Four cases of highly drug resistant HIV have been identified among recently diagnosed individuals with HIV infection.  Genotype results indicate high level resistance to most licensed antiretrovirals, including all protease inhibitors (PI) and non-nucleoside reverse transcriptase inhibitors (NNRTI).  Each virus had major mutations to nucleoside reverse transcriptase inhibitors (NRTI) but was sensitive to one or two NRTI.  Sensitivity testing to Fuzeon (T20) has not yet been conducted.  Acquisition of drug-resistant HIV is more of a concern than becoming infected with the standard, “wild-type” HIV because treatment options for such persons may be more limited. 

All four had a history of methamphetamine use, and all had sex with multiple, mostly anonymous, male partners.  The diagnoses of HIV infection were made in late 2005 (1), early 2006 (1), and late 2006 (2).  Three of the four had evidence of recent infection at the time of their HIV diagnoses and all were antiretroviral (ARV) naive.  The University of Washington/Children 's Hospital genotype laboratory determined that the viruses of these recent four cases were very similar by phylogenetic tree analyses.  This suggests the possibility of a common source or sources of infection.  We have no data on the transmissibility of this virus, the long-term clinical course of persons infected with the virus, or the extent to which persons with this strain of HIV might respond to standard antiretroviral therapies.  PCRS (partner counseling and referral services) investigations are ongoing.  With the cooperation of the medical providers and their patients, Public Health is attempting to locate and test sex partners of these cases for HIV infection and ARV resistance.

We are requesting the assistance of medical providers to let us know about any additional cases of multi-drug resistant HIV infection among patients who have not yet used ARV therapy.  Please call (206) 205-1470 anytime multiple class resistance is diagnosed in a patient with HIV infection who has not yet used ARV. 

These cases point out the importance of performing drug resistance assays on all newly-diagnosed HIV-infected individuals.  Obtaining a resistance test prior to initiating ARV therapy is recommended to guide the choice of drugs so as to avoid drugs to which the virus is resistant.  Testing near time of diagnosis may be superior to testing later in infection, as in some cases the initial drug-resistant HIV is obscured by the overgrowth of a non-resistant viral strain -- either due to the dominance of wild-type virus in persons infected with multiple strains, or from “super”infection with a non-resistant strain from another person (as may have happened for one of these cases).  In either case, the resistant strain does not go away, but it may be much more difficult to detect as resistant strains are more difficult when they are present as a minority of the viral populations.  However, resistant strains may still affect the outcome of ARV therapy.

The on-going local surveillance of ARV resistance among treatment-naïve and newly-identified persons with HIV has demonstrated that about 11% of these virus strains show at least some high-level resistance to one or more of the ARV drugs used for HIV; 3% have shown high-level resistance to one or more drug(s) in two or more drug classes.

For more information, please contact Public Health's HIV/AIDS Program, Public Health – Seattle & King County at 206-296-4649.