2027 ICD-10-CM Diagnosis Code A49.01Methicillin susceptible Staphylococcus aureus infection, unspecified site

ICD-10-CM Codes›A00–B99›A30-A49›A49

ICD-10-CM A49.01
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A49.01 is a billable ICD-10-CM diagnosis code for methicillin susceptible Staphylococcus aureus infection, unspecified site. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 867 through 869. Coders also document this condition as infection caused by Panton-Valentine leukocidin producing Staphylococcus aureus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections.

Code Identity

ICD-10-CM Code
A49.01
Billable Status
Yes — Valid for Submission
Code Describes
Methicillin susceptible Staphylococcus aureus infection, unspecified site
Short Description
Methicillin suscep staph infection, unsp site
Parent Code
A49.0
Staphylococcal infection, unspecified site

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA49Bacterial infection of unspecified site
This CodeA49.01Methicillin susceptible Staphylococcus aureus infection, unspecified site

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Infection caused by Panton-Valentine leukocidin producing Staphylococcus aureus
  • Recurrent infection caused by Staphylococcus
  • Recurrent infection caused by Staphylococcus aureus
  • Staphylococcal infectious disease

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A49.01: its own notes plus those printed at A49 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Methicillin susceptible Staphylococcus aureus (MSSA) infection
  • Staphylococcus aureus infection NOS

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From A49 Bacterial infection of unspecified site applies to 7 codes
  • bacterial agents as the cause of diseases classified elsewhere (B95-B96)
  • meningococcal infection NOS (A39.9)
  • rickettsial infection NOS (A79.9)
  • spirochetal infection NOS (A69.9)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From A49 Bacterial infection of unspecified site applies to 7 codes
  • chlamydial infection NOS (A74.9)
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Staphylococcal Infections

    infections with bacteria of the genus staphylococcus.

Patient EducationClinical

Staphylococcal Infections

Staphylococcus (staph) is a group of bacteria. There are more than 30 types. A type called Staphylococcus aureus causes most infections.

The full article covers:

  • What are Staphylococcal (staph) infections?
  • What causes staph infections?
  • Who is more likely to get a staph infection?
  • What are the symptoms of staph infections?
  • How are staph infections diagnosed?
  • What are the treatments for staph infections?
  • Can staph infections be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert A49.01 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
041.11 Mth sus Stph aur els/NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About A49.01Overview

Is A49.01 (Staphylococcal infection, unspecified site) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report methicillin susceptible Staphylococcus aureus infection, unspecified site on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does A49.01 group to?

When methicillin susceptible Staphylococcus aureus infection, unspecified site is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 869, 868, with relative weights from 0.6784 to 2.1855 depending on complications. Higher weights mean higher Medicare reimbursement.

Can A49.01 be reported with A39.9?

Not as a rule. The Excludes1 note at A49, which applies to A49.01, lists "meningococcal infection NOS (A39.9)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of A49.01?

Under the General Equivalence Mappings, methicillin susceptible Staphylococcus aureus infection, unspecified site converts to ICD-9-CM 041.11 (mth sus Stph aur els/NOS). The mapping is approximate, so confirm the match fits the documentation.