Genetic diversity of Trypanosoma cruzi strains isolated from chronic chagasic patients and non-human hosts in the state of São Paulo, Brazil.

BACKGROUND: Trypanosoma cruzi shows an exuberant genetic diversity. Currently, seven phylogenetic lineages, called discrete typing units (DTUs), are recognised: TcI-TcVI and Tcbat. Despite advances in studies on T. cruzi and its populations, there is no consensus regarding its heterogeneity. OBJECTIVES: This study aimed to perform molecular characterisation of T. cruzi strains, isolated in the state of São Paulo, to identify the DTUs involved and evaluate their genetic diversity. METHODS: T. cruzi strains were isolated from biological samples of chronic chagasic patients, marsupials and triatomines through culture techniques and subjected to molecular characterisation using the fluorescent fragment length barcoding (FFLB) technique. Subsequently, the results were correlated with complementary information to enable better discrimination between the identified DTUs. FINDINGS: It was possible to identify TcI in two humans and two triatomines; TcII/VI in 19 humans, two marsupials and one triatomine; and TcIII in one human host, an individual that also presented a result for TcI, which indicated the possibility of a mixed infection. Regarding the strains characterised by the TcII/VI profile, the correlation with complementary information allowed to suggest that, in general, these parasite populations indeed correspond to the TcII genotype. MAIN CONCLUSIONS: The TcII/VI profile, associated with domestic cycles and patients with chronic Chagas disease, was the most prevalent among the identified DTUs. Furthermore, the correlation of the study results with complementary information made it possible to suggest that TcII is the predominant lineage of this work.

ADIPOQ-rs2241766 polymorphism is associated with changes in cholesterol levels of Mexican adolescents.

BACKGROUND: The ADIPOQ gene encodes a fat-derived protein hormone with a preponderant role in the homeostasis of glucose and fatty acids. However, previous association studies between ADIPOQ genetic variants and metabolic disorders have shown controversial results. In this study, we evaluated the effect of the ADIPOQ-rs2241766 polymorphism on diverse biochemical parameters (i.e., insulin resistance, atherogenic index, overweight and obesity) in an adolescent population from Mexico. METHODS: A cross-sectional study with convenience sampling was carried out in 356 adolescents from Northern Mexico. They were classified by sex and BMI-z score. The biochemical parameters were measured from blood samples using conventional methods. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: In low and normal weight groups, GG carriers had a significantly higher cholesterol level (P ≤ 0.05) than TG and TT carriers. However, there was no association between ADIPOQ-rs2241766 polymorphism and atherogenic index, overweight, or obesity. CONCLUSIONS: Our findings suggest that the cholesterol levels are under the influence of the ADIPOQ-rs2241766 polymorphism in Mexican adolescents and may explain how ADIPOQ variants increase the risk of developing metabolic disorders. Nevertheless, further studies are required to rule out the influence of other genetic and non-genetic factors.

Type III Kounis Syndrome Secondary to Ciprofloxacin-Induced Hypersensitivity.

Kounis syndrome (KS) is a rare syndrome characterized by the co-occurrence of acute coronary syndromes in the setting of mast cell and platelet activation in response to hypersensitivity reactions. It can be manifested as coronary vasospasms, acute myocardial infarction, or stent thrombosis triggered by drugs, vaccines, foods, coronary stents, and insect bites. It is a life-threatening condition that needs to be adequately recognized for early diagnosis and appropriate treatment. In this case report, we present a 71-year-old patient with a history of arterial hypertension and non-ST elevation myocardial infarction six months earlier that was treated percutaneously with angioplasty plus stent implantation in the circumflex artery, who subsequently presented to the emergency department due to generalized itching associated with tongue swelling, dyspnea, and chest pain after ingestion of ciprofloxacin for the treatment of a urogenital infection. An electrocardiogram showed ST elevation in II, III, and aVF leads, and positive troponin; thus, a coronary arteriography was performed that showed complete thrombotic stent occlusion in the circumflex artery. Consequently, diagnosis of type 4b inferolateral acute myocardial infarction secondary to ciprofloxacin-triggered type III Kounis syndrome was made. The aim of this report is to understand the relationship between the allergic reaction to ciprofloxacin and the acute coronary syndrome, and to create awareness of the importance of early diagnosis and treatment of this potentially fatal syndrome.

Genomic comparison of Trypanosoma conorhini and Trypanosoma rangeli to Trypanosoma cruzi strains of high and low virulence.

