Resistant bacterial infections are a major health problem in many parts of the world. The major commercial antibiotic classes often fail to combat common bacteria. Although antimicrobial peptides are able to control bacterial infections by interfering with microbial metabolism and physiological processes in several ways, a large number of cases of resistance to antibiotic peptide classes have also been reported. To gain a better understanding of the resistance process various technologies have been applied. Here we discuss multiple strategies by which bacteria could develop enhanced antimicrobial peptide resistance, focusing on sub-cellular regions from the surface to deep inside, evaluating bacterial membranes, cell walls and cytoplasmic metabolism. Moreover, some high-throughput methods for antimicrobial resistance detection and discrimination are also examined. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.

BackgroundPathogens depend on peptidase activities to accomplish many physiological processes, including interaction with their hosts, highlighting parasitic peptidases as potential drug targets. In this study, a major leucyl aminopeptidolytic activity was identified in Trypanosoma cruzi, the aetiological agent of Chagas disease.ResultsThe enzyme was isolated from epimastigote forms of the parasite by a two-step chromatographic procedure and associated with a single 330-kDa homohexameric protein as determined by sedimentation velocity and light scattering experiments. Peptide mass fingerprinting identified the enzyme as the predicted T. cruzi aminopeptidase EAN97960. Molecular and enzymatic analysis indicated that this leucyl aminopeptidase of T. cruzi (LAPTc) belongs to the peptidase family M17 or leucyl aminopeptidase family. LAPTc has a strong dependence on neutral pH, is mesophilic and retains its oligomeric form up to 80°C. Conversely, its recombinant form is thermophilic and requires alkaline pH.ConclusionsLAPTc is a 330-kDa homohexameric metalloaminopeptidase expressed by all T. cruzi forms and mediates the major parasite leucyl aminopeptidolytic activity. Since biosynthetic pathways for essential amino acids, including leucine, are lacking in T. cruzi, LAPTc could have a function in nutritional supply.

A judicialização como fenômeno de garantia do direito social à saúde é uma questão com discussão crescente no Brasil, devido à definição constitucional de saúde no país, que contempla a integralidade. Objetivo: A forma como as demandas judiciais vêm impactando nas políticas públicas de saúde nos três níveis de gestão coloca esse item como ponto premente na discussão de uma agenda para o sistema de saúde. Métodos: Esse estudo analisou o perfil do gasto da saúde pública no Distrito Federal com medicamentos não-padronizados, a fim de compreender quais as circunstâncias em que a judicialização de medicamentos ocorre nesse local. Resultados: Foram utilizados registros administrativos de distribuição dos medicamentos no período de Setembro/2014 a Agosto/2016. O gasto apurado foi classificado por item e por grupo de doença conforme CID-10. Foi verificado que o gasto total apurado foi de R$ 43,7 milhões. Dentre os medicamentos com maior gasto, observou-se o fator IX recombinante, utilizado para tratamento de hemofilia, como maior responsável (22,53%), seguido da alfaglicosidase (9,74%), do fingolimode (8,44%) e da abiraterona (6,63%). As doenças com maior demanda de atendimento via judicial foram as doenças do sangue que incluem as hemofilias (26,6%), as neoplasias (24,9%) e as doenças metabólicas (17,5%). Conclusão:Os resultados obtidos permitiram verificar um padrão de demandas particular do DF, com uma participação importante no orçamento destinado à compra de medicamentos.

In recent years the antimicrobial peptides (AMPs) have been prospected and designed as new alternatives to conventional antibiotics. Indeed, AMPs have presented great potential toward pathogenic bacterial strains by means of complex mechanisms of action. However, reports have increasingly emerged regarding the mechanisms by which bacteria resist AMP administration. In this context, we performed a comparative proteomic study by using the total bacterial lysate of magainin I-susceptible and –resistant E. coli strains. After nanoUPLC-MSE analyses we identified 742 proteins distributed among the experimental groups, and 25 proteins were differentially expressed in the resistant strains. Among them 10 proteins involved in bacterial resistance, homeostasis, nutrition and protein transport were upregulated, while 15 proteins related to bacterial surface modifications, genetic information and β-lactams binding-protein were downregulated. Moreover, 60 exclusive proteins were identified in the resistant strains, among which biofilm and cell wall formation and multidrug efflux pump proteins could be observed. Thus, differentially from previous studies that could only associate single proteins to AMP bacterial resistance, data here reported show that several metabolic pathways may be related to E. coli resistance to AMPs, revealing the crucial role of multiple “omics” studies in order to elucidate the global molecular mechanisms involved in this resistance.