ICD-10-CM Code A49.9

Bacterial infection, unspecified

Version 2020 Billable Code

Valid for Submission

A49.9 is a billable code used to specify a medical diagnosis of bacterial infection, unspecified. The code is valid for the year 2020 for the submission of HIPAA-covered transactions. The ICD-10-CM code A49.9 might also be used to specify conditions or terms like abscess of aortic valve, abscess of mitral valve, abscess of pulmonary valve, acne with gram negative folliculitis, acute bacterial otitis externa, acute bacterial tubulointerstitial nephritis, etc

Short Description:Bacterial infection, unspecified
Long Description:Bacterial infection, unspecified

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code A49.9:

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code A49.9 are found in the index:


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Abscess of aortic valve
  • Abscess of mitral valve
  • Abscess of pulmonary valve
  • Acne with gram negative folliculitis
  • Acute bacterial otitis externa
  • Acute bacterial tubulointerstitial nephritis
  • Acute infectious tubulointerstitial nephritis
  • Acute infective otitis externa
  • Acute interstitial nephritis
  • Acute pyelonephritis
  • Angular cheilitis
  • Angular cheilitis due to bacterial infection
  • Bacterial abscess of aortic valve
  • Bacterial abscess of mitral valve
  • Bacterial abscess of pulmonary valve
  • Bacterial cellulitis
  • Bacterial corneal ulcer
  • Bacterial encephalitis
  • Bacterial endophthalmitis
  • Bacterial esophagitis
  • Bacterial folliculitis
  • Bacterial genital infection
  • Bacterial infection associated with peritoneal dialysis catheter
  • Bacterial infection by site
  • Bacterial infection of central nervous system
  • Bacterial infection of skin
  • Bacterial infectious disease
  • Bacterial musculoskeletal infection
  • Bacterial nephritis
  • Bacterial oral infection
  • Bacterial osteomyelitis
  • Bacterial otitis media
  • Bacterial respiratory infection
  • Bacterial sinusitis
  • Bacterial tonsillitis
  • Bacterial upper respiratory infection
  • Bacterial urogenital infection
  • Beta lactam resistant bacterial infection
  • Botryomycosis
  • Cutaneous reaction caused by bacterial toxin
  • Disease due to Gram-negative bacteria
  • Erythema nodosum due to bacterial infection
  • Gram-negative bacterial cellulitis
  • Gram-negative folliculitis
  • Herpes zoster with secondary bacterial infection
  • Infection associated with peritoneal dialysis catheter
  • Infection caused by multi drug resistant bacteria
  • Infection due to anaerobic bacteria
  • Infection due to carbapenem resistant bacteria
  • Infection due to quinolone and fluoroquinolone resistant bacteria
  • Infection due to resistant bacteria
  • Infective esophagitis
  • Moderate cavitated lesion limited to outer half of dentin
  • Neuropathy due to bacterial toxin
  • Non-pyogenic bacterial infection of skin
  • Peripheral neuropathy caused by toxin
  • Pleural effusion due to another disorder
  • Pleural effusion due to bacterial infection
  • Pyogenic bacterial infection due to deficiency of myeloid differentiation primary response 88
  • Recurrent bacterial infection
  • Superficial bacterial infection of skin
  • Toxic polyneuropathy

Clinical Information

  • BACTERIAL INFECTIONS AND MYCOSES-. infections caused by bacteria and fungi general specified or unspecified.
  • BACTERIAL INFECTIONS-. infections by bacteria general or unspecified.
  • GRAM NEGATIVE BACTERIAL INFECTIONS-. infections caused by bacteria that show up as pink negative when treated by the gram staining method.
  • GRAM POSITIVE BACTERIAL INFECTIONS-. infections caused by bacteria that retain the crystal violet stain positive when treated by the gram staining method.
  • CENTRAL NERVOUS SYSTEM BACTERIAL INFECTIONS-. bacterial infections of the brain spinal cord and meninges including infections involving the perimeningeal spaces.

Diagnostic Related Groups

The ICD-10 code A49.9 is grouped in the following groups for version MS-DRG V37.0 What are Diagnostic Related Groups?
The Diagnostic Related Groups (DRGs) are a patient classification scheme which provides a means of relating the type of patients a hospital treats. The DRGs divides all possible principal diagnoses into mutually exclusive principal diagnosis areas referred to as Major Diagnostic Categories (MDC).
applicable from 10/01/2019 through 09/30/2020.


Convert A49.9 to ICD-9

  • 041.9 - Bacterial infection NOS (Approximate Flag)

Code Classification

  • Certain infectious and parasitic diseases (A00–B99)
    • Other bacterial diseases (A30-A49)
      • Bacterial infection of unspecified site (A49)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020

Information for Patients

Bacterial Infections

Bacteria are living things that have only one cell. Under a microscope, they look like balls, rods, or spirals. They are so small that a line of 1,000 could fit across a pencil eraser. Most bacteria won't hurt you - less than 1 percent of the different types make people sick. Many are helpful. Some bacteria help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt and cheese.

But infectious bacteria can make you ill. They reproduce quickly in your body. Many give off chemicals called toxins, which can damage tissue and make you sick. Examples of bacteria that cause infections include Streptococcus, Staphylococcus, and E. coli.

Antibiotics are the usual treatment. When you take antibiotics, follow the directions carefully. Each time you take antibiotics, you increase the chances that bacteria in your body will learn to resist them causing antibiotic resistance. Later, you could get or spread an infection that those antibiotics cannot cure.

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