Effects of sodium chlorate on antibiotic resistance in Escherichia coli O157:H7.
The spread of antibiotic resistance from farm animals to human pathogens has become a matter of great public health significance, and methods to reduce foodborne pathogenic bacteria without utilizing traditional antibiotics have been sought. Chlorate kills Escherichia coli O157:H7 in vitro and in vivo and has been proposed as a feed additive to be included in food animal rations immediately prior to slaughter to reduce E. coli O157:H7 populations in the animal gastrointestinal tract. This study was designed to examine the effect that the development of chlorate resistance in E. coli O157:H7 has on resistance to 32 medically important antibiotics. Chlorate resistance numerically increased antibiotic resistance in E. coli O157:H7 strain 6058 and strain 933 to six and four antibiotics, respectively, but chlorate resistance affected resistance to only two antibiotics (cefoxotin and sulfadimethoxine) in both strains examined. Based on the fact that chlorate resistant mutants do not appear to compete well in vivo and based on the results of the current study, it appears unlikely that chlorate treatment will result in a dissemination of antibiotic resistance. However, further research is needed to confirm these results.
Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, Texas 77845, USA. callaway@ffsru.tamu.edu
T R
TR
Callaway
R C
RC
Anderson
T S
TS
Edrington
K M
KM
Bischoff
K J
KJ
Genovese
T L
TL
Poole
J A
JA
Byrd
R B
RB
Harvey
D J
DJ
Nisbet
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002704:Chlorates / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005506:Food Contamination / Q000517:prevention & control*; D006801:Humans; D008460:Meat / Q000382:microbiology; D008826:Microbial Sensitivity Tests
D000900:Anti-Bacterial Agents; D002704:Chlorates; C032706:sodium chlorate