title: Escherichia coli producing CTX-M beta-lactamases in food animals in Hong Kong.
abstract: A study was conducted to evaluate the occurrence of extended-spectrum beta-lactamases (ESBLs)-producing Escherichia coli from fecal samples of healthy food animals in Hong Kong. Rectal or cloacal swabs were obtained from cattle, pigs, chicken, ducks, geese, and pigeons in slaughterhouses or wholesale markets over a 5- month period in 2002. Antibiotic-containing medium was used for selective isolation of potentially ESBL-producing E. coli. Of 734 samples analyzed, six (2%) from pigs, three (3.1%) from cattle, and one (3%) from pigeons had E. coli strains with the ESBL phenotype. The ESBL content for the 10 isolates include CTXM- 3 (n = 4), CTX-M-13 (n = 3), CTX-M-14 (n = 2), and CTX-M-24 (n = 1). In five isolates, the bla (CTX-M) gene was encoded on transferable plasmids (60 or 90 kb), and the gene was found to transfer to E. coli (J53 or JP995) with frequencies of 10(7) to 10(3) per donor cells. The ten isolates had five distinct pulsotypes with some clonal spread. However, the isolates from the different kinds of animals were not clonally related. These findings imply that bacteria of animal origins may serve as reservoirs of some ESBL genes.
authors.affiliation: Division of Infectious Diseases, Department of Microbiology and Centre of Infection, University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: R S
authors.initials: RS
authors.lastname: Duan
authors.forename: Thomas H C
authors.initials: TH
authors.lastname: Sit
authors.forename: Samson S Y
authors.initials: SS
authors.lastname: Wong
authors.forename: River C W
authors.initials: RC
authors.lastname: Wong
authors.forename: K H
authors.initials: KH
authors.lastname: Chow
authors.forename: Gannon C
authors.initials: GC
authors.lastname: Mak
authors.forename: W C
authors.initials: WC
authors.lastname: Yam
authors.forename: L T
authors.initials: LT
authors.lastname: Ng
authors.forename: K Y
authors.initials: KY
authors.lastname: Yuen
authors.forename: P L
authors.initials: PL
authors.lastname: Ho
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005516:Food Microbiology; D005798:Genes, Bacterial; D006723:Hong Kong / Q000453:epidemiology; D011200:Poultry; D013552:Swine; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; C456079:beta-lactamase CTX-M-13; C456080:beta-lactamase CTX-M-14; C417271:beta-lactamase CTX-M-3; D001618:beta-Lactamases