Incidência de escherichia coli enterotoxigênica (ETEC), rotavirus e Clostridium perfringens de casos de diarréia em crianças, na região de Campinas, SP, Brasil

A survey for the detection of enterotoxigenic Escherichia coli (ETEC), rotavirus and enterotoxigenic Clostridium perfringens in diarrheic stools of children up to 2 years old was carried out in the region of Campinas, SP, Brazil. Twenty-seven (20.45% ) faecal specimens were positive for ETEC. From these samples 41 strains of ETEC were isolated from which 40 produced only thermolabile (LT) enterotoxin, as detected by a modified radial immune haemolysis test. Among the 183 faecal specimens examined for the detection of rotavirus, 29 (15.84% ) were post tive when examined by polyacrilamide gel electrophoresis (PAGE) and immunoenzimatic assay (EIA) being 15 (51.7%), derived from stools collected from winter months. All strains of rotavirus belonged to group A and through the PAGE technique, it was ob served that the most frequent (9 strains) electro phoretype, according to the adopted classifica tion, was lb, lie. Illb, IVa. Only 113 fecal specimens were examined for the presence of enterotoxigenic C. perfringens. For the detection of enterotoxin in culture supernatants the reverse passive haemagglutination and intravenous inoculation of mice were used. Twelve ( 10.61% ) ente rotoxigenic C. perfringens strains were found. Taking into consideration these findings the authors call the attention of the relative value of conventional coprocultures for diagnostic pur poses, pointing out the importante of establishing simplified methods which would render easier, the detection and identification of the groups of enteropathogenic agents studied in this research.Foi realizada uma pesquisa na região de Campinas, SP, Brasil, sobre a presença de Escherichia coli enterotoxigênica (ETEC), rotavírus e Clostridium perfringens enterotoxigênico em fezes diarréicas de crianças com até 2 anos de idade. Dos 132 espécimens fecais examinados quanto à presença de ETEC 27 (20,45%) foram positivos. Destes foram isoladas 41 amostras de ETEC, das quais 40 produziram apenas a enterotoxina termolábil (LT) detectada pelo teste de imuno hemólise radial modifi cado. Entre as 183 amostras de fezes examinadas para rotavírus, 29 (15,84%) foram positivas pelas técnicas de eletroforese em gel de poliacrilamida (PAGE) e ensaio imunoenzimático (EIE), sendo que destas, 15 (51,7% ) foram provenientes de materiais coletados nos meses de inverno. Todas as amostras pertenciam ao grupo A e, através da técnica de PAGE, pode-se observar que o tipo eletroforético mais freqüente (9 amostras) foi designado Ib, IIc, Illb, IVa, de acordo com a classificação por nós adotada. Apenas 113 amostras de fezes foram examinadas para a presença de C. perfringens enterotoxigênico. Para a detecção da enterotoxina nos sobrenadantes das culturas foram utilizadas as técnicas de hemaglutinação passiva reversa e inoculação intravenosa em camundongos, sendo encontradas 12 (10,61%) amostras entero-toxigênicas. Diante destes resultados é chamada a atenção sobre o valor apenas relativo de uma coprocultura convencional para fins de diagnóstico, ressaltando-se a importância da criação de métodos simplificados que favoreçam a detecção e identificação dos grupos de agentes enteropatogênicos estudados na presente pesquisa

Use of an indirect haemagglutination test, for the detection of Clostridium perfringens type A enterotoxin

An indirect haemagglutination (IH) test is described for the detection of Clostridium perfringentype A enterotoxin, produced by strains isolated from human cases of food poisoning and from contaminated food. Though no strict relationship could be observed between titers in the IH test and the time it took mice to die from the intravenous inoculation of mice (IIM), results of the supernatants examined by both methods demonstrated that the IH test was more sensitive than the ILM one. No unspecific reaction was obtanined int he IH wirh a negative control and the inhibitions of the IH and IIM tests by specific antiserum against C. perfringens enterotoxin showed that the IH test is very spcific. The IH assay is recommended for its sensitivity and easy performance by less-equipped laboratories, by these and other data.252

