Drug Resistance in Eukaryotic Microorganisms

Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies

Alterações citopatológicas e fatores de risco para a ocorrência do câncer de colo uterino Alteraciones citopatológicas y factores de riesgo para la ocurrencia del cáncer de cuello de útero Citopathological alterations and risk factors for uterine cervical neoplasm

O objetivo do estudo foi verificar alterações citopatológicas e fatores de risco para o câncer de colo uterino em mulheres usuárias do Sistema Único de Saúde de um município de pequeno porte do norte do Paraná, de 2001 a 2006. Trata-se de um estudo observacional transversal descritivo. A coleta de dados foi realizada com os resultados dos exames, prontuários e entrevistas. Foram realizados 6.356 exames e 65(1,02%) apresentaram alterações. Dos exames realizados, 4.869 (70,8%) foram em mulheres de 25 a 59 anos. 38,5% dos exames apresentaram Neoplasia Intraepitelial Cervical (NIC) I, 32,3% NIC II e 18,5% NIC I e Papiloma Vírus Humano (HPV). Foram entrevistadas 25 mulheres, a maioria apresentou algum fator de risco como: tabagismo, doenças sexualmente transmissíveis, uso de anticoncepcional hormonal, número de parceiros, início precoce da atividade sexual. Conclui-se pela necessidade de ações educativas mais efetivas no sentido de reduzir as alterações principalmente entre as mulheres adolescentes.<br>El objetivo del estudio fue verificar alteraciones citopatológicas y factores de riesgo para la ocurrencia del cáncer de cuello de útero en mujeres atendidas por el Sistema Único de la Salud de una ciudad de pequeño porte en la Región Norte de la Provincia del Paraná, Brasil en el período de 2001 al 2006. Se trata de un estudio observacional transversal descriptivo. La colección de los datos fue realizada con los resultados de los exámenes, prontuarios y entrevistas. Fueron realizados 6.356 exámenes y 65(1,02%) presentaron alteraciones. De los exámenes hechos 4.869 (70,8%) fue compuesto de mujeres con edad entre los 25 a los 59 años. Un total de 38,5% de los exámenes presentaron Neoplasia Intra-epitelial del Cuello Uterino (NIC) I, 32,3% NIC II y 18,5% NIC I y Virus de Papiloma Humano (HPV). Fueron entrevistadas 25 mujeres, la mayoría presentó factores de riesgo como: tabaquismo, enfermedades de transmisión sexual, uso de anticonceptivo hormonal, número de parejas sexuales, inicio precoz de la actividad sexual. Concluyese ser necesarias acciones educativas para efectivamente producir la reducción de las alteraciones antes de todo entre mujeres más jóvenes.<br>The aim of the present study was to verify the occurrence of citopathological alterations and risk factors of Uterine Cervical Neoplasm in women attended by SUS - the Public Healthcare System - in a district situated in the North of Paraná State, Brazil from 2001 to 2006. It was a descriptive transversal observational study. The data collection consisted in collection of test results from medical records and interviews. It was achieved 6.356 tests and, 1.02% (65) of the women examined presented alterations. From the tests made 4.869 (70,8%) were from women aged between 25 and 59 years. And 38,5% of the tests presented Cervical Intraepithelial Neoplasm (CIN) I, 32,3% CIN II, 18,5% CIN I and Human Papiloma Virus (HPV). It was interviewed 25 women from the total sample. Most of them presented a risk factor as: smoking habits, sexually transmitted diseases, use of hormonal contraceptive, number of sexual partners, early sexual intercourse. This study concludes that is required educative and more effective actions in order to reduce the alterations, meanly among teenagers

The level of ascorbate peroxidase is enhanced in benznidazole-resistant populations of Trypanosoma cruzi and its expression is modulated by stress generated by hydrogen peroxide

