Prevalencia de cepas cagA-positivo en la región de Coquimbo, determinada mediante nested-qPCR en muestras fecales / Frequency of CagA-positive Helicobacter pylori strains in 160 patients subjected to endoscopy

Background: Helicobacter pylori is the most significant pathogen associated with gastric diseases, including gastric cancer. Infected patients with strains that are CagA-positive generally have worse outcomes than those infected with CagA-negative strains. Patients infected with CagA-positive strains have a higher risk for developing gastric cancer. Aim: To determine the prevalence of CagA-positive H. pylori strains in fecal samples of patients from the Coquimbo Region of Chile, using a non-invasive, nested-qPCR method. Material and Methods: We evaluated 160 patients with gastrointestinal symptoms subjected to an upper gastrointestinal endoscopy. DNA was extracted from fecal samples and tested for the presence of H. pylori using nested-qPCR for the ureC gene, and subsequently compared with the results of histology-Giemsa stain from the patients' endoscopic biopsies. When H. pylori was found, the presence of CagA-positive strains was determined via nested-qPCR. Results: The histology-Giemsa stain was positive for H. pylori infection in 123 patients (76.9%), while the analysis of fecal samples detected H. pylori in 129 patients (80.6%). The sensitivity and specificity of nested-qPCR to detect the bacterium was 96.7 and 73.0% respectively. Among patients with the infection, 25% had CagA-positive strains. Conclusions: In this sample of patients, there is a low prevalence of CagA-positive H. pylori strains.

Prevalence of iffection with caga-positive heliobacter pylori strains among chhildren and adolescents in southern Brazil / Prevalência da infecção por cepas de Helicobacter pylori cagA-positivo em crianças e adolescentes do Sul do Brasil

Context Helicobacter pylori (H. pylori) has a worldwide distribution, but the prevalence of infection, virulence factors, and clinical presentation vary widely according to the studied population. In Brazil, a continental country composed of several ethnicities and cultural habits, the behavior of infection also appears to vary, as many other studies have shown. Objectives Describe the prevalence of infection with cagA-positive H. pylori strains in a group of children and adolescents who underwent esophagogastroduodenoscopy in Porto Alegre, Rio Grande do Sul. Methods Fifty-four gastric biopsy specimens of children and adolescents with H. pylori infection demonstrated by histology, urease test and molecular analysis were tested for the presence of cagA positive H. pylori strains by the polymerase chain reaction method. Results he prevalence of cagA-positive H. pylori was 29.6% (95% confidence interval, 18 to 43.6%). There were no statistically significant differences in clinical or demographic characteristics or in the endoscopic and histological features of patients infected with cagA-positive strains as compared with those infected by cagA-negative strains. Conclusions he study showed a low prevalence of infection with cagA-positive H. pylori strains among children and adolescents who underwent EGD in southern Brazil, in comparison to studies conducted with children from other regions of Brazil. There was no association between the presence of cagA-positive strains and more severe clinical presentations in the studied sample. .

Contexto Helicobacter pylori (H. pylori) tem distribuição geográfica universal, embora a prevalência da infecção, os fatores de virulência, bem como a apresentação clínica, variem de acordo com a população estudada. No Brasil, um país continental composto por várias etnias e hábitos culturais diversos, o comportamento da infecção também parece variar, como muitos estudos têm demonstrado. Objetivos Descrever a prevalência da infecção por cepas de H. pylori cagA-positivo em um grupo de crianças e adolescentes submetidos a esofagogastroduodenoscopia em Porto Alegre, Rio Grande do Sul. Métodos Cinquenta e quatro (54) fragmentos de biópsia gástrica com presença de H. pylori demonstrada pela análise histológica, teste da urease e análise molecular foram testados para a presença de cepas de H. pylori cagA-positivo pelo método da reação em cadeia da polimerase. Resultados prevalência de cepas de H. pylori cagA-positivo foi de 29,6% (intervalo de confiança de 95%, 18% a 43,6%). Não houve diferenças estatisticamente significativas nas características clínicas e demográficas e nos achados endoscópicos e histológicos entre os pacientes infectados por cepas de H. pylori cagA-positivo em comparação com os cagA-negativo. Conclusões O estudo demonstrou uma baixa prevalência de infecção por cepas de H. pylori cagA-positivo nas crianças e adolescentes submetidas a esofagogastroduodenoscopia no Sul do Brasil em comparação com os estudos realizados com crianças de outras regiões do Brasil. Não houve associação entre a presença de cepas cagA-positivo e desfechos clínicos desfavoráveis na amostra estudada. .

