title: blaCTX-M-1/9/1 Hybrid Genes May Have Been Generated from blaCTX-M-15 on an IncI2 Plasmid.
abstract: Three hybrid CTX-M β-lactamases, CTX-M-64, CTX-M-123, and CTX-M-132, with N and C termini matching CTX-M-1 group enzymes and centers matching CTX-M-9 group enzymes, have been identified. The hybrid gene sequences suggested recombination between blaCTX-M-15 and blaCTX-M-14, the two most common blaCTX-M variants worldwide. However, blaCTX-M-64 and blaCTX-M-123 are found in an ISEcp1-blaCTX-M transposition unit with a 45-bp "spacer," rather than the 48 bp usually associated with blaCTX-M-15, and 112 bp of IncA/C plasmid backbone. This is closer to the context of blaCTX-M-55, which has one nucleotide difference from blaCTX-M-15, on IncI2 plasmid pHN1122-1. Here, we characterized an IncI2 plasmid carrying blaCTX-M-15 with a 45-bp spacer (pHNY2-1) by complete sequencing and also sequenced IncI2 plasmids carrying blaCTX-M-64 (pHNAH46-1) or blaCTX-M-132 (pHNLDH19) and an IncI1 plasmid carrying blaCTX-M-123 (pHNAH4-1). pHNY2-1 has the same ISEcp1-blaCTX-M-IncA/C insertion as pHN1122-1, pHNAH46-1, and pHNLDH19, and all four plasmid backbones are almost identical. pHNAH4-1 (IncI1 sequence type 108 [ST108]) carries a transposition unit that includes a 2,720-bp fragment of the IncI2 backbone, suggesting ISEcp1-mediated transfer of blaCTX-M-IncA/C-IncI2 to an IncI1 plasmid. All three hybrid blaCTX-M genes may have resulted from recombination between blaCTX-M-14 and blaCTX-M-15 with a 45-bp spacer on an IncI2 plasmid. Five additional Escherichia coli isolates of different sequence types from different provinces, farms, and/or animals had blaCTX-M-64 on a pHNAH46-1-like IncI2 plasmid and 9 had blaCTX-M-123 on a pHNAH4-1-like IncI1 ST108 plasmid. Thus, epidemic IncI plasmids may be responsible for the spread of blaCTX-M-64 and blaCTX-M-123 between different animals and different locations in China.
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China.
authors.forename: Lanping
authors.initials: L
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China.
authors.forename: Dandan
authors.initials: D
authors.lastname: He
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China.
authors.forename: Luchao
authors.initials: L
authors.lastname: Lv
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China.
authors.forename: Wuling
authors.initials: W
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China.
authors.forename: Zhenling
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, The University of Sydney and Westmead Hospital, Westmead, New South Wales, Australia sally.partridge@health.nsw.gov.au jhliu@scau.edu.cn.
authors.forename: Sally R
authors.initials: SR
authors.lastname: Partridge
authors.affiliation: College of Veterinary Medicine, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, People's Republic of China sally.partridge@health.nsw.gov.au jhliu@scau.edu.cn.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Liu
mesh_terms: D000818:Animals; D002681:China; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D001618:beta-Lactamases