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U.S. Department of Health and Human Services

About FDA

Impact of Antimicrobial Drug Residues on Human Gastrointestinal Microorganisms

Description: Determine the impact of antimicrobial residues on the human intestinal microbiota using "omics" and analytical chemistry methods. These studies will evaluate metabolism and inactivation of antimicrobial drugs by gastrointestinal bacteria which may impact the effectiveness of these agents at their intended target sites.

Definition: DM performs methods to assess risks to the gastrointestinal microflora of humans when antimicrobial compounds are ingested in food residues, probiotics and dietary supplements.

Understanding the impact of antimicrobial residues on the human intestinal microbiota will provide a new tool in determining acceptable daily-intake limits of antibiotic residues.

Public Health Outcome: Data from these studies is being used by CVM to evaluate the safety of veterinary drugs in foods of animal origin. In addition, Division of Microbiology/NCTR scientists are actively providing guidance to CVM, WHO and VICH - International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medical Products concerning specific methodologies used to determine if the ingestion of residues of antimicrobial agents in food impact the health of the consumer.

Milestone DescriptionMilestone DateMilestone StatusMilestone Completion Date

1. Develop analytical chemistry and bioassay methods to detect veterinary drugs or metabolites in complex matrices


Completed 4/30/2010

2. Start fecal collection from human subjects to determine the impact of drug residues on human intestinal microbiota


Completed 5/31/2010

3. Develop molecular based "omics" methods to determine composition of human intestinal microbiota affected by veterinary drug exposure



Completed 6/30/2011

4. Complete the assessment of research findings


Completed 9/30/2011

5. Develop draft technical report/manuscript/publication



Completed 2/12/2013

6. Complete the peer review (NCTR and other researchers) of draft technical report, manuscript, and/or publication



Completed 5/1/2013

7. Obtain NCTR Center Director approval on the draft technical report, manuscript, and/or publication via the document tracking system



Completed 5/31/2013

8. Submit final technical report, manuscript, and/or publication on human intestinal microbiota to a scientific journal



Completed 6/9/2013


  • The dates in italics under the milestone due dates are modified milestone due dates which had to be updated due to real-time delays. The milestone status reflects the revised dates.

Key Projects Legend

Milestone StatusDefinition
Not Yet StartedWork for specific milestone has not yet been started.
CompletedMilestone and/or overall project is completed.
On TrackMilestone - On track for completion by milestone deadline. Quarter status - Project is on track for completion based on overall milestone status.
On HoldMilestone - On hold, but deadline for completion has not passed. Quarter status - Project is on hold, based on overall milestone status.
DelayedMilestone - Delayed as it has not been completed and deadline has passed. Quarter status - Project is delayed based on overall milestone status.



World Health Organization


Veterinarian International Conference on Harmonization

bioassay methods

experiment to determine the effect of a substance on an organism

Note: The data provided on this website is produced on an ongoing basis for performance management purposes and is subject to change due to updates of preliminary estimates, corrections, or other reasons. In addition, FDA may change the type or amount of data provided on this website at any time. Information marked as "Completed" may include measures and/or key projects for which activities are ongoing but no longer tracked as part of FDA-TRACK.