Cloned lysins could be used as antimicrobials

The microbiologist and research leader with the Poultry Microbiological Safety Research Unit for the Agricultural Research Service of the Department of Agriculture said in an interview with JAVMA News that he hopes to use lysins cloned from the genomes of bacteriophages, or viruses that lyse bacteria, to target and kill specific species or subspecies of pathogenic bacteria. The lytic enzymes are produced by bacteriophages to digest cell walls and escape from within bacteria after infecting the host and reproducing. Dr. Seal is among researchers whose work indicates lysin genes can be cloned and expressed, with the resulting enzyme used to attack the cell walls of bacteria from the outside, all without requiring introduction of intact bacteriophages.

For example, Dr. Seal was one of the researchers on a study that indicated Clostridium perfringens-targeting bacteriophage lysin genes could be cloned into Escherichia coli and that the gene product could then be used to lyse strains of C perfringens, according to a Journal of Agriculture and Food Chemistry report published online in September.

However, Dr. Seal said lytic enzymes produced by E coli could not be used in commercial animal feed, and further study is needed to determine whether the enzymes can be developed for expression in yeast.

Such enzymes could be used instead of, or in conjunction with, current antimicrobials, depending on factors such as the types of pathogens involved, Dr. Seal said. He thinks research has proved the approach is valid, and he hopes the C perfringens application will be evaluated in a trial involving chicken feed following large-scale production of the enzyme.