Dynamic of humoral response to SARS-CoV-2 anti-Nucleocapsid and Spike proteins after CoronaVac vaccination.

This study aimed to calculate the seroconversion rate and IgG antibody dynamic range of the CoronaVac vaccine in healthcare workers (HCWs) after immunization. Serum samples from 133 HCWs from Southern Brazil were collected 1 day before (Day 0) and +10, +20, +40, + 60, +110 days after administering the vaccine's first dose. Immunoglobulin G (IgG) was quantified using immunoassays for anti-N-protein (nucleocapsid) antibodies (Abbott, Sligo, Ireland) and for anti-S1 (spike) protein antibodies (Euroimmun, Lübeck, Germany). Seroconversion by day 40 occurred in 129 (97%) HCWs for the S1 protein, and in 69 (51.87%) HCWs for the N protein. An absence of IgG antibodies (by both methodologies), occurred in 2 (1.5%) HCWs undergoing semiannual rituximab administration, and also in another 2 (1.5%) HCWs with no apparent reason. This study showed that CoronaVac has a high seroconversion rate when evaluated in an HCW population.

Staphylococcus aureus Resistente à Meticilina: uma análise da presença na microbiota nasal de estudantes de saúde em período de estágio

Objetivo: A disseminação da resistência bacteriana se tornou o principal obstáculo no tratamento das infecções em todo o mundo. As infecções relacionadas aos cuidados de saúde (IRCS) constituem grande parte do total de infecções diagnosticadas no Brasil. A principal causa para a elevação deste índice é a disseminação bacteriana por profissionais de saúde. O principal patógeno isolado nas IRCS no Brasil é o Staphylococcus aureus e em grande parte dos casos é confirmado seu perfil multirresistente a diversos antibióticos, sendo que algumas destas cepas são denominadas Staphylococcus aureus resistente à meticilina (MRSA). O objetivo deste estudo foi analisar a prevalência de S. aureus e MRSA na microbiota nasal dos acadêmicos de biomedicina, enfermagem e fisioterapia da instituição de ensino superior de Araucária (PR) em período de estágio. Métodos: Foram coletadas amostras de swab nasal de 51 indivíduos, semeadas em ágar manitol salgado 7,5%. As colônias sugestivas de S. aureus tiveram confirmação com bacterioscopia, testes de catalase e coagulase. Após confirmadas, as cepas de S. aureus foram semeadas em ágar cromogênico seletivo e diferencial para MRSA. Resultados: A taxa de colonização nasal por S. aureus foi de 45,1%; destas cepas 91,3% eram MRSA, o que representa 41,2% do total de indivíduos. Conclusão: Os dados alcançados evidenciam a necessidade de vigilância de resistência bacteriana em profissionais e estudantes de saúde para evitar a ocorrência de IRCS.

Objective: The spread of bacterial resistance has become the main obstacle in the treatment of infections worldwide. Healthcare-Associated Infections (HAI) constitute a large part of the total number of infections diagnosed in Brazil and the main cause for these rates is the bacterial spread by healthcare professionals. The main pathogen isolated in the HAI in Brazil is S. aureus and, in most cases, its multi-resistant profile to several antibiotics is confirmed, some of these strains are called Methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to analyze the prevalence of S. aureus and MRSA in the nasal microbiota of biomedicine, nursing and physiotherapy students at the Araucária (PR) higher education institution during the internship period. Methods: Nasal swab samples were collected from 51 individuals, sown on mannitol salt agar 7.5%. Colonies suggestive of S. aureus were confirmed with bacterioscopy, catalase and coagulase tests. After confirmed, the strains of S. aureus were sown on selective and differential chromogenic agar for MRSA. Results: The rate of nasal colonization by S. aureus was 45.1%, of these strains 91.3% were MRSA, which represents 41.2% of the total of individuals. Conclusion: The data obtained show the need for surveillance of bacterial resistance in health professionals and students to prevent the occurrence of HAI.

Standardization of Antigenemia and qPCR Cut-off Values in Whole Blood for the Detection of Cytomegalovirus Disease in HIV Patients.

INTRODUCTION: We defined the cut-off values of the antigenemia and cytomegalovirus (CMV) DNA tests in HIV/AIDS patients to identify CMV disease. METHODS: A total of 97 samples from 68 patients with and without CMV disease were analyzed by viral DNA detection and antigenemia assay. RESULTS: Qualitative and quantitative results significantly differed between assays. The cut-off values for the antigenemia and qPCR assays were 1.5 positive cells/200,000 leukocytes and 3.715 log/mL, respectively. CONCLUSIONS: Antigenemia and qPCR are suitable for monitoring CMV disease in HIV patients, however, the threshold values should be determined within the centers where the patients are monitored.

Standardization of antigenemia and qpcr cut-off values in whole blood for the detection of cytomegalovirus disease in hiv patients

Abstract INTRODUCTION: We defined the cut-off values of the antigenemia and cytomegalovirus (CMV) DNA tests in HIV/AIDS patients to identify CMV disease. METHODS: A total of 97 samples from 68 patients with and without CMV disease were analyzed by viral DNA detection and antigenemia assay. RESULTS: Qualitative and quantitative results significantly differed between assays. The cut-off values for the antigenemia and qPCR assays were 1.5 positive cells/200,000 leukocytes and 3.715 log/mL, respectively. CONCLUSIONS: Antigenemia and qPCR are suitable for monitoring CMV disease in HIV patients, however, the threshold values should be determined within the centers where the patients are monitored.

Human cytomegalovirus detection by real-time PCR and pp65-antigen test in hematopoietic stem cell transplant recipients: a challenge in low and middle-income countries.

