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L R Ward

Publications and source records attributed to L R Ward.

103 records · Page 6Linked to original sources
PubMed1980

Plasmid-encoded trimethoprim resistance in multiresistant epidemic Salmonella typhimurium phage types 204 and 193 in Britain.

Multiresistant strains of Salmonella typhimurium phage types 204 and 193 appeared in calves in 1977 and then spread epidemically in cattle. Food poisoning is the main route by which drug-resistant strains from cattle are spread to man, and by the end of 1979 these two multiresistant strains had been identified in 290 cases of human salmonellosis in Britain. Trimethoprim-resistant S typhimurium were rare until a strain of a new phage type, designated type 204c, spread in cattle in 1979. All isolations of type 204c were trimethoprim resistant. Trimethoprim had been used to treat cattle and this usage has probably contributed to the establishment of type 204c and the increased incidence of trimethoprim-resistant strains. The responsibility to prevent or control drug resistance in bovine S typhimurium lies with the veterinary profession, and more stringent regulatiions governing the use of antibiotics in animals bred for food may be necessary.

Animals↗
PubMed1980

Epidemic spread of Salmonella hadar in England and Wales.

Salmonella hadar is now the second commonest serotype isolated from cases of food poisoning in England and Wales. Turkeys are the main reservoir of the organism and there is an urgent need to eradicate it from the breeding stocks; though this would be expensive, the cost must be balanced against the cost of treating the human disease.

Animals↗
PubMed1978

Correlation of phaga type, biotype and source in strains of Salmonella typhimurium.

A series of 2092 cultures of Salmonella typhimurium isolated from human, animal and other sources in 57 countries were differentiated into 204 phage types and 19 primary and 147 full biotypes. Different biotypes belonged to the same phage type and different phage types to the same biotype, so the combination of typing methods differentiated strains more finely than either method alone: 574 different ;phage type/biotypes' were distinguished in 1937 cultures belonging to the 204 recognized phage types.The combination of biotyping with phage-typing was valuable in studying the phylogeny and spread of epidemic strains by distinguishing clones of different biotype within the same phage type and by confirming the relationship between cultures isolated from widely dispersed clones and that between cultures isolated before and after a clone had undergone variation in phage type, biotype, colicin type or antibiotic-sensitivity pattern.A widespread outbreak of infection with S. typhimurium phage type 141 in Scotland comprised independent dissemination of three clones of different biotypes, 1f, 9f and 31bd. During its epidemic spread in cattle in Britain between 1962 and 1969, another strain underwent variations in phage type (type 44 to type 29), biotype (type 26a to types 26d, 26bd, 26dgi, 26dz and 26i) and antibiotic sensitivity. A group of 275 non-fimbriate, non-inositol-fermenting and non-rhamnose fermenting (FIRN) strains, particularly associated with avian infections and thought to be clonal in origin, contained 27 phage types and 22 full biotypes in the primary biotypes 29-32.

Bacteriophage Typing↗
PubMed1977

Bacteriophage-typing designations of Salmonella typhimurium.

The phage-typing scheme of Callow (1959) has been extended. The original number of types was 34; this has now risen to 207. Tables are presented which show the provisional type designations and the definitive designations now being introduced.

Bacteriophage Typing↗
PubMedDate not supplied

Molecular fingerprinting of multidrug-resistant Salmonella enterica serotype Typhi.

For epidemiologic investigations, the primary subdivision of Salmonella Typhi is vi-phage typing; 106 Vi-phage types are defined. For multidrug-resistant strains the most common types have been M1 (Pakistan) and E1 (India, Pakistan, Bangladesh, and the Arabian Gulf); a strain untypable with the Vi phages has been responsible for a major epidemic in Tajikistan. Most often, isolates from the Indian subcontinent have been resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, tetracyclines, and trimethoprim; but in the 1997 Tajikistan outbreak, the epidemic strain was also resistant to ciprofloxacin. For multidrug-resistant strains, subdivision within phage type can be achieved by plasmid profile typing and pulsed-field gel electrophoresis.

Asia↗
PubMedDate not supplied

Decreased susceptibility to ciprofloxacin in Salmonella enterica serotype typhi, United Kingdom.

In 1999, 23% of Salmonella enterica serotype Typhi isolates from patients in the United Kingdom exhibited decreased susceptibility to ciprofloxacin (MIC 0.25-1.0 mg/L); more than half were also resistant to chloramphenicol, ampicillin, and trimethoprim. Increasing numbers of treatment failures have been noted. Most infections have been in patients with a recent history of travel to India and Pakistan.

Anti-Infective Agents↗