECTIVES: Glycopeptide-resistant enterococci are still present within the broiler sector, despite the EU ban of avoparcin more than a decade ago. In the present study, we have developed a rapid method for screening the flanking regions at the integration point of Tn1546 in glycopeptide-resistant Enterococcus faecium isolated from broiler farms. METHODS: Total DNA was digested, ligated and amplified using primers from inside Tn1546. The resulting amplicons were purified and sequenced. Two new primers were designed based on obtained sequences. RESULTS: Two main insertion points have been repeatedly found in isolates from the UK (n = 150). The first insertion point revealed that 25 isolates harboured Tn1546 positioned in a sequence with 96% homology to a streptomycin adenyltransferase gene (AY604739) from a Staphylococcus intermedius plasmid. At this insertion point, a direct repeat (GTCCT) was duplicated as previously described, indicating transposition at the target site. Furthermore, this 'hot spot' was also detected in isolates from Norway (2/8) and Denmark (17/20). The second insertion point detected in 45 isolates from the UK revealed integration into an Inc18-like plasmid, most likely by a process of target site recombination. CONCLUSIONS: The presence of a common insertion point for isolates from different geographical areas could suggest the insertion of Tn1546 by transposition in a plasmid-specific site, followed by genetic rearrangement both inside the transposon and in the flanking regions.
OBJECTIVES: Glycopeptide-resistant enterococci are still present within the broiler sector, despite the EU ban of avoparcin more than a decade ago. In the present study, we have developed a rapid method for screening the flanking regions at the integration point of Tn1546 in glycopeptide-resistant Enterococcus faecium isolated from broiler farms. METHODS: Total DNA was digested, ligated and amplified using primers from inside Tn1546. The resulting amplicons were purified and sequenced. Two new primers were designed based on obtained sequences. RESULTS: Two main insertion points have been repeatedly found in isolates from the UK (n = 150). The first insertion point revealed that 25 isolates harboured Tn1546 positioned in a sequence with 96% homology to a streptomycin adenyltransferase gene (AY604739) from a Staphylococcus intermedius plasmid. At this insertion point, a direct repeat (GTCCT) was duplicated as previously described, indicating transposition at the target site. Furthermore, this 'hot spot' was also detected in isolates from Norway (2/8) and Denmark (17/20). The second insertion point detected in 45 isolates from the UK revealed integration into an Inc18-like plasmid, most likely by a process of target site recombination. CONCLUSIONS: The presence of a common insertion point for isolates from different geographical areas could suggest the insertion of Tn1546 by transposition in a plasmid-specific site, followed by genetic rearrangement both inside the transposon and in the flanking regions.
Authors: Wenming Zhu; Patrick R Murray; W Charles Huskins; John A Jernigan; Lawrence C McDonald; Nancye C Clark; Karen F Anderson; Linda K McDougal; Jeff C Hageman; Melissa Olsen-Rasmussen; Mike Frace; George J Alangaden; Carol Chenoweth; Marcus J Zervos; Barbara Robinson-Dunn; Paul C Schreckenberger; L Barth Reller; James T Rudrik; Jean B Patel Journal: Antimicrob Agents Chemother Date: 2010-07-26 Impact factor: 5.191
Authors: H Sletvold; P J Johnsen; O-G Wikmark; G S Simonsen; A Sundsfjord; K M Nielsen Journal: J Antimicrob Chemother Date: 2010-06-17 Impact factor: 5.790
Authors: Ana R Freitas; Carla Novais; Ana P Tedim; María Victoria Francia; Fernando Baquero; Luísa Peixe; Teresa M Coque Journal: PLoS One Date: 2013-03-29 Impact factor: 3.240
Authors: E Wardal; A Kuch; I Gawryszewska; D Żabicka; W Hryniewicz; E Sadowy Journal: Eur J Clin Microbiol Infect Dis Date: 2016-10-17 Impact factor: 3.267