Incidence of enterotoxigenic Escherichia coli (ETEC), rotaviruses and Clostridium perfringens from cases of diarrhea among children, in the region of Campinas, SP, Brazil

A survey for the detection of enterotoxigenic Escherichia coli (ETEC), rotavirus and enterotoxigenic Clostridium perfringens in diarrheic stools of children up to 2 years old was carried out in the region of Campinas, SP, Brazil. Twenty-seven (20.45% ) faecal specimens were positive for ETEC. From these samples 41 strains of ETEC were isolated from which 40 produced only thermolabile (LT) enterotoxin, as detected by a modified radial immune haemolysis test. Among the 183 faecal specimens examined for the detection of rotavirus, 29 (15.84% ) were post tive when examined by polyacrilamide gel electrophoresis (PAGE) and immunoenzimatic assay (EIA) being 15 (51.7%), derived from stools collected from winter months. All strains of rotavirus belonged to group A and through the PAGE technique, it was ob served that the most frequent (9 strains) electro phoretype, according to the adopted classifica tion, was lb, lie. Illb, IVa. Only 113 fecal specimens were examined for the presence of enterotoxigenic C. perfringens. For the detection of enterotoxin in culture supernatants the reverse passive haemagglutination and intravenous inoculation of mice were used. Twelve ( 10.61% ) ente rotoxigenic C. perfringens strains were found. Taking into consideration these findings the authors call the attention of the relative value of conventional coprocultures for diagnostic pur poses, pointing out the importante of establishing simplified methods which would render easier, the detection and identification of the groups of enteropathogenic agents studied in this research.Foi realizada uma pesquisa na região de Campinas, SP, Brasil, sobre a presença de Escherichia coli enterotoxigênica (ETEC), rotavírus e Clostridium perfringens enterotoxigênico em fezes diarréicas de crianças com até 2 anos de idade. Dos 132 espécimens fecais examinados quanto à presença de ETEC 27 (20,45%) foram positivos. Destes foram isoladas 41 amostras de ETEC, das quais 40 produziram apenas a enterotoxina termolábil (LT) detectada pelo teste de imuno hemólise radial modifi cado. Entre as 183 amostras de fezes examinadas para rotavírus, 29 (15,84%) foram positivas pelas técnicas de eletroforese em gel de poliacrilamida (PAGE) e ensaio imunoenzimático (EIE), sendo que destas, 15 (51,7% ) foram provenientes de materiais coletados nos meses de inverno. Todas as amostras pertenciam ao grupo A e, através da técnica de PAGE, pode-se observar que o tipo eletroforético mais freqüente (9 amostras) foi designado Ib, IIc, Illb, IVa, de acordo com a classificação por nós adotada. Apenas 113 amostras de fezes foram examinadas para a presença de C. perfringens enterotoxigênico. Para a detecção da enterotoxina nos sobrenadantes das culturas foram utilizadas as técnicas de hemaglutinação passiva reversa e inoculação intravenosa em camundongos, sendo encontradas 12 (10,61%) amostras entero-toxigênicas. Diante destes resultados é chamada a atenção sobre o valor apenas relativo de uma coprocultura convencional para fins de diagnóstico, ressaltando-se a importância da criação de métodos simplificados que favoreçam a detecção e identificação dos grupos de agentes enteropatogênicos estudados na presente pesquisa.392398Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Adhesive properties of an outer structure of Clostridium perfringens type A isolated from piglets with with catarrhal enteritis Propriedades adesivas de uma estrutura externa de Clostridium perfringens tipo A isolada de leitões com enterite catarral