BACKGROUND: Trypanosoma conorhini and Trypanosoma rangeli, like Trypanosoma cruzi, are kinetoplastid protist parasites of mammals displaying divergent hosts, geographic ranges and lifestyles. Largely nonpathogenic T. rangeli and T. conorhini represent clades that are phylogenetically closely related to the T. cruzi and T. cruzi-like taxa and provide insights into the evolution of pathogenicity in those parasites. T. rangeli, like T. cruzi is endemic in many Latin American countries, whereas T. conorhini is tropicopolitan. T. rangeli and T. conorhini are exclusively extracellular, while T. cruzi has an intracellular stage in the mammalian host. RESULTS: Here we provide the first comprehensive sequence analysis of T. rangeli AM80 and T. conorhini 025E, and provide a comparison of their genomes to those of T. cruzi G and T. cruzi CL, respectively members of T. cruzi lineages TcI and TcVI. We report de novo assembled genome sequences of the low-virulent T. cruzi G, T. rangeli AM80, and T. conorhini 025E ranging from ~ 21-25 Mbp, with ~ 10,000 to 13,000 genes, and for the highly virulent and hybrid T. cruzi CL we present a ~ 65 Mbp in-house assembled haplotyped genome with ~ 12,500 genes per haplotype. Single copy orthologs of the two T. cruzi strains exhibited ~ 97% amino acid identity, and ~ 78% identity to proteins of T. rangeli or T. conorhini. Proteins of the latter two organisms exhibited ~ 84% identity. T. cruzi CL exhibited the highest heterozygosity. T. rangeli and T. conorhini displayed greater metabolic capabilities for utilization of complex carbohydrates, and contained fewer retrotransposons and multigene family copies, i.e. trans-sialidases, mucins, DGF-1, and MASP, compared to T. cruzi. CONCLUSIONS: Our analyses of the T. rangeli and T. conorhini genomes closely reflected their phylogenetic proximity to the T. cruzi clade, and were largely consistent with their divergent life cycles. Our results provide a greater context for understanding the life cycles, host range expansion, immunity evasion, and pathogenesis of these trypanosomatids.

Training physiotherapy students in basic wheelchair provision. Experiences at two universities in Colombia.

Wheelchair provision training is essential to overcome barriers related to the lack of knowledge of health professionals on this topic. Appropriate knowledge of the service provision process may lead to higher quality service and products, and thus be more likely to help people with mobility impairments achieve the fundamental human right of personal mobility. This study aimed to describe a training intervention for two groups of future physiotherapists in Colombia, assess cohort differences in performance on a knowledge test, and explore their post-training perceptions. A quantitative retrospective study with a historical, descriptive-comparative design was conducted. 525 sixth-semester participants completed the International Society of Wheelchair Professionals Wheelchair Service Provision - Basic Test online in Spanish after curriculum modifications were implemented. The test assesses knowledge in seven domains: Assessment; Prescription; Products; Fitting; User training; Follow-up, maintenance, and repairs; and Process. The training intervention was successfully implemented with Physiotherapy students from two institutions, resulting in a 57% increase in test approval rates. Participants demonstrated increased knowledge, satisfaction with the course content, and application of learning to their current work. These results suggest implications for what pedagogical approach to employ, when curricular change may be warranted, and specific considerations for the Colombian context. Furthermore, identifying the minimal knowledge basis for undergraduate programs and facilitating its dissemination can support interprofessional education and enhance professionals' capacity to support wheelchair provision services.

Developing pedagogical materials and resources should address academic needs while also being adaptable to the healthcare system and cultural and economic resources.Establishing minimal knowledge bases for physiotherapists and facilitating their dissemination to support interprofessional education are crucial steps.Sharing pedagogical experiences that improve health workforce training promotes the quality of wheelchair service provision, benefiting the functional independence and well-being of people with disabilities.The use of international resources such as the ISWP test in the training of the health workforce contributes to the standardization of the training process regardless of the context.

Use of Intralesional and Perilesional Human Recombinant Epidermal Growth Factor (hrEGF) in the Local Treatment of Venous Ulcer - Review Article - Expert Recommendation.

