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BACKGROUND: Little is known about the extent and predictors of polymorphisms potentially influencing the susceptibility to HIV integrase inhibitors (INIs). METHODS: Genetic sequences of HIV integrase were obtained from INI-naive patients at two European clinics. The 39 amino acid changes at 29 integrase positions so far associated with INI resistance were examined according to HIV clade, prior antiretroviral exposure and duration of HIV infection. RESULTS: Integrase sequences were obtained from 418 patients, 294 (70.3%) infected with clade B and 124 (29.7%) infected with non-B variants (predominantly CRF02, A, C and D). Overall, 40% of patients were antiretroviral experienced and 32.8% were recent seroconverters. The most prevalent INI resistance-associated mutations were V72I (63.9%), V201I (54.8%), T206S (25.4%), I203M (9.8%) and K156N (7.4%). Major INI resistance mutations at positions 66, 92, 143, 148 and 155 were not detected. The mean number of polymorphic sites was greater in non-B than in B variants (2.17 versus 1.59; P < 0.001), and in antiretroviral-experienced than in drug-naive patients (1.89 versus 1.68; P = 0.034), whereas no significant differences were seen comparing recent seroconverters and chronically infected persons. CONCLUSIONS: Major INI resistance-associated mutations are very rare, if indeed ever present, in INI-naive patients. However, polymorphisms at positions which may influence the genetic barrier and/or drive the selection of specific INI resistance pathways are common, especially in HIV non-B subtypes.

Background: Increasing data shows the relevance of HBV genotypes in the outcome of infection. Most studies investigating the relationship between the genotypic characteristics of hepatitis B virus (HBV) and the clinical or epidemiological aspects of HBV infection originate from studies of patients with chronic rather than acute hepatitis B. Objectives: To study a convenience sample representing ca. 5% of reported acute hepatitis B in England between 1997 and 2001 to investigate the distribution of HBV genotypes and specific HBV variants with epidemiological risk factors, thereby providing baseline data for ongoing surveillance. Study design: From 160 serum samples, PCR was carried out to amplify the first 600 bases of the HBV S gene. Amplicons were sequenced and subjected to phylogenetic analysis and risk factor analysis. Results: Fifty-seven percent of the study samples carried HBV belonging to subtype A2, 13% to subtype D2, and the rest to genotype E (8%) and subtypes C2 and D3 (each 6%), D1 and D4 (each 3%) and B4 (1%). One particular A2 isolate was dominant, accounting for 23% of the total sample set. Drug use and homosexual transmission were equally implicated as risks within genotype A2. No mutations associated with vaccine escape or resistance to antiviral therapy were identified. Conclusion: Immigration and travel likely shape the observed genotype distribution and consequent prevalence of genotypes other than A2 or D in this population. Data suggests no genetic separation of parenteral and sexually transmitted virus. These data demonstrate the value in pursuing more extensive and recent surveillance. © 2008 Elsevier B.V. All rights reserved.