One strain (S32) of Clostridium perfringens type A was isolated from a case of catarrhal enteritis of piglets. This strain was able to adhere to HeLa cells showing an adherence index (AI) of 25.15 ± 1.26 (mean ± 1 standard error of the mean). Treatment of the bacterial cells with trypsin (0.25mg/ml) decreased in 70%-80% the AI and metaperiodate (10mg/ml) abolished completely the adherence, suggesting that the structure responsible for this phenomenon was probably a glycoprotein. Heating of bacterial suspensions (100ºC/5 min) before carrying out the adhesion test decreased the AI rendering it equal to the negative controls. Rabbit homologous S32 antiserum inhibited the adherence up to dilutions of 1: 640, at least. The piglet ileal loop assay, carried out with strains S32 and Jab-1 (negative control) demonstrated that the strain S32 was able to adhere to the intestinal epithelial cells when examined after Gram staining. Transmission electron microcopy (TEM) demonstrated that S32 strain displayed a loose fibrillar material not seen with Jab-1. Stabilization of the bacterial cells with homologous antiserum of strain S32, followed by staining with rhuteniun red, revealed loose long fibrillar material on the outer surface of the cells, that sometimes could be seen spreading out from the cells and linking bacterial cells. The question whether this structure might be an adhesin for this strain of Cl. perfringes type A, perhaps playing a role in the pathogenesis of the catarrhal enteritis of piglets, is dependent on further studies.<br>Uma amostra (S32) de Clostridium perfringens tipo A foi isolada de um caso de enterite catarral em leitões. Esta amostra foi capaz de aderir a células HeLa mostrando um índice de adesão (AI) de 25,15 ± 1,26 (media ± 1 erro padrão da media). Tratamento das células bacterianas com tripsina (0,25mg/ml) diminuiu 70%-80% e metaperiodato (10mg/ml) aboliu significantemente a adesão, sugerindo que a estrutura responsável por esta adesão era provavelmente uma glicoproteína. O tratamento pelo calor das suspensões bacterianas (100ºC/5min) diminuiu o AI ao nível dos controles negativos. Soro de coelho anti-S32 inibiu a aderência a células HeLa até a diluição de 1:640, pelo menos. O teste da alça ligada de leitão recem nascido demonstrou que a amostra S32 era capaz de aderir às células epiteliais intestinais, conforme demonstrado pela coloração de Gram de secções histológicas do intestino dos animais inoculados. O estudo em Microscópio Eletrônico de Transmissão demonstrou que a amostra S32 de Cl. perfringens mostrava um material de natureza fibrilar frouxa, ao contrário da amostra Jab-1 (controle negativo) que demonstrava uma aparência "nua ou lisa". A estabilização das células bacterianas com antissoro homólogo (S32), seguida de coloração com vermelho de rutenio, revelou de maneira mais nítida que longos materiais fibrilares, de aparência frouxa, se estendendo para longe da célula bacteriana, ligando por vezes estas células entre si. A possibilidade desta estrutura ser uma adesina para esta amostra de Cl. perfringens tipo A, talvez desempenhando um papel na patogenia da enterite catarral de leitões, depende de mais estudos

Nutrient limitation is the main regulatory factor for carotenoid accumulation and for Psy and Pds steady state transcript levels in Dunaliella salina (Chlorophyta) exposed to high light and salt stress

Dunaliella salina (Dunal) Teodoresco (1905) is a green unicellular alga able to withstand severe salt, light, and nutrient stress, adaptations necessary to grow in harsh environments such as salt ponds. In response to such growth conditions, this microalga accumulates high amounts of β-carotene in its single chloroplast. In this study, we show that carotenoid accumulation is consistently inhibited in cells grown in nutrient-supplemented media and exposed either to high-light or medium-low-light conditions. Likewise, carotenogenesis in cells shifted to higher salinity (up to 27% NaCl) under medium-low-light conditions is inhibited by the presence of nutrients. The steady-state levels of transcripts encoding phytoene syn- thase and phytoene desaturase increased substantially in D. salina cells shifted to high light or high salt under nutrient- limiting conditions, whereas the presence of nutrients inhibited this response. The regulatory effect of nutrient availability on the accumulation of carotenoids and mes- senger RNA levels of the first two enzymes committed to carotenoid biosynthesis is discussed.FC