Venous Ulcers (VU) represent 60-80% of all leg ulcers and are the final stage of the disease secondary to venous hypertension or valve insufficiency. Conventional treatment that focuses on its etiological factors continues to be the gold standard; however, 30% of ulcers do not heal with this treatment; thus, it has been seen that the use of growth factor can be used as an adjuvant for this pathology. A literature review was carried out to evaluate the evidence from systematic reviews, meta-analyses, case studies, and quantitative studies that respond to the objective of this analysis review in the different databases with specific inclusion criteria with publications between 2002 and 2022, initially finding the topical application of the factor and later, more recently, the intralesional and perilesional application, the latter being an alternative treatment for this type of pathology and generating some recommendations for using the Factor.

Development of the Drosophila entero-endocrine lineage and its specification by the Notch signaling pathway.

In this paper we have investigated the developmental-genetic steps that shape the entero-endocrine system of Drosophila melanogaster from the embryo to the adult. The process starts in the endoderm of the early embryo where precursors of endocrine cells and enterocytes of the larval midgut, as well as progenitors of the adult midgut, are specified by a Notch signaling-dependent mechanism. In a second step that occurs during the late larval period, enterocytes and endocrine cells of a transient pupal midgut are selected from within the clusters of adult midgut progenitors. As in the embryo, activation of the Notch pathway triggers enterocyte differentiation and inhibits cells from further proliferation or choosing the endocrine fate. The third step of entero-endocrine cell development takes place at a mid-pupal stage. Before this time point, the epithelial layer destined to become the adult midgut is devoid of endocrine cells. However, precursors of the intestinal midgut stem cells (pISCs) are already present. After an initial phase of symmetric divisions which causes an increase in their own population size, pISCs start to spin off cells that become postmitotic and express the endocrine fate marker, Prospero. Activation of Notch in pISCs forces these cells into an enterocyte fate. Loss of Notch function causes an increase in the proliferatory activity of pISCs, as well as a higher ratio of Prospero-positive cells.

A novel tissue in an established model system: the Drosophila pupal midgut.

The Drosophila larval and adult midguts are derived from two populations of endodermal progenitors that separate from each other in the early embryo. As larval midgut cells differentiate into an epithelial layer, adult midgut progenitors (AMPs) remain as small clusters of proliferating, undifferentiated cells attached to the basal surface of the larval gut epithelium. During the first few hours of metamorphosis, AMPs merge into a continuous epithelial tube that overgrows the larval layer and differentiates into the adult midgut; at the same time, the larval midgut degenerates. As shown in this paper, there is a second, transient pupal midgut that develops from the AMPs at the beginning of metamorphosis and that intercalates between the adult and larval midgut epithelia. Cells of the transient pupal midgut form a multilayered tube that exhibits signs of differentiation, in the form of septate junctions and rudimentary apical microvilli. Some cells of the pupal midgut develop as endocrine cells. The pupal midgut remains closely attached to the degenerating larval midgut cells. Along with these cells, pupal midgut cells are sequestered into the lumen where they form the compact "yellow body." The formation of a pupal midgut has been reported from several other species and may represent a general feature of intestinal metamorphosis in insects.

Gender and Polysomnographic Profiles Findings in Obstructive Sleep Apnea Syndrome Patients Living in High Altitude.

PURPOSE: Obstructive sleep apnea (OSA) is a common sleep disorder which prevalence is 22% in men and 17% in women. It is well described that females presented different clinical and polysomnographic characteristics compared with men. Those studies were performed in plain areas. We described the analysis by gender and clinical profiles of a sample of patients with diagnostic of OSA and living at high altitude. PATIENTS AND METHODS: It is an observational study that describes differences between clinical and polysomnographic characteristics by gender in patients with OSA. Additionally, an unsupervised cluster algorithm was used to find groups of patients with similar clinical and polysomnographic characteristics. RESULTS: We included 709 patients, 51.6% were females and 48.3% were males with mean age of 64 and 62 years old, respectively, in which 90.97% presented OSA. Men presented a higher apnea and hypopnea index than women (p=0.002), besides presented more sleep polysomnographic alterations. Meanwhile, women evidenced better sleep quality based on parameters. Additionally, in the sample of patients, we found four separated clinical profiles characterized mainly by differences in the severity of polysomnographic parameters. CONCLUSION: The patients were more obese, older, and had lower SpO2 values than most of those previously reported. Men had greater severity in most of the parameters measured by polysomnography. Polysomnographic variables were different both in the OSA patient profiles and in the gender comparison. However, the REM sleep apnea hypopnea index did not differ between sexes, indicating the importance of this variable in the evaluation of OSA severity in women. In contrast to previous reports, clinical and demographic characteristics showed few differences in both analyses. This result suggests that the behavior of OSA at high altitudes may have particularities with respect to low altitudes.

