Phage therapy as a solution for antibiotic resistance and super bugs

Foad Ramasi,1,* Negar ahmadian,2

1. Shahid Beheshti university of Tehran
2. Shahid beheshti university

Abstract

Introduction

Since 1929,with penicillin discovering, antibiotics were the most efficient drugs for bacterial infections; but abusing these drugs and evolution based on natural selection theory made antibiotic rsistant pathogens. for instance, resistance of staphylococcus aureus to methicillin. annualy, mrsa has more casualities typanites, hiv and parkinson. in this situation, to cope with this challenge, antimicrobal solutions should be provided. one of these can be phage therapies. phages are kind of viruses that target bacteria cell walls and have two circles of life:lytic and lisogenic. phages were studied a few years before antibiotics and penicillin. results show that phages can have effects on biological control and food industry immune.

Methods

Observing strange antibacterial activity against vicholerae in ganga and jumna by the year 1896, ernest hankin, supposed that an unknown substance is behind the cause of this phenomenon. after wards, de’ herel a canadian – french scientist, when hemorrhagic dysentery prevailed among russian soldiers, made free-bacterial filtrates of their feces and incubated them with some strains of shiegella contaminated by sick people. as a part of trial proposing to make vaccines for dysentery, he spread those handmade materials on agar medium for bacterial growth; interestingly, clear areas with no bacterial growth were seen on agar medium at the end of the trial. he named those areas as plaques and declared that the phenomenon is bacteriophage (bacterium eater). these preliminaries provided sufficient interest to study phage therapy in some countries like usa, as health institute of michigan during 1920-1930 arranged an experiment in which 208 patients contaminated by staphylococcus, streptococcus, salmonella, e. coli, klepsiella, pseudomonas infections were treated using phage therapy. success rate variated between 75-100 percent and sometimes even 94%. overall phage therapy efficacy was demonstrated in a clinical trial during 1950-1960 in which 607 patients all of whom were failed to respond to conventional treatment by antibiotics, were treated by phage therapy. the results were reportedly good; 80 % of the patients recovered completely, 18 % improved, and only 2% exhibited no changes. all of these experiments and observations proved the efficacy and preference of phage therapy over antibiotic drugs.

Results

Phage therapy according to experiments, has some benefits over than antibiotics: 1. phages are more allocated, therefore they reduce secondary infections in comparison to antibiotics. 2. phages concentrate on the infection site but antibiotics circulate all over the body organs. 3. lateral effects in phage therapy are at the minimum range but bacteral resistance, allergic reaction, anaphylaxis, and secondary infections are caused by abusing antibiotics. 4.phage mutation appears with bacterial mutation and they can predominate these resistant, mutant bacteria in necessary, but antibiotics are constant materials that are unable to challenge and combat with these kinds of bacteria. 5. phages in contrast to antibiotics have exponential growth, so they replicate in infection site and there is no need of extra injections. the substantial point is that phages curb the pathogens to the point that immune system is enable to combat them. phage therapy has some limitations and problems too but in comparison to antibiotics it can be solved by genetic engineering, as phages are able to change, in the way we want them to be. some of these issues are : 1.low host range due to high specification 2. insufficient sincerity 3. insufficient knowledge about heterogeneity ad performance of phages. the last point to say is that we can make the treatment more efficient by incubating phages and antibiotics both.

Conclusion

Along with superiority of phage therapy on antibiotic drugs we must know that only lytic phages are suitable for this way of treatment. they have exponential growth in the body, and they breeding speed is so high, therefore they are appropriate candidates for infection cure. but it worth nothing that some antibiotics are in our personal drugs that there is no bacterial resistance to them, but there is still possibility of developing a comolex genetic resistance in them. so we have not to abuse these drugs. it is also essential that great drug designing companies and laboratories should concentrate on discovering new antibiotics which can keep us from returning to the era before antibiotics.

Keywords

Bacteriophages, phage therapy, antibiotic resistance