Identificación de antígenos inmunorreactivos de Leptospira interrogans / Identification of immunoreactive antigens of Leptospira interrogans

Se estudió un lote de 28 sueros de llama (Lama gama) de la provincia de Jujuy, Argentina, a fin de identificar antígenos inmunorreactivos contra Leptospira interrogans. Se utilizaron distintas preparaciones antigénicas de la bacteria para estudiar la inmunorreactividad mediante microaglutinación (MAT), ELISA y Western inmunoblot. Un pool de sueros bovinos positivos a la MAT fue empleado como control. Todos los sueros de llama fueron negativos mediante MAT e igual resultado se observó mediante ELISA. Dos de los 28 sueros de llama y el pool de sueros bovinos positivos, al ser evaluados por Western inmunoblot, arrojaron resultados positivos y permitieron identificar proteínas inmunorreactivas. Por MALDI-TOF se logró establecer que la proteína asociada a los dos sueros de llama inmunorreactivos era una flagelina periplásmica de Leptospira interrogans serovar Lai STR, mientras que la asociada al pool de sueros bovinos positivos a Leptospira sp. se trataba de una lipoproteína de la membrana externa de Leptospira interrogans serovar Ballum, LipL21. Estas proteínas podrían ser utilizadas en el diseño de un nuevo ELISA aplicado al diagnóstico temprano de leptospirosis, ya sea en distintos tipos de ganado como así también en reservorios silvestres.

A batch of 28 llama (Lama gama) sera from Jujuy province in Argentina was studied in order to identify immune reactive antigens to Leptospira interrogans. Different antigenic preparations from the bacterium were used to study the immune reactivity by the microagglutinattion (MAT), ELISA and Western immunoblot tests. A control pool of positive bovine sera was used. All the llama sera were negative to MAT as well as to ELISA. Two of the llama sera and the positive bovine sera pool rendered positive results when evaluated by Western immunoblot, allowing the identification of immune reactive proteins. These proteins were identified by MALDI-TOF. A periplasmic flagellin of Leptospira interrogans serovar Lai STR called FlaB1 was identified from the reactive llama sera, and an external membrane lipoprotein of Leptospira interrogans serovar Ballum called LipL21 was identified from the pool of bovine positive sera. These proteins could be used in a new ELISA applied to the early diagnosis of leptospirosis in different kind of cattle or wild reservoirs.

Isolation, characterisation and kinetic studies on SEVA TB ES-31 antigen, a metallo-serine protease of interest in serodiagnosis.

BACKGROUND: SEVA TB Excretory secretory-31 (ES-31) antigen, a glycoprotein isolated from M. tb H37Ra culture filtrate, was found to be useful in the serodiagnosis of pulmonary tuberculosis (TB), extrapulmonary TB and in HIV-TB coinfection. Further, it has been shown to be a zinc containing serine protease. AIM: To isolate and purify SEVA TB ES-31 antigen from M. tb H37Ra culture filtrate and study of its enzyme properties and peptide sequence. METHODS: ES-31 antigen was purified from culture filtrate of M. tuberculosis H37Ra strain by ammonium sulphate precipitation, SDS-PAGE fractionation and FPLC. Protease activity of ES-31 antigen was studied using azocasein as substrate. ES-31 antigen was further fractionated by two dimensional polyacrylamide gel electrophoresis (2D PAGE) followed by LCMS-T analysis. RESULTS: Mycobacterial metallo-serine protease was purified 3096 fold from M. tb H37Ra culture filtrate protein. Purified enzyme showed optimum activity at pH 7.0 at 37 degrees C. Of the four substrates explored, the enzyme has shown maximum activity with azocasein and had a Km value of 0.01 mM with specific activity of 6250 x 10(-6) U/mg protein. Further, analysis of ES-31 antigen by 2D PAGE showed two protein spots (A and B). CONCLUSION: Kinetic studies on SEVA TB ES-31 protein, an immunogen with metallo serine protease activity are reported for the first time. Purified enzyme had a Km value of 0.01 mM with azocasein as substrate. Further, study on structure and biological role of serine protease will be of interest.

