By Liz Highleyman

In early February, public health officials in Seattle/King County, WA, reported 4 cases of gay men newly infected with a strain of HIV resistant to at least 2 classes of antiretroviral drugs, with partial resistance to a third class.

The same genetic strain of HIV was reported in all 4 men within 15 months of their HIV diagnoses. The men, who had not been treated with antiretroviral therapy, reported methamphetamine use and multiple sexual partners, but none of the 4 men is known to have had sex with any of the others.

The King County health agency said it would distribute fliers warning of the new strain at gay bars and bathhouses, and asked physicians to test all newly diagnosed HIV patients for drug resistance.

These cases are reminiscent of case of multidrug-resistant HIV reported in a gay New York City man in 2004. This was the first report of HIV that was both dual-tropic (able to use both CCR5 and CXCR4 co-receptors) and resistant to 3 major classes of antiretroviral medications. The man progressed rapidly to AIDS within months of his suspected date of HIV infection.

While health officials initially warned that the case might herald a new, aggressive "super strain" of HIV, further evidence suggested it was an isolated phenomenon. Details of the case were discussed at a special symposium at the 2005 Conference on Retroviruses and Opportunistic Infections and were published in the March 19, 2005 issue of The Lancet.

It is not yet known whether the Seattle men will progress more rapidly to AIDS, but the presence of a multidrug-resistant viral strain means they will be harder to treat. These recent cases highlight the important of resistance testing for newly diagnosed patients with HIV.

"Men who have sex with men need to know that drug-resistant strains can and are being transmitted and may be much less treatable," said county HIV/AIDS program director Dr. Bob Wood.

02/13/07

References

W King. Health officials warn of new HIV threat found in King County. Seattle Times. February 2, 2007.

T Paulson. Four local men found to have drug-resistant strain of HIV. Seattle Post-Intelligencer. February 2, 2007.

CDC. Investigation of a New Diagnosis of Multidrug-Resistant, Dual-Tropic HIV-1 Infection -- New York City, 2005. Morbidity and Mortality Weekly Report 55(29): 793-796. July 28, 2006.

M Markowitz, H Mohri, S Mehandru, and others. Infection with multidrug resistant, dual-tropic HIV-1 and rapid progression to AIDS: a case report. The Lancet 365(9464): 1031-1038. March 19, 2005.