Occurrence of Plesiomonas shigelloides in water environments of Rio de Janeiro city.

Fresh and salt water samples analyzed in Rio de Janeiro city showed the presence of Plesiomonas shigelloides. Forty-six strains were isolated from both environments. A high incidence of P. shigelloides was achieved in polluted fresh and salt waters as well as in samples from non-polluted streams. P. shigelloides isolates had biochemical characteristics similar to those already described in the literature. None of the isolates analyzed produced enterotoxin in the suckling mouse assay. Hemolytic activity against sheep and human type A erythrocytes was detected in the strains tested. The results of the antibiotic susceptibility tests indicated that all the isolates were susceptible to the cephalosporins, penicillins combined with a beta-lactamase inhibitor, aminoglycosides, imipenem, norfloxacin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole. All the isolates were resistant to the penicillins.

Production of enterotoxin and cytotoxin by Aeromonas veronii.

Fourteen strains of Aeromonas veronii were isolated from salt and fresh water in Rio de Janeiro and investigated for the presence of virulence factors. Eleven (79%) A. veronii strains were positive for enterotoxin by the suckling-mouse test and thirteen (93%) produced hemolysin. Of the 13 A. veronii strains that produced hemolysin, seven were investigated for cytotoxin production using Vero cells as indicator cells and all of them were positive.

Production of enterotoxin and cytotoxin by aeromonas veronii

Fourteen strains of Aeromonas veronii were isolated from salt and fresh water in Rio de Janeiro and investigated for the presence of birulence factors. Eleven (79%) A. veronii strains were positive for enterotoxin by the suckling-mouse test and thirteen (93%) produced hemolysin. Of the 13 A. veronii strains that produced hemolysin, seven were investigated for cytotoxin production using Vero cells as indicator cells and all of them were positive

Chemical composition of lipopolysaccharide from Moraxella bovis.

Lipopolysaccharide from Moraxella bovis was isolated and its components characterized by paper and gas-liquid chromatography and mass spectrometry. The endotoxin showed a small amount of protein and contained 2-keto-3-deoxyoctonic acid glucose, mannose, glucosamine, heptose and phosphate. Six fatty acids (palmitic, palmitoleic, margaric, stearic, oleic and arachidic acids) were also identified. Margaric acid was the most prevalent fatty acid present in the lipid fraction.

Invasibilidade e enterotoxigenicidade de Yersinia enterocolitica e das especies atipicas de Yersinia isoladas do homem e de caes no Brasil. / Invasion and enterotoxigenicity of Yersinia enterocolitica and atypical Yersinia isolated from human and dogs in Brazil

A producao de enterotoxina termoestavel (ST) e a invasibilidade foram estudadas em 58 amostras de Yersinia (54 Y. enterocolitica, 3 Y. frederiksenii, e 1 Y. intermedia), isoladas do homen e de caes na cidade do Rio de Janeiro. A invasibilidade foi pesquisada em cultura de celulas HeLa e pelo teste de Sereny, enquanto que a enterotoxina ST foi pesquisada pelo metodo do camundongo recem-nascido 98,1% das amostras de Y. enterocolitica invadiram celulas Hela, 88,9% produziram enterotoxina ST e 64,8% provocaram conjuntivite intensa no cobaio, sem causar ceratite; nao se observou diferencas entre as amostras isoladas do homen e de caes. As amostras de Y. frederiksenii e Y. frederiksenii e Y. intermedia mostraram-se nao invasoras, nos dois testes utilizados sendo que todas as amostras produziram enterotoxina ST

Determinacao da composicao quimica e acao biologica do lipopolissacarideo (LPS) de Campylobacter fetus SS. jejuni. / Chemical composition and biological action of lipopolysaccharide (LPS) of Campylobacter fetus ss. jejuni

Foi estudado o lipopolissacarideo (LPS) de Campylobacter jejuni. O metodo de extracao utilizado proporcionou um lipopolissacarideo de consideravel pureza. A caracterizacao quimica do material revelou a ocorrencia dos chamados acucares basais glicose, galactose, hexosamina, acido 2-ceto 3-deoxi D-octonico (KDO), alem de acido glicuronico e fosfato. No estudo da atividade biologica realizado em animais, uma DL50 de 274 micrograma em camundongos e o aparecimento das lesoes caracteristicas da reacao de Shwartzman local, demonstraram claramente o potencial endotoxico do LPS de C. jejuni

Campylobacter fetus subsp, jejuni (C.Jejuni): isolamento e caracterizacao de amostras obtidas em galinhas, na cidade do Rio de Janeiro. / Campylobacter fetus subsp. jejuni (C. jejuni): identification of strains isolated from chickens in Rio de Janeiro

Ocorrencia de C. jejuni em galinhas vivas e abatidas, comercializada na cidade do Rio de Janeiro. De 168 amostras fecais e 227 amostras de carcacas, foram isoladas e caracterizadas 287 cepas de C. jejuni, sendo 108 (64,2%) provenientes de amostras fecais e 179 (78,7%) provenientes de carcacas. Os dados sugerem a possibilidade das aves serem reservatorios potenciais de de infeccao para o homem. A incidencia em carcacas admite a hipotese de que trabalhadores ou donas-de-casa, que lidem diretamente com frangos, constituam grupos populacionais com maior risco de contagio

Detection of Yersinia enterocolitica heat-stable enterotoxin by suckling mouse bioassay.

