Detection of CTX-M-15, CTX-M-22, and SHV-2 extended-spectrum beta-lactamases (ESBLs) in Escherichia coli fecal-sample isolates from pig farms in China.
The aim of the present study was to investigate the antibiotic resistance profiles and the molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates from two production swine operations in Sichuan Province, China, between August 2002 and February 2007. The prevalence of ESBL-producing E. coli increased dramatically from 2.2% to 10.7% during this period. This increase appeared mostly related to dissemination of CTX-M-type ESBLs among E. coli isolates. Of 212 E. coli isolates studied, 14 harbored ESBL genes. Among them, 13 harbored bla(CTX-M-15/22) and one harbored bla(SHV-2). To our knowledge, this is the first study to identify bla(CTX-M-22) from production animals. One isolate in 2002 harbored bla(SHV-2), indicating that ESBL genes have been present in farm animals in China since at least 2002. Molecular characterization and pulsed-field gel electrophoresis of the ESBL-producing isolates suggested that different mechanisms may be involved in the dissemination of the CTX-M genes and revealed that additional resistance determinants for non-beta-lactam antibiotics were carried by plasmids encoding certain ESBL genes. Results of this study provide an example of how ESBL genes, particularly those of CTX-M lineages, are rapidly spreading among E. coli isolates from commercial pig farms in Sichuan province of China.
Tian
Guo-Bao
GB
Bioengineering Research Center for Animal Disease Prevention and Control, Sichuan University, Chengdu, P.R. China.
Wang
Hong-Ning
HN
Zou
Li-Kou
LK
Tang
Jun-Ni
JN
Zhao
Ying-Wang
YW
Ye
Man-Yu
MY
Tang
Jing-Yuan
JY
Zhang
Yi
Y
Zhang
An-Yun
AY
Yang
Xin
X
Xu
Chang-Wen
CW
Fu
Yue-Jun
YJ
D000383:Agriculture; D000818:Animals; D001483:Base Sequence; D002681:China; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000032:analysis* / Q000235:genetics; D005243:Feces / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D013552:Swine / Q000382:microbiology*; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C473109:beta-lactamase CTX-M-15; C062760:beta-lactamase SHV-2; D001618:beta-Lactamases; C542394:beta-lactamase CTX-M-22, E coli