Vast amounts of information on virology, including drug resistance, across many therapeutic categories.

Database of HIV resistance mutations published by International Medical Press. Includes phenotypic data, unlike other databases listed in this section, but its not possible to check cross-resistance patterns easily.

A review for clinicians from the Medscape site

Database of mutations and monthly articles from leading experts on resistance-related issues; you can also sign up for a newsletter to alert you to new material. Lots of useful data.

Allows you to search for data on specific codon changes or for all data on changes between specific codon positions and gives a list of references regarding those changes (references are not linked to Medline or full text, unfortunately).

Information-rich site on phenotypic resistance testing from ViroLogic, manufacturer of the Phenosense assay, including a useful selection of abstracts supporting the use of phenotypic testing.

A curated database containing nearly all published HIV RT and protease sequences: a resource designed for researchers studying evolutionary and drug-related variation in the molecular targets of anti-HIV therapy. This database is quite confusing to use.

Information about Vircos online database of genotypic and phenotypic resistance information. Access to the database is only available to people using Vircos resistance tests.