Prevalence and characterization of pertactin deficient Bordetella pertussis strains in Brazil, a whole-cell vaccine country

Many countries have reported antigenic divergence among circulating Bordetella pertussis strains, mainly in those countries which introduced the acellular pertussis (aP) vaccine. This phenomenon can be seen, for example, with the recent rise of pertactin (Prn)-deficient B. pertussis strains, one of the antigens included in aP vaccine formulas. The whole cell pertussis (wP) vaccine has been used in Brazil since 1977 for the primary pertussis, diphtheria and tetanus immunization series. In 2014, the aP vaccine was recommended for women during pregnancy to protect infants in the first months of life. Our objective was to determine the prevalence of Prn-deficiency in 511 isolates of B. pertussis collected in Brazil during 2010­2016. All isolates were characterized, through PFGE and serotyping, and screened for the loss of Prn by ELISA. Prn-deficiency was confirmed by immunoblotting, and identification of the possible genetic markers was performed with PCR and Sanger sequencing. Results indicate that 110 PFGE profiles are currently circulating, with five profiles representing the majority, and the predominant serotype 3, has been gradually replaced by serotype 2 and serotype 2,3. ELISA screening and immunoblotting identified three Prn-deficient isolates. Genotypic characterization by PCR and sequencing indicated that one isolate had a promoter mutation in prn, while the other two did not have an obvious genetic explanation for their deficiency. While the lack of Prn was identified in a few isolates, this study did not detect a relevant occurrence of Prn-deficiency, until 2016, confirming previous observations that Prn-deficiency is likely aP vaccine-driven. (AU)

Incidence and clinical characteristics of the infection by the Respiratory Syncytial Virus in children admitted in Santa Casa de São Paulo Hospital

The purpose of this study was to identify the rate of infections due to RSV and other viruses in children. In addition we have analyzed demographic data and clinical characteristics of the RSV-positive patients comparing with patients infected by other respiratory viruses. We also described the seasonality of the RSV occurrence in a hospital in São Paulo. Children below 5 years old admitted in Santa Casa de São Paulo Hospital between February 2005 and September 2006 due to acute respiratory infections (ARI) were included. A nasopharyngeal specimens were obtained with sterile No. 5 French feeding catheters as soon as possible (usually within 24 h). Specimens were kept refrigerated at 4ºC and transported to Adolfo Lutz Institute, where the indirect immunofluorescent assay was performed. Virus identified by these assay included RSV, Adenovirus, Influenza A and B virus and Parainfluenza 1, 2, and 3. Clinical data from each group was compared. Four hundred and fifty five cases were included in the study, with 30 percent positive for some type of virus. Viruses that were identified included Respiratory Syncytial Virus (73.03 percent), Influenza (8.42 percent), Parainfluenza (8.42 percent) and Adenovirus (3.37 percent). We divided the subjects in 3 groups: Group 1 RSV-Positive, Group 2 Other Positive Viruses and Group 3 Negative for Respiratory Virus. Mean age (months) was of 7.5 for RSV-positive children, 7.6 for other viruses, and 8 for negative for respiratory virus. The RSV-Positive Group was significantly younger than the Group Negative for Respiratory Virus (p<0.05). Signs of UAI were more present in the Positive RSV Group (p<0.05). General mortality was of 2.41 percent. There was a higher incidence of RSV between the months of March and August in the two years of the study. Our study indicates RSV as the most prevalent viral agent in children admitted due to (ARI), especially in infants below 3 months old. We have also found that infections...

Incidence and clinical characteristics of the infection by the respiratory syncytial virus in children admitted in Santa Casa de São Paulo Hospital.

The purpose of this study was to identify the rate of infections due to RSV and other viruses in children. In addition we have analyzed demographic data and clinical characteristics of the RSV-positive patients comparing with patients infected by other respiratory viruses. We also described the seasonality of the RSV occurrence in a hospital in São Paulo. Children below 5 years old admitted in Santa Casa de São Paulo Hospital between February 2005 and September 2006 due to acute respiratory infections (ARI) were included. A nasopharyngeal specimens were obtained with sterile No. 5 French feeding catheters as soon as possible (usually within 24 h). Specimens were kept refrigerated at 4 degrees C and transported to Adolfo Lutz Institute, where the indirect immunofluorescent assay was performed. Virus identified by these assay included RSV, Adenovirus, Influenza A and B virus and Parainfluenza 1, 2, and 3. Clinical data from each group was compared. Four hundred and fifty five cases were included in the study, with 30% positive for some type of virus. Viruses that were identified included Respiratory Syncytial Virus (73.03%), Influenza (8.42%), Parainfluenza (8.42%) and Adenovirus (3.37%). We divided the subjects in 3 groups: Group 1 RSV-Positive, Group 2 Other Positive Viruses and Group 3 Negative for Respiratory Virus. Mean age (months) was of 7.5 for RSV-positive children, 7.6 for other viruses, and 8 for negative for respiratory virus. The RSV-Positive Group was significantly younger than the Group Negative for Respiratory Virus (p<0.05). Signs of UAI were more present in the Positive RSV Group (p<0.05). General mortality was of 2.41%. There was a higher incidence of RSV between the months of March and August in the two years of the study. Our study indicates RSV as the most prevalent viral agent in children admitted due to (ARI), especially in infants below 3 months old. We have also found that infections due to RSV can occur in months others than the classic seasonal period.

