Drug resistance found in SE area, representing poor, rural population
Drug resistance found in SE area, representing poor, rural population
Resistance screening is indicated
A recent study about HIV drug resistance among untreated HIV patients highlights the growing problem of resistance in a Southeastern region of the country.1
An infectious diseases clinic in Jackson, MS, had a rate of 10.5 percent in 2004 for drug resistance found in patients who were seen at their first visit upon diagnosis of HIV infection, says Harold Henderson, MD, professor of medicine at the University of Mississippi Medical Center in the division of infectious diseases in Jackson.
The 124 patients included in the study had not received antiretroviral treatment and did not represent new infections, but could be described as chronically infected, Henderson says.
"Our conclusions are that the ability to detect anti-HIV drug resistance in chronically HIV-infected persons who had never been treated before was significant," Henderson says. "The most common mutation was the mutation that confers resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs)."
Existing research data about drug resistance mostly has looked at newly-infected patients in large urban areas, and has found resistance of 8 percent to 15 percent, Henderson says.
"The major difference from what we did was we did resistance testing on patients who came to our clinic for the first time, but who weren’t necessarily newly infected patients," Henderson says. "They may have been infected for quite a while before the time they ever came to our clinic."
HIV clinicians and researchers long have discussed whether drug-resistant strains remain detectable in the absence of drug therapy, with many theorizing that wild type virus is more dominant in this untreated population.
"Some people have questioned whether such strains would remain detectable for a significant period of time," he says. "A lot of people had felt that in untreated patients if they had gotten infected with drug resistant strains those drug resistant strains would only be detectable for a short period of time and then fade into the background."
If that happened then it wouldn’t be much use to do resistance testing in patients who had never been treated before, Henderson explains.
"If patients on medication have drug-resistant strains, and those particular strains are resistant to the drugs they are being given then those strains will be replicating preferentially to other strains that are being suppressed by the drugs," Henderson says.
"If the medication is subsequently changed and the patient starts taking different drugs then those resistant strains may now be suppressed by the new medication," Henderson says. "But there may be other strains present in that person that previously were being suppressed by old medicines, and now in the presence of new medicines those strains can emerge from the backgrounds and become the predominant strains."
All of these factors play into decisions about resistance testing, so any study which shows durability of drug-resistant virus is notable.
"There is coming to be a recognition that the shifting of viral strains in persons who are on treatments may not occur to the same degree in persons who have never been treated before," Henderson says. "In someone who has never been treated before, if that person is infected with a drug resistant strain then that strain may persist in detectable levels for a long time."
The 10.5 percent detectable drug resistance found in the Jackson clinic’s population is significant, Henderson says.
"Most people feel that a level that high would justify routinely doing resistance testing in this setting," Henderson says. "And that is among patients who’ve never been treated before and who appear for their initial evaluation."
The other implication of the research is that drug resistance is present in smaller cities and rural areas, as well as large urban regions, Henderson says.
Reference
- Henderson H, Brown B. HIV Drug Resistance Among Untreated Chronically HIV-Infected Person in an Infectious Diseases (ID) Clinic in Jackson, Mississippi. Presented at the 43rd Annual Meeting of the IDSA, Oct. 6-9, 2004, in San Francisco, CA. Abstract: 801.
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