Prevalência de anticorpos contra agentes virais e bacterianos em eqüídeos do município de Monte Negro, Rondônia, Amazônia ocidental brasileira / Seroprevalence of viral and bacterial agents in equids from Monte Negro municipality, State of Rondônia. brazilian western Amazon

Foram examinados 176 eqüídeos (15 muares e 161 eqüinos) do município de Monte Negro, Rondônia, Amazônia Ocidental Brasileira, frente a agentes virais e bacterianos. A amostra correspondeu ao total de eqüídeos no município, considerando um nível de confiança de 99%, prevalência esperada de 50% e erro padrão de 10%. As infecções virais foram investigadas pelas provas de Imunodifusão em gel de Agar (Anemia Infecciosa Eqüina - AIE), Inibição da hemaglutinação (Influenza eqüina tipos 1 e 2 - IE-1 e 2) e Soroneutralização em cultura celular (Arterite Viral Eqüina - AVE, Herpesvírus Eqüino tipo 1 - HVE1, Estomatite Vesicular - EV e Encefalomielite Eqüina do Leste - EEE, do Oeste - WEE e Venezuela - VEE). Para o diagnóstico da leptospirose, foi utilizada a prova de Soroaglutinação Microscópica (SAM); para o diagnóstico da brucelose, o teste do Antígeno Acidificado Tamponado (AAT) foi utilizado como teste de triagem e as provas de Soroaglutinação Lenta em Tubos (SLT) e 2- mercaptoetanol como testes diagnósticos. Foram constatados 9,6% dos eqüídeos reativos para AIE, 22,7% para HVE1, 19,9% para IE- 1, 42,0% para IE-2, 21,0% para EEE, 11,3% para VEE, 3,4% para Brucella spp. e 91,4% para Leptospira spp. Os sorovares de leptospira mais freqüentes foram Bratislava (10,5%), Icterohaemorrhagiae (8,7%) e Autumnalis (8,7%) nos eqüinos e Patoc (26,6%) nos muares. Não foram encontrados animais com anticorpos contra AVE, EV e WEE.

Sera from 174 equidaes (15 mules and 161 equines) of Monte Negro municipality, Rondônia State were analyzed against viral and bacterial agents. The serum sample corresponded the total equid population in the municipality considering a confidence interval of 99%, expected prevalence of 50% and absolute desired of 10%. For the viral agents, sera were tested by the Agar Gel Immunodiffusion Test (Equine Infection Anemia - EIA), Inhibition Haemagglutination Test (Equine Influenza 1 and 2 - EI - 1 and 2), and Virusneutralizating Tests (Equine Viral Arteritis - EVA, Equine Herpesvirus 1 - EHV1, Vesicular Stomatitis - VS, Equine Encephalitis Eastern - EEE, Western - WEE and Venezuelan VEE). The diagnosis for brucellosis was made by Agglutination Tests and the Microscopic Agglutination Test was used for leptospirosis. The results showed positivity of 9.6% for EIA, 22.7% for HVE1, 19.9% for IE-1, 42.0% for IE-2, 21.0% for EEE, 11.3% for VEE, 3.4% for brucellosis, and 91.4% for leptospirosis. The most frequent serovars detected were Bratislava (10.5%), Icterohaemorrhagiae (8.7%), Autumnalis (8.7%) for equines and Patoc (26.6%) for mules. No one of the examined samples reacted to EVA, VS, or WEE.

