http://www.bdtd.uerj.br/handle/1/3562 Sat, 11 Jul 2026 08:06:26 GMT 2026-07-11T08:06:26Z http://www.bdtd.uerj.br/handle/1/25566 Título: Avaliação da influência da obesidade materna no desenvolvimento de resposta humoral no baço da prole em modelo experimental murino Autor: Durão, César Vieira Primeiro orientador: Silva, Flávia Márcia de Castro e Abstract: INTRODUCTION: The increase in maternal obesity cases has raised significant concern, as it is associated with a higher overall mortality rate and represents a major risk factor for several diseases. During pregnancy, this condition can trigger metabolic changes that influence fetal development, impacting various systems, including the immune system. OBJECTIVE: This study aimed to evaluate the influence of maternal obesity on the development of the humoral immune response in the offspring’s spleen. METHODS: A murine experimental model using BALB/c mice was employed. Females were subjected to a high-fat diet (60% of calories derived from fat) for ten weeks and subsequently mated. Offspring were selected at different ages (1, 3, 7, and 24 days of life) for experimental procedures, in which the spleen and serum were collected for analysis of cell phenotypes by flow cytometry, histology, and detection of antibody isotypes by ELISA. RESULTS: Flow cytometry analyses revealed differences in the frequency of cell groups and in the membrane molecule expression of splenic cells. On the first day of life, an increase in B lymphocytes and a reduction in CD19⁺CD138⁺ plasma cells were observed in offspring from obese mothers compared to the control group. On the seventh day, there was an increase in B lymphocytes and MHCII expression in these cells, along with a reduction in CD19⁺CD138⁺IgG2a⁺ plasma cells and T lymphocytes expressing CXCR5. By the twenty-fourth day of life, B lymphocytes, plasma cells, and T lymphocytes were increased; however, MHCII and PD-L1 expression was reduced in CD19⁺ cell populations. Additionally, histological evaluation showed a greater number of lymphoid follicles and a lower eosinophil count in the offspring of obese mothers. A reduction in serum immunoglobulin isotypes IgM and IgG was detected in these animals, although an increase in IgG1 and IgG2a isotypes was observed in the more developmentally advanced group. CONCLUSION: The results demonstrate that maternal obesity affects the development of the humoral immune response in the offspring, compromising immune activation. The reduction of T lymphocytes and the low serum levels of IgG and IgM suggest impairments in class switching and immunological memory. These changes may result in a less efficient immune response, potentially leading to more prolonged infections. Instituição: Universidade do Estado do Rio de Janeiro Tipo do documento: Dissertação Sat, 04 Apr 2026 00:00:00 GMT http://www.bdtd.uerj.br/handle/1/25566 2026-04-04T00:00:00Z http://www.bdtd.uerj.br/handle/1/25501 Título: Tipificação molecular e análise da resistência aos antimicrobianos em Acinetobacter spp. recuperados do período pré-pandêmico e pandêmico da COVID-19 Autor: Rosa, Heloisa da Silva Primeiro orientador: Marques, Elizabeth de Andrade Abstract: Acinetobacter spp. are nosocomial pathogens that present a significant public health challenge due to their ability to resist disinfection and desiccation, primarily attributed to the rising incidence of multidrug-resistant strains, thereby limiting therapeutic options. Throughout the COVID-19 pandemic, Acinetobacter spp. emerged as a prominent pathogen linked to secondary infections, resulting in prolonged stays in the ICU and heightened patient mortality. Therefore, this study aims to evaluate the antimicrobial resistance profile, its correlation with carbapenemase enzyme production, and the phylogenetic relationships among 60 Acinetobacter spp. samples retrieved from patients hospitalized at a university hospital in Rio de Janeiro during both the pre-pandemic and pandemic phases of COVID-19. Antimicrobial susceptibility tests were conducted using agar diffusion and broth microdilution methods. The detection of carbapenemase production was performed using the modified carbapenem inactivation method (mCIM) and the NG-TEST CARBA 5 immunochromatographic assay. The determination of the phylogenetic relationships among isolates was carried out using pulsed-field gel electrophoresis (PFGE). Whole-genome sequencing (WGS) of selected samples was performed to identify the species, determine the sequence type (ST), and detect polymyxin B resistance determinants. Out of the 60 samples tested, 58.3% (n = 35) exhibited resistance to all tested antimicrobials. Only one isolate displayed a multidrug-resistant (MDR) phenotype, and 95% (n = 57) demonstrated extensively drug-resistant (XDR) profiles. Minimum inhibitory concentration values for polymyxin B ranged from 0.25 to 4µg/mL. Through the mCIM, 52 carbapenemase-producing isolates were detected, and through the NG-TEST CARBA 5, 20 isolates were found to produce the IMP carbapenemase. Thirty-six pulsotypes were identified, with pulsotype L being the most prevalent, comprising ten isolates. WGS of isolates 22319 and 22718 was conducted due to polymyxin B resistance and susceptibility to other tested antimicrobials. The analysis of WGS data revealed that both isolates were identified as Acinetobacter nosocomialis, with 22319 associated with ST 395 and 22718 with the new ST 2261, characterized in this study. These isolates did not belong to any clonal complex. Both isolates exhibited mutations in the lpsB, lpxC, and lptD genes, while 22718 also displayed mutations in lpxD and pldA, potentially linked to polymyxin B resistance. The mcr gene was not detected. These results signify a widespread epidemiological profile in Brazil and worldwide, where the high rate of antimicrobial resistance and the presence of carbapenemases are alarming. Further studies are imperative to formulate measures for the control and prevention of healthcare-associated infections caused by these microorganisms. Additionally, polymyxin B resistance may be associated with mutations in the lpsB, lpxC, lpxD, lptD, and pldA