Scientific Publications by FDA Staff

J Mol Microbiol Biotechnol 2012 Dec 5;22(5):317-25

In vitro Analysis of the Impact of Enrofloxacin Residues on the Human Intestinal Microbiota Using H-NMR Spectroscopy.

Ahn Y, Jung JY, Chung YH, Chae M, Jeon CO, Cerniglia CE

Exposure of humans to antimicrobial residues in food-producing animals may alter the intestinal microbiota which could result in a potential risk to human health. To determine the effect of enrofloxacin on the human intestinal microbiota, fecal suspensions (25%) were cultured in the presence of 0.06-5 microg/ml enrofloxacin. The bacterial community was analyzed by plating on selective culture media, pyrosequencing and nuclear magnetic resonance (NMR) spectroscopy. Pyrosequencing analysis of 16S rRNA genes and viable counts on Bacteroides sp., Enterococcus sp., and Bifidobacterium sp. selection medium indicated that there were no significant changes in the bacteria numbers at the selected enrofloxacin concentrations (0.06, 0.1, and 1 microg/ml) relative to the control samples after a 48 h incubation. NMR analysis showed remarkably similar spectra in cultures treated with 0.06, 0.1, and 1 microg/ml enrofloxacin, with some slight differences in peak heights. However, hierarchical clustering analysis indicated significant differences in metabolite concentrations between the control and those samples treated with 1 microg/ml enrofloxacin. Leucine, phenylalanine, proline, and 2-oxovalerate were positively correlated with the concentration of enrofloxacin. NMR analysis is a potentially useful tool to monitor changes of the human intestinal microbiota, in addition to traditional culture methods and pyrosequencing.