A comparison of heat-stable enterotoxins from Escherichia coli and Yersinia enterocolitica by the suckling mouse bioassay showed that whereas E. coli heat-stable enterotoxin evoked a maximum ratio of gut weight to remaining body weight after a 4-h incubation period, the maximum ratio for Y. enterocolitica was achieved at 2 h, decreasing thereafter to values regarded as negative (less than 0.083). This action of Y. enterocolitica heat-stable enterotoxin may give false-negative results for the standard suckling mouse bioassay.

Influencia da vacinacao BCG na infeccao experimental de camundongos por Yersinia enterocolitica. / Yersinia enterocolitica infection in mice after BCG immunization

Avaliacao da resistencia de camundongos albinos, vacinados com BCG, a infeccao com Yersinia enterocolitica, utilizando-se para este fim as sub-amostras Brasil e Glaxo da vacina BCG, inoculadas pelas vias subcutanea, intraperitoneal e oral. A inoculacao com Yersinia enterocolitica foi realizada pela via intraperitoneal injetando-se aproximadamente 500 DL50. Os camundongos vacinados pelas vias subcutanea e intraperitoneal foram reinfectados com BCG, pela via intraperitoneal, quando era mais intensa a hipersensibilidade tuberculinica o decrescimo na mortalidade foi significativo (P < 0,01). A amostra Glaxo induziu um nivel de resistencia mais pronunciado do que o observado com a amostra Brasil

Indirect hemagglutination employing enterobacterial common antigen and Yersinia somatic antigen: a technique to differentiate brucellosis from infections involving cross-reacting Yersinia enterocolitica.

The existence of enterobacterial common antigen in Yersinia enterocolitica and its absence in Brucella abortus were utilized in an attempt to provide a method to distinguish Brucella infections from infections with cross-reacting Yersinia. The indirect hemagglutination test was employed for this purpose. In experimental laboratory animals, the presence of anti-enterobacterial common antigen was found to be indicative of prior exposure to Y. enterocolitica rather than B. abortus. In cattle, however, low titers of anti-enterobacterial common antigen were present in all animals. It was observed that anti-enterobacterial common antigen titers either equaled or exceeded anti-Yersinia O titers in Yersinia-exposed animals, whereas in animals infected with B. abortus the anti-Yersinia O titer generally exceeded the anti-enterobacterial common antigen titer.

Thermophilic Campylobacter-associated diarrhoea in Rio de Janeiro.

Thermophilic Campylobacter is reported as the agent associated with chronic and acute diarrhoea in Rio de Janeiro. Nine strains were isolated from 186 children with gastroenteritis. To our knowledge this is the first report of human Campylobacteriosis in Latin-America.

An experimental study of the pathology and ecology of Yersinia enterocolitica infection in mice.

Four experiments are described in which laboratory mice were infected with Y. enterocolitica using an American serotype 0:8 (WA) and two European strains, serotypes 0:3 and 0:9. The pathogenicity and histopathological responses of strain WA (0:8) were determined in the Porton white outbred mouse by three route of inoculation. The LD50 after infection by the intraperitoneal route was 8.8 x 10(1) organisms, which is similar to results obtained by previous workers using disease-free and hybrid mouse strains. European strains 0:3 and 0:9 were shown to infect the Porton white outbred mice when injected intraperitoneally but no deaths occurred. Chronic faecal excretion was demonstrated up to 135 days. Specific antibodies were detected in the 0:3 and 0:9 infected mice and the immune response was further assessed by challenging the excreter mice with 50LD50S of the virulent WA strain. A significant degree of protection occurred in mice previously injected with 10(7) organisms of the avirulent strains. No evidence of phenotypic variation, as measured by 40 markers, was detected in 67 isolates of Y. enterocolitica recovered during the course of the four experiments. These results suggest that laboratory rodents could be a useful model for studying the infection produced by virulent and avirulent strains, and since it has been clearly established that a wide range of serotypes and non-typeable strains may be isolated from wild rodents, our findings could be extrapolated to the wildlife situation. Further work on the laboratory model could give a more detailed insight into the mechanism and extent to which rodents act as reservoirs of Y. enterocolitica.

Yersinia enterocolitica as a cause of infantile diarrhoea in Rio de Janeiro, Brazil.

Yersinia enterocolitica is reported as the causative agent of infantile diarrhoea in Rio de Janeiro. Four strains were isolated from 70 children with diarrhoea. Apparently, this is the first report of Y. enterocolitica-associated diarrhoea in Latin-America.

A microagglutination test for Yersinia enterocolitica infection: recognition of multiple serotypes in experiments with stained suspensions of serotype O5,27.

When suspensions of Yersinia enterocolitica were stained with triphenyl-tetrazolium chloride (TTC) their antigenic specificity, as determined by tube and microtitre-plate agglutination tests, was altered. Thus, a TTC-stained suspension of serotype O5,27 detected antibodies to nine O serotypes of Y. enterocolitica in sera from experimentally infected animals but did not cross-react with antisera to organisms of five other unrelated genera including Brucella. The same suspension did, however, cross-react weakly with antisera to four serotypes of Yersinia pseudotuberculosis. The value of this antigen preparation in detecting antibodies to the wide range of Y. enterocolitica serotypes likely to cause infection in man should now be assessed.

Long-term fecal excretion and resistance induced in mice infected with Yersinia enterocolitica.

European isolates of Yersinia enterocolitica serotypes O3 and O9 were shown to infect but not kill mice, which became fecal excreters for up to 135 days. The mice challenged with 500 50% lethal doses of the virulent WA strain of Y. enterocolitica serotype O8 survived, and some excreted the virulent strain. This rodent model may be of value in assessing the ecological significance of rodents in the maintenance of Y. enterocolitica.