Key facts
• Antimicrobial
resistance threatens the effective prevention and treatment of an
ever-increasing range of infections caused by bacteria, parasites, viruses and
fungi.
• It
is an increasingly serious threat to global public health that requires action
across all government sectors and society.
• Antimicrobial
resistance is present in all parts of the world. New resistance mechanisms
emerge and spread globally.
• In
2012, WHO reported a gradual increase in resistance to HIV drugs, albeit not
reaching critical levels. Since then, further increases in resistance to
first-line treatment drugs were reported, which might require using more
expensive drugs in the near future.
• In
2013, there were about 480 000 new cases of multidrug-resistant tuberculosis
(MDR-TB). Extensively drug-resistant tuberculosis (XDR-TB) has been identified
in 100 countries. MDR-TB requires treatment courses that are much longer and
less effective than those for non-resistant TB.
• In
parts of the Greater Mekong subregion, resistance to the best available
treatment for falciparum malaria, artemisinin-based combination therapies
(ACTs), has been detected. Spread or emergence of multidrug resistance,
including resistance to ACTs, in other regions could jeopardize important
recent gains in control of the disease.
• There
are high proportions of antibiotic resistance in bacteria that cause common
infections (e.g. urinary tract infections, pneumonia, bloodstream infections)
in all regions of the world. A high percentage of hospital-acquired infections
are caused by highly resistant bacteria such as methicillin-resistant
Staphylococcus aureus(MRSA) or multidrug-resistant Gram-negative bacteria.
• Treatment
failures due to resistance to treatments of last resort for gonorrhoea
(third-generation cephalosporins) have been reported from 10 countries.
Gonorrhoea may soon become untreatable as no vaccines or new drugs are in
development.
• Patients
with infections caused by drug-resistant bacteria are generally at increased
risk of worse clinical outcomes and death, and consume more health-care
resources than patients infected with the same bacteria that are not resistant.
Antimicrobial resistance is resistance of a
microorganism to an antimicrobial drug that was originally effective for
treatment of infections caused by it.
Resistant microorganisms (including
bacteria, fungi, viruses and parasites) are able to withstand attack by
antimicrobial drugs, such as antibacterial drugs (e.g. antibiotics),
antifungals, antivirals, and antimalarials, so that standard treatments become
ineffective and infections persist, increasing the risk of spread to others.
The evolution of resistant strains is a
natural phenomenon that occurs when microorganisms replicate themselves
erroneously or when resistant traits are exchanged between them. The use and
misuse of antimicrobial drugs accelerates the emergence of drug-resistant
strains. Poor infection control practices, inadequate sanitary conditions and
inappropriate food-handling encourage the further spread of antimicrobial
resistance.
What is the difference between antibiotic
and antimicrobial resistance?
Antibiotic resistance refers specifically
to the resistance to antibiotics that occurs in common bacteria that cause
infections. Antimicrobial resistance is a broader term, encompassing resistance
to drugs to treat infections caused by other microbes as well, such as
parasites (e.g. malaria), viruses (e.g. HIV) and fungi (e.g. Candida).
Why is antimicrobial resistance a global
concern?
New resistance mechanisms emerge and spread
globally threatening our ability to treat common infectious diseases, resulting
in death and disability of individuals who until recently could continue a
normal course of life.
Without effective anti-infective treatment,
many standard medical treatments will fail or turn into very high risk
procedures.
Antimicrobial resistance kills
Infections caused by resistant
microorganisms often fail to respond to the standard treatment, resulting in
prolonged illness, higher health care expenditures, and a greater risk of
death.
As an example, the death rate for patients
with serious infections caused by common bacteria treated in hospitals can be
about twice that of patients with infections caused by the same non-resistant
bacteria. For example, people with MRSA (methicillin-resistant Staphylococcus
aureus, another common source of severe infections in the community and in
hospitals) are estimated to be 64% more likely to die than people with a
non-resistant form of the infection.
Antimicrobial resistance hampers the
control of infectious diseases
Antimicrobial resistance reduces the
effectiveness of treatment; thus patients remain infectious for a longer time,
increasing the risk of spreading resistant microorganisms to others. For
example, the emergence of Plasmodium falciparummultidrug resistance, including
resistance to ACTs in the Greater Mekong subregion is an urgent public health
concern that is threatening global efforts to reduce the burden of malaria.
Although MDR-TB is a growing concern, it is
still largely under-reported, compromising control efforts.
Antimicrobial resistance increases the
costs of health care
When infections become resistant to
first-line drugs, more expensive therapies must be used. A longer duration of
illness and treatment, often in hospitals, increases health care costs as well
as the economic burden on families and societies.
Antimicrobial resistance jeopardizes health
care gains to society
The achievements of modern medicine are put
at risk by antimicrobial resistance. Without effective antimicrobials for
prevention and treatment of infections, the success of organ transplantation,
cancer chemotherapy and major surgery would be compromised.
Present situation
Resistance in bacteria
WHO’s 2014 report on global surveillance of
antimicrobial resistance revealed that antibiotic resistance is no longer a
prediction for the future; it is happening right now, across the world, and is
putting at risk the ability to treat common infections in the community and
hospitals. Without urgent, coordinated action, the world is heading towards a
post-antibiotic era, in which common infections and minor injuries, which have
been treatable for decades, can once again kill.
• Treatment
failure to the drug of last resort for gonorrhoea – third-generation
cephalosporins – has been confirmed in several countries. Untreatable
gonococcal infections result in increased rates of illness and complications,
such as infertility, adverse pregnancy outcomes and neonatal blindness, and has
the potential to reverse the gains made in the control of this sexually
transmitted infection.
