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Biomedical subjects

B C Hobbs

Publications and source records attributed to B C Hobbs.

At least 19 recordsLinked to original sources

Shigella isolates in stool.

A total of 447 Shigella strains were isolated from stool samples during 1989-1991. Of these 270 (60%) were from children. Among the different species and serotypes Sh. flexneri 60 (13.4%) and Sh. sonnei Phage 139 (65%) were the most frequently isolated strains. 154 (34.4%) strains were resistant to three and 179 (40%) to more than three antibiotics. Some strains of Shigella were found to be resistant to furazolidine and neomycin.

Adult

Acinetobacter meningitis.

10,468 CSF samples from cases of meningitis in different age groups were cultured during 1988-1991. Acinetobacter calcoaceticus was isolated in 12 (5.6%) of 211 positive cultures. The strain were 100% resistant to ampicillin, cotrimoxazole and tetracycline 50% resistant to cephazolin gentamicin and kanamycin but 100% susceptible to chloramphenicol.

Acinetobacter

Escherichia coli O 27 in adult diarrhoea.

Escherichia coli O 27 H 7 was found in 16 stool samples submitted during a Caribbean cruise (Cruise Z) by 29 patients reporting with diarrhoea. A retrospective search revealed E. coli O 27 H 7 in 11 of 20 and 2 of 14 stool cultures from patients on two previous cruises (Y and X respectively) and in a culture from fresh cream (Cruise Y). The repeated occurrence of E. coli O 27 H 7 in the absence of any other apparent cause suggested that this serotype may have been responsible for the diarrhoea. The results of pathogenicity tests suggested that this strain elaborated heat-stable (ST) enterotoxin. The possibility that food may have been the vector is discussed.

Adult

An international serotyping system for Clostridium perfringens (welchii) type A in the near future.

The importance of Clostridium perfringens (welchii) type A as an agent of clinical infection in man is well known and, more recently, its role as a cause of human food poisoning has become well recognized. There has been a growing awareness of the need for a system of finer subdivision within the type A group for better understanding of the epidemiology of Cl. perfringens in infections and food poisoning. A set of antisera used for typing and developed in the Food Hygiene Laboratory over a period of some years has proved to be of considerable value in this respect; it is now being integrated with similar sets of antisera prepared independently in the USA and Japan to form a comprehensive and internationally workable serotyping scheme. Negotiations regarding commercial production of the main type antisera are now in progress. It is hoped that serotyping facilities will be available in the near future to workers and institutions concerned with Cl. perfringens type A.

Clostridium Infections

The effect of two methods of cooking and cooling on Clostridium welchii and other bacteria in meat.

A comparison was made of beef cooked in conventional and moist air (Rapidaire) ovens. In both large (ca. 4.5 kg.) and small (ca. 2.7 kg.) joints, spores of Clostridium welchii survived after cooking but vegetative cells, Escherichia coli, and Staphylococcus aureus, did not, regardless of the type of oven used.Cooling at room temperature after cooking permitted growth of Cl. welchii. Although some multiplication also occurred in the centre of large roasts cooled under refrigeration, the viable counts were considered too low to constitute a potential health risk.

Animals

The use of gamma radiation for the elimination of Salmonella from frozen meat.

The use of a gamma radiation process for the elimination of Salmonella from frozen meat is considered with particular reference to the treatment of boned-out horsemeat and kangaroo meat imported into the UK and intended for use as pet meat.Examination of dose/survival curves produced for several serotypes of Salmonella in frozen meat shows that a radiation dose of 0.6 Mrad. will reduce a population by at least a factor of 10(5). The influence on the radiation resistance of salmonellas of such factors as preirradiation growth in the meat and temperature during irradiation have been examined and considered. It is also demonstrated with both preinoculated and naturally contaminated meat that postirradiation storage in the frozen state does not lead to the revival of irradiated salmonellas.The properties of Salmonella survivors deliberately produced in meat using conditions of irradiation designed to simulate a commercial process are studied after six recycling treatments through the process. There were no important changes in characteristics normally used for identification of Salmonella but radiation resistance was lowered. Survivors grown in situ in meat after irradiation showed an abnormally long lag phase, and removal of competitive microflora in meat by the radiation treatment can influence the growth of salmonellas.

Animals