Molecular characterization of extended-spectrum beta-lactamase-producing Escherichia coli isolates from chickens in Henan Province, China.
Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has spread rapidly worldwide and poses a serious threat to human and animal health. This study collected 51 non-replicate E. coli isolates from 14 different chicken farms in Henan Province in China from December 2007 to August 2008. The prevalence of ESBL-producing E. coli, molecular characterization of the ESBL-related bla genes, including bla(TEM), bla(SHV) and bla(CTX-M), and the susceptibilities of these bacteria to various antimicrobial agents were determined. Thirty-one of the 51 isolates were positive for an ESBL phenotype and 29 of these isolates carried one or more bla genes. Twenty-two isolates harboured bla(TEM) genes and 15 isolates carried bla(CTX-M) genes (one CTX-M-14, three CTX-M-24 and 11 CTX-M-65). One isolate carried bla(TEM)(-57); the remaining bla(TEM) isolates carried bla(TEM-1) with one silent nucleotide base variation (T18C). We believe that this is the first study to report TEM-57 in E. coli isolates. All isolates harbouring bla(CTX-M-24) and bla(CTX-M-14) and five of the bla(CTX-M-65) isolates also harboured the bla(TEM-1) gene. To our knowledge, this study is the first to describe detection of CTX-M-65-producing E. coli isolated from chickens. None of the isolates contained the bla(SHV) gene. Conjugation experiments demonstrated that bla(CTX-M) and bla(TEM) genes could be transferred to E. coli DH5 alpha. The results indicate that ESBL frequency has reached an alarming level in chicken isolates in China, with TEM-1 and CTX-M-65 enzymes being the two predominant beta-lactamases detected.
Yuan
Li
L
Department of Pharmacology and Toxicology, College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, PR China.
Liu
Jian-Hua
JH
Department of Pharmacology and Toxicology, College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, PR China.
Hu
Gong-Zheng
GZ
Department of Pharmacology and Toxicology, College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, PR China.
Pan
Yu-Shan
YS
Department of Pharmacology and Toxicology, College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, PR China.
Liu
Zhi-Ming
ZM
Henan Bureau of Animal Husbandry, Zhengzhou 450002, PR China.
Mo
Juan
J
Department of Pharmacology and Toxicology, College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, PR China.
Wei
Yong-Jun
YJ
Department of Pharmacology and Toxicology, College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, PR China.
D000818:Animals; D002645:Chickens / Q000382:microbiology*; D002681:China; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000201:enzymology / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011201:Poultry Diseases / Q000453:epidemiology* / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000096:biosynthesis / Q000145:classification / Q000235:genetics
D004269:DNA, Bacterial; C055184:beta-lactamase TEM-3; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1