Measles serodiagnosis: production and evaluation of the IgM-measles ELISA(IAL) reagent

Recent measles outbreaks in different countries led to an increase of laboratory measles diagnosis. Thus, we developed the IgM-Measles ELISAIAL, using measles virus antigens obtained from cell cultured in microcarriers in order to supply reagent kits to Brazilian public health laboratories. A batch of antigenic reagent was produced and evaluated in the enzyme immunoassay in comparison with clinical diagnosis and with as reference assay (IgM Capture ELISA(CDC)) data. This study was performed in a positive panel with 70 serum samples from patients with measles, and a negative panel with 132 samples from patients with unrelated diseases and without recent measles or vaccination history. In relation to other diagnostic methods, the IgM ELISAIAL presented sensitivity higher than 97.1 per cente, specificity and precision of 97 per cente, and agreement kappa (k) index higher than 0.94 (P < 0.05). Moreover, the IgM antibody profile from measles acute phase revealed by the assay was similar to the reference assay. A practical analysis system for checking the quality of new reagent batches was proposed based on the diagnostic features and agreement kappa index. Our findings suggest that measles antigenic reagents can be produced with reliable quality control system, and supplied to public health laboratories for routine serodiagnosis or population surveys.

Clinical and laboratory evaluation of measleslike rash in children and young adults

A clinical and laboratory evaluation of 11 childrens and young adults with measleslike rash was done during the measles outbreak in the Greater São Paulo Metropolitan area at the end of 1996 and spread over the country during 1997. Measles was laboratory confirmed in 07 patients by specific IgM detection in acute serum specimens using an IgM-capture EIA, by specific IgG seroconversion in serum pairs, and by reverse transcription PCR and virus isolation in peripheral blood lymphocytes. Clinical presentations were not always classic; one of the 07 cases had received measles vaccine and corresponded to modified clinical case of measles. The 4 remaining cases were negative for measles and were diagnosed as exanthem subitum (2 cases), scarlet fever and Kawasaki disease. The present study reinforces the view that clinical features alone are not sufficient for establishing an accurate diagnosis in the post-vaccine era, and a surveillance system based on sensitive laboratory results is needed so that it can confirm IgM-negative measles cases.

Sarampo: padronização e avaliação do "Dot-Elisa" como teste alternativo no diagnóstico sorológico

No presente trabalho padronizamos o "Dot-Elisa" (DE) para pesquisa de anticorpos IgG, IgM e IgA anti-vírus do sarampo e comparamos os resultados com a reação de imunofluorescência indireta (IFI). Foram estudados três tipos de antígeno sendo selecionado o antigeno obtido a partir de cultura de células verso e extraído com desoxicolato de sódio (DOC). Após determinção da concentração ótima dos reagentes foram estudados 46 amostras de soros de 23 pacientes com sarampo nas fases agudas e convalescentes; 31 amostras de soros de individuos supostamente normais; 20 amostras de soros de 10 crianças antes e após a vacinação e 29 amostras de crianças sem quadro clínicos de sarampo e com sorologia negativa. Os resultados obtidos no DE, no grupo de pacientes com sarampo mostraram índices de sensibilidade que variam de 0,91 a 0,96 para anticorpos IgM. Na IFI obtivemos índices de sensibilidade que variam 0,91 a 0,96 para anticorpos IgG e 0,57 a 0,87 para anticorpos IgM Na IFI obtivemos índice que variam 0,91 a 0,96 para anticorpos IgG e 0,56 a 0,87 para anticorpos IgM. Ambos os testes fornecem especificidade máxima para anticorpos IgG e IgM. No grupo de vacinas os e DE foi sensivel que a IFI para a pesquisa de anticorpo IgM. Observamos no DE comportamento semelhamte de anticporpos de IgG e IgA anti-virus do sarampo, fatos s aser investigado na IFI. Pela simplicidade do teste , baixo custo, facilidade de execução e bons índices de sensibilidade e especificidade de sugerimos o DE como teste alternativo na sorologia do sarampo...