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AbstractPakistan is experiencing a growing HIV epidemic. Antiretroviral drugs (ARV) have been smuggled into the country and available without prescription since the early 1990s, but are now provided free of cost by the government. We assessed the prevalence of HIV-1, drug resistance, and subtype distributions. Blood specimens were collected from HIV-1-infected participants registered in Sindh Province on dry blood spot (DBS) cards in 2008. Pol, protease, and partial reverse transcriptase regions were sequenced after reverse transcriptase PCR (RT-PCR). HIV-1 subtype was assigned by phylogenetic analysis. Primary drug resistance was analyzed by the Calibrated Population Resistance (CPR) tool using the Stanford Surveillance Drug Resistance Mutation (SDRM) major mutation list. Out of 100 blood samples collected, 42 were suitable for testing. Out of 42, 11 were ARV-receiving and 31 ARV-naive patients. Among them, 24 were injection drug users (IDUs), four immigrants, two hijras (male transvestites), two men who have sex with men (MSM), four prisoners, one female sex workers, two spouses of HIV-infected persons, and four from the general population. ARV resistance among naive patients was 2/31 (6.5%) and 36.4% (4/11) among ARV-experienced patients making an overall resistance of 14.2%. HIV-1 subtype A1 was the predominant subtype found in 35/42 (83.3%) followed by CRF35_AD and C, 6.5% each. Subtype D and G were found in one (2.4%) each. A significant proportion of Pakistani HIV patients has ARV drug resistance. Physicians treating patients should consider the magnitude of drug resistance while selecting regimens, and address drug adherence aggressively. [ABSTRACT FROM AUTHOR]

The partial polgene was analyzed to determine circulating HIV-1 subtypes and the prevalence of drug resistance among recently infected injecting drug users in the west of China. Phylogenetic and bootscanning analyses showed that all 25 sequences belonged to CRF07_BC. No major drug resistance mutations were found, while the CRF07_BC sequences harbored a few highly prevalent polymorphic positions in both the protease and reverse transcriptase regions. It is notable that D60E, L63P and I93L substitutions, which were more common in HIV-1 isolates from PI-treated than untreated patients, were present in most of the isolates. Compared with subtype B, the CRF07_BC strains had a decreased genetic barrier for the V106M mutation, which is selected by efavirenz and leads to high-level resistance to all present nonnucleoside RT inhibitors. Further studies are needed to determine the impact of genetic features of CRF07-BC on antitretroviral susceptibility and evolution of drug resistance mutations. [ABSTRACT FROM AUTHOR]

It is known that transmitted drug resistance (TDR) will most likely emerge in regions where antiretroviral therapy (ART) has been widely available for years. However, after a decade of rapid scale-up of ART in China, there are few data regarding TDR among HIV-infected patients prior to initiating first-line ART in China. A prospective, observational cohort study was performed at sentinel sites in five provinces or municipalities. Study participants were recruited at the county- or city-level centers for disease control (CDCs), during routine monitoring visits following referral from diagnosing parties (e.g., hospitals). Each province or municipality recruited 140 patients through sequential sampling throughout the 2011 calendar year. A total of 627 eligible subjects were included in the analysis, the median CD4+ cell count was 206 cells/ml at the baseline survey. The majority of patients (93.5%) had plasma HIV viral load >1,000 copies/ml. Of the 627 patients, 17 (2.7%) had drug resistance mutations for any type of HIV drugs. The prevalence of drug resistance mutations to non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs (8/627, 1.3%) was higher than to nucleoside reverse transcriptase inhibitor (NRTI) drugs (5/627, 0.8%) and protease inhibitor (PI) drugs (4/627, 0.6%). A logistic regression model showed that the only predictive factor was the route of infection through homosexual inter-course, i.e., men who have sex with men (MSM) status. As HIV prevalence is rising rapidly among Chinese MSM, it is essential to continue surveying this risk group and related high-risk populations with low awareness of HIV, and to develop new public health interventions that help to reduce the spread of drug-resistant HIV. [ABSTRACT FROM AUTHOR]