Full nucleotide sequencing of ribosomal DNA internal transcribed spacer of Leishmania species causing cutaneous leishmaniasis in Brazil and its potential for species typing.

Species-specific diagnosis still represents a challenge in leishmaniasis management, particularly in regions with multiple endemic species. In Brazil, seven species have been recognized as etiological agents of cutaneous leishmaniasis. The disease comprises complex clinical presentation patterns, classified as localized, diffuse, disseminated and mucocutaneous leishmaniasis. In this study, we characterized the full nucleotide sequence of a region comprising the ribosomal DNA internal transcribed spacers 1 and 2 and 5.8 S gene of reference strains of Leishmania (Viannia) species reported as causative agents of human leishmaniasis in Brazil. The analysis of the nucleotide sequence of this region was able to discriminate species in the Leishmania (Viannia) subgenus and to determine intra- and interspecies phylogenetic relationships.

Treatment of chronic venous insufficiency in Latin America.

OBJECTIVE: Venous disease is common in Latin America, with an estimated 68.11% prevalence of chronic venous disease. The diverse social, political, and economic characteristics of the many nations that make up Latin America mean that different conditions affect how these diseases are diagnosed and treated, which may differ markedly from the way they are treated by the health care systems of the United States and Europe. Our goal was to review the current state of treatment of chronic venous insufficiency (CVI) in Latin America. METHODS: This is a narrative review of the medical literature on the subject and synthesizes sometimes fragmentary information on CVI across a large and diverse region. RESULTS: CVI represents an unmet medical need in Latin America. Conservative treatments, such as compression stockings, may be used at first, and there are nonpharmacologic and complementary and alternative medicine approaches in use. Endovenous approaches, such as endovenous thermal ablation, have largely replaced surgical interventions. In Europe and the United States, such procedures are mainly carried out in ambulatory facilities, whereas they are mainly performed in the hospital in Latin America. CONCLUSIONS: Recent strong economic growth in Latin America and improvements in social security and health care suggest that innovative approaches to chronic venous disease and CVI will be implemented.

Listeria monocytogenes Prevalence Varies More within Fields Than between Fields or over Time on Conventionally Farmed New York Produce Fields.

ABSTRACT: Past studies have shown that the on-farm distribution of Listeria monocytogenes is affected by environmental factors (e.g., weather). However, most studies were conducted at large scales (e.g., across farms), whereas few studies examined drivers of L. monocytogenes prevalence at smaller scales (e.g., within a single field). This study was performed to address this knowledge gap by (i) tracking L. monocytogenes distribution in two fields on one farm over a growing season and (ii) identifying factors associated with L. monocytogenes isolation from drag swab, soil, and agricultural water samples. Overall, L. monocytogenes was detected in 78% (21 of 27), 19% (7 of 36), and 8% (37 of 486) of water, drag swab, and soil samples, respectively. All isolates were characterized by pulsed-field gel electrophoresis. Of the 43 types identified, 14 were isolated on multiple sampling visits and/or from multiple sample types, indicating persistence in or repeated introduction into the farm environment during the study. Our findings also suggest that L. monocytogenes prevalence, even at the small spatial scale studied here, (i) was not uniform and (ii) varied more within fields than between fields or over time. This is illustrated by plot (in-field variation), field (between-field variation), and sampling visit (time), accounting for 18, 2, and 3% of variance in odds of isolating L. monocytogenes, respectively. Moreover, according to random forest analysis, water-related factors were among the top-ranked factors associated with L. monocytogenes isolation from all sample types. For example, the likelihood of isolating L. monocytogenes from drag and soil samples increased monotonically as rainfall increased. Overall, findings from this single-farm study suggests that mitigation strategies for L. monocytogenes in produce fields should focus on water-associated risk factors (e.g., rain and distance to water) and be tailored to specific high-risk in-field areas.

Zoonotic Trypanosomes in Rats and Fleas of Venezuelan Slums.

