Similarity between human and chicken Escherichia coli isolates in relation to ciprofloxacin resistance status.
BACKGROUND
The food supply is suspected to be a source of fluoroquinolone-resistant Escherichia coli that cause disease in humans, but supporting molecular data are lacking.


METHODS
We performed a molecular-epidemiological comparison, in Barcelona, Spain (1996-1998), of 117 contemporaneous, geographically matched E. coli isolates from humans (35 blood isolates and 33 fecal) or chickens (49 fecal) that were either susceptible (n = 57) or resistant (n = 60) to ciprofloxacin and analyzed them by phylogenetic group, virulence genotype, and O antigens using random amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis (PFGE).


RESULTS
When analyzed by phylogenetic distribution, virulence profiles, and O antigens, resistant human isolates were distinct from susceptible human isolates but were largely indistinguishable from chicken isolates, whereas resistant and susceptible chicken isolates were similar. Susceptible human isolates contained more virulence-associated genes and more frequently expressed virulence-associated O antigens than did resistant human or any chicken isolates. Certain resistant human isolates closely resembled chicken isolates by RAPD and PFGE analysis.


CONCLUSIONS
Ciprofloxacin-resistant E. coli may arise de novo in poultry from susceptible progenitors, be transmitted to humans via the food supply, and go on to cause potentially life-threatening infections. If confirmed, these findings would mandate efforts to eliminate this reservoir of drug-resistant pathogens and/or to block their transmission to humans.
Johnson
James R
JR
Mucosal and Vaccine Research Center, University of Minnesota, Minneapolis, USA. johns007@umn.edu
Kuskowski
Michael A
MA
Menard
Megan
M
Gajewski
Abby
A
Xercavins
Mariona
M
Garau
Javier
J
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002645:Chickens / Q000382:microbiology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D016000:Cluster Analysis; D024881:Drug Resistance, Bacterial / Q000502:physiology*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000097:blood / Q000453:epidemiology / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005838:Genotype; D006801:Humans; D017720:Molecular Epidemiology; D010802:Phylogeny; D011201:Poultry Diseases / Q000382:microbiology; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods; D012703:Serotyping; D014774:Virulence / Q000235:genetics
D000890:Anti-Infective Agents; D002939:Ciprofloxacin