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Assessment of the rapid test based on an immunochromatography technique for detecting anti-Treponema pallidum antibodies

A rapid test based on an immunochromatography assay - Determine Syphilis TP (Abbott Lab.) for detecting specific antibodies to Treponema pallidum was evaluated against serum samples from patients with clinical, epidemiological and serological diagnosis of syphilis, patients with sexually transmitted disease other than syphilis, and individuals with negative serology for syphilis. The Determine test presented the sensitivity of 93.6%, specificity of 92.5%, and positive predictive value and negative predictive value of 95.2% and 93.7%, respectively. One serum sample from patient with recent latent syphilis showed a prozone reaction. Determine is a rapid assay, highly specific and easy to perform. This technique obviates the need of equipment and its diagnostic features demonstrate that it may be applicable as an alternative assay for syphilis screening under some emergency conditions or for patients living in remote localities.

Analysis of Treponema pallidum recombinant antigens for diagnosis of syphilis by western blotting technique.

Three GST fusion recombinant antigen of Treponema pallidum, described as GST-rTp47, GST-rTp17 and GST-rTp15 were analyzed by Western blotting techniques. We have tested 53 serum samples: 25 from patients at different clinical stages of syphilis, all of them presenting anti-treponemal antibody, 25 from healthy blood donors and three from patients with sexually transmitted disease (STD) other than syphilis. Almost all samples from patients with syphilis presented a strong reactivity with GST-rTp17 antigen. Some samples were non-reactive or showed a weak reaction with GST-rTp47 and/or GST-rTp15, and apparently there was no correlation with the stage of disease. There was no seropositivity among blood donors. No sample reacted with purified GST. We concluded that due to their specificity these recombinant antigens can be used as GST fusion protein for development of syphilis diagnostic assays.

Parainfluenza virus as a cause of acute respiratory infection in hospitalized children.

BACKGROUND Human parainfluenza viruses account for a significant proportion of lower respiratory tract infections in children. OBJECTIVE To assess the prevalence of Human parainfluenza viruses as a cause of acute respiratory infection and to compare clinical data for this infection against those of the human respiratory syncytial virus. METHODS A prospective study in children younger than five years with acute respiratory infection was conducted. Detection of respiratory viruses in nasopharyngeal aspirate samples was performed using the indirect immunofluorescence reaction. Length of hospital stay, age, clinical history and physical exam, clinical diagnoses, and evolution (admission to Intensive Care Unit or general ward, discharge or death) were assessed. Past personal (premature birth and cardiopathy) as well as family (smoking and atopy) medical factors were also assessed. RESULTS A total of 585 patients were included with a median age of 7.9 months and median hospital stay of six days. No difference between the HRSV+ and HPIV+ groups was found in terms of age, gender or length of hospital stay. The HRSV+ group had more fever and cough. Need for admission to the Intensive Care Unit was similar for both groups but more deaths were recorded in the HPIV+ group. The occurrence of parainfluenza peaked during the autumn in the first two years of the study. CONCLUSION Parainfluenza was responsible for significant morbidity, proving to be the second-most prevalent viral agent in this population after respiratory syncytial virus. No difference in clinical presentation was found between the two groups, but mortality was higher in the HPIV+ group.

Profile of Anti-Tp47 antibodies in patients with positive serology for syphilis analized by western blot

In Brazil, syphilis is still a great problem of public health. Serological test is essential for syphilis diagnosis and the current trend is the use of recombinant antigen in the treponemal tests, due to its confirmed higher sensibility and specificity. The purpose of the present study was to analyze the profile of anti-Tp47 antibodies in patients with positive serology for syphilis. One hundred positive sera samples were analyzed by Western Blot (WB) technique, using the recombinant antigen (rTp47). Ten of them did not present antibodies against the fraction rTp47, the results were confirmed by WB using native T. pallidum antigen. All ten samples had antibodies against the fractions Tp17 and Tp15 and presented low reactivity in VDRL, negative results or title below than 1:4. Considering that VDRL is used for therapeutic monitoring due to seroreversion of nontreponemal antibodies in response to the treatment, and that some studies reported loss of treponemal antibodies after treatment, we could speculate if these ten samples are cases of serological memory from patients previously treated for syphilis. In addition, although several features state the Tp47 fraction as one of the major antigenic components, based on our results we point out to the importance of including other antigenic proteins such as Tp17 and Tp15 in addition to Tp47 in tests for serological screening of syphilis.

