RESUMO
Several reports on the microbiology of spices and herbs indicate the presence of Clostridium perfringens, a spore-forming foodborne pathogen responsible for gastrointestinal disease. In the present study, a total of 380 samples of spices and herbs (cumin seed, black pepper, oregano, garlic powder, and bay leaves) widely used in Mexico were analyzed for the presence of C. perfringens, and the enterotoxigenicity of the isolates was determined by a dot-blot technique using an enterotoxin degoxigenin-labeled DNA probe. C. perfringens counts varied from <100 to 433 CFU/g in garlic powder, from <100 to 200 CFU/g in black pepper, from <100 to 433 CFU/g in cumin seed, from <100 to 340 CFU/g in oregano, and from < 100 to 450 CFU/g in bay leaves. The dot-blot technique detected the enterotoxin gene in 8 (4.25%) of 188 confirmed isolates of C. perfringens. dot-blot.
Assuntos
Clostridium perfringens/isolamento & purificação , Especiarias/microbiologia , Clostridium perfringens/genética , Contagem de Colônia Microbiana , DNA Bacteriano/análise , Enterotoxinas/genética , México , Técnicas de Sonda Molecular , Vigilância de Produtos ComercializadosRESUMO
A refractile inclusion body produced by vegetative cells of Clostridium perfringens at temperatures above 40 degrees C was isolated and partially characterized. The inclusion was composed of protein and could be solubilized by sodium dodecyl sulphate plus either dithiothreitol or beta-mercaptoethanol. The solubilized inclusion showed no antigenic relationship with Cl. perfringens enterotoxin. One major band with an apparent MW of 47 kDa was demonstrated after polyacrylamide gel electrophoresis of the solubilized inclusion. Both enterotoxin-positive and enterotoxin-negative strains produced the inclusion body. No effect on the morphology of several eucaryotic cell lines was observed when solubilized or intact inclusion was added to the cell cultures.
Assuntos
Proteínas de Bactérias/isolamento & purificação , Clostridium perfringens/ultraestrutura , Corpos de Inclusão/química , Animais , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/farmacologia , Bovinos , Linhagem Celular , Galinhas , Chlorocebus aethiops , Clostridium perfringens/química , Clostridium perfringens/crescimento & desenvolvimento , Humanos , Corpos de Inclusão/ultraestrutura , Camundongos , Peso MolecularRESUMO
Enterotoxin-positive strains of Clostridium perfringens were grown in Duncan-Strong sporulation medium in the presence of 0.4% (7.9 mM) raffinose at 37 and 43 degrees C. Enterotoxin- and heat-resistant spores were produced at similar concentrations but sooner at 43 degrees C than at 37 degrees C. There was a direct relationship between spore heat resistance and sporulation temperature (32, 37, and 43 degrees C).
Assuntos
Clostridium perfringens/fisiologia , Enterotoxinas/biossíntese , Clostridium perfringens/metabolismo , Clostridium perfringens/ultraestrutura , Temperatura Alta , Esporos BacterianosRESUMO
Enterotoxin-positive (Ent+) and enterotoxin-negative (Ent-) strains of Clostridium perfringens were cultured in Duncan-Strong sporulation medium containing starch at 37 and 46 degrees C. At 37 degrees C, all strains degraded starch and sporulated well. However, only Ent- strains could hydrolyze starch, grow extensively, and sporulate at 46 degrees C. Growth, sporulation, and starch hydrolysis by Ent+ strains at 46 degrees C were equivalent to those obtained at 37 degrees C when alpha-amylase was added to the cultures during growth. The total amount of extracellular plus intracellular amylase in cultures of Ent+ strains was significantly less in cells incubated at 46 degrees C than in cells incubated at 37 degrees C. These results contradict an earlier report that Ent+ strains cannot sporulate well near their optimal growth temperature (R. G. Labbe and C. L. Duncan, Can. J. Microbiol. 20:1493-1501, 1974) and suggest that synthesis of alpha-amylase in Ent+ strains is regulated by temperature.
Assuntos
Clostridium perfringens/metabolismo , Amido/metabolismo , Amilases/metabolismo , Clostridium perfringens/fisiologia , Clostridium perfringens/ultraestrutura , Enterotoxinas/metabolismo , Hidrólise , Cinética , Microscopia Eletrônica , Especificidade da Espécie , Esporos Bacterianos , TemperaturaRESUMO
The effect of human bile juice and bile salts (sodium cholate, sodium taurocholate, sodium glycochenodeoxycholate and sodium chenodeoxycholate) on growth, sporulation and enterotoxin production by enterotoxin-positive and enterotoxin-negative strains of Clostridium perfringens was determined. Each bile salt inhibited growth to a different degree. A mixture of bile salts completely inhibited the growth of enterotoxin-positive strains of this organism. Human bile juice completely inhibited the growth of all the strains at a dilution of 1:320. A distinct stimulatory effect of the bile salts on sporulation was observed in the case of C. perfringens strains NCTC 8239 and NCTC 8679. The salts also increased enterotoxin concentrations in the cell extracts of the enterotoxin-positive strains tested. No effect on enterotoxin production was detected when an enterotoxin-negative strain was examined.