Immunodominant antigens of helicobacter pylori strains isolated from patients with different gastroduodenal diseases

To detect the immunogenic proteins in Helicobacter pylori [H. pylori] strains isolated from patients with different gastric diseases. We performed this study in the Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran, during July 2003 to September 2004. Total proteins of H. pylori strains isolated from the gastric biopsies of 3 groups of patients were separated by 1D-SDS-PAGE and then blotted with the sera of their respective hosts. In SDS-PAGE the members of each group showed high correlation according to similarity in their patterns, resulting in considering them in the same cluster. The patterns of immunoblots differed from that of Coomassie Brilliant Blue stained gels. The blotting method did not recognize some of the protein bands in the SDS-PAGE. Only the bands of 106 and 45 kDa from H. pylori strains isolated from patients with gastric cancer were significantly [p<0.05] recognized specifically with the sera of their respective patients, and the band of 13 kDa was recognized specifically [p<0.05] with the sera of nonulceric patients. With the exception of these bands, in the patterns of blotting of the sera from all patients no significant differences were observed. By using 1D blotting methods we could find 2 antigenic protein bands [106 and 45 kDa] for H. pylori strains isolated from cancerous patients, and one [13 kDa] for the strains isolated from nonulceric patients, which were specifically recognized with their respective host

Helicobacter pylori stool antigen test.

OBJECTIVE: Helicobacter pylori ( H.pylori ) infection is usually acquired in early childhood. Invasive techniques used for diagnosis of H.pylori infection require endoscopic examination which is expensive and inconvenient and may cause complications. The aim of this study was to evaluate the performance of a new noninvasive diagnostic method, stool antigen test for H.pylori in untreated children with recurrent abdominal pain. METHODS: Eighty children (35 female, 45 male) who have undergone upper gastrointestinal endoscopy due to recurrent abdominal pain were included in the study. The H.pylori stool antigen test (HpSA) is based on a sandwich enzyme immunoassay with antigen detection. HpSA sensitivity, specificity, and positive and negative predictive values were determined with reference to the results of both histology and rapid urease test as a gold standard ( H. pylori status). RESULTS: While 49 of the 80 children (61%) tested were positive for H.pylori according to the results of both histology and rapid urease test, 28 children had negative H.pylori status. Among those 49 children, 48 were found to be positive by HpSA. Of 28 patients with negative H.pylori status, 28 were H.pylori -negative also in the stool test. The sensitivity, specificity, and positive and negative predictive values of HpSA were found to be 98%, 100%, 100%, and 96.5%, respectively. CONCLUSION: These findings have demonstrated that HpSA as a relatively simple, inexpensive and time saving noninvasive test is a reliable method for detection of H.pylori infections in children.

H antigen presence in an Ascaris lumbricoides extract

Experiencias previas han demostrado los mismos antígenos del Sistema ABO y del Sistema P en extractos de A. lumbricoides y en sus huéspedes. El objetivo fue mostrar el comportamiento de un extracto de A. lumbricoides de un paciente Grupo O frente a anticuerpos monoclonales de diferentes especificidades. Se hicieron pruebas de Inhibición de la Aglutinación enfrentando el extracto contra anticuerpos monoclonales (anti A 2.23; anti B 2.54; anti B 2.62; anti AB 2.39 y anti H 2.72) en dosis óptimas. El sistema revelador fue una suspensión fresca de eritrocitos Grupo O. El extracto sólo inhibió la aglutinación de anti H 2.72 con eritrocitos O. Se hizo la inhibición de la aglutinación semicuantitativa del extracto frente a dos series de diluciones de anti H 272 usando eritrocitos frescos Grupo O como sistema revelador. Se observó una diferencia de 5 diluciones entre los títulos de ambas series y se confirmó significativamente la presencia de antígeno H en el extracto. La no inhibición de la aglutinación del extracto frente a anti A, anti B y anti AB ha corroborado nuestras observaciones previas sobre ausencia de epitopes A y B en extractos de pacientes Grupo O. Los resultados de los estudios previos y de esta experiencia, han demostrado la importancia de los glicoconjugados de membrana en A. lumbricoides, los que podrían estar involucrados en el mimetismo antigénico para este parásito.

Chlamydia pneumoniae e Mycoplasma pneumoniae nos nódulos de calcificacão da estenose da valva aórtica / Chlamydia pneumoniae and Mycoplasma pneumoniae in calcified nodes of stenosed aortic valves

OBJETIVO: Investigar se chlamydia pneumoniae (CP) ou mycoplasma pneumoniae (MP) estão presentes na estenose da valva aórtica (EA). MÉTODOS: Imuno-histoquímica foi utilizada para identificar os antígenos de CP (Ag-CP), a hibridizacão in situ para identificar o DNA de MP, e microscopia eletrônica para avaliacão dos dois agentes, nos grupos: normal - 11 valvas normais de autópsia; aterosclerose - 10 valvas de pacientes com aterosclerose sistêmica de autópsia e sem EA; e EA - 14 espécimes cirúrgicos provenientes de pacientes com EA analisados em 3 sub-regiões: EA-preservada - regiões mais preservadas na periferia da valva; EA-fibrose - tecido fibrótico peri-calcificacão; e EA-calcificacão - nódulos calcificados. RESULTADOS: As medianas da fracão de área positiva para Ag-CP foram 0,09; 0,30; 0,18; 1,33; e 3,3 nos grupos acima descritos, respectivamente. A densidade de CP foi significativamente maior nos grupos aterosclerose e EA-calcificacão em relacão ao normal (p<0,05). Dentro do grupo EA, a quantidade de CP foi maior nas regiões de fibrose e calcificacão (p<0,05). As fracões de área positivas para MP-DNA (medianas) foram 0,12; 0,44; 0,07; 0,36; e 1,52 nos grupos acima descritos, respectivamente. A quantidade de MP-DNA foi maior na EA-calcificacão em relacão ao normal (p<0,05). Dentro do grupo EA, maior quantidade de MP-DNA foi encontrada nas regiões de calcificacão e fibrose (p<0,05). CONCLUSAO: Os nódulos de calcificacão da EA tinham maior concentracão de CP e MP sugerindo que essas bactérias possam estar associadas ao desenvolvimento de calcificacão e inflamacão, apontando novas semelhancas entre os processos de EA e aterosclerose, que podem ter mecanismos infecciosos envolvidos.

Papel do teste de deteccão rápida do antígeno do estreptococcus pyogenes do grupo a em pacientes com faringoamigdalites / Role of rapid antigen detection test for the diagnosis of group A beta-hemolytic streptococcus in patients with pharyngotonsillitis

O Streptococcus pyogenes do grupo A (SGA) é o agente etiológico mais comum das faringoamigdalites (FA). O diagnóstico etiológico correto e tratamento adequado evitam complicacões supurativas e não-supurativas da faringoamigdalite estreptocócica, entretanto, métodos clínicos de diagnóstico não são confiáveis. Os métodos rápidos de deteccão do antígeno do SGA podem ser utilizados no diagnóstico deste agente e evitar uso indevido de antibióticos. OBJETIVOS: Os autores objetivaram avaliar a sensibilidade e especificidade dos testes rápidos para deteccão do antígeno do SGA em nosso meio. FORMA DE ESTUDO: Clínico prospectivo. CASUíSTICA E MÉTODO: Oitenta e um pacientes com faringoamigdalite aguda, atendidos no PS-ORL do Hospital das Clínicas da FMUSP, no período de maio de 2001 a abril de 2002, foram submetidos a duas coletas simultâneas de material de orofaringe com swabs. O teste rápido de deteccão do SGA foi confrontado com a cultura em placa agar-sangue ("gold standard" para o diagnóstico etiológico). RESULTADOS: De 81 pacientes, 56 por cento tiveram teste rápido positivo e 44 por cento negativo; 40.7 por cento apresentaram crescimento de SGA na cultura; a sensibilidade e especificidade do teste rápido foram, respectivamente, 93,9 por cento e 68,7 por cento. O valor preditivo negativo e positivo foram, respectivamente, 94,2 por cento e 67,4 por cento. COMENTARIOS FINAIS: A alta sensibilidade do exame permite utilizá-lo com intuito de identificar pacientes com SGA. Os testes de deteccão rápida do antígeno estreptocócico se mostraram uma importante arma coadjuvante no diagnóstico etiológico das faringoamigdalites.

A test strip IgM dot-ELISA assay using leptospiral antigen of endemic strains for serodiagnosis of acute leptospirosis.