Reatividade do anticorpo IgM anti-Treponema pallidum na soroconversão e na resposta sorológica ao tratamento de sífilis

INTRODUCTION: The appropriateness of IgM antibody detection in the diagnosis of syphilis has been extensively discussed. OBJECTIVE: This study aimed at assessing the detection of anti-T. pallidum IgM antibody (TP-IgMAb) in serum samples from patients with recent syphilis in seroconversion and in the monitoring of post-treatment serological response. METHODS: Serum samples from 11 individuals. RESULTS: At seroconversion, positive Tp-IgMAb was detected in 10 samples and IgM reactivity previous to Venereal Disease Research Laboratory (VDRL) was detected in one sample. Seroreversion was found in samples from three treated patients with secondary syphilis and in one individual with reinfection. CONCLUSION: Tp-IgMAb detection proved to be a potential diagnostic marker for active syphilis, and IgM capture enzyme linked immunosorbent assay (ELISA-IgM) performance was similar to VDRL in post-treatment monitoring.

Diagnóstico laboratorial da neurocisticercose: revisão e perspectivas

A neurocisticercose e causada por Cysticercus cellulose, a forma larval de Taenia solium, quando este se aloja no sistema nervoso central. O seu diagnostico e realizado com base em dados clinicos, epidemiologicos, demonstracao do agente etiologico pelas tecnicas de imagem e testes laboratoriais. No presente estudo, apresentamos uma revisao do diagnostico laboratorial, com enfase no desempenho dos testes para pesquisa de anticorpos especificos e deteccao de antigenos circulantes, utilizacao de antigeno homologo ou heterologo, nativo e recombinante, bem como a aplicacao de metodos moleculares.

P1.44 Molecular typing and detection of macrolide resistence in treponema pallidum dna from patients with primary syphilis in são paulo,brazil

Introduction Syphilis is a globally occurring sexually transmitted disease caused by Treponema pallidum, a non-cultured in vitro bacterium. Molecular typing of Treponema pallidum strains isolated from patients are useful for investigating the molecular epidemiologic patterns, diversity of strains and antimicrobial resistance patterns.To date, there was no data on the circulating or prevalent subtype in Brazil. In this study we aimed to determine T. pallidum strain diversity and analyse for the mutation associated with macrolide resistance from patients with primary syphilis attended at CSEGPS. Methods We analysed 24 samples of primary lesion collected from patients attended at CSEGPS between 2013 and 2015. DNA was extracted with DNeasy kit (Qiagen). Standard PCR targeting tpp47 and polA genes was used for screening. Molecular typing was performed by CDC established methods, by determination of the 60 bp repeats within the arp gene, and RFLP analysis of tpr subfamily II genes (E, G and J). Completed by sequence analysis of a variable region of the tp0548 gene. The 23S rDNA mutation was analysed by DNA sequencing of PCR product. Results: T. pallidum DNA was detected in samples from 15 patients. Among 12 specimes typed, subtype found were 14d/g (6), 14d/d (5) and 12b/d (1). From 10 samples analysed for 23 rDNA mutation, all showed A2058-G, no mutation was detected at A2059. One case presented a different subtype in re-infection. The first was 14d/g and the second was 14d/d. Conclusion: T. pallidum detected in the samples of patients with primary syphilis are of subtypes 14d/g, 14d/d and 12b/d. The macrolide resistance mutation A2058-G was detected in all samples analysed. T. pallidum subtyping discriminated re-infection.