ABSTRACT
Oral inoculation of neonatal MFI mice with enterotoxigenic strains of Escherichia coli that possessed the K99 or F41 antigen or both resulted in severe diarrhoea with high mortality. The diarrhoea was associated with increased fluid in the gut, greatly increased numbers of E. coli in gut homogenates and reduced weight gain compared to control animals. Further studies with strain B44 demonstrated greatly increased numbers of E. coli on the surface of the intestinal mucosa and haemo-concentration. The infection was transmissible between litter-mates. There was no evidence of invasion of the intestinal tissue of infected animals. Gnotobiotic Balb C mice and endotoxin-resistant mice were susceptible to oral inoculation with bovine enterotoxigenic E. coli strains, but neonatal rats were not susceptible to infection with enterotoxigenic E. coli strains B44 or 431. Porcine strains of E. coli that possessed K88 or 987P antigen did not infect neonatal MFI mice but an "atypical" porcine strain (431) which possessed both K99 and F41 antigens caused diarrhoea and a high mortality. The disease in neonatal mice resembled acute diarrhoea caused by these bacteria in other species, particularly the calf, and the model should be of value in assessing the efficacy of therapeutic agents.
Subject(s)
Antigens, Bacterial , Bacterial Toxins , Diarrhea/microbiology , Escherichia coli Infections/microbiology , Escherichia coli Proteins , Escherichia coli/pathogenicity , Animals , Animals, Newborn , Antigens, Surface/analysis , Bacterial Outer Membrane Proteins/analysis , Diarrhea/pathology , Disease Models, Animal , Endotoxins , Enterotoxins/biosynthesis , Escherichia coli/immunology , Escherichia coli/metabolism , Escherichia coli Infections/pathology , Escherichia coli Infections/transmission , Germ-Free Life , Ileum/microbiology , Intestinal Mucosa/microbiology , Mice , Mice, Inbred BALB C , Mice, Inbred C3H , Rats , VirulenceABSTRACT
Experimental or naturally acquired subclinical infections with rotavirus caused a significant increase in mortality of infant mice after challenge with enterotoxigenic Escherichia coli B44.
Subject(s)
Diarrhea/etiology , Escherichia coli Infections/complications , Rotavirus Infections/complications , Animals , Antibodies, Viral/analysis , Bacterial Toxins , Enterotoxins , Enzyme-Linked Immunosorbent Assay , Escherichia coli Proteins , Mice , Mice, Inbred BALB CSubject(s)
Adrenergic alpha-Agonists/pharmacology , Bacterial Toxins , Enterotoxins/pharmacology , Adrenergic alpha-Antagonists/pharmacology , Animals , Chlorides/metabolism , Escherichia coli Proteins , In Vitro Techniques , Intestinal Absorption/drug effects , Mice , Rabbits , Rats , Receptors, Adrenergic, beta/drug effects , Sodium/metabolism , Water-Electrolyte Balance/drug effectsABSTRACT
Escherichia coli P16 infant mouse active heat-stable enterotoxin may be fractionated into two distinct active moieties by ion-exchange chromatography, Sephadex G-25 chromatography, and isoelectric focusing.
Subject(s)
Bacterial Toxins/isolation & purification , Enterotoxins/isolation & purification , Escherichia coli/analysis , Chromatography, Gel , Chromatography, Ion Exchange , Hot Temperature , Isoelectric FocusingABSTRACT
Several adsorbent materials were evaluated for their ability to bind Escherichia coli enterotoxins. Cholestyramine, a strong anion-exchange resin, bound the heat-labile and the heat-stable types of enterotoxin and reduced significantly their effects in some animal models. However, its efficacy in the treatment of diarrhoeic piglets appeared to be adversely affected by the presence of milk in the alimentary tract.
