ABSTRACT
The induction of acid-shock proteins and the degree of acid resistance conferred on Clostridium perfringens by acid shock, and the kinetics of this resistance were determined. A sublethal acid shock at pH 4.5 for 20 min increased the acid tolerance of cells at least fifteenfold. The acquired tolerance was maintained for 3 h after acid treatment. The response of the microorganism to acid shock was also examined by analysis of pulse-labeled proteins. Five acid-shock proteins (molecular weights 120, 84, 58, 45 and 17 kDa) were identified by polyacrylamide gel electrophoresis.
Subject(s)
Clostridium perfringens/metabolism , Bacterial Proteins/biosynthesis , Bacterial Proteins/genetics , Clostridium perfringens/classification , Clostridium perfringens/drug effects , Electrophoresis, Polyacrylamide Gel , Hydrogen-Ion ConcentrationABSTRACT
Clostridium perfringens has been implicated as a causative agent of foodborne poisoning, infectious diarrhea (not associated with foods), gas gangrene, and several veterinary diseases. Fecal carriage of enterotoxigenic strains of this bacterium appears to be important in the development of infectious diarrhea and as a source of C. perfringens contamination of foods. In this work, carriage of this bacterium in feces of a Mexican population was analyzed. C. perfringens was found in 126 of the 200 fecal samples obtained from healthy individuals from northern Mexico. The samples had an average of 7.4 x 10(3) spores per gram, with the elderly population showing the highest levels. Dot blot analyses using a dig-labeled probe specific for the enterotoxin gene showed that 7% of the samples had isolates with toxigenic potential.
Subject(s)
Carrier State/diagnosis , Clostridium perfringens/isolation & purification , DNA Probes , Enterotoxins/genetics , Feces/microbiology , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle AgedABSTRACT
Application of a heat shock (43 to 50 degrees C) applied early during the sporulation process of Clostridium perfringens delayed spore and enterotoxin production. Final levels of heat-resistant spores were similar to the control, but enterotoxin levels were reduced when the heat shock was applied at the third hour of incubation. The response of the microorganism to the heat shock was also examined by analysis of pulse-labeled proteins. Seven heat shock proteins (HSPs) associated with vegetative cells were identified by polyacrylamide gel electrophoresis. Most were localized mainly in the membrane, although one small protein was mostly present in the cytoplasm. Fewer HSPs were detected during sporulation. Two HSPs were immunologically related to the GroEL and DnaK HSPs from Lactobacillus lactis and Escherichia coli, respectively.
Subject(s)
Clostridium perfringens/growth & development , Clostridium perfringens/metabolism , Enterotoxins/biosynthesis , Heat-Shock Proteins/biosynthesis , Hot Temperature , Blotting, Western , Clostridium perfringens/chemistry , Electrophoresis, Polyacrylamide Gel , Heat-Shock Proteins/analysis , SporesABSTRACT
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.
Subject(s)
Clostridium perfringens/isolation & purification , Spices/microbiology , Clostridium perfringens/genetics , Colony Count, Microbial , DNA, Bacterial/analysis , Enterotoxins/genetics , Mexico , Molecular Probe Techniques , Product Surveillance, PostmarketingABSTRACT
Dilution methods were employed to determine the effect of ethanolic extracts of Agave lecheguilla Torr. (Agavaceae), Baccharis glutinosa Pers. (Compositae) and Larrea tridentata (DC.) Cov. (Zygophyllaceae) on growth of yeasts, molds and bacteria. The three extracts analyzed showed good antimicrobial activity against more than one organism. The minimal inhibitory concentration of the extracts was also determined.
Subject(s)
Anti-Infective Agents/pharmacology , Plant Extracts/pharmacology , Anti-Bacterial Agents , Bacteria/drug effects , Fungi/drug effects , Mexico , Microbial Sensitivity Tests , Plants, MedicinalABSTRACT
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.
