title: Determination of fluoroquinolone residues in animal tissues using Escherichia coli as indicator organism.
abstract: Three strains of Escherichia coli (ATCC 128, 10536, and 25922) and one strain of Bacillus subtilis (ATCC 3491) were compared as indicator microorganisms in microbial inhibition tests for their ability to detect fluoroquinolone residues. E. coli strains 128 and 10536 were most susceptible to fluoroquinolone residues, with detection limits of 35-50 micrograms/kg for enrofloxacin. Of the 2 strains, E. coli 10536 was slightly less susceptible. Ciprofloxacin was detected consistently by E. coli 128 at 30 micrograms/kg. Other fluoroquinolone drugs of veterinary interest detected by E. coli 128 were sarafloxacin and difloxacin at 100-250 micrograms/kg concentration. E. coli 25922 yielded 100% sensitivity in detection of enrofloxacin only at the 250 micrograms/kg concentration, and ciprofloxacin and sarafloxacin at 200 micrograms/kg. B. subtilis detected only enrofloxacin 100% of the time at 250 micrograms/kg. The E. coli strains tested were insensitive to other antibacterials commonly used in animals, with the exception of ceftiofur which was detected by E. coli 128 and 10536 at 500 micrograms/kg. The B. subtilis strain was not effective in detecting the fluoroquinolone drugs, whereas the E. coli strains were selective for the fluoroquinolones. E. coli 128 was 100% effective in detecting enrofloxacin and ciprofloxacin in spiked diaphragm homogenate samples at 50 micrograms/kg. Of the microorganisms tested, E. coli strain ATCC 128 was highly suitable as an indicator microorganism in a microbial inhibition assay for selective detection of fluoroquinolone antibacterial residues in animal tissues.
authors.affiliation: University of Guelph, Laboratory Services Division, ON, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Choi
authors.forename: A J
authors.initials: AJ
authors.lastname: Yee
authors.forename: D
authors.initials: D
authors.lastname: Thompson
authors.forename: J
authors.initials: J
authors.lastname: Samoluk
authors.forename: M
authors.initials: M
authors.lastname: Mitchell
authors.forename: W D
authors.initials: WD
authors.lastname: Black
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000032:analysis*; D001412:Bacillus subtilis / Q000187:drug effects; D002939:Ciprofloxacin / Q000031:analogs & derivatives / Q000032:analysis; D003964:Diaphragm / Q000737:chemistry; D004350:Drug Residues / Q000032:analysis*; D000077422:Enrofloxacin; D004926:Escherichia coli / Q000187:drug effects*; D024841:Fluoroquinolones; D011807:Quinolizines / Q000032:analysis; D015363:Quinolones / Q000032:analysis; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D011807:Quinolizines; D015363:Quinolones; D000077422:Enrofloxacin; D002939:Ciprofloxacin; C047225:difloxacin; C047224:sarafloxacin; C012976:flumequine