The widespread use of antibiotics in the last century coupled
with the development gap of the 1960s-1990s has led to a wave of antibiotic
resistant infections. This report will outline some promising new approaches to
treating these infections.
Scale of the problem
Before the discovery of antibiotics, it is estimated that
30% of all deaths were due to bacterial infection and it is estimated that improved
hygiene coupled with antibiotic treatment added over 29 years to average life
expectancy.1 A review funded by the British
government has estimated that the death toll due to antibiotic resistance is
currently 700,000 worldwide and is set to escalate to 10 million by 2050.2 This would cause a global
loss of 2% to 3.5% of GDP costing up to 100 trillion USD worldwide by 2050.
Why resistance develops
resistance evolves via natural selection through random mutation. Resistance
genes are then transferred vertically to future generations. Resistance genes
can also be transferred horizontally between organisms by conjugation between
bacteria, transduction by viruses or by transformation (incorporation and expression of exogenous DNA).
This allows resistance mechanisms to spread rapidly between populations and
species. The presence of antibiotics leads to increased selection for resistant
diagnosis, unnecessary prescriptions, improper use of antibiotics by patients,
and the use of antibiotics as livestock food additives for growth promotion all
contribute to widespread development of resistance.
Human use of antibiotics has increased by 6.5% over
the past 4 years. Rates of unnecessary prescriptions are rampant with 97% of
patients who ask for antibiotics getting them and 9 out of 10 GPs feeling
pressured to prescribe antibiotics.3 Patients taking antibiotics
erratically is also problematic and increases the risk of resistance.
Prophylactic medication in agriculture accounts
for 45% of total antibiotic usage in the UK and 80% in the USA. Extensive use
of antibiotics in agriculture is linked with the development of multidrug
resistant (MDR) pathogens. These MDR pathogens can be transferred to humans
through contact or consumption of animal products.
Slow diagnosis and poor hygiene in hospitals increase
infection rates and thus antibiotic usage, as well as providing an ideal
environment for natural transformation to occur allowing resistance genes to spread
There is a lack of investment in novel antibiotics
due to problems with risk and profitability. Patents only protect antibiotics
for 20 years after discovery and bringing a new antibiotic to market requires
an average investment of US$800 million and takes more than 10 years. This
means that a drug has less than 10 years to make a profit before the patent
runs out. 4