By Colin Harwood, Professor of Molecular Biology, Newcastle University
More than a century ago Paul Ehrlich, a German scientist and physician, reasoned that it should be possible to identify chemical compounds that were toxic to disease-causing microbes but not their human or animal hosts. He used the term “Magic Bullets” to describe and popularise the potential of such compounds.
The first effective antimicrobial agents, the sulfonamides, were introduced into clinical practice in 1937 for the treatment of streptococcal and staphylococcal infections. However, within a few years of use in the clinic, resistant strains began to appear. Similarly within five years of their introduction in the 1940s, penicillin and streptomycin resistant strains were found in patients.
By the 1960s, antibiotic-resistant plasmids and viruses, which can transfer genes for resistance between bacteria, were identified, showing that antibiotic resistance could be transferred from one bacterium to another. This was not only limited to the same strains; resistance can be transferred between two completely different strains of bacteria.
The last century has seen a battle between the scientist and bacterium; new antibiotics were discovered and developed only for the bacteria to develop new mechanisms of resistance. More significantly, multi-drug resistant (and even extremely drug-resistant) bacteria have evolved; the so-called Superbugs.
The uncontrolled, often unnecessary use of antibiotics has accelerated the spread of antibiotic resistance. Even the most potent antibiotics, which are often only used as a last resort, are being compromised. There is the danger that, for many disease-causing microbes, we are inevitably slipping back to the pre-antibiotic era. However, the battle is not lost.
More intelligent strategies for treating infections have been developed and hospitals routinely monitor the levels of specific antibiotic resistances among their infections. By effectively measuring the resistance of disease-causing microbes, the clinician is able to administer the most effective forms of treatment and adopt a personalised medicine approach. The development of patient-side devices for detecting antibiotic resistance would provide a powerful weapon for the challenges ahead.