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Biomedical subjects

R J Gilbert

Publications and source records attributed to R J Gilbert.

At least 127 records · Page 7Linked to original sources
PubMed1980

Application of serological typing to the investigation of outbreaks of Clostridium perfringens food poisoning, 1970-1978.

Serological typing was used as an epidemiological tool in the investigation of 524 outbreaks of Clostridium perfringens food poisoning in the United Kingdom and 37 outbreaks in other countries. Five thousand five hundred and fifty-four (77%) of 7245 strains of C. perfringens associated with the 561 outbreaks were typable with the 75 Food Hygiene Laboratory antisera; in 354 (63%) of these outbreaks a specific serotype was established as being responsible for the outbreak. An assessment is made of the ability of two additional sets of antisera, prepared against 34 American and 34 Japanese strains of C. perfringens, to increase the number of strains which can be typed. The extent of cross-reaction between the three sets of antisera was determined and the results are discussed in relation to the source and history of the type strains.

Clostridium Infections↗
PubMed1980

Laboratory induced variations in a standardized Salmonella isolation method.

Four microbiologists from four European laboratories came together to a single laboratory for two weeks and during that period examined 100 samples of minced meat artificially contaminated with salmonellae and 100 naturally contaminated samples using a standardized technique. No significant differences were found between the results obtained by the different analysts with 92 to 97 of the artificially contaminated and 30 to 42 of the naturally contaminated samples being found positive. Over a further period of eight weeks, these analysts examined the same number of samples in their own laboratories again using an identical procedure. There were no significant containing approximately 100 salmonellae per gram but significant differences (43 to 93) were found in isolation rates from the artificially contaminated samples copntaining approximately 1 salmonella per gram. The differences in findings between the first and the second part of the experiments may have been caused fairly by variations in media preparation, temperature of incubators, storage conditions of media and thawing conditions of samples etc., and secondly by differences in working conditions such as performing only one task during two weeks in contrast to examining the samples as part of the daily routine. At high levels of contamination, these factors do not appear to have an important influence on the performance of a laboratory.

Animals↗
PubMed1980

Botulism.

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Botulism↗
PubMed1979

Survival and growth of non-cholera vibrios in various foods.

A study was made of the growth of three strains of non-cholera vibrio in a range of foodstuffs and of the effect of temperatures and pH on their ability to grow. Growth was tested at 4 degrees, 10 degrees, 22 degrees, 30 degrees, 37 degrees and 43 degrees C in a range of foods likely to be incorporated into cold hors d'oeuvres, e.g. egg, cream, rice, cold meat, seafood, aspic and mayonnaise. Non-cholera vibrios grew well in all these foods except mayonnaise, the rate of growth increasing with increased temperature of storage. At acid pH values the organisms died or grew very poorly but growth improved as the pH became more alkaline. None of the three strains showed any resistance to heat, an initial inoculum of greater than 10(7) organisms/g was reduced to less than 100 organisms/g in 2--3 min at 55 degrees C.

Food Microbiology↗
PubMed1979

Food poisoning in hospitals in Scotland.

A review of 50 hospital-based outbreaks of food poisoning which were reported in Scotland during 1973--7, is described. At least 1530 persons consuming hospital-prepared food were involved. Thirty-one episodes were associated with Clostridium perfringens (C. welchii), 11 were due to food-borne salmonella infection, three to enterotoxigenic Staphylococcus aureus, and five incidents were of undetermined aetiology. This differs noticeably from the experience in England and Wales where salmonellas appear to predominate as the main cause of hospital outbreaks. Twenty-two incidents occurred in hospitals for psychiatric or mentally subnormal patients, and ten others were located in geriatric units. Only 33 hospitals were involved in the 50 outbreaks as nine hospitals experienced two or more episodes. The role of the hospital in the occurrence of food poisoning may be over-emphasized in comparison with other catering establishments, as outbreaks are more readily recognized and laboratory facilities are usually available for investigation, but it is also believed that many episodes may not be reported. The peculiar problems of the hospital-catering service and particularly those of the older long-stay hospitals, are discussed in relation to preventive measures which would minimize the hazards of food poisoning.

Aged↗
PubMed1979

Properties and production characteristics of vomiting, diarrheal, and necrotizing toxins of Bacillus cereus.

Evidence is provided that the enterotoxin of Bacillus cereus variously described in the literature as diarrheagenic toxin, diarrheal agent, fluid accumulation factor, vascular permeability factor, dermonecrotic toxin, and intestinonecrotic toxin is a single relatively unstable protein of molecular weight approximately 50,000 and isoelectric point of the order of 4.9. It is presumed to be the enterotoxin responsible for the diarrheal-type B. cereus food poisoning syndrome and it may also be the pyogenic and pyrogenic factor in nongastrointestinal B. cereus infections of man and animals. The enterotoxin is a vegetative growth metabolite produced to one degree or another by almost all B. cereus strains and is readily separated from phospholipase and heat-labile cereolysin but less readily differentiated from a heat-stable hemolysin. It is lethal to mice but may also be separable from another mouse lethal factor by electrofocusing. The emetic toxin responsible for the vomiting-type B. cereus food poisoning syndrome is clearly distinguishable from the diarrheal and other toxic factors and appears to be a highly stable compound of molecular size less than 5000.

Animals↗
PubMed1979

Severe clinical conditions associated with Bacillus cereus and the apparent involvement of exotoxins.

