Imported chicken meat as a potential source of quinolone-resistant Escherichia coli producing extended-spectrum beta-lactamases in the UK.
OBJECTIVE
Escherichia coli producing CTX-M-15 enzyme began to rapidly spread in the UK from around 2003 but other types also occur, notably CTX-M-14. We examined breasts from UK-reared (n = 62) and imported (n = 27) chickens as potential sources of quinolone-resistant E. coli with bla(CTX-M) genes. A further 40 samples for which the country of rearing could not be identified were examined.


METHODS
During 2006, 129 fresh and frozen chicken breast fillets were purchased from retail outlets in the West Midlands. These were cultured for E. coli on CLED agar containing 8 mg/L ciprofloxacin and carrying a 10 microg cefpodoxime disc. Resistant isolates were identified and typed by RAPD fingerprinting; bla(CTX-M) was identified by PCR and genotyped by reverse-line hybridization.


RESULTS
The country of rearing was identified from the packaging for 89 of 129 purchased samples. Only one of the 62 UK-reared chicken samples carried E. coli producing a CTX-M-1 enzyme, whereas 10 of 27 samples reared overseas had E. coli with CTX-M enzymes. Specifically, 4/10 Brazilian, 3/4 Brazilian/Polish/French, and 2/2 Dutch samples had E. coli with CTX-M-2 enzymes. Six of 40 samples for which the country of rearing was not known had producers of CTX-M enzymes, 5 of them with CTX-M-14.


CONCLUSIONS
Quinolone-resistant E. coli with various CTX-M beta-lactamase genes that are common in human infections worldwide were found in imported chicken breasts, indicating a possible source for gut colonization. Samples from Brazil were commonly positive for E. coli with CTX-M-2, the dominant bla(CTX-M) genotype from human infections in South America, which is currently rare in clinical infections in the UK. CTX-M-15, the dominant CTX-M type in human infections in the UK, was not found in chicken isolates, suggesting that the UK-reared chickens are not a reservoir of CTX-M-15.
Warren
R E
RE
Microbiology Laboratory, Shrewsbury and Telford Hospital NHS Trust, Shrewsbury SY3 8XQ, UK. roderic.warren@homecall.co.uk
Ensor
V M
VM
O'Neill
P
P
Butler
V
V
Taylor
J
J
Nye
K
K
Harvey
M
M
Livermore
D M
DM
Woodford
N
N
Hawkey
P M
PM
D000818:Animals; D001938:Brazil; D002645:Chickens; D024881:Drug Resistance, Bacterial / Q000502:physiology*; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control; D005060:Europe; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D008460:Meat / Q000382:microbiology*; D006113:United Kingdom; D001618:beta-Lactamases / Q000096:biosynthesis / Q000302:isolation & purification*
D001618:beta-Lactamases