Submitted to: Antimicrobial Agents and Chemotherapy
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/20/2003
Publication Date: 6/1/2003
Citation: ZAIDI, M.B., ZAMORA, E., DIAZ, P., TOLLEFSON, L., CRAY, P.J., HEADRICK, M. 2003. RISK FACTORS FOR FECAL QUINOLONE-RESISTANT ESCHERICHIA COLI IN MEXICAN CHILDREN. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY. 47(6):1999-2001. Interpretive Summary: Misuse of antimicrobials in both humans and animals can lead to the development of resistant bacteria including those that cause food borne illness. While, illness caused by food borne bacteria typically resolves without complications, if treatment with antimicrobials is necessary, they may not be effective if the bacteria are already resistant to them. Of particular concern is the use of low doses of antimicrobials in standard diets fed to meat producing animals such as pigs, cattle and poultry to promote growth and maintain animal health. We studied the effect of three feed-based antimicrobials (apramycin, carbadox, and tetracycline) on both the development of antimicrobial resistance in normal gut bacteria (Escherichia coli) in growing piglets and piglet growth. Results were compared to control animals fed standard diets without antimicrobials. Fecal samples were cultured for Escherichia coli at regular intervals from all piglets from birth to market weight. Antimicrobial susceptibility profiles of fecal Escherichia coli populations were determined using standard testing methods. Piglets were also weighed when fecal samples were collected. Resistance to tetracycline in Escherichia coli varied widely by sample, group, and trial. However, a significant increase in the percentage of resistant isolates was observed in piglets fed antimicrobials when compared to controls. Resistance to apramycin also increased in piglets when compared to controls. However, upon removal of apramycin, resistance in Escherichia coli declined. Resistance to carbadox remained unchanged after feeding carbadox when compared to controls. Piglets fed low doses of antimicrobials demonstrated improved growth when compared to controls. These data are useful for veterinarians, pharmaceutical manufacturers, and scientists as they devise ways to limit the development of resistance to antimicrobials while maintaining animal health.
Technical Abstract: We determined the prevalence of, and risk factors for, fecal quinolone-resistant Escherichia coli (QREC) in 324 children from Yucatan, Mexico. QREC was higher in children with recent Salmonella infection (100%) than in children with diarrhea (61%) or healthy children (54%), (p= 0.007). Multivariate analysis identified recent hospitalization of a family member (p=0.011, OR=5.1) and carriage of Salmonella (p= 0.004, OR=3.7) as independent risk factors for QREC.