AIM: Cytomegalovirus (CMV) infection is one of the most common complications in patients submitted to hematopoietic stem cell transplant (HSCT). Pre-emptive therapy has been indicated in patients with laboratory evidence of CMV replication. The aims of this study were to compare real-time PCR or pp65 antigen assay methodologies to detect CMV replication in HSCT patients, define a viral load threshold for initiation of pre-emptive therapy, and assess the feasibility of its implementation in hospitals of countries with low and middle income. MATERIAL AND METHODS: Human CMV detection by real-time PCR and pp65 antigen assay was carried out in blood and plasma samples of HSCT patients collected weekly during 3 months. Pre-emptive therapy was based on CMV antigenemia results. RESULTS: Twenty-one patients were monitored with a total of 227 samples collected; 13 (62%) patients were children. A poor correlation was observed between qualitative results, though quantitative results showed statistically significant difference, with higher viral loads detected in patients with positive antigenemia. Compared to a positive antigenemia, a cutoff value of 1067·5 copies/ml, 3·03 log10/ml, for viral load was obtained with 100% sensitivity and 71% specificity. CONCLUSION: CMV real-time PCR in whole blood was suitable for monitoring HSCT patients. However, its high cost is a limiting factor, and it could be used to monitor selected patients, those with prolonged leukopenia and underweight children, and subsequently switched to pp65 antigen test. Further studies involving larger numbers of patients should be performed to confirm this statement.

Hantavirus infection prevalence in wild rodents and human anti-hantavirus serological profiles from different geographic areas of South Brazil.

Paraná state presents the fourth highest number of accumulated cases of hantavirus pulmonary syndrome in Brazil. To map the risk areas for hantavirus transmission we carried out a study based on rodent trapping and determined the anti-hantavirus seroprevalence in these animals and in the inhabitants of these localities. Overall seroprevalence in rodents and humans were 2.5% and 2.4%, respectively. Eighty-two percent of the seropositive rodents were genetically analyzed. Phylogenetic analyses revealed that hantaviruses from rodent samples cluster with Araucária (Juquitiba-like) or Jaborá hantavirus genotypes. The Jaborá strain was identified in Akodon serrensis and Akodon montensis, whereas the Araucária strain was detected in Oligoryzomys nigripes, Oxymycterus judex, A. montensis, and Akodon paranaensis, with the latter species being identified for the first time as a natural host. These findings expose the complex relationships between virus and reservoirs in Brazil, which could have an impact on hantavirus transmission dynamics in nature and human epidemiology.

Production and characterization of monoclonal antibodies against the recombinant nucleoprotein of Araucaria hantavirus.

Hantaviruses are rodent-borne RNA viruses that cause hemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome (HPS). From the first detection of infection in Brazil in 1993 until 2009, 1161 cases of HPS have been reported, with mortality rates of around approximately 40%. Currently, due to the absence of a vaccine or specific antiviral therapy, the only way to reduce mortality by hantavirus infection is a fast and precise diagnosis that allows for supportive clinical health care. To improve the detection of hantavirus infection, we developed monoclonal antibodies (Mabs) against the nucleoprotein (rNDelta85) of the Araucaria hantavirus strain (ARAUV). The specificity of generated Mabs for rNDelta85 was demonstrated by western blot, indirect immunofluorescence and immunohistochemistry. These are the first monoclonal antibodies to be produced and characterized against the South American hantavirus strain, and may be of special interest in the development of diagnostic assays and epidemiological studies.

Phylogenetic characterization of hantaviruses from wild rodents and hantavirus pulmonary syndrome cases in the state of Parana (southern Brazil).

Over 1,100 cases of hantavirus pulmonary syndrome (HPS) have occurred in Brazil since 1993, but little is known about Brazilian hantaviruses, and many of their rodent hosts remain unknown. The Araucaria hantavirus (ARAUV) was described recently from HPS patients from Paraná, in southern Brazil, but its host could not be identified. In this study, rodents were captured from regions with high HPS prevalence to address this issue. ARAUV RNA was detected in three distantly related rodent species: Oligoryzomys nigripes, Oxymycterus judex and Akodon montensis. Furthermore, a specimen of A. montensis was infected with a Jaborá-like virus, implying that A. montensis can be infected by at least two different hantaviruses. The presence of the same hantavirus strain in three different rodent species and the co-circulation of two different strains in the same rodent species highlight the potential for genomic reassortment, which could have an impact on hantavirus transmission dynamics in nature and on human epidemiology.

Evidence of circulation of Laguna Negra-like hantavirus in the Central West of Brazil: case report.

BACKGROUND: Hantavirus pulmonary syndrome has been reported with increasing frequency in some Brazilian regions, but information about viral genetic identification is still limited. Recently, the state of Mato Grosso, in the Legal Amazon of Brazil, experienced a growing number of hantavirus pulmonary syndrome (HPS) cases but the genetic characterization of the causative hantavirus is still missing. OBJECTIVES: Our goal was to identify the hantavirus strain involved in a fatal HPS case in the Central region of Brazil. STUDY DESIGN: Nested RT-PCR was conducted on blood clot samples from an HPS patient from Mato Grosso. PCR-positive samples were sequenced, and the resulting sequences were compared with reference samples. Viral antigens were detected by immunohistological analyses in lung and liver tissues. RESULTS: Analyses of the viral RNA isolated from the patient identified a Laguna Negra (LN)-like virus as the causative agent and histological analysis of lung sections were compatible with the genetic characterization. CONCLUSIONS: This is the first report of circulation and human infection by a Laguna Negra-like hantavirus in Brazil.