Increasing levels of drug resistance are threatening to erode the
medical advances of recent decades, according to a report released today by the World
Health Organization (WHO).
"We currently have effective medicines to cure almost every major
infectious disease," said Dr Gro Harlem Brundtland, Director-General of WHO.
"But we risk losing these valuable drugs and our opportunity to eventually
control many infectious diseases - because of increasing antimicrobial resistance."
WHO sounded this alarm with the release of its annual Report on
Infectious Diseases, titled "Overcoming Antimicrobial Resistance." The report is
the first of its kind to present a comprehensive picture of the perilous situation the
world is facing as once-effective medicines become increasingly ineffective.
The report describes how almost all major infectious diseases are
slowly but surely becoming resistant to existing medicines. In Estonia,
Latvia, and parts of Russia and China, over 10% of tuberculosis (TB) patients have strains
resistant to the two most powerful TB medicines. Because of resistance, Thailand has
completely lost the means of using three of the most common anti-malaria drugs.
Approximately 30% of patients taking lamivudine a drug recently developed to treat
hepatitis B show resistance to therapy after the first year of treatment. In India,
60% of all cases of the tropical disease visceral leishmaniasis no longer respond to
first-line drugs. A small but growing number of patients are already showing primary
resistance to AZT and other new therapies for HIV-infected persons.
In many instances, poorly planned or haphazard use of medicines has
caused the world to lose these drugs as quickly as scientists have discovered them.
"It took 20 years to develop penicillin for medical use, and then
20 years for this drug to become virtually useless for treating gonorrhoea in most parts
of the world," said Dr David Heymann, Executive Director of WHO's programme on
Communicable Diseases. In much of South-East Asia, resistance to penicillin has been
reported in 98% of gonorrhoea strains.
A decade ago in New Delhi, India, typhoid could be cured by three
inexpensive drugs. Now, these drugs are largely ineffective in the battle against this
life-threatening disease. Likewise, ten years ago, a shigella dysentery epidemic could
easily be controlled with cotrimoxazole a drug cheaply available in generic form.
Today, nearly all shigella are non-responsive to the drug.
Those admitted to hospital wards are especially vulnerable. In the
United States alone, some 14,000 people are infected and die each year as a result of
drug-resistant microbes picked up in hospitals. Around the world, as many as 60% of
hospital-acquired infections are caused by drug-resistant microbes.
Antimicrobial resistance is a naturally occurring biological phenomenon
amplified many-fold due to human misuse and neglect of antimicrobial drugs. The effect of
antimicrobial resistance is that it can reduce the curative power of once life-saving
medicines to that of a sugar pill.
The social causes fuelling the spread of antimicrobial resistance are
paradoxical. In some settings especially in poorer countries the under-use
of drugs encourages the development of resistance. For example, where patients are
unable to afford the full course of the medicines to be cured of their illnesses, or can
only afford to purchase counterfeit drugs on the black market, the weakest microbes in the
body may be killed by these insufficient doses while the more resistant microbes are given
opportunity to survive and multiply.
In wealthy countries, resistance is emerging for the opposite reason
the overuse of drugs. Unnecessary demands for drugs by patients are often
eagerly met by health services prone to over-prescription. Similarly, overuse of
antimicrobials in food production in wealthy countries is also contributing to increased
drug resistance. Currently, 50% of all antibiotic production is used to treat sick
animals, promote livestock and poultry growth, or rid cultivated foods of destructive
Regardless of where drug resistance originates, globalization,
increased travel and trade ensure that these strains quickly travel elsewhere. With new
DNA finger-printing technology, scientists have been able to identify drug resistant TB
strains originating in Eastern Europe, Asia and Africa and track them as they increasingly
reappear in patients in Western Europe and North America.
"The world may only have a decade or two to make optimal use of
many of the medicines presently available to stop infectious diseases," said Dr
Heymann. "We are literally in a race against time to bring levels of infectious
disease down worldwide, before the diseases wear the drugs down first."
The economic consequences of antimicrobial resistance can be
staggering. The cost of treating one person with multidrug-resistant TB is a hundred times
greater than the cost of treating non-resistant cases. New York City needed to spend
nearly US$1 billion to control an outbreak of multi-drug resistant TB in the early 1990s;
a cost beyond the reach of most of the world's cities.
"If we fail to make full and proper use of medicines discovered in
our lifetime, many of these drugs will slip through our grasp," said Dr Rosamund
Williams, who heads WHO's team working on drug resistance. "Before long, we may
have missed our opportunity to control the most dangerous infectious diseases. Indeed, if
we fail to make rapid progress during this decade, it may become very difficult and
expensive if not impossible to do so later."
A common misconception is that the pharmaceutical industry is
frequently making new drug discoveries to replace those drugs that become ineffective in
fighting the major infectious diseases. In reality, while new versions of older drugs
continue to be developed, there is a dearth of new classes of antibacterials. On average,
research and development of anti-infective drugs takes 15 to 20 years, and can cost over
$500 million, according to pharmaceutical companies.
"Currently, there are no new drugs or vaccines ready to quickly
emerge from the research and development pipeline," said Dr Heymann. "We are
making a high-risk gamble with the public's health if we are betting on the discovery
of new medicines and vaccines, and neglecting our opportunity to make wiser and wider use
of the effective medicines we currently have available."
According to the report, the most effective strategy against
antimicrobial resistance is to get the job done right the first time to
unequivocally destroy microbes thereby defeating resistance before it starts. The
challenge is to get the right treatment to the patient, each and every time.
"Used wisely and widely, the drugs we have today can be used to
prevent the infections of today and the antimicrobial-resistant catastrophes of
tomorrow," said Dr Brundtland. "However, if the world fails to mount a more
serious effort to fight infectious diseases, antimicrobial resistance will increasingly
threaten to send the world back to a pre-antibiotic age. Our grandparents lived during an
era without effective antibiotics. We don't want the same situation for our