U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Food and Feed Safety Research: College Station, TX
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Plains Area College Station, Texas Southern Plains Agricultural Research Center Food and Feed Safety Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Poole, Toniitem
                                            Byrd Ii, James

                                                         - *Allen*item
                                            Callaway, Todditem
                                            Nisbet, David
  Submitted to: Foodborne Pathogens and Disease
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 4/20/2009
                                    Publication  Date: 9/16/2009
                                    Citation: Poole, T.L., Byrd II, J.A., Callaway, T.R., Nisbet, D.J. 2009. Ecology of Enterococcus faecalis and niche-adapted or non-niche-adapted Enterococcus faecium in continuous-flow anaerobic cultures. Foodborne Pathogens and Disease. 6:901-906.Interpretive Summary: Bacteria must compete with each other in the environment in order to survive.  Some bacterial strains produce antimicrobial compounds as a means to kill competing bacteria.  One such bacterium is Enterococcus faecalis which produces a toxin that kills other bacterial cells including a closely related species, Enterococcus faecium.  We have studied a mixed culture of chicken gastrointestinal bacteria that contains both of these species and have found that the Enterococcus faecium from this culture is resistant to the toxin produced by Enterococcus faecalis.  The present study was done to understand the ecology that exists between the Enterococcus faecalis from the mixed culture and various strains of Enterococcus faecium because both of these bacterial species can cause fatal diseases in humans.
                                Technical Abstract: Objectives: To study the survivability of niche adapted Enterococcus faecium I.3rif (I.3rif) vs. non-niche adapted Enterococcus faecium (GRE47) in cultures that contain Enterococcus faecalis I.2.  Methods: An anaerobic continuous-flow culture of chicken microflora (CCF) that models the chicken gastrointestinal tract was used for ecological survivability studies.  Pure continuous-flow co-cultures were used to assess an inhibitory effect of E. faecalis I.2 on E. faecium isolates.  Results: CCF eliminated GRE47 at a rate of 1.01 log10 cfu/mL/day; whereas, I.3rif survived in CCF at 4.5-6.5 log10 cfu/mL.  In continuous-flow monocultures of GRE47 with an average concentration of 8.93 log10 cfu/mL, the addition of 100 mL (9.5% total volume) of CCF resulted in the displacement of GRE47 in approximately 14 days at a rate of 0.66 log10 cfu/mL/day.  In continuous-flow co-cultures of E. faecalis I.2 and GRE47, GRE47 was eliminated from the culture at a rate of 1.24 log10 cfu/mL/day. In co-cultures of I.3rif and E. faecalis I.2, the I.3rif population fluctuated, but was at 6.86 log10 CFU/ml on day 21.  Conclusions: A fit subset of the E. faecium I.3rif population was able to survive in CCF and in the presence of E. faecalis I.2 alone.  No subset of the non-niche adapted E. faecium GRE47 was able to survive under the same conditions.  Tolerance may be due to mutations or genes acquired by I.3rif during the initial colonisation of the chicken gastrointestinal tract.  The mechanism by which E. faecium I.3rif is tolerant in CCF and in E. faecalis co-culture is currently unknown.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov