Genetic relationships among serogroup B: serotype 4 Neisseria meningitidis strains

We compared the results obtained by serotyping of PorB epitopes using an expanded panel of monoclonal antibodies (mAb) including mAb 7 and mAb 10, with results obtained by RFLP of rRNA genes (ribotyping). The purpose of this study was to assess the correlation between phenotypic- and genotypic- methods for typing N. meningitidis. The ribotypes obtained using ClaI or EcoRV endonucleases grouped the strains in seven and two different patterns, respectively. This additional characterization of PorB epitopes improved the correlation between these two methods of typing N. meningitidis

Molecular characterization of Listeria monocytogenes isolated from foods

A total of 30 strains of "Listeria monocytogenes" isolated from different foods (16 of different kinds of sausage, 14 cheese) purchased at groceries of São Paulo City were ribotyped and analysed for the presence and expression of hemolysin gene and production of phosphatidylinositol-specific phospholipase C-PI-PLC enzyme. The "L. monocytogenes" strains were differentiated into six ribotype classes. A total of 13 (43.3(per cent)) from these strains belong to the same ribotype (ribotype I), and was coincident to the ribotype of the standard "L. monocytogenes" prototype strain (ATCC-15313). The hemolytic activity was observed in 29 (96.7(per cent)) strains when incubated at 37ºC, but not at 4ºC. The direct colony hibridizatioon method for hemolysin gene detection showed a positive reaction with other "Listeria" spp. The PI-PLC was produced by (90(per cent)) of the strains analysed. There was no correlation between the six identified ribotypes and the virulence facors (hemolysin and PI-PLC) studied

Meningococcal disease caused by Neisseria meningitidis serogroup B serotype 4 in Säo Paulo, Brazil, 1990 to 1996

Epidemia de doença meningococica por sorogrupo B tem ocorrido na Grande Säo Paulo desde 1988. Uma vacina cubana, baseada em proteina de membrana externa de uma cepa de Neisseria meningitidis sorogrupo B : sorotipo 4: sorosubtipo P1.15 (B:4:P1.15), foi administrada em cerca de 2,4 milhöes de crianças entre 3 meses a 6 anos de idade durante 1989 e 1990. A administraçäo da vacina teve pouco ou nenhum efeito na evoluçäo da epidemia. Para detectar mudança clonal que poderia explicar o continuo aumento da doença depois da vacinaçäo, foram sorotipadas 834 cepas isoladas entre 1990 e 1996 de pacientes com doença sistemica. Cepas B:4:P1.15 isoladas desde 1977, tem sido o fenotipo mais prevalente desde 1988. Essas cepas ainda säo prevalentes na regiäo e foram responsaveis por cerca de 68 por cento dos 834 casos por sorogrupo B nos ultimos 7 anos. Foram analisados 438 (52 por cento) dessas cepas por RFLP do rRNA gene (ribotipagem), e o perfil mais frequente foi o Rbl (68 por cento). Concluimos que o clone B:4:P1.15 - Rbl foi o mais prevalente e responsável pelo continuo aumento da doenca meningococica na Grande Säo Paulo durante os ultimos 7 anos apesar da campanha de vacinaçäo

Use of oligonucleotide probes for meningococcal serotype characterization

No presente trabalho nos examinamos o uso potencial de sondas de oligonucleotideos para caracterizar sorotipos de Neisseria meningitidis sem o uso de anticorpos monoclonais (MAbs). A diversidade antigenica da proteina PorB forma a base do metodo de sorotipagem, todavia, o atual painel de MAbs utilizados, sub-estima em no minimo 50 por cento a diversidade desta proteina devido a falta de reagentes para as varias regiöes variáveis (VRs) da proteina PorB ou porque varias variantes das VRs nao sao reagentes com os MAbs disponíveis. Nos analisamos o uso de sondas de oligonucleotideos para caracterizar os sorotipos 10 e 19 de N. meningitidis. O gene porB da cepa prototipo do sorotipo 10 foi sequenciado e alinhado com outras 7 sequencias de diferentes sorotipos, e as individuais VRs foram entäo analisadas. Os resultados com as sondas 21U (VRI-A) e 615U (VR3-B) contra 72 cepas de N. meningitidis os MAbs 19 e 10 respectivamente. E possivel o uso de sondas para a caracterizaçäo dos sorotipos e podemos tipar 100 por cento da diversidade da VR do gene porB. Trata-se de um metodo simples, rapido, e especialmente util para a analise de um grande numero de amostras

Molecular epidemiology of Lyme disease spirochetes based on a probe complementary to ribosomal RNA

Lyme disease is caused by the spirochete, Borrelia burgdorferi, a bacteria which infects many vertebrates including humans. Borrelia have been isolated from many parts of the world, and there is interest to identify commun genetic markers to improve molecular methods of diagnosis, and to aid in understanding varied manifestations of the disease. A total of 48 Borrelia burgdorferi strains, including: 38 isolated from ticks (Ixodes dammini, I. persulcatus, I. ricinus and I. pacificus), 3 from animals (dog, bird and hamster), and 7 from human clinical cases (skin, CSF, plasma and blood) from different geographic areas, were studied by DNA/DNA hybridization and rRNA gene restriction patterns by using a biotinylated pKK3535 probe (Altewegg M., Mayer L.W., 1989). The migration patterns of rRNA generestriction fragments after clevage by Hind III separate these strains into 5 ribotypes of Borrelia burgdorferi: Type I (38 American, 2 European strains); Type II (13 American strains); Type III (3 Asian and 1 European strains); Type IV (1 European and 2 Asian strains) and Type V (1 Asian strain). The use of ribotyping has provided and additional tool to investigate the diferences or commun patterns which cause various Lyme disease syndromes.