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Bactérias pulmonares de morcegos do cerrado brasileiro: diversidade e suscetibilidade a antimicrobianos

2026-09-16T18:08:43Z

Título: Bactérias pulmonares de morcegos do cerrado brasileiro: diversidade e suscetibilidade a antimicrobianos Abstact: Bats play key ecological roles, with broad adaptability to different environments, favoring contact with humans and mitigating the role of these animals as potential reservoirs of pathogens. Pathogenic bacteria, already isolated from bats such as Bartonella spp., Leptospira sp., Rickettsia rickettsii, and Escherichia coli, reinforce the importance of investigating the biology, ecology, and health relevance of these animals. Recent studies show that, contrary to what was previously believed, lungs are not sterile and can harbor stable bacterial communities with important functions. Thus, the present study aimed to analyze the composition of the lung microbiota of bats from the Brazilian Cerrado and determine the susceptibility profile of isolated bacterial strains to antimicrobials. The bats were collected using mist nets in the municipalities of Caxias/MA, Floriano/PI, and Barão de Grajaú/MA, all of which belong to the Cerrado biome, and were sent to the Genetics Laboratory/LABGEN, based at the GENBIMOL UEMA complex, Caxias Campus, for subsequent laboratory procedures to identify the bat species and obtain the pulmonary bacteria. Lung bacteria were obtained using two approaches: a culture-independent approach and a culture-dependent approach. In the culture-independent approach, DNA was extracted directly from the bats' lung tissue, followed by amplification of the 16S rRNA gene to verify the presence or absence of bacteria. In the culture-dependent approach, a swab was taken from the lung, and the bacteria were cultured on plates containing sheep blood agar, nutrient agar, eosin-methylene blue agar, and Mueller- Hinton agar. DNA was extracted from the cultured bacteria, and the 16S rRNA gene was amplified and sequenced. Penicillin was added to the nutrient agar to select bacteria resistant to β-lactams, and resistance to other antibiotics was evaluated using the disc diffusion method (Kirby–Bauer) on Mueller–Hinton agar. Morphological, molecular, and ecological markers were used to identify and classify the bats. As a result, 21 bat species were recorded in the sampled municipalities, distributed across five families, with a predominance of the species Carollia perspicillata, family Phyllostomidae. Of the 21 species recorded, 11 showed bacterial presence, where molecular analysis of the lungs confirmed the presence of bacterial DNA in eight bat species: Rhynophylla pumilio, Molossus molossus, Carollia perspicillata, Artibeus cinereus, Phyllostomus hastatus, Glossophaga soricina, Sturnira lilium, Artibeus planirostris, and plaque analysis in four species, namely: Eumops glaucinus, Myotis riparius, C. perspicillata, and Artibeus lituratus. Only four bacterial species were isolated from the 11 bat species: Bacillus subtilis, Staphylococcus saprophyticus, Acinetobacter spp., and Gordonia spp., the latter being recorded for the first time in bat lungs. It was possible to isolate and identify bacteria that presented distinct antimicrobial susceptibility profiles, with emphasis on resistance to penicillin and other β-lactams, as well as an intermediate response to polymyxin B by Acinetobacter spp., suggesting the occurrence of adaptive mechanisms even in non-clinical environments.

Monitoramento ambiental do médio rio Tocantins: elementos potencialmente tóxicos e essenciais em água, sedimentos e peixes, biomarcadores e implicações para a saúde ribeirinha

