Exhibit 3.15

Delaware	PAGE 1
The First State

     I, JEFFREY W. BULLOCK, SECRETARY OF STATE OF THE STATE OF DELAWARE, DO HEREBY CERTIFY THE ATTACHED ARE TRUE AND CORRECT COPIES OF ALL DOCUMENTS ON FILE OF “AMG-SOUTHERN TENNESSEE, LLC” AS RECEIVED AND FILED IN THIS OFFICE.

     THE FOLLOWING DOCUMENTS HAVE BEEN CERTIFIED:

     CERTIFICATE OF FORMATION, FILED THE FIFTEENTH DAY OF DECEMBER, A.D. 1998, AT 9 O’CLOCK A.M.

     CERTIFICATE OF MERGER, FILED THE TWENTY-SECOND DAY OF APRIL, A.D. 1999, AT 2:15 O’CLOCK P.M.

     CERTIFICATE OF AMENDMENT, FILED THE TWENTY-SECOND DAY OF JANUARY, A.D. 2002, AT 10 O’CLOCK A.M.

     AND I DO HEREBY FURTHER CERTIFY THAT THE AFORESAID CERTIFICATES ARE THE ONLY CERTIFICATES ON RECORD OF THE AFORESAID LIMITED LIABILITY COMPANY, “AMG-SOUTHERN TENNESSEE, LLC”.

2980138     8100H		/s/ Jeffrey W. Bullock
110292094 You may verify this certificate online at corp.delaware.gov/authver.shtml		Jeffrey W. Bullock, Secretary of State AUTHENTICATION: 8619740 DATE: 03-14-11

STATE OF DELAWARE

SECRETARY OF STATE

DIVISION OF CORPORATIONS

FILED 09:00 AM 12/15/1998

981485701 — 2980138

CERTIFICATE OF FORMATION
OF
AMG — SOUTHERN TENNESSEE, LLC

Under Section 18-201 of the
Delaware Limited Liability Company Act

     FIRST: The name of the limited liability company is AMG — Southern Tennessee, LLC (the “Company).

     SECOND: The address of the registered office of the Company in the State of Delaware is 1013 Centre Road, Wilmington, Delaware 19805.

     THIRD: The name and address of the Company’s registered agent for service of process is Corporation Service Company, 1013 Centre Road, Wilmington, Delaware 19805.

     IN WITNESS WHEREOF, the undersigned has executed this Certificate of Formation as of December, 15, 1998.

By:	/s/ John M. Franck II
	Name:	John M. Franck II
	Title:	Authorized Person

STATE OF DELAWARE

SECRETARY OF STATE

DIVISION OF CORPORATIONS

FILED 02:15 PM 04/22/1999

991159165 — 2980138

CERTIFICATE OF MERGER

OF

COLUMBIA MEDICAL GROUP — SOUTHERN TENNESSEE, INC.

INTO

AMG—SOUTHERN TENNESSEE, LLC

Pursuant to Section 18-209 of the
Delaware Limited Liability Company Act

     The undersigned limited liability company and corporation DO HEREBY CERTIFY:

     FIRST: The name and the state of formation or organization of each of the constituent entities to the merger are as follows:

Name	State of Formation or Organization
AMG—Southern Tennessee, LLC (the “LLC”)	Delaware
Columbia Medical Group — Southern Tennessee, Inc. (the “Company”)	Tennessee

     SECOND: An Agreement and Plan of Merger between the constituent entities to the merger (the “Merger Agreement”) has been approved and executed by each of the constituent entities to the merger.

     THIRD: The Company shall be merged with and into the LLC, with the LLC being the surviving entity (the “Surviving Entity”) in the merger, and the name of the Surviving Entity shall be AMG—Southern Tennessee, LLC.

     FOURTH: The Certificate of Formation of the LLC at the effective time of the merger shall be the Certificate of Formation of the Surviving Entity.

     FIFTH: The executed Merger Agreement is on file at the principal place of business of the Surviving Entity. The address of the Surviving Entity is One Park Plaza, Nashville, Tennessee 37203.

     SIXTH: A copy of the Merger Agreement will be furnished by the Surviving Entity, on request and without cost, to any shareholder or member, as the case may be, of the constituent entities.

     SEVENTH: This Certificate of Merger shall be effective on April 22, 1999.

*****

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     IN WITNESS WHEREOF, this Certificate of Merger has been executed on this 21^st day of April, 1999.

AMG—SOUTHERN TENNESSEE, LLC
By:	/s/ John M. Franck II
	Name:	John M. Franck II
	Title:	Manager
COLUMBIA MEDICAL GROUP — SOUTHERN TENNESSEE, INC.
By:	/s/ R. Milton Johnson
	Name:	R. Milton Johnson
	Title:	Vice President

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STATE OF DELAWARE

SECRETARY OF STATE

DIVISION OF CORPORATIONS

FILED 10:00 AM 01/22/2002

020041701 — 2980138

CERTIFICATE OF AMENDMENT

OF

AMG-Southern Tennessee, LLC

     1. The name of the limited liability company is AMG-Southern Tennessee, LLC

     2. The Certificate of Formation of the limited liability company is hereby amended as follows:

     The name and address of the registered agent is The Corporation Trust Company, Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware 19801.

     IN WITNESS WHEREOF, the undersigned has executed this Certificate of Amendment of AMG-Southern Tennessee, LLC this 15 day of January, 2002.

AMG-Southern Tennessee, LLC
 

/s/ William F. Carpenter III  

William F. Carpenter III 

Title Manager