A novel gene for quinolone resistance was cloned from a transferable plasmid carried by a clinical isolate of Shigella flexneri 2b that was resistant to fluoroquinolones. The plasmid conferred low-level resistance to quinolones on Escherichia coli HB101. The protein encoded by the gene showed 59% amino acid identity with Qnr.

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Background: Terminal deoxynucleotidyltransferase (TdT) is a DNA polymerase that enhances Ig and TcR gene diversity in the N region in B-and T-cells. TdT is found as a member of a large protein complex in the lysate of the thymocytes. To elucidate the molecular mechanism of the synthesis of the N region, we first attempted to isolate the genes with products that are interacting directly with TdT.

We recently identified HIV-2 CRF01_AB cases in Japan. This ectopic observation of the virus outside its original endemic area suggests an ongoing global spread of HIV-2 CRF01_AB.

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ObjectiveDrug-resistant (DR) HIV emerges during combined antiretroviral treatment (cART), creating concern about widespread transmission of DR-HIV as cART is expanded in resource-limited countries. The aim of this study was to determine the predominant HIV-1 subtypes and prevalence of transmitted DR mutations among antiretroviral-naïve patients in Iran.DesignTo monitor transmission of DR HIV, a threshold surveillance based on the world health organization (WHO) guidelines was implemented in Iran.MethodsFor this HIVDR threshold surveillance study, blood samples were collected from 50 antiretroviral-naïve HIV-1-infected patients. Antiretroviral-resistant mutations were determined by sequencing HIV-1 protease, reverse transcriptase and integrase regions. The HIV-1 subtype was determined by sequencing the p17 and C2-V5 regions of the gag and env genes, respectively.ResultsPhylogenetic analyses of the sequenced regions revealed that 45 (95.7%) of 47 samples that were successfully obtained were CRF35_AD. The remaining two cases were subtype B (2.1%) and CRF01_AE (2.1%). Consistent results were obtained also from Env and Gag sequences. Regarding prevalence of transmitted DR viruses, two cases were found to harbor reverse transcriptase-inhibitor-resistant mutations (4.3%). In addition, although not in the WHO list for surveillance of transmitted mutations, 13 minor protease-inhibitor-resistant mutations listed in the International AIDS Society-USA panel of drug resistance mutations were found. No DR mutations were detected in the integrase region.ConclusionsOur study clarified that CRF35_AD is the major subtype among HIV-1-infected patients in Iran. According to the WHO categorization method of HIVDR threshold survey, the prevalence of transmitted drug resistant HIV in Iran was estimated as moderate (5–15%).

The major routes of hepatitis B virus (HBV) infection inThe narrow genetic diversity in genotype A cases suggests that genotype A has been recently introduced into the MSM population and that sexual contacts among MSM were more active than speculated from HIV-1 tree analyses. In addition, we found a lamivudine resistance mutation in one naïve case, suggesting a risk of drug-resistant HBV transmission. As genotype A infection has a higher risk than infection with other genotypes for individuals to become HBV carriers, prevention programs are urgently needed for the target population.

We detected several types of human immunodeficiency virus type 1 (HIV‐1) variants with an insertion mutation in the p6gag and p6pol genes in eight of twenty‐two (36.4%) patients who possessed drug‐resistant viruses under highly active antiretroviral therapy (HAART). It was characteristic that a conserved proline‐rich motif “PTAPP” in the N‐terminus of p6gag protein was completely or partially duplicated in all cases. Five among the eight cases were retrospectively investigated in terms of the occurrence of dynamic change in the gag gene between the inserted and wild‐type HIV‐1 in the course of HAART. The longitudinal analysis revealed the following: 1) The inserted‐type viruses were selected over the wild‐type during HAART in three cases in which the both types coexisted in the beginning of the therapy. 2) In two cases in which the inserted‐type HIV‐1 alone was detected before the beginning of HAART, the inserted‐type HIV‐1 alone was continuously detected during the therapy. The inserted‐type HIV‐1 was also detected in four of thirty‐nine (10.3%) therapy‐naive patients. However, the frequency of inserted‐type HIV‐1 detection in the HAART‐receiving patients is significantly higher than that in the therapy‐naive patients (P=0.02). These results suggest that this type of insertion mutation is a polymorphism of the p6gag and p6pol genes, however, it consequently gave an advantage on proliferation and/or survival of the HIV‐1 variant under the presence of antiretroviral drugs.