2026-08-25T18:11:27Z

Título: Monitoramento ambiental do médio rio Tocantins: elementos potencialmente tóxicos e essenciais em água, sedimentos e peixes, biomarcadores e implicações para a saúde ribeirinha Abstact: The Tocantins–Araguaia basin is one of the largest hydrographic systems in South America, spanning the states of Maranhão, Tocantins, and Pará, and is part of the Brazilian Legal Amazon. Despite draining extensive Cerrado and tropical forest ecosystems, this basin has undergone significant environmental degradation in recent decades due to agricultural expansion, deforestation, and the introduction of non-native species. This scenario is particularly relevant for riverine communities along the middle Tocantins River, which depend on the river for water supply, recreation, and fish consumption. In this context, fish can act as biomonitors of contaminant exposure in aquatic environments, as they integrate ecological processes and represent an important food and economic resource. Thus, the aim of this study was to perform environmental monitoring of the middle Tocantins River through an integrated approach, including the analysis of physicochemical water parameters, the determination of potentially toxic and essential elements in water, sediments, and fish, and the assessment of enzymatic biomarkers in native fish species. Sampling was conducted at four sites: P1 (Beira Rio – urban area), P2 (Bananal village), P3 (Embiral village), and P4 (Cidelândia village). The thesis is structured into five chapters. Chapter 1 presents a literature review on the Tocantins–Araguaia basin and ecotoxicological aspects related to contaminants in aquatic environments. Chapter 2 describes a socio-environmental study assessing riverine perceptions of water quality through structured questionnaires. The results showed that 34% of respondents consume and commercialize native fish, 62% use them for subsistence consumption, and 4% do not consume fish. Additionally, 84% reported the absence of sewage systems, highlighting high dependence on water and fish resources and significant socio-environmental vulnerability. Chapter 3 evaluated potentially toxic and essential elements in water, along with physicochemical parameters. Aluminum, copper, iron, magnesium, and selenium exceeded regulatory limits at certain sites and periods, with seasonal variations influenced by climatic factors. Site P1 exhibited higher electrical conductivity, total dissolved solids, chlorophyll, and nitrogen compounds, indicating anthropogenic influence and potential risks associated with untreated water consumption. In Chapter 4, sediment analysis revealed elevated concentrations of aluminum, iron, manganese, and selenium, as well as chromium, nickel, copper, zinc, and lead exceeding quality guidelines, particularly in areas influenced by urban activities. Higher concentrations during the rainy season highlighted the role of seasonality in contaminant mobilization and deposition processes. Chapter 5 investigated the bioaccumulation of potentially toxic and essential elements and enzymatic responses in native fish species (Psectrogaster amazonica and Caenotropus labyrhinthicus). Elevated concentrations of arsenic, lead, and selenium were detected in fish tissues, exceeding recommended limits. Enzymatic activities (AChE, AST, ALT, and ALP) indicated physiological responses associated with environmental exposure and were interpreted as sublethal alterations, without allowing direct inference of causality or specific mechanisms. Overall, the results indicate that the dynamics of elements in the middle Tocantins River are controlled by the interaction between natural processes and anthropogenic influences. The concentrations of elements such as iron, aluminum, and manganese partly reflect the regional geochemical background, characterized by highly weathered tropical soils, while physicochemical parameters and spatial patterns indicate the influence of human activities, particularly in urban areas. The observed bioaccumulation in fish and enzymatic responses indicate organism exposure to environmental contaminants and associated physiological alterations. These findings, combined with the strong dependence of riverine populations on water and fish resources, highlight the importance of integrated environmental monitoring approaches that consider regional specificities and their implications for environmental health and food safety, in line with the One Health framework

Ocorrência de hemoparasitas em cães: diagnóstico molecular e avaliação de coinfecções