Rattus spp. are reservoirs of many human zoonoses, but their role in domestic transmission cycles of human trypanosomiasis is underestimated. In this study, we report trypanosome-infected Rattus norvegicus and Rattus rattus in human dwellings in slums neighboring Maracay, a large city near Caracas, the capital of Venezuela. Blood samples of R. norvegicus and R. rattus examined by PCR and FFLB (fluorescent fragment length barcoding) revealed a prevalence of 6.3% / 31.1% for Trypanosoma lewisi (agent of rat- and flea-borne human emergent zoonosis), and 10.5% / 24.6% for Trypanosoma cruzi (agent of Chagas disease). Detection in flea guts of T. lewisi (76%) and, unexpectedly, T. cruzi (21.3%) highlighted the role of fleas as carriers and vectors of these trypanosomes. A high prevalence of rats infected with T. lewisi and T. cruzi and respective flea and triatomine vectors poses a serious risk of human trypanosomiasis in Venezuelan slums. Anthropogenic activities responsible for growing rat and triatomine populations within human dwellings drastically increased human exposure to trypanosomes. This scenario has allowed for the reemergence of Chagas disease as an urban zoonosis in Venezuela and can propitiate the emergence of atypical T. lewisi infection in humans.

Diagnosis and genetic analysis of the worldwide distributed Rattus-borne Trypanosoma (Herpetosoma) lewisi and its allied species in blood and fleas of rodents.

Trypanosoma (Herpetosoma) lewisi is a cosmopolitan parasite of rodents strongly linked to the human dispersal of Rattus spp. from Asia to the rest of the world. This species is highly phylogenetically related to trypanosomes from other rodents (T. lewisi-like), and sporadically infects other mammals. T. lewisi may opportunistically infect humans, and has been considered an emergent rat-borne zoonosis associated to poverty. We developed the THeCATL-PCR based on Cathepsin L (CATL) sequences to specifically detect T. (Herpetosoma) spp., and assess their genetic diversity. This method exhibited high sensitivity using blood samples, and is the first molecular method employed to search for T. lewisi in its flea vectors. THeCATL-PCR surveys using simple DNA preparation from blood preserved in ethanol or filter paper detected T. lewisi in Rattus spp. from human dwellings in South America (Brazil and Venezuela), East Africa (Mozambique), and Southeast Asia (Thailand, Cambodia and Lao PDR). In addition, native rodents captured in anthropogenic and nearby human settlements in natural habitats harbored T. (Herpetosoma) spp. PCR-amplified CATL gene fragments (253bp) distinguish T. lewisi and T. lewisi-like from other trypanosomes, and allow for assessment of genetic diversity and relationships among T. (Herpetosoma) spp. Our molecular surveys corroborated worldwide high prevalence of T. lewisi, incriminating Mastomys natalensis as an important carrier of this species in Africa, and supported its spillover from invader Rattus spp. to native rodents in Brazil and Mozambique. THeCATL-PCR provided new insights on the accurate diagnosis and genetic repertoire of T. (Herpetosoma) spp. in rodent and non-rodent hosts, revealing a novel species of this subgenus in an African gerbil. Phylogenetic analysis based on CATL sequences from T. (Herpetosoma) spp. and other trypanosomes (amplified using pan-trypanosome primers) uncovered rodents harboring, beyond mammal trypanosomes of different subgenera, some species that clustered in the lizard-snake clade of trypanosomes.

Identification of Leishmania (Viannia) species and clinical isolates of Leishmania (Leishmania) amazonensis from Brazil using PCR-RFLP of the heat-shock protein 70 gene reveals some unexpected observations.

Hsp70 is a cytoplasmic heat-shock protein, encoded by a multicopy tandemly repeated gene that has recently been gaining popularity as a valuable marker for typing Leishmania species. In this study, we used a previously described hsp70 PCR-RFLP method for identifying Brazilian Leishmania isolates. We identified two distinct L. (L.) amazonensis hsp70 alleles that resulted in two different RFLP patterns. Also, we found RFLP polymorphisms amongst L. (Viannia) naiffi strains. The profiles of both L. (V.) shawi and L. (V.) lindenbergi were very similar to those of other L. (Viannia) species. The observations described herein reflect the polymorphism found within species of Leishmania and indicate that results from this hsp70 PCR-RFLP method should be used with caution when typing isolates from clinical cases of leishmaniasis and Leishmania species from Brazil.

Trypanosoma rangeli is phylogenetically closer to Old World trypanosomes than to Trypanosoma cruzi.