A test strip IgM dot-ELISA assay for the detection of leptospire-specific IgM antibodies in human sera was developed. Antigen dotted on a nitrocellulose paper strip was the pool sonicated antigen prepared from three predominant reactive Leptospira serovars currently in endemic area, i.e., Bratislava, Sejroe and Pyrogenes. The ability of the test to diagnose acute leptospiral infection was assessed by testing 343 single serum samples from 96 laboratory-confirmed leptospirosis case patients with positive result in the standard microscopic agglutination test (MAT), 55 serum samples from patients with various diseases other than leptospirosis, and 192 serum samples from healthy individuals. Using the results of the MAT as a gold standard, the sensitivity and specificity of the test strip IgM dot-ELISA assay were 98.96 and 93.93 per cent, respectively. The assay offered relatively high negative predictive values (99.57%) thus making the assay ideally suited for rapid screening. The stability of the test strip was assessed with a panel of five positive and five negative control sera after storage at 4 degrees C and -20 degrees C at different times. The results showed a good performance of the test strip at both storage temperatures for up to one year. In conclusion, the test strip IgM dot-ELISA assay was sufficiently sensitive for use as a screening test for serodiagnosis of acute leptospirosis. The assay was simple, inexpensive, and easy to perform for both a single test format and a large number of specimens. However, further studies are still needed to improve the stability of the test strip and assay reagents at ambient temperature, and to make the assay more rapidly and more user friendly.

Estudo do efeito adjuvante de CTB em fusões com as proteínas pneumocócicas PsaA e PspA no desenvolvimento de vacinas protéicas contra Streptococcus pneumoniae / Study of CTB adjuvant effect in fusions with PsaA and PspA pneumococcal proteins in the development of protein vaccines against Streptococcus pneumoniae

A colonização da mucosa respiratória é a primeira etapa na patogênese de Streptococcus pneumoniae, bactéria causadora de pneumonia, menigite, e otite média, responsável por mais de um milhão de mortes por ano no mundo. As proteínas de superfície PsaA e PspA têm sido investigadas como candidatos vacinais para estas doenças. CTB é a porção não tóxica da toxina colérica (CT), responsável pela ligação da toxina ao receptor celular GM1 e descrita como adjuvante de mucosas. Neste trabalho, estes genes de S. pneumoniae foram clonados em pAE, um vetor de expressão de E. coli, que utiliza o promotor T7, ou a 3´ de ctxB no plasmídeo pAE-ctxB. As proteínas recombinantes CTB, PsaA, CTB-PsaA, PspA1, CTB-PspA1, PspA3 e CTB-PspA3 foram expressas em E. coli BL21 (SI) e purificadas através de coluna carregada com níquel...

Prevalence of Helicobacter pylori infection among low socio-economic workers.

Epidemiological studies have shown that the prevalence of Helicobacter pylori infection in a community and occupational health are closely related to lifestyle and socio-economic status. There is little information on H. pylori profile in industrial workers in the literature. The aim of this study was to investigate the prevalence rate of H. pylori profiles among low socio-economic workers in the United Arab Emirates (UAE). This study was undertaken by determining IgG H. pylori antibody profiles among industrial exposed and referent workers, sera. Presence of anti-H. pylori antibodies in the frozen stored sera was determined by ELISA. Also, data on dietary and lifestyle were obtained. The result was considered positive if IgG anti-H. pylori antibody titers was > 300. People with seropositive levels of IgG antibodies to H. pylori were assumed to be infected with H. pylori. Most of the industrial workers lived in less modern accommodation, were less educated, ate their vegetable products unwashed and did not have drinking water facilities, when compared to referents. H. pylori serology by IgG was positive in 167 industrial workers (78.4%) and 137 in referent workers (64.3%) respectively, (p < 0.002). The sensitivity and specificity of the IgG serology assay were 94.5%, and 97.2% respectively. There was statistically significant difference between the exposed industrial and non-exposed control groups in respect of their H. pylori profiles.

Isolamento e propagação da Ehrlichia canis em células DH82 e obtenção de antígeno para a reação de imunofluorescência indireta / Isolation and propagation of Ehrlichia canis in DH82 cells as a source of antigens in indirect immunofluorescence test

Ehrlichia canis, agente etiológico da Ehrlichiose Monocítica Canina, foi obtida a partir de um cão naturalmente infectado e propagada em outro por infecção experimental. A camada de mononucleares deste animal foi separada e inoculada em células macrofágicas de linhagem contínua de origem canina, denominadas DH82. A cultura apresentou-se positiva 18 dias pós a infecção. A propagação da Ehrlichia canis in vitro foi acompanhada a partir da observação de mórulas nas células presentes no sobrenadante da cultura infectada, pelas técnicas de citocentrifugação, inoculação em tubos de Leighton e imunofluorescência direta. O cultivo apresentou cerca de 30 por cento de infecção após 30º dia, alcançando 80 por cento no 47º, sendo então dividido a 1:2. As células DH82 permitiram o isolamento de E. canis e foram utilizadas como fonte de antígeno para o teste de imunofluorescência indireta.