Twenty-one cases of infection with Bacillus cereus are summarised. The histories supplied showed that at least 15 of these were associated with severe or potentially severe symptoms including two deaths. Analysis of the production of exotoxins, including haemolysin and phospholipase, by these strains is given, and the relevance of these metabolites to the severity of the condition is discussed. Three incidents of bovine mastitis resulting from B. cereus and involving three deaths are also included. The observations presented here together with those of previous reports which are reviewed indicate that B. cereus may be of clinical importance, not just an opportunist but also as an agent of potentially severe infections in its own right.

Bacillus cereus↗
PubMed1979

ICMSF methods studies. XII. Comparative study for the enumeration of Clostridium perfringens in feces.

As the second phase of an international comparative study for the enumeration of Clostridium perfringens, four methods were compared for "total" and spore counts of C. perfringens in fecal specimens: the SFP (Shahidi-Ferguson perfringens) agar (A), TSC (tryptose-sulfite-cycloserine) agar (B), SC (sulfite-cycloserine) agar (C), and neomycin blood agar (D) methods. In both the total and spore count procedures, the confirmed C. perfringens counts in method D were lower than in methods A, B, and C. Little differences among methods were found in the percentages of presumptive colonies confirmed as C. perfringens. The nonspecific counts in methods A and D were generally greater than in B and C, but nonspecific microorganisms did not interfere in the enumeration of C. perfringens spores by any of the four methods. In overall performance, methods B and C were superior to A and D. The mean C. perfringens spore count was only 0.17 log lower than the mean total count. Spore counts alone are, therefore, adequate in investigations of C. perfringens outbreaks.

Bacteriological Techniques↗
PubMed1978

Infant botulism in England.

A 24-week-old girl presented with an acute illness characterised by constipation at 22 weeks, followed a week later by the sudden onset of generalised weakness, poor feeding, and a weak cry. Laboratory examination of her stools confirmed the clinical diagnosis of infant botulism.

Acute Disease↗
PubMed1978

Enumeration of micro-organisms in food: a comparative study of five methods.

Five methods for the enumeration of micro-organisms in food (pour plate, surface spread plate, surface drop, agar droplet, and microdilution) were used in parallel to examine 100 samples selected from a wide range of food products. Statistical analyses of the results showed that the regression and correlation coefficients between the methods were highly significant; the lowest correlation coefficient derived for any pair of methods was 0.979. A variation in count between the methods of less than 0.5 log10 cycles was given by 98% of the samples. Analysis of the operation times and material requirements of each method showed that substantial savings in cost, time, space and support labour were achieved with the microdilution and agar droplet techniques as compared with the conventional pour plate and spread plate methods.

Food Contamination↗
PubMed1978

ICMSF methods studies. X. An international comparative study of four media for the enumeration of Staphylococcus aureus in foods.

An international comparative study, undertaken by six laboratories to assess the performance of four selective media commonly used for the enumeration of Staphylococcus aureus in foods, revealed that Baird-Parker agar performed most satisfactorily. There was no significant difference among milk salt, tellurite polymyxin egg yolk, and kalium rhodanid - actidione - natriumazid - eigelb - pyruvat (KRANEP) agars. The type of food examined appeared to influence the performance of the media, but no specific patterns could be determined. Cultures yielding 3+ and 4+ coagulase reactions are most likely to possess thermostable nuclease activity, and are therefore most likely to be S. aureus.

Culture Media↗
PubMed1978

Comparative studies on the isolation of salmonella from minced meat.

Comparative studies carried out in four laboratories revealed that in the examination of frozen or fresh minced meat samples tryptone soya broth and glucose mineral salts medium used for pre-enrichment gave the same results as buffered peptone water. The three tetrathionate media (Cardiff formula, Difco and Oxoid) used for enrichment after pre-enrichment, yielded approximately the same number of positive samples and about the same number of frozen and cooled samples was found positive when data of all four laboratories were considered. Between laboratories a considerable variation in results was found. This indicates the necessity to conduct comparative trials in more than one laboratory to validate the use of a specific method for regulatory purposes.

Bacteriological Techniques↗
PubMed1977

An unusual outbreak of food-poisoning associated with meals-on-wheels.

An outbreak of food-poisoning after a meals-on-wheels lunch affected 49 persons, 1 of whom died. Bacillus cereus serotype 10 and Bacillus licheniformis were isolated in large numbers from many of the patients including the deceased and from the remains of the meal. Clostridium perfringens (C. welchii) serotype 68, which was isolated from many of the patients and the deceased but not from the food, may also have been responsible. Food kept warm during distribution can produce an ideal environment for bacterial multiplication and similar outbreaks may occur again.

Aged↗
PubMed1977

Serotypes of Bacillus cereus from outbreaks of food poisoning and from routine foods.

A provisional serotyping scheme was used to type cultures of Bacillus cereus from 84 outbreaks of food poisoning in seven countries; 283 of the 337 (84%) cultures tested were typable. In 35 of the 61 outbreaks associated with a vomiting-type syndrome, foods, clinical specimens or both yielded H-serotype 1 only. Type 1 strains together with other sterotypes were isolated in seven outbreaks. In 14 outbreaks types 3, 4, 5, 8 or a mixture of serotypes were present. Untypable strains were isolated in five outbreaks. Two of the nine diarrhoeal-type outbreaks yielded serotype 1 only. Types 2, 6, 8, 9, 10 and a mixture of type 12 and an untypable strain appeared to be responsible for one outbreak each. Although 16 of the 18 recognized serotypes were present among cultures of B. cereus from various routine foods, only 156 of the 400 (39%) isolates tested were typable.

Australia↗