ICD-10-CM 2027
ICD-10 code for bacillus infection
From the official ICD-10-CM alphabetic index entry “Infection, infected, infective (opportunistic) › Bacillus”. Page updated September 29, 2026.
About coding bacillus infection
The ICD-10-CM code for bacillus infection is A49.9 (Bacterial infection, unspecified). The official index lists 14 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on A49.9.
Within A49, choose A49.9 (Bacterial infection, unspecified) only when documentation doesn't support a more specific option: staphylococcal infection, unspecified site (A49.0), streptococcal infection, unspecified site (A49.1), hemophilus influenzae infection, unspecified site (A49.2), mycoplasma infection, unspecified site (A49.3) and other bacterial infections of unspecified site (A49.8).
Don't report A49.9 together with the conditions in its Excludes1 note: bacteremia NOS (R78.81).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
More specific bacillus infection codes (official index)
- abortus A23.1 — Brucellosis due to Brucella abortus
- anthracis
- ducreyi (any location) A57 — Chancroid
- Flexner's A03.1 — Shigellosis due to Shigella flexneri
- Friedländer's NEC A49.8 — Other bacterial infections of unspecified site
- gas (gangrene) A48.0 — Gas gangrene
- mallei A24.0 — Glanders
- melitensis A23.0 — Brucellosis due to Brucella melitensis
- paratyphoid, paratyphosus A01.4 — Paratyphoid fever, unspecified
- A A01.1 — Paratyphoid fever A
- B A01.2 — Paratyphoid fever B
- C A01.3 — Paratyphoid fever C
- Shiga (-Kruse) A03.0 — Shigellosis due to Shigella dysenteriae
- suipestifer
- swimming pool A31.1 — Cutaneous mycobacterial infection
- typhosa A01.00 — Typhoid fever, unspecified
- welchii
Don't confuse with (Excludes1 for A49.9)
- bacteremia NOS (R78.81)
Common questions about bacillus infection ICD-10 codes
What is the ICD-10 code for bacillus infection?
- A49.9 — Bacterial infection, unspecified. More specific codes apply when the documentation supports them: A23.1, A57, A03.1, A49.8 and others below.
What is the ICD-10 code for abortus bacillus infection?
- A23.1 — Brucellosis due to Brucella abortus.
What is the ICD-10 code for ducreyi bacillus infection?
- A57 — Chancroid.
What is the ICD-10 code for flexner's bacillus infection?
- A03.1 — Shigellosis due to Shigella flexneri.
What is the ICD-10 code for friedländer's nec bacillus infection?
- A49.8 — Other bacterial infections of unspecified site.
What is the ICD-10 code for gas bacillus infection?
- A48.0 — Gas gangrene.
What is the ICD-10 code for mallei bacillus infection?
- A24.0 — Glanders.
Is A49.9 billable?
- Yes. A49.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A49.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A49.9 as a principal diagnosis.
Is A49.9 a CC or MCC?
- No. A49.9 is neither a CC nor an MCC under MS-DRG v44.0.