Subject(s)
Bacterial Toxins/metabolism , Cholestyramine Resin/metabolism , Enterotoxins/metabolism , Escherichia coli , Adsorption , Animals , Cholestyramine Resin/therapeutic use , Diarrhea/drug therapy , Intestinal Absorption , Milk , SwineABSTRACT
Infant rabbits were shown to respond to Escherichia coli heat-labile enterotoxin by a consistent increase in intestinal fluid content, which was maximal 5 h after oral dosing. Infant rabbits could be used in a simple quantitative assay for heat-labile E. coli enterotoxin based on the ratios of gut weight to remaining body weight 5 h after oral dosing. Infant rabbits remained responsive to heat-labile enterotoxin up to 14 days of age, after which their gastric pH became low enough to destroy the enterotoxin. Rabbits that had been deprived of food before being dosed had a reduced gastric pH and a reduced response to the enterotoxin. Lincomycin andmitomycin C were found not to increase th e yield of heat-labile enterotoxin from E. coli strain P307.
Subject(s)
Enterotoxins/analysis , Escherichia coli/analysis , Intestines/drug effects , Animals , Dose-Response Relationship, Drug , Drug Stability , Enterotoxins/biosynthesis , Enterotoxins/pharmacology , Escherichia coli/metabolism , Hot Temperature , Lincomycin/pharmacology , Mitomycins/pharmacology , RabbitsABSTRACT
Partially purified heat-stable enterotoxin obtained from Escherichia coli strain F11/P155 caused an accumulation of cyclic GMP in the intestines of 8-day-old mice.
Subject(s)
Bacterial Toxins/pharmacology , Cyclic GMP/metabolism , Enterotoxins/pharmacology , Escherichia coli , Intestinal Mucosa/metabolism , Animals , Cyclic AMP/metabolism , MiceABSTRACT
Escherichia coli P16 was shown to produce two heat-stable toxins (ST) with differing biological activity. The toxins were separated by methanol extraction, and the first, STa, was methanol soluble, partially heat stable, active in neonatal piglets (1 to 3 days old) and infant mice, but inactive in weaned pigs (7 to 9 weeks old); the second, STb, was methanol insoluble, active in weaned pigs and rabbit ligated loops, but inactive in infant mice. It is therefore suggested that use of suckling mice as indicators of ST production will fail to identify certain ST-producing strains.
Subject(s)
Enterotoxins/biosynthesis , Escherichia coli , Methanol , Animals , Cattle , Dose-Response Relationship, Immunologic , Evaluation Studies as Topic , Hot Temperature , Mice , Rabbits , Solubility , SwineABSTRACT
While studying the involvement of cyclic adenosine 3',5'-monophosphate (cAMP) in the fluid secretion caused by heat-stable enterotoxin (ST) from Escherichia coli P16 in infant mice, it was noted that the culture filtrate containing ST also contained large amounts of cAMP. The present paper details attempts to obtain a cAMP-free ST preparation. The organisms were grown in a defined medium, and the heated culture filtrate was concentrated by reverse osmosis. After methanol extraction of the filtrate, which removed 80% of the nonactive solids, the methanol-soluble ST was further purified by gel filtration through a Sephadex G-10 column. The first fraction recovered after gel chromatography contained ST with a negligible amount of cAMP. Treatment with methanol did not adversely affect the enterotoxic activity. Certain parameters of the infant mouse model have been investigated, and using our ST preparation it has been found that animals remain responsive up to 15 days of age with an optimum assay time of 2 h after toxin challenge.
Subject(s)
Bacterial Toxins , Enterotoxins , Escherichia coli , Age Factors , Animals , Animals, Newborn , Bacterial Toxins/isolation & purification , Bacterial Toxins/pharmacology , Chromatography, Gel , Dose-Response Relationship, Drug , Enterotoxins/isolation & purification , Enterotoxins/pharmacology , Hot Temperature , Methanol , Mice , Solubility , Time FactorsSubject(s)
Limulus Test , Penicillins/pharmacology , Animals , Cloxacillin/pharmacology , Protein BindingABSTRACT
The ability of antisera to lipid A, induced in rabbits by immunization with lipid A complexed to various carriers, to protect mice against gram-negative infection and to inhibit the fluid loss caused by an enteropathogenic strain of Escherichia coli in the piglet ligated gut was investigated. No significant protection was obtained in either case, although passive hemolysis and quantitative precipitation tests showed the presence of antilipid A antibodies in the sera. Fluorescent antibody studies suggest that the lipid A is in a cryptic position on the surface of smooth strains of gram-negative bacteria.