Professor Emeritus John Tagg's story is both fascinating and inspiring.
It all started with John’s first significant encounter with Streptococcus pyogenes, the bacteria responsible for strep sore throat infections. John was a 12-year-old living in Melbourne when he experienced a series of sore throat infections that led to the development of rheumatic fever. He was administered penicillin tablets to be taken daily over the next decade to help prevent any reoccurrence of the disease. Fortunately, with this antibiotic regime, he escaped the risk of any residual heart or kidney damage that can occur from recurrences of rheumatic fever.
While pursuing his Microbiology degree at Melbourne University, John was influenced by Dr. Rose Mushin's teachings on the potential applications of bacterial interference as a targeted and natural means of infection prevention. Such bacteriocins were proteinaceous antibiotics produced by bacteria and had bactericidal properties that work against various other relatively closely related bacteria that were capable of competing with them for occupancy of the same ecological niche. This led to John’s hypothesis that perhaps a similar strategy could be applied in the human oral cavity to gain some relatively specific protection against S. pyogenes infections.
This led to John’s Ph.D. research at Monash University, as he began his studies in the exploration of the relationship between S. pyogenes infections and the induction of the autoimmune manifestations of rheumatic fever. Screening hundreds of oral streptococci for their bacteriocin-producing capability and included amongst these streptococci were a series of S. pyogenes isolates from the Fairfield Infectious Diseases Hospital in Melbourne. On September 1, 1969, John discovered that number 22 in this series produced bacteriocin-like inhibitory activity against some other S. pyogenes strains when tested in a deferred antagonism assay. The inhibitory agent, later given the name streptococcin A-FF22, was the first of the streptococcal bacteriocins to be isolated and characterised.
On the other side of the world, Dr. Lewis Wannamaker at the University of Minnesota was an influential leader in the field of streptococcal research and had played a major role in developing the original guidelines for the use of penicillin prophylaxis as a preventative against rheumatic fever recurrences. In 1972, Dr. Wannamaker hosted a workshop on ‘Streptococci and Streptococcal Diseases’ at the University of Minnesota which was attended by many of the leading S. pyogenes researchers of that era. John wrote to him asking if they could work together, seeking a bacterial interference-based alternative to the use of penicillin for rheumatic fever prophylaxis.
Three years of total streptococcal research followed, and Dr. Wannamaker was generous in his support for John’s endeavours to find a harmless oral streptococcus capable of effectively engaging in bacteriocin-mediated warfare against S. pyogenes, while at the same time maintaining the view that what S. pyogenes really needed was greater scientific understanding – not extermination.
Prior to leaving Minnesota, John wrote the first major review of the bacteriocins of gram-positive bacteria and upon purifying streptococcin A-FF22 demonstrated that it was closely similar to nisin, the best known and still the most widely applied of all the bacteriocins of gram-positive bacteria.
Rheumatic fever is a major public health concern in New Zealand, with a particularly high occurrence in the native Maori and Pacific Islander populations. In 1975, John obtained an academic position in the Microbiology Department at the University of Otago in Dunedin. His research agenda in New Zealand became firmly focused on finding a harmless oral streptococcal antagonist of S. pyogenes. He developed a procedure for the bacteriocin ‘fingerprinting’ of streptococci based on the deferred antagonism test in which a set of nine standard indicator bacteria are evaluated for their relative sensitivity to inhibitory substances released into an agar medium during the growth of a diametric streak culture of the test bacterium. It soon became clear that most (if not all) streptococci were probably capable of producing some sort of bacteriocin-like inhibitory activity.
The commercialization of these laboratory discoveries led to the launch of Dunedin-based company Blis Technologies Limited in August 2000 and within two years, the first oral probiotic product, BLIS K12™ ThroatGuard, appeared on the shelves of New Zealand pharmacies. A wide variety of BLIS K12™ products followed in various formats such as powder, lozenge, chewing gum, and ice cream formulations have subsequently been developed and many are now marketed internationally.
To this day, John continues his legacy with Blis Technologies in our Dunedin laboratory. He has isolated more than 2000 strains of bacteria during the course of his study and research and continues to look at how these strains can be used to benefit human health.