Antibiotic-Resistant Infections can be Killed by Genetically Engineered Viruses
Bacteria and viruses caused many of the
infectious diseases plaguing humans. Scientists recently used viruses to
eradicate a bacterium that was potentially life-threatening in a 15-year-old
girl suffering from cystic fibrosis.
A new paper suggests that this age-old approach to fighting bacterial infections might be worth looking at, especially with modern bacteria that resist antibiotics.
Researchers in the new study report, viruses that first infect and then destroy bacteria (genetically engineered bacteriophages) were successfully used to clear up a serious bacterial infection in the sick teenager. The bacteria were resistant to antibiotics.
Graham Hatfull, a professor of biotechnology at the University of Pittsburgh and study co-author, said this was the first time 'phages' were used to treat infections with this type of bacteria. It is also the first time that genetically engineered 'phages' were more effective.
Bacteriophages have been used to battle human disease for close to a century. The BioTherapeutics Education & Research Foundation reports that with the discovery of antibiotics, including penicillin in the 1940s, the old method fell out of favor.
The idea of using bacteriophage is being looked at again as various dangerous bacteria are developing resistance to antibiotics that are used widely.
The young girl had been plagued by an infection of Mycobacterium abscessus for eight years which was wiped out by a cocktail of three phages.
A senior scholar at the Johns Hopkins Center for Health Security in Baltimore, Dr. Amesh Adalja, said there is a desperate need of effective therapies against Mycobacterium abscessus as this bacterium is extremely difficult to treat.
Although Adalja was not involved in the study, he noted that the patient’s response to intravenous phage therapies was very positive, and this is an important milestone. He was hopeful that it would lead to using more phages for this and other types of infection.
Adalja added that the pipeline for an antibiotic was running dry and using bacteriophages is proving to be an important solution to the infectious disease crisis facing the world.
The patient had undergone a lung transplant occurred without problems, but immunosuppressive drugs used after the procedure to assist the body in adapting to the new lung had allowed the bacterial infection to become widespread.
Multiple intravenous antibiotic treatments did not help, and the surgical wound site was infected, sores flared up on more than 20 places on her buttocks, arms, and legs, and her liver became inflamed.
Hatfull said that as she was not responding to antibiotics, and they were experienced with bacteriophages. The team tried to find phages in their collection to infect and kill this specific bacterial strain.
Three different phages were identified that might kill off the bacteria effectively. These were genetically improved to enable them to better fight the infection.
The phages were administered topically to the infected skin areas and intravenously. The skin lesions and the surgical wound healed within six months, and there were no adverse effects.
Hatfull thinks that bacteriophage therapy holds huge promises as it only attacks specific bacteria. This is decidedly different from antibiotics, which often simply attack all bacteria in the body.
The specificity does, however, also have drawbacks as they are often so specific that although they may infect a strain that infects one patient, it may not be effective against a similar bacteria in other patients.
Hatfull added that genetic research into bacteriophage therapy and how it selects its targets might help improve phages as alternatives to antibiotics.