Electrophoretic analysis of Salmonella typhi and other bacteria.

A comparative study involving SDS-PAGE of Salmonella typhi and other Bacteria was conducted. Protoplasmic antigens of Salmonella typhi. Salmonella paratyphi A, Salmonella typhimurium, Proteus sp, Klebsiellas sp. Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus were separated and compared on SDS-PAGE followed by checking of their cross reactivity by gel diffusion using antisera raised against whole cell and lysates of Salmonella typhi. Lines of identity between Salmonella typhi, Salmonella paratyphi A and Salmonella typhimurium were observed. No lines of identity were seen among Salmonella typhi, Pseudomonas aeruginosa and Sfaphylococcus aureus.

Diferencias proteómicas entre una cepa argentina de Mycobacterium bovis con la cepa de referencia AN5 / Proteomic differences between an argentine mycobacterium bovis strain and the reference AN5 strain

La tuberculosis bovina es en Argentina una enfermedad que provoca graves pérdidas económicas y que afecta a un 5 por ciento del ganado. En un trabajo previo de tipificación de cepas por RFLP mediante el uso de las sondas PGRS y DR se identificó una cepa altamente predominante que se llamó AA. A diferencia de la cepa salvaje AA, la cepa de referencia AN5, de origen europeo, que se utiliza para elaborar la tuberculina, es una cepa adaptada al crecimiento en laboratorio, que puede haber sufrido mutaciones en genes de antígenos o de virulencia. Para ello se analizó la producción de proteínas secretadas y del extracto celular, de la cepa salvaje AA comparada con la cepa de referencia AN5, con el propósito de identificar diferencias que puedan dar cuenta de la virulencia y para identificar nuevos antígenos. Se utilizaron técnicas como electroforesis en geles de policrilamida, geles de 2 dimensiones y Western blot utilizando antisueros específicos contra antígenos ya caracterizados y sueros de bovinos infectados con tuberculosis confirmada por aislamiento de M. bovis, empleando proteínas celulares y secretadas (a los 25 y 100 días de cultivo) de ambas cepas. Se pudieron identificar, una proteína secretada de aproximadamente 29 kDa y otra de 28 kDa del estracto celular que parecen ser exclusivas o producidas en mayor cantidad por la cepa AA. También, se identificaron otras pero cuyas bandas eran más débiles. En conclusión, algunas de las proteínas identificadas pueden servir para mejorar el diagnóstico de la tuberculosis bovina

Leptospira interrogans serovar Pomona: detección de diferencias antigenicas entre tres aislamientos regionales de bovinos y una cepa de referencia / Leptospira interrogans serovar Pomona: detection of antigenic differences among 3 regional isolates from cattle and a reference strain

Leptospirosis is a zoonosis caused by Leptospira interrogans. This disease is diagnosed by quantification of specific immunoglobulins in serum by the microagglutination test (MAT). The aims of this research were: a) to compare the protein profiles of 3 clinical isolates of bovine leptospirosis with the reference strain used for the MAT, and b) to identify the immunodomain antigens of the regional isolates through PAGE and immunoblotting techniques of bovine sera from infected, vaccinated and MAT-negative animals. Coomassie-blue stained gels revealed extensive protein similarities between pathogenic and reference strain. Most infected (8/10) and vaccinated animal sera (4/7) showed by immunoblotting a similar reactivity against the proteins from pathogenic leptospires, with a strong band of 25-30 kDa which was not detected in the reference strain. The lack of correlation between MAT and immunoblotting techniques for infected animals could be due either to the infection stage at which the diagnosis was made or to the immunoglobulin isotype involved in the response. Results obtained would confirm the antigenic differences between the 3 isolates and the reference strain.