Trypanosoma rangeli and Trypanosoma cruzi are generalist trypanosomes sharing a wide range of mammalian hosts; they are transmitted by triatomine bugs, and are the only trypanosomes infecting humans in the Neotropics. Their origins, phylogenetic relationships, and emergence as human parasites have long been subjects of interest. In the present study, taxon-rich analyses (20 trypanosome species from bats and terrestrial mammals) using ssrRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH), heat shock protein-70 (HSP70) and Spliced Leader RNA sequences, and multilocus phylogenetic analyses using 11 single copy genes from 15 selected trypanosomes, provide increased resolution of relationships between species and clades, strongly supporting two main sister lineages: lineage Schizotrypanum, comprising T. cruzi and bat-restricted trypanosomes, and Tra[Tve-Tco] formed by T. rangeli, Trypanosoma vespertilionis and Trypanosoma conorhini clades. Tve comprises European T. vespertilionis and African T. vespertilionis-like of bats and bat cimicids characterised in the present study and Trypanosoma sp. Hoch reported in monkeys and herein detected in bats. Tco included the triatomine-transmitted tropicopolitan T. conorhini from rats and the African NanDoum1 trypanosome of civet (carnivore). Consistent with their very close relationships, Tra[Tve-Tco] species shared highly similar Spliced Leader RNA structures that were highly divergent from those of Schizotrypanum. In a plausible evolutionary scenario, a bat trypanosome transmitted by cimicids gave origin to the deeply rooted Tra[Tve-Tco] and Schizotrypanum lineages, and bat trypanosomes of diverse genetic backgrounds jumped to new hosts. A long and independent evolutionary history of T. rangeli more related to Old World trypanosomes from bats, rats, monkeys and civets than to Schizotrypanum spp., and the adaptation of these distantly related trypanosomes to different niches of shared mammals and vectors, is consistent with the marked differences in transmission routes, life-cycles and host-parasite interactions, resulting in T. cruzi (but not T. rangeli) being pathogenic to humans.

[Trypanosoma rangeli parasite-vector-vertebrate interactions and their relationship to the systematics and epidemiology of American trypanosomiasis]. / Interacción tripanosoma-vector-vertebrado y su relación con la sistemática y la epidemiología de la tripanosomiasis Americana.

INTRODUCTION: Trypanosoma rangeli is a species of trypanosome second to T. cruzi, that is infective to humans in Latin America. Variability in the biological, biochemical and molecular characteristics between different isolates isolates of this parasite have been recorded. OBJECTIVE: Morphological and molecular characteristics were recorded from strains of T. rangeli that were isolated from different species of Rhodnius and maintained in different vertebrate species. MATERIALS AND METHODS: Nineteen strains of T. rangeli were isolated from R. prolixus, R. pallescens and R. colombiensis in Colombia, R. ecuadoriensis in Peru and R. pallescens in Panama. Polymorphism of blood trypomastigotes in ICR mice was evaluated and pleomorphism of P53 strain of T. rangeli KP1(-) inoculated in mouse, marsupial and canine was studied. RAPD analysis (randomly amplified polymorphic DNA analysis) of 12 strains isolated from four species of Rhodnius was performed. RESULT: Based on the total length of blood trypomastigotes, three discrete groups were observed. The P53 strain showed significant differences in the size of blood trypomastigotes in mouse, marsupial and canine. RAPD analysis showed that the strains segregated into two branches corresponding to strains of T. rangeli KP1(+) and T. rangeli KP1(-). All strains of T. rangeli KP1(-) clustered according to the species of Rhodnius from which they were isolated. CONCLUSION: These data reveal, for the first time, a close association amongst T. rangeli strains and Rhodnius species, confirming that each species of Rhodnius transmits to vertebrate hosts a parasite population with clear phenotypic and genotypic differences. This is further evidence that supports the concept of clonal evolution of these parasites.

Genetic diversity of Trypanosoma cruzi strains isolated from chronic chagasic patients and non-human hosts in the state of São Paulo, Brazil