2026-08-17T19:54:44Z

Título: Ocorrência de hemoparasitas em cães: diagnóstico molecular e avaliação de coinfecções Abstact: Tick-borne diseases in dogs represent a significant challenge for veterinary practice in urban areas of tropical regions. In São Luís, Maranhão, Brazil, the circulation of pathogens from the genera Ehrlichia, Anaplasma, Babesia, and Hepatozoon has been presumed based on previous serological studies, but remains poorly documented using molecular methods that allow sensitive detection, species-level identification, and assessment of coinfections. This study aimed to estimate the frequency of these agents and describe coinfection patterns in dogs treated at the Veterinary Hospital “Francisco Edilberto Uchoa Lopes” of the State University of Maranhão. A molecular survey was conducted using 200 whole blood samples collected between November 2024 and September 2025. DNA was extracted using a commercial kit, followed by screening with multiplex qPCR for Ehrlichia canis, Anaplasma platys, and Babesia spp., and nested PCR for Hepatozoon spp. Positive samples were confirmed by Sanger sequencing and BLASTn analysis. Overall, 39% (78/200) of samples were positive for at least one agent: 23% (46/200) for E. canis, 16.5% (33/200) for A. platys, 13% (26/200) for Babesia spp., and 3% (6/200) for Hepatozoon spp. Among positive samples, 32 presented coinfections. The most frequent association was A. platys + E. canis (10%; 20/200), followed by E. canis + Babesia spp. (4.5%; 9/200). Other combinations occurred at a frequency of 0.5% each (1/200): A. platys + Babesia spp., E. canis + Hepatozoon spp., and triple coinfection. Sequencing confirmed Babesia vogeli, A. platys, E. canis, and Hepatozoon canis (98.53–100% identity with national and international isolates). No significant differences were observed regarding sex or age group (p > 0.05), although a higher frequency trend was noted in dogs older than 5 years. These findings demonstrate the circulation of hemoparasites in dogs from São Luís, with predominance of E. canis and a notable occurrence of coinfections, contributing to the epidemiological understanding of these infections.

Infecção natural por Leishmania spp. em felinos domésticos (Felis catus domesticus) em área endêmica para Leishmaniose visceral canina e humana

2026-08-06T19:28:44Z

Título: Infecção natural por Leishmania spp. em felinos domésticos (Felis catus domesticus) em área endêmica para Leishmaniose visceral canina e humana Abstact: In endemic areas, case reports of Leishmania spp. in domestic felines (Felis catus domesticus). The state of Maranhão, more specifically the municipality of São Luís, is an area with many cases of canine and human visceral leishmaniasis, but with few studies on the occurrence of the infection in cats and how it presents itself clinically in this species. Given the above, the objective of the study was to evaluate the clinical and parasitological aspects of cats naturally infected by Leishmania spp. For this, thirty-six cats were screened from veterinary clinics and Veterinary Hospital “Francisco Edilberto Uchôa Lopes”, in the city of São Luís, Maranhão, from which twenty animals were selected to compose the study groups. The diagnosis of leishmaniasis was made through direct parasitological examination of aspirates from popliteal lymph nodes, cytology of skin lesions and aspiration puncture of the bone marrow, and blood samples were collected for evaluation of hematological and biochemical parameters (urea, creatinine, aspartate aminotransferase, alanine aminotransferase, total proteins and albumin). After obtaining the results of the diagnostic tests, the animals were divided into two groups: (GP) formed by ten positive animals for leishmaniasis, with or without clinical signs of the disease and (GC) composed by ten animals free of the infection and clinically healthy. The data obtained were analyzed and stored in spreadsheets in Microsoft Excel, for subsequent performance of statistical tests. Positivity was found in 12.5% (3/24) in direct parasitological examination and 27.7% (10/36) in bone marrow qPCR. All positive cats for leishmaniasis showed three or more clinical signs, the most frequently observed were: dermatological lesions, lymphadenopathy, pale mucous membranes, ocular discharge and gingivostomatitis. In the analysis of the hematological parameters, monocytosis was observed, showing a statistically significant difference between the evaluated groups (p<0.05). In the biochemical evaluations of infected animals, there was a significant increase in urea levels (p<0.05). Regarding the quantification of the parasite load in the bone marrow of the animals in the GP group, there was a variation from 11,050 to 72,680,000 parasites/mL. There was no positive correlation between the number of clinical signs and the bone marrow parasite load (p>0.05). There was no statistically significant difference between the groups of oligosymptomatic and polysymptomatic cats and the amount of parasites in the bone marrow (p>0.05). Therefore, the presence of the protozoan infecting domestic cats in the city of São Luís was verified, and the importance of the association of clinical and parasitological findings for a better diagnosis and prognosis of leishmaniasis in cats was observed