• Resistance
to one of the most widely used antibacterial drugs for the oral treatment of
urinary tract infections caused by E. coli – fluoroquinolones – is very
widespread.
• Resistance
to first-line drugs to treat infections caused by Staphlylococcus aureus – a
common cause of severe infections acquired both in health-care facilities and
in the community – is also widespread.
• Resistance
to the treatment of last resort for life-threatening infections caused by
common intestinal bacteria – carbapenem antibiotics – has spread to all regions
of the world. Key tools to tackle antibiotic resistance – such as basic systems
to track and monitor the problem – reveal considerable gaps. In many countries,
they do not even seem to exist.
Resistance in tuberculosis
In 2013, there were an estimated 480 000
new cases of MDR-TB in the world. Globally, 3.5% of new TB cases and 20.5% of
previously treated TB cases are estimated to have MDR-TB, with substantial
differences in the frequency of MDR-TB among countries. Extensively
drug-resistant TB (XDR-TB, defined as MDR-TB plus resistance to any
fluoroquinolone and any second-line injectable drug) has been identified in 100
countries, in all regions of the world.
Resistance in malaria
The emergence of P. falciparum multidrug
resistance, including resistance to ACTs, in the Greater Mekong subregion is an
urgent public health concern that is threatening the ongoing global effort to
reduce the burden of malaria. Routine monitoring of therapeutic efficacy is
essential to guide and adjust treatment policies. It can also help to detect
early changes in P. falciparum sensitivity to antimalarial drugs.
Resistance in HIV
HIV drug resistance emerges when HIV
replicates in the body of a person infected with the virus who is taking
antiretroviral drugs. Even when antiretroviral therapy (ART) programmes are
very well-managed, some degree of HIV drug resistance will emerge.
Available data suggest that continued
expansion of access to ART is associated with a rise in HIV drug resistance. In
2013, 12.9 million people living with HIV were receiving antiretroviral therapy
globally, of which 11.7 million were in low- and middle-income countries.
HIV drug resistance may rise to such a
level that the first-line and second-line ART regimens currently used to treat
HIV become ineffective, jeopardizing people’s lives and threatening national
and global investments in ART programmes.
As of 2010, levels of HIV drug resistance
among adults who had not begun treatment in countries scaling up ART were found
to be about 5% globally. However, since 2010, there are reports suggesting that
pre-treatment resistance is increasing, peaking at 22% in some areas.
Continuous surveillance of HIV drug
resistance is of paramount importance to inform global and national decisions
on the selection of first and second-line ART and to maximize overall
population level treatment effectiveness.
Resistance in influenza
Over the past 10 years, antiviral drugs
have become important tools for treatment of epidemic and pandemic influenza.
Several countries have developed national guidance on their use and have
stockpiled the drugs for pandemic preparedness. The constantly evolving nature
of influenza means that resistance to antiviral drugs is continuously emerging.
By 2012, virtually all influenza A viruses
circulating in humans were resistant to drugs frequently used for the
prevention of influenza (amantadine and rimantadine). However, the frequency of
resistance to the neuraminidase inhibitor oseltamivir remains low (1-2%).
Antiviral susceptibility is constantly monitored through the WHO Global
Surveillance and Response System.
What accelerates the emergence and spread
of antimicrobial resistance?
The development of antimicrobial resistance
is a natural phenomenon. However, certain human actions accelerate its
emergence and spread. The inappropriate use of antimicrobial drugs, including
in animal husbandry, favours the emergence and selection of resistant strains,
and poor infection prevention and control practices contribute to further
emergence and spread of antimicrobial resistance.
Need for concerted actions
Antimicrobial resistance is a complex problem
driven by many interconnected factors. As such, single, isolated interventions
have little impact. Coordinated action is required to minimize emergence and
spread of antimicrobial resistance.
People can help tackle resistance by:
• hand
washing, and avoiding close contact with sick people to prevent transmission of
bacterial infections and viral infections such as influenza or rotavirus, and
using condoms to prevent the transmission of sexually-transmitted infections;
• getting
vaccinated, and keeping vaccinations up to date;
• using
antimicrobial drugs only when they are prescribed by a certified health
professional;
• completing
the full treatment course (which in the case of antiviral drugs may require
life-long treatment), even if they feel better;
• never
sharing antimicrobial drugs with others or using leftover prescriptions.
Health workers and pharmacists can help
tackle resistance by:
• enhancing
infection prevention and control in hospitals and clinics;
• only
prescribing and dispensing antibiotics when they are truly needed;
• prescribing
and dispensing the right antimicrobial drugs to treat the illness.
Policymakers can help tackle resistance by:
• improving
monitoring around the extent and causes of resistance;
• strengthening
infection control and prevention;
• regulating
and promoting appropriate use of medicines;
• making
information widely available on the impact of antimicrobial resistance and how
the public and health professionals can play their part;
• rewarding
innovation and development of new treatment options and other tools.
Policymakers, scientists and industry can
help tackle resistance by:
• fostering
innovation and research and development of new vaccines, diagnostics, infection
treatment options and other tools.
WHO's response
WHO is guiding the response to
antimicrobial resistance by:
• bringing
all stakeholders together to agree on and work towards a coordinated response;
• strengthening
national stewardship and plans to tackle antimicrobial resistance;
• generating
policy guidance and providing technical support for Member States;
• Actively
encouraging innovation, research and development.
WHO is already working closely with the
World Organisation for Animal Health (OIE) and the Food and Agriculture Organization
of the United Nations (FAO) to promote best practices to avoid the emergence
and spread of antibacterial resistance, including optimal use of antibiotics in
both humans and animals.
WHO has developed a draft global action
plan to combat antimicrobial resistance which has been submitted to the
sixty-eighth World Health Assembly.