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The efficacy of various antiretroviral (ARV) therapy regimens for human immunodeficiency virus type 2 (HIV-2) infection remains unclear. HIV-2 is intrinsically resistant to the nonnucleoside reverse-transcriptase inhibitors and to enfuvirtide and may also be less susceptible than HIV-1 to some protease inhibitors (PIs). However, the mutations in HIV-2 that confer ARV resistance are not well characterized.Twenty-three patients were studied as part of an ongoing prospective longitudinal cohort study of ARV therapy for HIV-2 infection in Senegal. Patients were treated with nucleoside reverse-transcriptase inhibitor (NRTI)- and PI (indinavir)-based regimens. HIV-2 pol genes from these patients were genotyped, and the mutations predictive of resistance in HIV-2 were assessed. Correlates of ARV resistance were analyzed.Multiclass drug-resistance mutations (NRTI and PI) were detected in strains in 30% of patients; 52% had evidence of resistance to at least 1 ARV class. The reverse-transcriptase mutations M184V and K65R, which confer high-level resistance to lamivudine and emtricitabine in HIV-2, were found in strains from 43% and 9% of patients, respectively. The Q151M mutation, which confers multinucleoside resistance in HIV-2, emerged in strains from 9% of patients. HIV-1-associated thymidine analogue mutations (M41L, D67N, K70R, L210W, and T215Y/F) were not observed, with the exception of K70R, which was present together with K65R and Q151M in a strain from 1 patient. Eight patients had HIV-2 with PI mutations associated with indinavir resistance, including K7R, I54M, V62A, I82F, L90M, L99F; 4 patients had strains with multiple PI resistance-associated mutations. The duration of ARV therapy was positively associated with the development of drug resistance (P = .02). Nine (82%) of 11 patients with HIV-2 with no [corrected] detectable ARV resistance had undetectable plasma HIV-2 RNA loads (1.4 log(10) copies/mL), compared with 3 (25%) of 12 patients with HIV-2 with detectable ARV resistance (P = .009). Patients with ARV-resistant virus had higher plasma HIV-2 RNA loads, compared with those with non-ARV-resistant virus (median, 1.7 log(10) copies/mL [range,1.4 to 2.6 log(10) copies/mL] vs.1.4 log(10) copies/mL [range,1.4 to 1.6 log(10) copies/mL]; P = .003).HIV-2-infected individuals treated with ARV therapy in Senegal commonly have HIV-2 mutations consistent with multiclass drug resistance. Additional clinical studies are required to improve the efficacy of primary and salvage treatment regimens for treating HIV-2 infection.

Among 767 rectal isolates of Chlamydia trachomatis obtained from men over the period 1981-1991, 7 were found to be a rare lymphogranuloma venereum serovar, L1. These isolates were from rectal specimens taken from five male patients in 1982-1983. Six of the seven isolates were available for DNA sequencing studies. All six of these isolates shared the same DNA sequence in the major outer membrane protein (MOMP) gene variable domains and had different MOMP sequences than did the prototype L1, L2, and L3 strains, suggesting a point source outbreak. All five patients infected with serovar L-1 were homosexual men who had symptomatic proctitis characterized by rectal pain, discharge, tenesmus, abnormalities seen on anoscopy, and leukocytes seen on gram stains of rectal specimens. We conclude that an unrecognized point source outbreak of the rare chlamydial L1 serovar occurred among homosexual men in Seattle in 1982-1983, and that the clinical manifestations of L1 infection may be less severe than those of L2 infections.