Salmonella isolated from rooibos tea.

Various Salmonella serovars were isolated from rooibos tea, a natural, untreated agricultural product. The results of a study to identify the serovars is reported. The possibility of lizard origin is discussed and the low pathogenicity of the salmonellae isolated is highlighted.

Resistance to various antibiotics of Salmonella and Escherichia coli isolated from registrable farm feeds.

Resistance to 20 antibiotics of 128 Salmonella and 97 Escherichia coli isolates from various registrable farm feeds was determined. A high frequency of comparatively low levels of resistance was found in both the Salmonella and E. coli isolates. This, together with an elevated frequency of multiple resistance, indicates that problems related to an effective transfer in bacterial populations of resistance to certain antibiotics are a distinct possibility. The addition of antibiotics, such as penicillin and tetracyclines, to animal feeds can create conditions for rapid selection amongst bacteria resistant to antibiotics. The numbers of resistant bacteria in the animal environment may be increased and may lead to the development of veterinary and human health problems from the possible transfer of antimicrobial resistance from animal pathogens to human pathogens or spreading in the human population of animal pathogens resistant to antibiotics. There is a need for caution in the use of antibiotics, particularly in animal feeds. Extended survey of, and epidemiological research on, farm feeds, manufacturing mills and animal production units are emphasized.

A study for the differentiation of Actinobacillus seminis, A. actinomycetem-comitans, Histophilus ovis and Pasteurella haemolytica.

By using well-defined techniques under optimum conditions it is possible adequately to define the biochemical characteristics of typical A. seminis strains. A. seminis can be distinguished from Histophilus ovis on the latter's distinctive colony morphology, but it cannot be distinguished from Actinobacillus actinomycetem-comitans. These organisms, however, can be differentiated from Pasteurella haemolytica on serological grounds and the latter's greater pathogenicity for mice. It is appreciated, however, that intermediate forms occur which cannot as yet be satisfactorily allocated to any of the above-mentioned genera.