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P R EDWARDS

Publications and source records attributed to P R EDWARDS.

At least 19 recordsLinked to original sources
PubMed1963

Resistance of salmonellae isolated in 1962 to chloretetracycline.

Among 652 salmonellae examined, Salmonella typhimurium displayed a much higher incidence of resistance to chlortetracycline than did other serotypes. Among S. typhimurium cultures from man, the incidence of resistance (38%) increased markedly over that of cultures isolated 3 years previously (13.9%), whereas a similar increase was not noted among cultures from fowls. Resistance among cultures from animals other than fowls (72.5%) was due largely to the high incidence of resistance among cultures from bovine sources (93.7%).

Animals↗
PubMed1962

Natural occurrence of induced or artificial flagellar antigens in Salmonella newport.

Douglas, G. W. (Communicable Disease Center, Atlanta, Ga.), Alma C. McWhorter, and P. R. Edwards. Natural occurrence of induced or artificial flagellar antigens in Salmonella newport. J. Bacteriol. 83:348-350. 1962.-Two epidemiologically related cultures of Salmonella newport, which possessed naturally occurring artificial or induced antigens in phase 2, were studied. It was demonstrated that similar antigens may be obtained by cultivation of normal S. newport cultures in appropriate antisera. These antigens were assigned the symbols 1,12. The diagnostic problems posed by the natural occurrence of induced antigens are mentioned.

Humans↗
PubMed1962

A culture of Salmonella infantis of complex antigenic constitution.

Edwards, P. R. (Communicable Disease Center, U.S. Public Health Service, Atlanta, Ga.), A. C. McWhorter, and G. W. Douglas. A culture of Salmonella infantis of complex antigenic constitution. J. Bacteriol. 84:95-98. 1962-An antigenically complex Salmonella serotype (6,7:z(49),r:z(49),1,5), in which the antigen z(49) is a major component of both phases, is described. Through loss variation, this form gives rise to cultures identical with S. infantis (6,7:r:1,5). Attention is drawn to the similarity of its behavior to that of S. montgomery and S. salinatis, and the possible origin of such complex forms is discussed briefly. The organism is not assigned a name, but is considered simply as a complex form of S. infantis.

Antigens↗
PubMed1962

Natural occurrence of four reversible flagellar phases in cultures of Salmonella mikawashima.

Edwards, P. R. (Communicable Disease Center, U.S. Public Health Service, Atlanta, Ga.), R. Sakazaki, and I. Kato. Natural occurrence of four reversible flagellar phases in cultures of Salmonella mikawashima. J. Bacteriol. 84:99-103. 1962-Study of cultures of Salmonella mikawashima isolated from reptiles revealed that single colonies of some strains contained three distinct H phases and that colonies of other cultures contained four such phases. In addition to the usual y and e,n,z(15) phases of S. mikawashima, two additional antigens which occurred naturally and which were identical with naturally occurring H antigens of the Arizona group, designated z(47) and z(50), were recognized. Some cultures were represented by the formula 6,7:y:-e,n,z(15):z(47), some by 6,7:y:e,n,z(15):z(50), and some by 6,7:y:e,n,z(15):z(47):z(50). The four H antigens were serologically unrelated, and each could be caused to revert to the others. Spontaneous reversions also were observed. The organisms underwent loss variation, and stable diphasic forms were encountered in which the e,n,z(15) phase occurred in conjunction with y, z(47), or z(50), indicating that the three antigens may be alternative forms of phase 1.

Antigens, Bacterial↗
PubMed1961

Resistance of Salmonellae isolated in 1959 and 1960 to tetracyclines and chloramphenicol.

The resistance of cultures of Salmonella typhimurium to tetracyclines and chloramphenicol has been examined periodically. Although none of 200 cultures isolated prior to 1948 was resistant to the antibiotics, 5% of 100 cultures from man and 9% of 100 cultures from fowls which were isolated in 1956 and 1957 were resistant to tetracyclines. Among 158 cultures isolated from man and 100 cultures isolated from fowls in 1959 and 1960, 13.9 and 29%, respectively, were resistant to tetracyclines. In the last series, cultures resistant to chloramphenicol were found for the first time. Among 150 cultures of other Salmonella serotypes from man and 137 similar cultures isolated from fowls in 1959 and 1960, 5.3 and 8%, respectively, were found resistant to tetracyclines. There is no obvious explanation for the higher percentage of resistant strains occurring in S. typhimurium than in other serotypes.

Anti-Bacterial Agents↗
PubMed1961

Lysine-iron agar in the detection of Arizona cultures.

A lysine-iron agar is described and recommended for the detection of Arizona strains which ferment lactose rapidly. Black colonies which appear on bismuth sulfite agar should be transferred to the medium. Salmonellae and Arizona cultures produce a distinctive reaction since they are the only recognized groups of enteric bacteria which regularly produce lysine decarboxylase rapidly and form large amounts of hydrogen sulfide. Use of the medium is particularly recommended in the examination of specimens from enteric infections in which shigellae and salmonellae are not detected.

Agar↗