Ascorbate peroxidases (APX) are class I heme-containing enzymes that convert hydrogen peroxide into water molecules. The gene encoding APX has been characterized in 11 strains of Trypanosoma cruzi that are sensitive or resistant to benznidazole (BZ). Bioinformatic analysis revealed the presence of two complete copies of the T. cruzi APX (TcAPX) gene in the genome of the parasite, while karyotype analysis showed that the gene was present in the 2.000-kb chromosome of all of the strains analyzed. The sequence of TcAPX exhibited greater levels of similarity to those of orthologous enzymes from Leishmania spp than to APXs from the higher plant Arabidopsis thaliana. Northern blot and real-time reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed no significant differences in TcAPX mRNA levels between the T. cruzi strains analyzed. On the other hand, Western blots showed that the expression levels of TcAPX protein were, respectively, two and three-fold higher in T. cruzi populations with in vitro induced (17 LER) and in vivo selected (BZR) resistance to BZ, in comparison with their corresponding susceptible counterparts. Moreover, the two BZ-resistant populations exhibited higher tolerances to exogenous hydrogen peroxide than their susceptible counterparts and showed TcAPX levels that increased in a dose-dependent manner following exposure to 100 and 200 µM hydrogen peroxide

Response to chemotherapy with benznidazole of clones isolated from the 21SF strain of Trypanosoma cruzi (biodeme Type II, Trypanosoma cruzi II) Resposta à quimioterapia com benzonidazol de clones isolados da cepa 21SF do Trypanosoma cruzi (biodema Tipo II, Trypanosoma cruzi II)

Susceptibility to chemotherapy with benznidazole was investigated of 5 clones isolated from the 21 SF strain (biodeme Type II, Trypanosoma cruzi II). Swiss mice were infected with the parental strain for each clone and submitted to chemotherapy with benznidazole (100mg/kg/day during 90 days). Treatment determined negativity of the parasitemia. Cure rates were evaluated by parasitological cure tests. Serology was evaluated for treated animals (titers from negative to 1:640) and untreated controls (1:160 to 1:640). Cure rates varied from 30 to 100% for the 5 clones, and were 25% for the parental strain. Results suggested that the variability of response to treatment of the clonal populations of Trypanosoma cruzi II strains is responsible for the high variation in the response to chemotherapy with benznidazole and nifurtimox by strains of this biodeme.<br>A suscetibilidade à quimioterapia com o benzonidazol, de 5 clones isolados da cepa 21SF (biodema Tipo II, T. cruzi II), foi investigada. Camundongos suíços foram infectados com a cepa parental e com cada clone e submetidos à quimioterapia com benzonidazol (100mg/k/dia durante 90 dias). Os índices de cura foram avaliados pelos testes de cura parasitológicos. A sorologia foi avaliada para os animais tratados e (de negativo a 1: 640) e para os controles não tratados( 1:160 a 1:640). Os índices de cura variaram de 30% a 100% para os 5 clones sendo de 25% para a cepa parental. Os resultados sugerem que a variabilidade de resposta ao tratamento das populações clonais das cepas Trypanosoma cruzi II é responsável pela grande variação na resposta à quimioterapia com benzonidazol e nifurtimox das cepas deste biodema

&#945;-N-acetylglucosamine-linked O-glycans of sialoglycoproteins (Tc-mucins) from Trypanosoma cruzi Colombiana strain

Trypanosoma cruzi sialoglycoproteins (Tc-mucins) are mucin-like molecules linked to a parasite membrane via a glycosylphosphatidylinositol anchor. We previously determined the structures of Tc-mucin O-glycan domains from several T. cruzi strains and observed significant differences among them. We now report the amino acid content and structure of Tc-mucin O-glycan chains from T. cruzi Colombiana, a strain resistant to common trypanocidal drugs. Amino acid analysis demonstrated the predominance of threonine residues (42%) and helped to identify the O-glycans as belonging to a Tc-mucin family that contain a ²-galactofuranose (²-Galf) residue attached to an &#945;-N-acetylglucosamine (&#945;-GlcNAc) O-4, with the most complex glycan, a pentasaccharide-GlcNAc-ol with a branched trigalactopyranose chain, on the GlcNAc O-6. The presence of ²-Galf on O-glycans from T. cruzi Colombiana mucins supports the use of glycosylation as a phylogenetic marker for the classification of Colombiana in the T. cruzi I group