BACKGROUND Trypanosoma cruzi shows an exuberant genetic diversity. Currently, seven phylogenetic lineages, called discrete typing units (DTUs), are recognised: TcI-TcVI and Tcbat. Despite advances in studies on T. cruzi and its populations, there is no consensus regarding its heterogeneity. OBJECTIVES This study aimed to perform molecular characterisation of T. cruzi strains, isolated in the state of São Paulo, to identify the DTUs involved and evaluate their genetic diversity. METHODS T. cruzi strains were isolated from biological samples of chronic chagasic patients, marsupials and triatomines through culture techniques and subjected to molecular characterisation using the fluorescent fragment length barcoding (FFLB) technique. Subsequently, the results were correlated with complementary information to enable better discrimination between the identified DTUs. FINDINGS It was possible to identify TcI in two humans and two triatomines; TcII/VI in 19 humans, two marsupials and one triatomine; and TcIII in one human host, an individual that also presented a result for TcI, which indicated the possibility of a mixed infection. Regarding the strains characterised by the TcII/VI profile, the correlation with complementary information allowed to suggest that, in general, these parasite populations indeed correspond to the TcII genotype. MAIN CONCLUSIONS The TcII/VI profile, associated with domestic cycles and patients with chronic Chagas disease, was the most prevalent among the identified DTUs. Furthermore, the correlation of the study results with complementary information made it possible to suggest that TcII is the predominant lineage of this work.

[Risk factors for methicillin-resistant Staphylococcus aureus bacteremia: A multicenter matched case-control study].

INTRODUCTION: Methicillin-resistant Staphylococcus aureus is a frequent pathogen at critical care services. Its presence leads to increased hospital stays and mortality risk in patients with bacteremia. However, the etiology of this resistance marker has not been fully studied. OBJECTIVE: To identify risk factors associated with the emergence of methicillin-resistant S. aureus bacteremia in critically ill patients treated at intensive care units in Bogotá, Colombia. MATERIALS AND METHODS: We conducted a retrospective paired case-control study, nested in a cohort of patients diagnosed with S. aureus bacteremia and treated at intensive care units between 2006 and 2008 in Bogotá. Cases were patients with positive blood culture to methicillin resistance, matched in a 1:1 ratio with methicillin-sensitive controls isolated from the same institution and hospitalization year. We used conditional logistic regression to analyze the risk factors associated with the presence of resistance, with emphasis on prior antibiotic therapy. RESULTS: We included 372 patients with S. aureus bacteremia. Factors such as the use of pre-hospital devices: vascular (OR=1.986, 95% CI 1.038 to 3.801) and urinary (OR=2.559, 95% CI: 1.170 to 5.596), along with the number of previously used antibiotics, were associated with the emergence of resistance. The number of antibiotics used previously was determined to have a gradient effect, particularly carbapenems. CONCLUSIONS: The rational use of antibiotics and surveillance of exposure to surgical procedures or use of invasive devices are interventions that could diminish the emergence of methicillin-resistant S. aureus bacteremia causes.

Genetic diversity of Trypanosoma cruzi in bats, and multilocus phylogenetic and phylogeographical analyses supporting Tcbat as an independent DTU (discrete typing unit).

Trypanosoma cruzi is a complex of phenotypically and genetically diverse isolates distributed in six discrete typing units (DTUs) designated as TcI-TcVI. Five years ago, T. cruzi isolates from Brazilian bats showing unique patterns of traditional ribosomal and spliced leader PCRs not clustering into any of the six DTUs were designated as the Tcbat genotype. In the present study, phylogenies inferred using SSU rRNA (small subunit of ribosomal rRNA), gGAPDH (glycosomal glyceraldehyde 3-phosphate dehydrogenase) and Cytb (cytochrome b) genes strongly supported Tcbat as a monophyletic lineage prevalent in Brazil, Panama and Colombia. Providing strong support for Tcbat, sequences from 37 of 47 nuclear and 12 mitochondrial genes (retrieved from a draft genome of Tcbat) and reference strains of all DTUs available in databanks corroborated Tcbat as an independent DTU. Consistent with previous studies, multilocus analysis of most nuclear genes corroborated the evolution of T. cruzi from bat trypanosomes its divergence into two main phylogenetic lineages: the basal TcII; and the lineage clustering TcIV, the clade comprising TcIII and the sister groups TcI-Tcbat. Most likely, the common ancestor of Tcbat and TcI was a bat trypanosome. However, the results of the present analysis did not support Tcbat as the ancestor of all DTUs. Despite the insights provided by reports of TcIII, TcIV and TcII in bats, including Amazonian bats harbouring TcII, further studies are necessary to understand the roles played by bats in the diversification of all DTUs. We also demonstrated that in addition to value as molecular markers for DTU assignment, Cytb, ITS rDNA and the spliced leader (SL) polymorphic sequences suggest spatially structured populations of Tcbat. Phylogenetic and phylogeographical analyses, multiple molecular markers specific to Tcbat, and the degrees of sequence divergence between Tcbat and the accepted DTUs strongly support the definitive classification of Tcbat as a new DTU.