genes; however, additional studies are required to comprehend the significance and contribution of these mutations to polymyxin B resistance. Instituição: Universidade do Estado do Rio de Janeiro Tipo do documento: Dissertação Tue, 12 Dec 2023 00:00:00 GMT http://www.bdtd.uerj.br/handle/1/25501 2023-12-12T00:00:00Z http://www.bdtd.uerj.br/handle/1/25190 Título: Complexo Burkholderia cepacia isolados de pacientes com fibrose cística: caracterização molecular e aspectos fenotípicos de virulência Autor: Macharete, Thaís Campos Primeiro orientador: Leão, Robson de Souza Abstract: Cystic fibrosis (CF) is an autosomal recessive genetic disorder common in caucasian individuals, caused by CFTR protein dysfunction. Some microorganisms are traditionally associated to chronic airways infections in CF, such as the species of the Burkholderia cepacia complex (Bcc). This complex currently comprises 21 species that are phylogenetically differentiable, but phenotypically difficult to distinguish. Currently molecular methods, particularly, the amplification and sequencing of recA gene, have been considered the best option to characterize these species. Some of Bcc’s species have been described as highly transmissible and virulent. The motility capacity and the production of biofilm have been described as important virulence factors in bacterias belonging to Bcc. 66 samples obtained from differents clinical specimens between January 2014 and December 2016 were analyzed. The species were identified through sequencing of recA gene as B. vietnamiensis (n= 32; 48.4%), followed by B. cenocepacia (n= 24; 36.6%), B. multivorans (n=7; 10.6%), B. contaminans (n= 2; 3.0%) and B. cepacia (n=1; 1.51%). Among the 66 samples, 55 were from pediatric patients and 11 from adult patients. The patient data showed a standard distribution in sample numbers, except 2 patients that presented 11 samples each. When analyzed the capacity of the 2 types of motility, swarming and swimming, 80.3% of the samples were capable to perform swarming and swimming. B. cenocepacia obtained the largest diameters by swimming and the diameters by swarming didn’t change between species. As the capacity of the biofilm formation, 46 samples were producers, among them, 42 weak producers and 4 moderate producers. Among the species, B. cenocepacia was the weak producer of biofilm with 83.4% of the samples and B. vietnamiensis was the only moderate producer with 4 samples. The biofilm formation was compared between isolated Bcc species from chronic patients and non-chronic patients, however, it wasn’t observed association between the two groups. Swarming and biofilm also didn’t show association, though it was observed a weak association between swimming and the biofilm formation. Bacterial biofilms may have profound implications for the host and have been characterized as highly resistant to antibiotic treatment and immune responses. Despite the important role of flagella in infection, the clinical significance of motility in chronic lung infections of Bcc in CF is unclear. Instituição: Universidade do Estado do Rio de Janeiro Tipo do documento: Dissertação Thu, 12 Jul 2018 00:00:00 GMT http://www.bdtd.uerj.br/handle/1/25190 2018-07-12T00:00:00Z http://www.bdtd.uerj.br/handle/1/24589 Título: Aspectos microbiológicos de Escherichia coli ST 131, ST 648 e ST 405 isoladas de pacientes com infecção do trato urinário Autor: Lopes, Mariana Barros Primeiro orientador: Ignácio, Ana Cláudia de Paula Rosa Abstract: Urinary tract infections (UTIs) are among the most frequent extra-intestinal infections. The main etiological agent is the bacterial species Escherichia coli. E. coli from UTI is called uropathogenic E. coli (UPEC) and can colonize the bladder and kidneys as it ascends through the ureters. UPEC isolates express specific virulence properties such as fimbriae type 1 and P fimbriae, which participate in the adhesion to uroepithelial cells and biofilm formation. The biofilm present in human infections makes it difficult to eradicate the disease with antimicrobial therapy, being associated with the antimicrobial resistance and escape of the immune system in the host. The indiscriminate use of antimicrobials has resulted in the worldwide spread of resistance among bacteria becoming a public health concern. In this context, strains of clonal groups ST 131, ST 648 and ST 405 are inserted and they are associated with resistance and a high virulence potential. The objective of the present study was to analyze the microbiological characteristics related to the virulence of strains of E. coli ST 131, ST 648 and ST 405, from urinoculture of patients with urinary tract infection, attended at the Hospital Universitário Pedro Ernesto (HUPE), Fundação Bela Lopes de Oliveira (FBLO) and Hospital Rio-Laranjeiras (HRL), in the city of Rio de Janeiro. The assays were performed to evaluate the adherence pattern to the HEp-2 and Vero cell lines. To evaluate the biofilm formation, qualitative and semi-quantitative biofilm assays were performed on the abiotic surfaces, polystyrene and glass, respectively. The data were correlated with previous genetic data, more precisely, with the genetic profile of fimbriae and adhesins. The present study demonstrated that all the strains adhered to the cells, but with different adherence patterns. The typical pattern of aggregate adherence was observed only in ST 131 strains. ST 648 and ST 405 strains had no typical adherence pattern. In the abiotic surfaces, all the strains were able to form biofilm, exhibiting different intensities. Strains ST 131, ST 648 and ST 405 can form strong biofilm in polystyrene. In this study was possible to verify that the strains of the clonal groups studied have a virulence profile aimed at establishment on cellular surfaces and abiotic surfaces. Such strains have the ability to form structured biofilms, characterizing the pathogenic potential of strains resistant to antimicrobials in the hospital environment. Instituição: Universidade do Estado do Rio de Janeiro Tipo do documento: Dissertação Mon, 15 Apr 2019 00:00:00 GMT http://www.bdtd.uerj.br/handle/1/24589 2019-04-15T00:00:00Z