A new scheme for phage typing Salmonella bareilly and characterization of typing phages

Salmonella phages examined in the electron microscope

Out of 177 surveyed bacteriophages, 161 (91%) are tailed and belong to the Myoviridae, Siphoviridae, and Podoviridae families (43, 55, and 59 viruses, respectively). Sixteen filamentous or isometric phages are members of the Inoviridae, Leviviridae, Microviridae, and Tectiviridae families (9%). Many tailed phages belong to established phage genera (P22, T1, T5, and T7), which are widespread in enterobacteria and other Gram-negatives of the Proteobacteria phylum.

Bacteriophage typing in Salmonella bareilly

A total of 675 strains of Salmonella bareilly received from different parts of India and France during 1959-92 were phage typed using six bacteriophages. Overall typability achieved was 90.8% with 23 distinct phage types excluding a group of untypable strains. Phage types have been defined in octal code. Simpson's coefficient was applied for diversity index having a value of 0.839. This system was found to be reproducible, stable and epidemiologically useful.

Bacterial typing methods suitable for epidemiological analysis. Applications in investigations of salmonellosis among livestock

The ability to subtype bacteria by typing methods provides the bacteriologist with a powerful means to identify relationships between bacteria. This knowledge is used to identify routes of disease transmission among livestock and from livestock to humans. In the present paper, the principles of bacterial typing and the most commonly applied typing methods for use in veterinary public health are discussed in the context of their application in the investigation of salmonella epidemiology. Typing methods are now routinely used in most investigations on this subject and have provided insight into routes of transmission, reservoirs of infection and mechanisms of persistent infection. Under the EC order on zoonotic diseases, extended surveillance on the presence of zoonotic bacteria in livestock must be expected. To receive the maximum benefits of this surveillance, selected typing methods must be applied to all isolates of e.g. salmonella. At present, serotyping, and phage typing where applicable, are the most obvious choices for continuous surveillance of this organism. Random amplification of polymorphic DNA (PCR based typing) may have the potential for allocating strains into relevant groups quicker and without the requirement for additional manpower, and this method may be preferred in future.

A study of the epidemiology of Salmonella bareilly in India using a new phage-typing system

A total of 637 strains of Salmonella bareilly received from different parts of India between 1959 and 1985 were phage typed using five locally isolated wild phages. The overall typability was 94.5% and 11 different phage types could be defined. Phage types 10 and 1 were the most prevalent and the geographical and source distribution is described.