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Antimicrobial Agents and Chemotherapy

High prevalence of Pneumocystis jirovecii dihydropteroate synthase gene mutations in patients with a first episode of Pneumocystis pneumonia in Santiago, Chile, and clinical response to trimethoprim-sulfamethoxazole therapy

Mutations in the Dihydropteroate synthase (DHPS) gene of Pneumocystis jirovecii associate with failure of sulfa prophylaxis. They can develop by selection in patients receiving sulfa drugs, or be acquired via person-to-person transmission. DHPS mutations raise concern about decreasing efficacy of sulfa drugs, the main available therapeutic tool for Pneumocystis pneumonia (PCP).
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Role of the mmr ef- flux pump in drug resistance in Mycobacterium tuberculosis

Efflux pumps are membrane proteins capable of actively transporting a broad range of substrates from the cytoplasm to the exterior of the cell. Increased efflux activity in response to drug treatment may be the first step in the development of bacterial drug resistance.
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Genomewide Scan Reveals Amplification of mdr1 as a Common Denominator of Resistance to Mefloquine, Lumefantrine, and Artemisinin in Plasmodium chabaudi Malaria Parasites

Multidrug-resistant Plasmodium falciparum malaria parasites pose a threat to effective drug control, even to artemisinin-based combination therapies (ACTs). Here we used linkage group selection and Solexa whole-genome resequencing to investigate the genetic basis of resistance to component drugs of ACTs.
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Novel potent metallocenes against liver stage malaria

Novel conjugates of the antimalarial drug primaquine (compound 1) with ferrocene, named primacenes, have been synthesized and screened for their activities against blood stage and liver stage malaria in vitro and host-vector transmission in vivo.
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HIV-1 subtype is an independent predictor of reverse transcriptase mutation k65r in HIV-1 patients treated with combination antiretroviral therapy including tenofovir

Subtype-dependent selection of HIV-1 reverse transcriptase resistance mutation K65R was previously observed in cell culture and small clinical investigations. We compared K65R prevalence across subtypes A, B, C, F, G, and CRF02_AG separately in a cohort of 3,076 patients on combination therapy including tenofovir. K65R selection was significantly higher in HIV-1 subtype C. This could not be explained by clinical and demographic factors in multivariate analysis, suggesting subtype sequence-specific K65R pathways.
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Transmission Potential of Antimony-Resistant Leishmania Field Isolates

We studied the development of antimony-resistant Leishmania infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus to ascertain the risk of parasite transmission by sand flies.
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Plasmodium vivax Chloroquine Resistance and Anemia in the Western Brazilian Amazon

In Latin America, data on chloroquine (CQ)-resistant Plasmodium vivax is limited, even with the current research efforts to sustain an efficient malaria control program in all these endemic countries, where malaria still is a major public health issue. This study estimated in vivo CQ-resistance in uncomplicated patients with P. vivax in use of CQ and primaquine simultaneously, in the Brazilian Amazon. From a total of 135 enrolled subjects, who accomplished the 28-day follow-up, parasitological failure was observed in 7 (5.2%) patients, in which plasmatic CQ and desethylchloroquine (DCQ) concentrations were above 100ng/dL.
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