# Install bracken with Homebrew

Bayesian estimation of species abundance from Kraken output. Version 3.1 via Homebrew; verified 2026-07-13.

## Install

```sh
sudo av install brew:bracken
```

Additional install commands:

### macOS

- Homebrew (100%):

```sh
brew install bracken
```

  Evidence: local Homebrew formula metadata

## Package facts

- **Package key:** brew:bracken
- **Package manager:** Homebrew
- **Version:** 3.1
- **Source summary:** Bayesian estimation of species abundance from Kraken output
- **Homepage:** <https://ccb.jhu.edu/software/bracken/>
- **Repository:** <https://github.com/jenniferlu717/Bracken>
- **Last updated:** 2026-07-13T04:01:12Z
- **Generated:** 2026-08-03T19:37:03+00:00

## Executables

- bracken (alias)
- bracken-build (alias)

## Install behavior

- Bottle: not available

## Freshness

- Page generated: 2026-08-03
- Package-manager version: 3.1
## Project history and usage

Bracken, short for Bayesian Reestimation of Abundance with Kraken, is a command-line method for estimating species or higher-level taxonomic abundance from Kraken-classified metagenomic reads.

### Project history

Bracken was developed in the Johns Hopkins Center for Computational Biology ecosystem around Kraken. The official CCB page records the first public release in April 2016 and the Bracken paper in PeerJ Computer Science in January 2017.

The project evolved from Python and support scripts into a workflow with `bracken-build` for database preparation and `bracken` for abundance estimation. The CCB news log records the 2018 v2.0.0 release adding shell scripts for the combined workflow and later build-time optimizations.

### Adoption history

Bracken is adopted as a companion to Kraken 1, KrakenUniq, and Kraken 2 because Kraken assigns reads to taxonomy but does not itself estimate species abundance. Bracken re-estimates abundances by using k-mer distribution probabilities derived from the Kraken database.

The 2022 Nature Protocols Kraken suite paper incorporated Bracken into a step-by-step metagenomic workflow for microbiome analysis and pathogen detection, reinforcing its role as part of the standard Kraken command-line toolchain.

### How it is used

A typical Bracken run first builds or obtains a Kraken database, generates Bracken database files for a read length with `bracken-build`, classifies samples with Kraken or Kraken 2, creates a Kraken report, and then runs `bracken` or `estimate_abundance.py` to estimate abundance at a target taxonomic rank.

The manual notes that Bracken supports Kraken 1 and Kraken 2 and that users should account for the default k-mer length difference between those classifiers.

### Why package nerds care

Bracken matters to package maintainers because it is a small CLI package that depends operationally on large external Kraken databases and database-specific k-mer distribution files rather than on a self-contained config file.

It is also a packaging example where the executable surface includes both a user-facing abundance command and a build command that prepares data artifacts for downstream runs.

### Timeline

- 2016: First public Bracken release recorded by the official CCB page.
- 2017: Bracken paper published in PeerJ Computer Science.
- 2018: v2.0.0 release adds `bracken` and `bracken-build` shell-script workflow.
- 2022: Kraken protocol paper including Bracken published in Nature Protocols.
- 2025: GitHub releases list Bracken v3.1 as the latest release.

### Related projects

- Kraken 1, KrakenUniq, Kraken 2, and KrakenTools are the closest related tools in official Bracken documentation.
- Pavian is part of the broader Kraken-suite visualization workflow referenced in the Nature Protocols article.

### Sources

- <https://ccb.jhu.edu/software/bracken/index.shtml>
- <https://ccb.jhu.edu/software/bracken/index.shtml?t=manual>
- <https://github.com/jenniferlu717/Bracken>
- <https://peerj.com/articles/cs-104/>
- <https://www.nature.com/articles/s41596-022-00738-y>
- input.source_facts.package-manager


## Security Notes

No matching local secret-handling manifest was found for bracken. Nucleus package metadata is still published here so future coverage has a stable package URL.



## Combined YAML source

View the package source record on GitHub. [combined/bracken.yml](https://github.com/mxcl/pkgdb/blob/main/combined/bracken.yml)


## Sources

- pkg.so package database
- curated package history
- pkgdb category and tag curation
- cross-ecosystem install command graph